diff --git a/packages/babel-generator/src/generators/flow.ts b/packages/babel-generator/src/generators/flow.ts
index 587d3fcb85dd..25a5c33184fb 100644
--- a/packages/babel-generator/src/generators/flow.ts
+++ b/packages/babel-generator/src/generators/flow.ts
@@ -289,6 +289,18 @@ export function FunctionTypeAnnotation(
 ) {
   this.print(node.typeParameters, node);
   this.token("(");
+
+  if (node.this) {
+    this.word("this");
+    this.token(":");
+    this.space();
+    this.print(node.this.typeAnnotation, node);
+    if (node.params.length || node.rest) {
+      this.token(",");
+      this.space();
+    }
+  }
+
   this.printList(node.params, node);
 
   if (node.rest) {
diff --git a/packages/babel-generator/test/fixtures/flow/this-param/input.js b/packages/babel-generator/test/fixtures/flow/this-param/input.js
new file mode 100644
index 000000000000..deac524b714b
--- /dev/null
+++ b/packages/babel-generator/test/fixtures/flow/this-param/input.js
@@ -0,0 +1,45 @@
+function one (this : number) {}
+function two (this : number, a) {}
+function three (this : number, ...a) {}
+function four (this : number, a, b, ...c) {}
+function five<T> (this : T) {}
+
+type six = (this : number) => void
+type seven = (this : number, a : number) => void
+type eight = (this : number, ...a : any) => void
+type nine = <T>(this : T) => void
+
+type ten = {
+    m1(this : string) : void,
+    m2(this : string, a : number) : void,
+    m3(this : string, ...a : any) : void,
+    m4<T>(this : T) : void
+}
+
+declare function eleven (this : number) : void
+declare function twelve (this : string, a : number) : void
+declare function thirteen (this : string, ...a : any) : void
+declare function fourteen<T>(this : T) : void
+
+declare class Fifteen {
+    m1(this : string) : void,
+    m2(this : string, a : number) : void,
+    m3(this : string, ...a : any) : void,
+    m4<T>(this : T) : void
+}
+
+class Sixteen {
+    m1 (this : number) {}
+    m2 (this : number, a) {}
+    m3 (this : number, ...a) {}
+    m4 (this : number, a, b, ...c) {}
+    m5<T> (this : T) {}
+}
+
+let seventeen = {
+    m1 (this : number) {},
+    m2 (this : number, a) {},
+    m3 (this : number, ...a) {},
+    m4 (this : number, a, b, ...c) {},
+    m5<T> (this : T) {}
+}
diff --git a/packages/babel-generator/test/fixtures/flow/this-param/output.js b/packages/babel-generator/test/fixtures/flow/this-param/output.js
new file mode 100644
index 000000000000..6f10af88264b
--- /dev/null
+++ b/packages/babel-generator/test/fixtures/flow/this-param/output.js
@@ -0,0 +1,56 @@
+function one(this: number) {}
+
+function two(this: number, a) {}
+
+function three(this: number, ...a) {}
+
+function four(this: number, a, b, ...c) {}
+
+function five<T>(this: T) {}
+
+type six = (this: number) => void;
+type seven = (this: number, a: number) => void;
+type eight = (this: number, ...a: any) => void;
+type nine = <T>(this: T) => void;
+type ten = {
+  m1(this: string): void,
+  m2(this: string, a: number): void,
+  m3(this: string, ...a: any): void,
+  m4<T>(this: T): void,
+};
+declare function eleven(this: number): void;
+declare function twelve(this: string, a: number): void;
+declare function thirteen(this: string, ...a: any): void;
+declare function fourteen<T>(this: T): void;
+declare class Fifteen {
+  m1(this: string): void,
+  m2(this: string, a: number): void,
+  m3(this: string, ...a: any): void,
+  m4<T>(this: T): void,
+}
+
+class Sixteen {
+  m1(this: number) {}
+
+  m2(this: number, a) {}
+
+  m3(this: number, ...a) {}
+
+  m4(this: number, a, b, ...c) {}
+
+  m5<T>(this: T) {}
+
+}
+
+let seventeen = {
+  m1(this: number) {},
+
+  m2(this: number, a) {},
+
+  m3(this: number, ...a) {},
+
+  m4(this: number, a, b, ...c) {},
+
+  m5<T>(this: T) {}
+
+};
\ No newline at end of file
diff --git a/packages/babel-parser/src/plugins/flow/index.js b/packages/babel-parser/src/plugins/flow/index.js
index 0f606cfd35fa..2df5a06a9ad1 100644
--- a/packages/babel-parser/src/plugins/flow/index.js
+++ b/packages/babel-parser/src/plugins/flow/index.js
@@ -81,6 +81,7 @@ const FlowErrors = Object.freeze({
     "Number enum members need to be initialized, e.g. `%1 = 1` in enum `%0`.",
   EnumStringMemberInconsistentlyInitailized:
     "String enum members need to consistently either all use initializers, or use no initializers, in enum `%0`.",
+  GetterMayNotHaveThisParam: "A getter cannot have a `this` parameter.",
   ImportTypeShorthandOnlyInPureImport:
     "The `type` and `typeof` keywords on named imports can only be used on regular `import` statements. It cannot be used with `import type` or `import typeof` statements",
   InexactInsideExact:
@@ -97,7 +98,16 @@ const FlowErrors = Object.freeze({
   NestedFlowComment: "Cannot have a flow comment inside another flow comment",
   OptionalBindingPattern:
     "A binding pattern parameter cannot be optional in an implementation signature.",
+  SetterMayNotHaveThisParam: "A setter cannot have a `this` parameter.",
   SpreadVariance: "Spread properties cannot have variance",
+  ThisParamAnnotationRequired:
+    "A type annotation is required for the `this` parameter.",
+  ThisParamBannedInConstructor:
+    "Constructors cannot have a `this` parameter; constructors don't bind `this` like other functions.",
+  ThisParamMayNotBeOptional: "The `this` parameter cannot be optional.",
+  ThisParamMustBeFirst:
+    "The `this` parameter must be the first function parameter.",
+  ThisParamNoDefault: "The `this` parameter may not have a default value.",
   TypeBeforeInitializer:
     "Type annotations must come before default assignments, e.g. instead of `age = 25: number` use `age: number = 25`",
   TypeCastInPattern:
@@ -308,6 +318,7 @@ export default (superClass: Class<Parser>): Class<Parser> =>
       const tmp = this.flowParseFunctionTypeParams();
       typeNode.params = tmp.params;
       typeNode.rest = tmp.rest;
+      typeNode.this = tmp._this;
       this.expect(tt.parenR);
 
       [
@@ -905,21 +916,30 @@ export default (superClass: Class<Parser>): Class<Parser> =>
       node.params = [];
       node.rest = null;
       node.typeParameters = null;
+      node.this = null;
 
       if (this.isRelational("<")) {
         node.typeParameters = this.flowParseTypeParameterDeclaration();
       }
 
       this.expect(tt.parenL);
+      if (this.match(tt._this)) {
+        node.this = this.flowParseFunctionTypeParam(/* first */ true);
+        // match Flow parser behavior
+        node.this.name = null;
+        if (!this.match(tt.parenR)) {
+          this.expect(tt.comma);
+        }
+      }
       while (!this.match(tt.parenR) && !this.match(tt.ellipsis)) {
-        node.params.push(this.flowParseFunctionTypeParam());
+        node.params.push(this.flowParseFunctionTypeParam(false));
         if (!this.match(tt.parenR)) {
           this.expect(tt.comma);
         }
       }
 
       if (this.eat(tt.ellipsis)) {
-        node.rest = this.flowParseFunctionTypeParam();
+        node.rest = this.flowParseFunctionTypeParam(false);
       }
       this.expect(tt.parenR);
       node.returnType = this.flowParseTypeInitialiser();
@@ -1162,6 +1182,17 @@ export default (superClass: Class<Parser>): Class<Parser> =>
           if (kind === "get" || kind === "set") {
             this.flowCheckGetterSetterParams(node);
           }
+          /** Declared classes/interfaces do not allow spread */
+          if (
+            !allowSpread &&
+            node.key.name === "constructor" &&
+            node.value.this
+          ) {
+            this.raise(
+              node.value.this.start,
+              FlowErrors.ThisParamBannedInConstructor,
+            );
+          }
         } else {
           if (kind !== "init") this.unexpected();
 
@@ -1189,6 +1220,16 @@ export default (superClass: Class<Parser>): Class<Parser> =>
       const start = property.start;
       const length =
         property.value.params.length + (property.value.rest ? 1 : 0);
+
+      if (property.value.this) {
+        this.raise(
+          property.value.this.start,
+          property.kind === "get"
+            ? FlowErrors.GetterMayNotHaveThisParam
+            : FlowErrors.SetterMayNotHaveThisParam,
+        );
+      }
+
       if (length !== paramCount) {
         if (property.kind === "get") {
           this.raise(start, Errors.BadGetterArity);
@@ -1270,16 +1311,24 @@ export default (superClass: Class<Parser>): Class<Parser> =>
       return this.finishNode(node, "TupleTypeAnnotation");
     }
 
-    flowParseFunctionTypeParam(): N.FlowFunctionTypeParam {
+    flowParseFunctionTypeParam(first: boolean): N.FlowFunctionTypeParam {
       let name = null;
       let optional = false;
       let typeAnnotation = null;
       const node = this.startNode();
       const lh = this.lookahead();
+      const isThis = this.state.type === tt._this;
+
       if (lh.type === tt.colon || lh.type === tt.question) {
-        name = this.parseIdentifier();
+        if (isThis && !first) {
+          this.raise(node.start, FlowErrors.ThisParamMustBeFirst);
+        }
+        name = this.parseIdentifier(isThis);
         if (this.eat(tt.question)) {
           optional = true;
+          if (isThis) {
+            this.raise(node.start, FlowErrors.ThisParamMayNotBeOptional);
+          }
         }
         typeAnnotation = this.flowParseTypeInitialiser();
       } else {
@@ -1303,18 +1352,31 @@ export default (superClass: Class<Parser>): Class<Parser> =>
 
     flowParseFunctionTypeParams(
       params: N.FlowFunctionTypeParam[] = [],
-    ): { params: N.FlowFunctionTypeParam[], rest: ?N.FlowFunctionTypeParam } {
+    ): {
+      params: N.FlowFunctionTypeParam[],
+      rest: ?N.FlowFunctionTypeParam,
+      _this: ?N.FlowFunctionTypeParam,
+    } {
       let rest: ?N.FlowFunctionTypeParam = null;
+      let _this: ?N.FlowFunctionTypeParam = null;
+      if (this.match(tt._this)) {
+        _this = this.flowParseFunctionTypeParam(/* first */ true);
+        // match Flow parser behavior
+        _this.name = null;
+        if (!this.match(tt.parenR)) {
+          this.expect(tt.comma);
+        }
+      }
       while (!this.match(tt.parenR) && !this.match(tt.ellipsis)) {
-        params.push(this.flowParseFunctionTypeParam());
+        params.push(this.flowParseFunctionTypeParam(false));
         if (!this.match(tt.parenR)) {
           this.expect(tt.comma);
         }
       }
       if (this.eat(tt.ellipsis)) {
-        rest = this.flowParseFunctionTypeParam();
+        rest = this.flowParseFunctionTypeParam(false);
       }
-      return { params, rest };
+      return { params, rest, _this };
     }
 
     flowIdentToTypeAnnotation(
@@ -1408,6 +1470,7 @@ export default (superClass: Class<Parser>): Class<Parser> =>
             tmp = this.flowParseFunctionTypeParams();
             node.params = tmp.params;
             node.rest = tmp.rest;
+            node.this = tmp._this;
             this.expect(tt.parenR);
 
             this.expect(tt.arrow);
@@ -1423,7 +1486,7 @@ export default (superClass: Class<Parser>): Class<Parser> =>
 
           // Check to see if this is actually a grouped type
           if (!this.match(tt.parenR) && !this.match(tt.ellipsis)) {
-            if (this.match(tt.name)) {
+            if (this.match(tt.name) || this.match(tt._this)) {
               const token = this.lookahead().type;
               isGroupedType = token !== tt.question && token !== tt.colon;
             } else {
@@ -1462,6 +1525,7 @@ export default (superClass: Class<Parser>): Class<Parser> =>
 
           node.params = tmp.params;
           node.rest = tmp.rest;
+          node.this = tmp._this;
 
           this.expect(tt.parenR);
 
@@ -2311,6 +2375,11 @@ export default (superClass: Class<Parser>): Class<Parser> =>
       return !this.match(tt.colon) && super.isNonstaticConstructor(method);
     }
 
+    // determine whether a parameter is a this param
+    isThisParam(param) {
+      return param.type === "Identifier" && param.name === "this";
+    }
+
     // parse type parameters for class methods
     pushClassMethod(
       classBody: N.ClassBody,
@@ -2336,6 +2405,24 @@ export default (superClass: Class<Parser>): Class<Parser> =>
         isConstructor,
         allowsDirectSuper,
       );
+
+      if (method.params && isConstructor) {
+        const params = method.params;
+        if (params.length > 0 && this.isThisParam(params[0])) {
+          this.raise(method.start, FlowErrors.ThisParamBannedInConstructor);
+        }
+        // estree support
+      } else if (
+        // $FlowFixMe flow does not know about the face that estree can replace ClassMethod with MethodDefinition
+        method.type === "MethodDefinition" &&
+        isConstructor &&
+        method.value.params
+      ) {
+        const params = method.value.params;
+        if (params.length > 0 && this.isThisParam(params[0])) {
+          this.raise(method.start, FlowErrors.ThisParamBannedInConstructor);
+        }
+      }
     }
 
     pushClassPrivateMethod(
@@ -2377,6 +2464,19 @@ export default (superClass: Class<Parser>): Class<Parser> =>
       }
     }
 
+    checkGetterSetterParams(method: N.ObjectMethod | N.ClassMethod): void {
+      super.checkGetterSetterParams(method);
+      const params = this.getObjectOrClassMethodParams(method);
+      if (params.length > 0) {
+        const param = params[0];
+        if (this.isThisParam(param) && method.kind === "get") {
+          this.raise(param.start, FlowErrors.GetterMayNotHaveThisParam);
+        } else if (this.isThisParam(param)) {
+          this.raise(param.start, FlowErrors.SetterMayNotHaveThisParam);
+        }
+      }
+    }
+
     parsePropertyName(
       node: N.ObjectOrClassMember | N.ClassMember | N.TsNamedTypeElementBase,
       isPrivateNameAllowed: boolean,
@@ -2434,12 +2534,22 @@ export default (superClass: Class<Parser>): Class<Parser> =>
         if (param.type !== "Identifier") {
           this.raise(param.start, FlowErrors.OptionalBindingPattern);
         }
+        if (this.isThisParam(param)) {
+          this.raise(param.start, FlowErrors.ThisParamMayNotBeOptional);
+        }
 
         ((param: any): N.Identifier).optional = true;
       }
       if (this.match(tt.colon)) {
         param.typeAnnotation = this.flowParseTypeAnnotation();
+      } else if (this.isThisParam(param)) {
+        this.raise(param.start, FlowErrors.ThisParamAnnotationRequired);
       }
+
+      if (this.match(tt.eq) && this.isThisParam(param)) {
+        this.raise(param.start, FlowErrors.ThisParamNoDefault);
+      }
+
       this.resetEndLocation(param);
       return param;
     }
@@ -2609,6 +2719,16 @@ export default (superClass: Class<Parser>): Class<Parser> =>
       node.specifiers.push(this.finishNode(specifier, "ImportSpecifier"));
     }
 
+    parseBindingAtom(): N.Pattern {
+      switch (this.state.type) {
+        case tt._this:
+          // "this" may be the name of a parameter, so allow it.
+          return this.parseIdentifier(/* liberal */ true);
+        default:
+          return super.parseBindingAtom();
+      }
+    }
+
     // parse function type parameters - function foo<T>() {}
     parseFunctionParams(node: N.Function, allowModifiers?: boolean): void {
       // $FlowFixMe
@@ -2866,6 +2986,13 @@ export default (superClass: Class<Parser>): Class<Parser> =>
         return;
       }
 
+      // ensure the `this` param is first, if it exists
+      for (let i = 0; i < node.params.length; i++) {
+        if (this.isThisParam(node.params[i]) && i > 0) {
+          this.raise(node.params[i].start, FlowErrors.ThisParamMustBeFirst);
+        }
+      }
+
       return super.checkParams(...arguments);
     }
 
diff --git a/packages/babel-parser/test/fixtures/estree/object-method/invalid-setter/output.json b/packages/babel-parser/test/fixtures/estree/object-method/invalid-setter/output.json
index bba388a4344b..98c7c647bf60 100644
--- a/packages/babel-parser/test/fixtures/estree/object-method/invalid-setter/output.json
+++ b/packages/babel-parser/test/fixtures/estree/object-method/invalid-setter/output.json
@@ -16,6 +16,10 @@
         "expression": {
           "type": "ObjectExpression",
           "start":1,"end":14,"loc":{"start":{"line":1,"column":1},"end":{"line":1,"column":14}},
+          "extra": {
+            "parenthesized": true,
+            "parenStart": 0
+          },
           "properties": [
             {
               "type": "Property",
@@ -44,11 +48,7 @@
               },
               "shorthand": false
             }
-          ],
-          "extra": {
-            "parenthesized": true,
-            "parenStart": 0
-          }
+          ]
         }
       }
     ]
diff --git a/packages/babel-parser/test/fixtures/flow/anonymous-function-no-parens-types/good_10/output.json b/packages/babel-parser/test/fixtures/flow/anonymous-function-no-parens-types/good_10/output.json
index 33e95403e790..5e4a04fcf81c 100644
--- a/packages/babel-parser/test/fixtures/flow/anonymous-function-no-parens-types/good_10/output.json
+++ b/packages/babel-parser/test/fixtures/flow/anonymous-function-no-parens-types/good_10/output.json
@@ -50,6 +50,7 @@
             }
           ],
           "rest": null,
+          "this": null,
           "returnType": {
             "type": "NumberTypeAnnotation",
             "start":32,"end":38,"loc":{"start":{"line":1,"column":32},"end":{"line":1,"column":38}}
diff --git a/packages/babel-parser/test/fixtures/flow/anonymous-function-no-parens-types/good_14/output.json b/packages/babel-parser/test/fixtures/flow/anonymous-function-no-parens-types/good_14/output.json
index eadc2d985387..67e57a7f761b 100644
--- a/packages/babel-parser/test/fixtures/flow/anonymous-function-no-parens-types/good_14/output.json
+++ b/packages/babel-parser/test/fixtures/flow/anonymous-function-no-parens-types/good_14/output.json
@@ -39,6 +39,7 @@
                   }
                 ],
                 "rest": null,
+                "this": null,
                 "returnType": {
                   "type": "NumberTypeAnnotation",
                   "start":27,"end":33,"loc":{"start":{"line":1,"column":27},"end":{"line":1,"column":33}}
diff --git a/packages/babel-parser/test/fixtures/flow/anonymous-function-no-parens-types/good_15/output.json b/packages/babel-parser/test/fixtures/flow/anonymous-function-no-parens-types/good_15/output.json
index 64a149197c0c..cb3951a318b8 100644
--- a/packages/babel-parser/test/fixtures/flow/anonymous-function-no-parens-types/good_15/output.json
+++ b/packages/babel-parser/test/fixtures/flow/anonymous-function-no-parens-types/good_15/output.json
@@ -49,6 +49,7 @@
                           }
                         ],
                         "rest": null,
+                        "this": null,
                         "returnType": {
                           "type": "NumberTypeAnnotation",
                           "start":30,"end":36,"loc":{"start":{"line":1,"column":30},"end":{"line":1,"column":36}}
diff --git a/packages/babel-parser/test/fixtures/flow/anonymous-function-types/good_01/output.json b/packages/babel-parser/test/fixtures/flow/anonymous-function-types/good_01/output.json
index 00814ac01665..7e1547e59980 100644
--- a/packages/babel-parser/test/fixtures/flow/anonymous-function-types/good_01/output.json
+++ b/packages/babel-parser/test/fixtures/flow/anonymous-function-types/good_01/output.json
@@ -48,6 +48,7 @@
                 }
               ],
               "rest": null,
+              "this": null,
               "returnType": {
                 "type": "VoidTypeAnnotation",
                 "start":41,"end":45,"loc":{"start":{"line":1,"column":41},"end":{"line":1,"column":45}}
diff --git a/packages/babel-parser/test/fixtures/flow/anonymous-function-types/good_03/output.json b/packages/babel-parser/test/fixtures/flow/anonymous-function-types/good_03/output.json
index 8dcd1b0be60d..908fb3b42679 100644
--- a/packages/babel-parser/test/fixtures/flow/anonymous-function-types/good_03/output.json
+++ b/packages/babel-parser/test/fixtures/flow/anonymous-function-types/good_03/output.json
@@ -32,6 +32,7 @@
             }
           ],
           "rest": null,
+          "this": null,
           "returnType": {
             "type": "VoidTypeAnnotation",
             "start":21,"end":25,"loc":{"start":{"line":1,"column":21},"end":{"line":1,"column":25}}
diff --git a/packages/babel-parser/test/fixtures/flow/anonymous-function-types/good_04/output.json b/packages/babel-parser/test/fixtures/flow/anonymous-function-types/good_04/output.json
index 5dc10956fa1f..ed6189670eb8 100644
--- a/packages/babel-parser/test/fixtures/flow/anonymous-function-types/good_04/output.json
+++ b/packages/babel-parser/test/fixtures/flow/anonymous-function-types/good_04/output.json
@@ -32,6 +32,7 @@
             }
           ],
           "rest": null,
+          "this": null,
           "returnType": {
             "type": "VoidTypeAnnotation",
             "start":22,"end":26,"loc":{"start":{"line":1,"column":22},"end":{"line":1,"column":26}}
diff --git a/packages/babel-parser/test/fixtures/flow/anonymous-function-types/good_05/output.json b/packages/babel-parser/test/fixtures/flow/anonymous-function-types/good_05/output.json
index 0125e6307fa9..3ec32b39779b 100644
--- a/packages/babel-parser/test/fixtures/flow/anonymous-function-types/good_05/output.json
+++ b/packages/babel-parser/test/fixtures/flow/anonymous-function-types/good_05/output.json
@@ -47,6 +47,7 @@
             }
           ],
           "rest": null,
+          "this": null,
           "returnType": {
             "type": "VoidTypeAnnotation",
             "start":28,"end":32,"loc":{"start":{"line":1,"column":28},"end":{"line":1,"column":32}}
diff --git a/packages/babel-parser/test/fixtures/flow/anonymous-function-types/good_06/output.json b/packages/babel-parser/test/fixtures/flow/anonymous-function-types/good_06/output.json
index c8e969c81806..76bacf075852 100644
--- a/packages/babel-parser/test/fixtures/flow/anonymous-function-types/good_06/output.json
+++ b/packages/babel-parser/test/fixtures/flow/anonymous-function-types/good_06/output.json
@@ -47,6 +47,7 @@
             }
           ],
           "rest": null,
+          "this": null,
           "returnType": {
             "type": "VoidTypeAnnotation",
             "start":29,"end":33,"loc":{"start":{"line":1,"column":29},"end":{"line":1,"column":33}}
diff --git a/packages/babel-parser/test/fixtures/flow/anonymous-function-types/good_07/output.json b/packages/babel-parser/test/fixtures/flow/anonymous-function-types/good_07/output.json
index 9441e11a5d82..951c19736c73 100644
--- a/packages/babel-parser/test/fixtures/flow/anonymous-function-types/good_07/output.json
+++ b/packages/babel-parser/test/fixtures/flow/anonymous-function-types/good_07/output.json
@@ -46,6 +46,7 @@
             }
           ],
           "rest": null,
+          "this": null,
           "returnType": {
             "type": "VoidTypeAnnotation",
             "start":32,"end":36,"loc":{"start":{"line":1,"column":32},"end":{"line":1,"column":36}}
diff --git a/packages/babel-parser/test/fixtures/flow/anonymous-function-types/good_08/output.json b/packages/babel-parser/test/fixtures/flow/anonymous-function-types/good_08/output.json
index c39333b8861f..68b0835fdf42 100644
--- a/packages/babel-parser/test/fixtures/flow/anonymous-function-types/good_08/output.json
+++ b/packages/babel-parser/test/fixtures/flow/anonymous-function-types/good_08/output.json
@@ -45,6 +45,7 @@
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diff --git a/packages/babel-parser/test/fixtures/flow/anonymous-function-types/good_09/output.json b/packages/babel-parser/test/fixtures/flow/anonymous-function-types/good_09/output.json
index 7e3230844ebd..2c15f4a41e65 100644
--- a/packages/babel-parser/test/fixtures/flow/anonymous-function-types/good_09/output.json
+++ b/packages/babel-parser/test/fixtures/flow/anonymous-function-types/good_09/output.json
@@ -71,6 +71,7 @@
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diff --git a/packages/babel-parser/test/fixtures/flow/anonymous-function-types/good_10/output.json b/packages/babel-parser/test/fixtures/flow/anonymous-function-types/good_10/output.json
index 316359169e24..5f7e4b48271b 100644
--- a/packages/babel-parser/test/fixtures/flow/anonymous-function-types/good_10/output.json
+++ b/packages/babel-parser/test/fixtures/flow/anonymous-function-types/good_10/output.json
@@ -46,6 +46,7 @@
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diff --git a/packages/babel-parser/test/fixtures/flow/anonymous-function-types/good_13/output.json b/packages/babel-parser/test/fixtures/flow/anonymous-function-types/good_13/output.json
index 0aba1cc06f66..536676cd3770 100644
--- a/packages/babel-parser/test/fixtures/flow/anonymous-function-types/good_13/output.json
+++ b/packages/babel-parser/test/fixtures/flow/anonymous-function-types/good_13/output.json
@@ -42,6 +42,7 @@
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index 7d395e92050c..909ca9cce01e 100644
--- a/packages/babel-parser/test/fixtures/flow/array-types/4/output.json
+++ b/packages/babel-parser/test/fixtures/flow/array-types/4/output.json
@@ -26,6 +26,7 @@
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index f6fbb173576b..b38fb7bf0525 100644
--- a/packages/babel-parser/test/fixtures/flow/array-types/5/output.json
+++ b/packages/babel-parser/test/fixtures/flow/array-types/5/output.json
@@ -29,6 +29,7 @@
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diff --git a/packages/babel-parser/test/fixtures/flow/call-properties/1/output.json b/packages/babel-parser/test/fixtures/flow/call-properties/1/output.json
index 225c82bca9dc..812bbf31ad88 100644
--- a/packages/babel-parser/test/fixtures/flow/call-properties/1/output.json
+++ b/packages/babel-parser/test/fixtures/flow/call-properties/1/output.json
@@ -35,6 +35,7 @@
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diff --git a/packages/babel-parser/test/fixtures/flow/call-properties/2/output.json b/packages/babel-parser/test/fixtures/flow/call-properties/2/output.json
index 7c3d10f344ce..9fc09769bee6 100644
--- a/packages/babel-parser/test/fixtures/flow/call-properties/2/output.json
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@@ -35,6 +35,7 @@
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diff --git a/packages/babel-parser/test/fixtures/flow/call-properties/3/output.json b/packages/babel-parser/test/fixtures/flow/call-properties/3/output.json
index 84334ba4a90d..4b1644494a45 100644
--- a/packages/babel-parser/test/fixtures/flow/call-properties/3/output.json
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@@ -35,6 +35,7 @@
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@@ -66,6 +67,7 @@
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diff --git a/packages/babel-parser/test/fixtures/flow/call-properties/4/output.json b/packages/babel-parser/test/fixtures/flow/call-properties/4/output.json
index 3f664920aa97..086f5b45d748 100644
--- a/packages/babel-parser/test/fixtures/flow/call-properties/4/output.json
+++ b/packages/babel-parser/test/fixtures/flow/call-properties/4/output.json
@@ -67,6 +67,7 @@
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diff --git a/packages/babel-parser/test/fixtures/flow/call-properties/5/output.json b/packages/babel-parser/test/fixtures/flow/call-properties/5/output.json
index 891892e2f708..118b6d1a088e 100644
--- a/packages/babel-parser/test/fixtures/flow/call-properties/5/output.json
+++ b/packages/babel-parser/test/fixtures/flow/call-properties/5/output.json
@@ -33,6 +33,7 @@
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diff --git a/packages/babel-parser/test/fixtures/flow/class-properties/getter-setter/output.json b/packages/babel-parser/test/fixtures/flow/class-properties/getter-setter/output.json
index f35d695d38ca..46c34ef53135 100644
--- a/packages/babel-parser/test/fixtures/flow/class-properties/getter-setter/output.json
+++ b/packages/babel-parser/test/fixtures/flow/class-properties/getter-setter/output.json
@@ -42,6 +42,7 @@
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@@ -82,6 +83,7 @@
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@@ -111,6 +113,7 @@
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@@ -155,6 +158,7 @@
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@@ -184,6 +188,7 @@
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@@ -228,6 +233,7 @@
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diff --git a/packages/babel-parser/test/fixtures/flow/classes/constructor-override-with-class-prop-plugin/output.json b/packages/babel-parser/test/fixtures/flow/classes/constructor-override-with-class-prop-plugin/output.json
index e7dba971db17..078602d8aced 100644
--- a/packages/babel-parser/test/fixtures/flow/classes/constructor-override-with-class-prop-plugin/output.json
+++ b/packages/babel-parser/test/fixtures/flow/classes/constructor-override-with-class-prop-plugin/output.json
@@ -42,6 +42,7 @@
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diff --git a/packages/babel-parser/test/fixtures/flow/declare-export/export-class/output.json b/packages/babel-parser/test/fixtures/flow/declare-export/export-class/output.json
index 7e96f7035a5f..b2ef70379a47 100644
--- a/packages/babel-parser/test/fixtures/flow/declare-export/export-class/output.json
+++ b/packages/babel-parser/test/fixtures/flow/declare-export/export-class/output.json
@@ -76,6 +76,7 @@
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diff --git a/packages/babel-parser/test/fixtures/flow/declare-export/export-default-arrow/output.json b/packages/babel-parser/test/fixtures/flow/declare-export/export-default-arrow/output.json
index f479dcf7f189..1b6d2b652995 100644
--- a/packages/babel-parser/test/fixtures/flow/declare-export/export-default-arrow/output.json
+++ b/packages/babel-parser/test/fixtures/flow/declare-export/export-default-arrow/output.json
@@ -30,6 +30,7 @@
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diff --git a/packages/babel-parser/test/fixtures/flow/declare-export/export-default-function/output.json b/packages/babel-parser/test/fixtures/flow/declare-export/export-default-function/output.json
index 670fd3f48b4f..9f6fe31dd5f7 100644
--- a/packages/babel-parser/test/fixtures/flow/declare-export/export-default-function/output.json
+++ b/packages/babel-parser/test/fixtures/flow/declare-export/export-default-function/output.json
@@ -41,6 +41,7 @@
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diff --git a/packages/babel-parser/test/fixtures/flow/declare-export/export-function/output.json b/packages/babel-parser/test/fixtures/flow/declare-export/export-function/output.json
index db29c7c10d2b..b9bdc4a556d1 100644
--- a/packages/babel-parser/test/fixtures/flow/declare-export/export-function/output.json
+++ b/packages/babel-parser/test/fixtures/flow/declare-export/export-function/output.json
@@ -57,6 +57,7 @@
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diff --git a/packages/babel-parser/test/fixtures/flow/declare-module/10/output.json b/packages/babel-parser/test/fixtures/flow/declare-module/10/output.json
index ffea09887f0f..e360b80f3b80 100644
--- a/packages/babel-parser/test/fixtures/flow/declare-module/10/output.json
+++ b/packages/babel-parser/test/fixtures/flow/declare-module/10/output.json
@@ -36,6 +36,7 @@
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diff --git a/packages/babel-parser/test/fixtures/flow/declare-module/4/output.json b/packages/babel-parser/test/fixtures/flow/declare-module/4/output.json
index 4815b5f5dc06..31d82465a5dc 100644
--- a/packages/babel-parser/test/fixtures/flow/declare-module/4/output.json
+++ b/packages/babel-parser/test/fixtures/flow/declare-module/4/output.json
@@ -35,6 +35,7 @@
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diff --git a/packages/babel-parser/test/fixtures/flow/declare-module/5/output.json b/packages/babel-parser/test/fixtures/flow/declare-module/5/output.json
index 20e04284533f..b4a8c7abe620 100644
--- a/packages/babel-parser/test/fixtures/flow/declare-module/5/output.json
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@@ -54,6 +54,7 @@
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diff --git a/packages/babel-parser/test/fixtures/flow/declare-module/6/output.json b/packages/babel-parser/test/fixtures/flow/declare-module/6/output.json
index dcc3dbe0267f..b1e3e5d06ab9 100644
--- a/packages/babel-parser/test/fixtures/flow/declare-module/6/output.json
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@@ -48,6 +48,7 @@
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diff --git a/packages/babel-parser/test/fixtures/flow/declare-statements/10/output.json b/packages/babel-parser/test/fixtures/flow/declare-statements/10/output.json
index 06a5d571ff09..921856f92729 100644
--- a/packages/babel-parser/test/fixtures/flow/declare-statements/10/output.json
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@@ -42,6 +42,7 @@
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diff --git a/packages/babel-parser/test/fixtures/flow/declare-statements/12/output.json b/packages/babel-parser/test/fixtures/flow/declare-statements/12/output.json
index 63f60d28b1b1..beff50dce45d 100644
--- a/packages/babel-parser/test/fixtures/flow/declare-statements/12/output.json
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@@ -33,6 +33,7 @@
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diff --git a/packages/babel-parser/test/fixtures/flow/declare-statements/18/output.json b/packages/babel-parser/test/fixtures/flow/declare-statements/18/output.json
index faab69fb629c..bae862069da6 100644
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@@ -33,6 +33,7 @@
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@@ -72,6 +73,7 @@
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diff --git a/packages/babel-parser/test/fixtures/flow/declare-statements/3/output.json b/packages/babel-parser/test/fixtures/flow/declare-statements/3/output.json
index 64089206d0c7..bd3076f29bd3 100644
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@@ -23,6 +23,7 @@
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diff --git a/packages/babel-parser/test/fixtures/flow/declare-statements/4/output.json b/packages/babel-parser/test/fixtures/flow/declare-statements/4/output.json
index f377b44c81af..d3af8971977e 100644
--- a/packages/babel-parser/test/fixtures/flow/declare-statements/4/output.json
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@@ -23,6 +23,7 @@
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diff --git a/packages/babel-parser/test/fixtures/flow/declare-statements/5/output.json b/packages/babel-parser/test/fixtures/flow/declare-statements/5/output.json
index 033bfd0bfc02..8fb724f7edac 100644
--- a/packages/babel-parser/test/fixtures/flow/declare-statements/5/output.json
+++ b/packages/babel-parser/test/fixtures/flow/declare-statements/5/output.json
@@ -34,6 +34,7 @@
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index 7a8d40112005..e7a071e81948 100644
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+++ b/packages/babel-parser/test/fixtures/flow/declare-statements/6/output.json
@@ -52,6 +52,7 @@
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diff --git a/packages/babel-parser/test/fixtures/flow/declare-statements/7/output.json b/packages/babel-parser/test/fixtures/flow/declare-statements/7/output.json
index e5ae7dd2d318..8f4a842da29a 100644
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@@ -77,6 +77,7 @@
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diff --git a/packages/babel-parser/test/fixtures/flow/interface-types/identifier-named-static-method/output.json b/packages/babel-parser/test/fixtures/flow/interface-types/identifier-named-static-method/output.json
index db1accdec445..e6b9035c5bc4 100644
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@@ -43,6 +43,7 @@
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diff --git a/packages/babel-parser/test/fixtures/flow/interfaces-module-and-script/10/output.json b/packages/babel-parser/test/fixtures/flow/interfaces-module-and-script/10/output.json
index 08a97862a7d3..85dc1ab0ac20 100644
--- a/packages/babel-parser/test/fixtures/flow/interfaces-module-and-script/10/output.json
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@@ -61,6 +61,7 @@
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@@ -41,6 +41,7 @@
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diff --git a/packages/babel-parser/test/fixtures/flow/interfaces-module-and-script/identifier-named-static-method/output.json b/packages/babel-parser/test/fixtures/flow/interfaces-module-and-script/identifier-named-static-method/output.json
index b0834548218e..eac134286c30 100644
--- a/packages/babel-parser/test/fixtures/flow/interfaces-module-and-script/identifier-named-static-method/output.json
+++ b/packages/babel-parser/test/fixtures/flow/interfaces-module-and-script/identifier-named-static-method/output.json
@@ -42,6 +42,7 @@
                 "params": [],
                 "rest": null,
                 "typeParameters": null,
+                "this": null,
                 "returnType": {
                   "type": "NumberTypeAnnotation",
                   "start":24,"end":30,"loc":{"start":{"line":1,"column":24},"end":{"line":1,"column":30}}
diff --git a/packages/babel-parser/test/fixtures/flow/internal-slot/interface-method/output.json b/packages/babel-parser/test/fixtures/flow/internal-slot/interface-method/output.json
index 285585f5d6ac..e61dc7bd653e 100644
--- a/packages/babel-parser/test/fixtures/flow/internal-slot/interface-method/output.json
+++ b/packages/babel-parser/test/fixtures/flow/internal-slot/interface-method/output.json
@@ -43,6 +43,7 @@
                 "params": [],
                 "rest": null,
                 "typeParameters": null,
+                "this": null,
                 "returnType": {
                   "type": "GenericTypeAnnotation",
                   "start":25,"end":26,"loc":{"start":{"line":1,"column":25},"end":{"line":1,"column":26}},
diff --git a/packages/babel-parser/test/fixtures/flow/internal-slot/object-method/output.json b/packages/babel-parser/test/fixtures/flow/internal-slot/object-method/output.json
index 16491604be46..51061a05eb63 100644
--- a/packages/babel-parser/test/fixtures/flow/internal-slot/object-method/output.json
+++ b/packages/babel-parser/test/fixtures/flow/internal-slot/object-method/output.json
@@ -40,6 +40,7 @@
                 "params": [],
                 "rest": null,
                 "typeParameters": null,
+                "this": null,
                 "returnType": {
                   "type": "GenericTypeAnnotation",
                   "start":22,"end":23,"loc":{"start":{"line":1,"column":22},"end":{"line":1,"column":23}},
diff --git a/packages/babel-parser/test/fixtures/flow/iterator/01/output.json b/packages/babel-parser/test/fixtures/flow/iterator/01/output.json
index 9cf79269df16..f606edd83516 100644
--- a/packages/babel-parser/test/fixtures/flow/iterator/01/output.json
+++ b/packages/babel-parser/test/fixtures/flow/iterator/01/output.json
@@ -42,6 +42,7 @@
                 "params": [],
                 "rest": null,
                 "typeParameters": null,
+                "this": null,
                 "returnType": {
                   "type": "GenericTypeAnnotation",
                   "start":34,"end":48,"loc":{"start":{"line":2,"column":16},"end":{"line":2,"column":30}},
diff --git a/packages/babel-parser/test/fixtures/flow/iterator/02/output.json b/packages/babel-parser/test/fixtures/flow/iterator/02/output.json
index 91a02b2c7369..764bc1651365 100644
--- a/packages/babel-parser/test/fixtures/flow/iterator/02/output.json
+++ b/packages/babel-parser/test/fixtures/flow/iterator/02/output.json
@@ -42,6 +42,7 @@
                 "params": [],
                 "rest": null,
                 "typeParameters": null,
+                "this": null,
                 "returnType": {
                   "type": "GenericTypeAnnotation",
                   "start":39,"end":53,"loc":{"start":{"line":2,"column":21},"end":{"line":2,"column":35}},
diff --git a/packages/babel-parser/test/fixtures/flow/iterator/12/output.json b/packages/babel-parser/test/fixtures/flow/iterator/12/output.json
index c8866d697474..75fcbeb9c06d 100644
--- a/packages/babel-parser/test/fixtures/flow/iterator/12/output.json
+++ b/packages/babel-parser/test/fixtures/flow/iterator/12/output.json
@@ -44,6 +44,7 @@
                   "start":30,"end":42,"loc":{"start":{"line":1,"column":30},"end":{"line":1,"column":42}},
                   "params": [],
                   "rest": null,
+                  "this": null,
                   "returnType": {
                     "type": "StringTypeAnnotation",
                     "start":36,"end":42,"loc":{"start":{"line":1,"column":36},"end":{"line":1,"column":42}}
@@ -70,6 +71,10 @@
               "argument": {
                 "type": "TypeCastExpression",
                 "start":57,"end":63,"loc":{"start":{"line":2,"column":10},"end":{"line":2,"column":16}},
+                "extra": {
+                  "parenthesized": true,
+                  "parenStart": 56
+                },
                 "expression": {
                   "type": "NumericLiteral",
                   "start":57,"end":58,"loc":{"start":{"line":2,"column":10},"end":{"line":2,"column":11}},
@@ -86,10 +91,6 @@
                     "type": "AnyTypeAnnotation",
                     "start":60,"end":63,"loc":{"start":{"line":2,"column":13},"end":{"line":2,"column":16}}
                   }
-                },
-                "extra": {
-                  "parenthesized": true,
-                  "parenStart": 56
                 }
               }
             }
diff --git a/packages/babel-parser/test/fixtures/flow/iterator/13/output.json b/packages/babel-parser/test/fixtures/flow/iterator/13/output.json
index 3d995d3398b7..a7d70847b527 100644
--- a/packages/babel-parser/test/fixtures/flow/iterator/13/output.json
+++ b/packages/babel-parser/test/fixtures/flow/iterator/13/output.json
@@ -44,6 +44,7 @@
                   "start":35,"end":47,"loc":{"start":{"line":1,"column":35},"end":{"line":1,"column":47}},
                   "params": [],
                   "rest": null,
+                  "this": null,
                   "returnType": {
                     "type": "StringTypeAnnotation",
                     "start":41,"end":47,"loc":{"start":{"line":1,"column":41},"end":{"line":1,"column":47}}
@@ -70,6 +71,10 @@
               "argument": {
                 "type": "TypeCastExpression",
                 "start":62,"end":68,"loc":{"start":{"line":2,"column":10},"end":{"line":2,"column":16}},
+                "extra": {
+                  "parenthesized": true,
+                  "parenStart": 61
+                },
                 "expression": {
                   "type": "NumericLiteral",
                   "start":62,"end":63,"loc":{"start":{"line":2,"column":10},"end":{"line":2,"column":11}},
@@ -86,10 +91,6 @@
                     "type": "AnyTypeAnnotation",
                     "start":65,"end":68,"loc":{"start":{"line":2,"column":13},"end":{"line":2,"column":16}}
                   }
-                },
-                "extra": {
-                  "parenthesized": true,
-                  "parenStart": 61
                 }
               }
             }
diff --git a/packages/babel-parser/test/fixtures/flow/iterator/14/output.json b/packages/babel-parser/test/fixtures/flow/iterator/14/output.json
index 3e8644cc75b6..a511d794d29b 100644
--- a/packages/babel-parser/test/fixtures/flow/iterator/14/output.json
+++ b/packages/babel-parser/test/fixtures/flow/iterator/14/output.json
@@ -42,6 +42,7 @@
                 "params": [],
                 "rest": null,
                 "typeParameters": null,
+                "this": null,
                 "returnType": {
                   "type": "GenericTypeAnnotation",
                   "start":30,"end":44,"loc":{"start":{"line":2,"column":16},"end":{"line":2,"column":30}},
diff --git a/packages/babel-parser/test/fixtures/flow/iterator/15/output.json b/packages/babel-parser/test/fixtures/flow/iterator/15/output.json
index d88ede13e992..d9ce5b890371 100644
--- a/packages/babel-parser/test/fixtures/flow/iterator/15/output.json
+++ b/packages/babel-parser/test/fixtures/flow/iterator/15/output.json
@@ -42,6 +42,7 @@
                 "params": [],
                 "rest": null,
                 "typeParameters": null,
+                "this": null,
                 "returnType": {
                   "type": "GenericTypeAnnotation",
                   "start":35,"end":49,"loc":{"start":{"line":2,"column":21},"end":{"line":2,"column":35}},
diff --git a/packages/babel-parser/test/fixtures/flow/multiple-declarations/declare-function/output.json b/packages/babel-parser/test/fixtures/flow/multiple-declarations/declare-function/output.json
index f9915cba13fe..b1265cceb647 100644
--- a/packages/babel-parser/test/fixtures/flow/multiple-declarations/declare-function/output.json
+++ b/packages/babel-parser/test/fixtures/flow/multiple-declarations/declare-function/output.json
@@ -23,6 +23,7 @@
               "typeParameters": null,
               "params": [],
               "rest": null,
+              "this": null,
               "returnType": {
                 "type": "VoidTypeAnnotation",
                 "start":23,"end":27,"loc":{"start":{"line":1,"column":23},"end":{"line":1,"column":27}}
@@ -48,6 +49,7 @@
               "typeParameters": null,
               "params": [],
               "rest": null,
+              "this": null,
               "returnType": {
                 "type": "VoidTypeAnnotation",
                 "start":51,"end":55,"loc":{"start":{"line":2,"column":23},"end":{"line":2,"column":27}}
diff --git a/packages/babel-parser/test/fixtures/flow/object-types/complex-param-types/output.json b/packages/babel-parser/test/fixtures/flow/object-types/complex-param-types/output.json
index 948d1edb1a7a..7d0f9faf2d11 100644
--- a/packages/babel-parser/test/fixtures/flow/object-types/complex-param-types/output.json
+++ b/packages/babel-parser/test/fixtures/flow/object-types/complex-param-types/output.json
@@ -66,6 +66,7 @@
                 ],
                 "rest": null,
                 "typeParameters": null,
+                "this": null,
                 "returnType": {
                   "type": "VoidTypeAnnotation",
                   "start":25,"end":29,"loc":{"start":{"line":1,"column":25},"end":{"line":1,"column":29}}
diff --git a/packages/babel-parser/test/fixtures/flow/object-types/invalid-getter-param-count-rest/output.json b/packages/babel-parser/test/fixtures/flow/object-types/invalid-getter-param-count-rest/output.json
index e100d1aafcfe..200019bb51bd 100644
--- a/packages/babel-parser/test/fixtures/flow/object-types/invalid-getter-param-count-rest/output.json
+++ b/packages/babel-parser/test/fixtures/flow/object-types/invalid-getter-param-count-rest/output.json
@@ -57,6 +57,7 @@
                   }
                 },
                 "typeParameters": null,
+                "this": null,
                 "returnType": {
                   "type": "NumberTypeAnnotation",
                   "start":28,"end":34,"loc":{"start":{"line":2,"column":17},"end":{"line":2,"column":23}}
diff --git a/packages/babel-parser/test/fixtures/flow/object-types/invalid-getter-param-count/output.json b/packages/babel-parser/test/fixtures/flow/object-types/invalid-getter-param-count/output.json
index 0c62673bf17e..d98c7d2c4130 100644
--- a/packages/babel-parser/test/fixtures/flow/object-types/invalid-getter-param-count/output.json
+++ b/packages/babel-parser/test/fixtures/flow/object-types/invalid-getter-param-count/output.json
@@ -57,6 +57,7 @@
                 ],
                 "rest": null,
                 "typeParameters": null,
+                "this": null,
                 "returnType": {
                   "type": "NumberTypeAnnotation",
                   "start":32,"end":38,"loc":{"start":{"line":2,"column":21},"end":{"line":2,"column":27}}
diff --git a/packages/babel-parser/test/fixtures/flow/object-types/invalid-setter-param-count/output.json b/packages/babel-parser/test/fixtures/flow/object-types/invalid-setter-param-count/output.json
index 345f3c0c34f3..fa18c3c235cd 100644
--- a/packages/babel-parser/test/fixtures/flow/object-types/invalid-setter-param-count/output.json
+++ b/packages/babel-parser/test/fixtures/flow/object-types/invalid-setter-param-count/output.json
@@ -42,6 +42,7 @@
                 "params": [],
                 "rest": null,
                 "typeParameters": null,
+                "this": null,
                 "returnType": {
                   "type": "VoidTypeAnnotation",
                   "start":22,"end":26,"loc":{"start":{"line":2,"column":11},"end":{"line":2,"column":15}}
diff --git a/packages/babel-parser/test/fixtures/flow/object-types/invalid-setter-param-type/output.json b/packages/babel-parser/test/fixtures/flow/object-types/invalid-setter-param-type/output.json
index 07259bb3363e..b2207b3a6f28 100644
--- a/packages/babel-parser/test/fixtures/flow/object-types/invalid-setter-param-type/output.json
+++ b/packages/babel-parser/test/fixtures/flow/object-types/invalid-setter-param-type/output.json
@@ -57,6 +57,7 @@
                   }
                 },
                 "typeParameters": null,
+                "this": null,
                 "returnType": {
                   "type": "VoidTypeAnnotation",
                   "start":26,"end":30,"loc":{"start":{"line":2,"column":15},"end":{"line":2,"column":19}}
diff --git a/packages/babel-parser/test/fixtures/flow/predicates/1/output.json b/packages/babel-parser/test/fixtures/flow/predicates/1/output.json
index bd9ce6276726..6ff5da59cb69 100644
--- a/packages/babel-parser/test/fixtures/flow/predicates/1/output.json
+++ b/packages/babel-parser/test/fixtures/flow/predicates/1/output.json
@@ -38,6 +38,7 @@
                 }
               ],
               "rest": null,
+              "this": null,
               "returnType": {
                 "type": "BooleanTypeAnnotation",
                 "start":32,"end":39,"loc":{"start":{"line":1,"column":32},"end":{"line":1,"column":39}}
diff --git a/packages/babel-parser/test/fixtures/flow/predicates/6/output.json b/packages/babel-parser/test/fixtures/flow/predicates/6/output.json
index e3602f7e23c7..2300a1b2991e 100644
--- a/packages/babel-parser/test/fixtures/flow/predicates/6/output.json
+++ b/packages/babel-parser/test/fixtures/flow/predicates/6/output.json
@@ -124,6 +124,7 @@
                 }
               ],
               "rest": null,
+              "this": null,
               "returnType": {
                 "type": "GenericTypeAnnotation",
                 "start":64,"end":85,"loc":{"start":{"line":1,"column":64},"end":{"line":1,"column":85}},
diff --git a/packages/babel-parser/test/fixtures/flow/regression/issue-321/output.json b/packages/babel-parser/test/fixtures/flow/regression/issue-321/output.json
index 0c22b938a43e..f2be47a37da1 100644
--- a/packages/babel-parser/test/fixtures/flow/regression/issue-321/output.json
+++ b/packages/babel-parser/test/fixtures/flow/regression/issue-321/output.json
@@ -63,6 +63,7 @@
                     }
                   ],
                   "rest": null,
+                  "this": null,
                   "returnType": {
                     "type": "VoidTypeAnnotation",
                     "start":33,"end":37,"loc":{"start":{"line":1,"column":33},"end":{"line":1,"column":37}}
@@ -155,6 +156,7 @@
                     }
                   ],
                   "rest": null,
+                  "this": null,
                   "returnType": {
                     "type": "VoidTypeAnnotation",
                     "start":93,"end":97,"loc":{"start":{"line":2,"column":35},"end":{"line":2,"column":39}}
diff --git a/packages/babel-parser/test/fixtures/flow/scope/declare-function-export/output.json b/packages/babel-parser/test/fixtures/flow/scope/declare-function-export/output.json
index 2e2941394998..905af01b1765 100644
--- a/packages/babel-parser/test/fixtures/flow/scope/declare-function-export/output.json
+++ b/packages/babel-parser/test/fixtures/flow/scope/declare-function-export/output.json
@@ -23,6 +23,7 @@
               "typeParameters": null,
               "params": [],
               "rest": null,
+              "this": null,
               "returnType": {
                 "type": "VoidTypeAnnotation",
                 "start":24,"end":28,"loc":{"start":{"line":1,"column":24},"end":{"line":1,"column":28}}
diff --git a/packages/babel-parser/test/fixtures/flow/scope/dupl-decl-declare-func-declare-func/output.json b/packages/babel-parser/test/fixtures/flow/scope/dupl-decl-declare-func-declare-func/output.json
index de9cd47bb358..6656daffab8f 100644
--- a/packages/babel-parser/test/fixtures/flow/scope/dupl-decl-declare-func-declare-func/output.json
+++ b/packages/babel-parser/test/fixtures/flow/scope/dupl-decl-declare-func-declare-func/output.json
@@ -23,6 +23,7 @@
               "typeParameters": null,
               "params": [],
               "rest": null,
+              "this": null,
               "returnType": {
                 "type": "VoidTypeAnnotation",
                 "start":22,"end":26,"loc":{"start":{"line":1,"column":22},"end":{"line":1,"column":26}}
@@ -48,6 +49,7 @@
               "typeParameters": null,
               "params": [],
               "rest": null,
+              "this": null,
               "returnType": {
                 "type": "VoidTypeAnnotation",
                 "start":50,"end":54,"loc":{"start":{"line":2,"column":22},"end":{"line":2,"column":26}}
diff --git a/packages/babel-parser/test/fixtures/flow/scope/dupl-decl-declare-func-declare-var/output.json b/packages/babel-parser/test/fixtures/flow/scope/dupl-decl-declare-func-declare-var/output.json
index 27ab9b95ad66..3d0bf7fb3866 100644
--- a/packages/babel-parser/test/fixtures/flow/scope/dupl-decl-declare-func-declare-var/output.json
+++ b/packages/babel-parser/test/fixtures/flow/scope/dupl-decl-declare-func-declare-var/output.json
@@ -23,6 +23,7 @@
               "typeParameters": null,
               "params": [],
               "rest": null,
+              "this": null,
               "returnType": {
                 "type": "VoidTypeAnnotation",
                 "start":22,"end":26,"loc":{"start":{"line":1,"column":22},"end":{"line":1,"column":26}}
diff --git a/packages/babel-parser/test/fixtures/flow/scope/dupl-decl-declare-func-func/output.json b/packages/babel-parser/test/fixtures/flow/scope/dupl-decl-declare-func-func/output.json
index 6895d0b4ef67..583414100a2f 100644
--- a/packages/babel-parser/test/fixtures/flow/scope/dupl-decl-declare-func-func/output.json
+++ b/packages/babel-parser/test/fixtures/flow/scope/dupl-decl-declare-func-func/output.json
@@ -23,6 +23,7 @@
               "typeParameters": null,
               "params": [],
               "rest": null,
+              "this": null,
               "returnType": {
                 "type": "VoidTypeAnnotation",
                 "start":22,"end":26,"loc":{"start":{"line":1,"column":22},"end":{"line":1,"column":26}}
diff --git a/packages/babel-parser/test/fixtures/flow/scope/dupl-decl-func-declare-func/output.json b/packages/babel-parser/test/fixtures/flow/scope/dupl-decl-func-declare-func/output.json
index e088b316d6c6..ac0fe1790e79 100644
--- a/packages/babel-parser/test/fixtures/flow/scope/dupl-decl-func-declare-func/output.json
+++ b/packages/babel-parser/test/fixtures/flow/scope/dupl-decl-func-declare-func/output.json
@@ -44,6 +44,7 @@
               "typeParameters": null,
               "params": [],
               "rest": null,
+              "this": null,
               "returnType": {
                 "type": "VoidTypeAnnotation",
                 "start":38,"end":42,"loc":{"start":{"line":2,"column":22},"end":{"line":2,"column":26}}
diff --git a/packages/babel-parser/test/fixtures/flow/this-annotation/declare-function/input.js b/packages/babel-parser/test/fixtures/flow/this-annotation/declare-function/input.js
new file mode 100644
index 000000000000..a11916d5e736
--- /dev/null
+++ b/packages/babel-parser/test/fixtures/flow/this-annotation/declare-function/input.js
@@ -0,0 +1,7 @@
+declare function foo (this : number, a : string, b : number) : void
+
+declare function bar (this : number): void
+
+declare function baz (this : number, ...a : any): void
+
+declare function qux<T> (this : T) : void
diff --git a/packages/babel-parser/test/fixtures/flow/this-annotation/declare-function/output.json b/packages/babel-parser/test/fixtures/flow/this-annotation/declare-function/output.json
new file mode 100644
index 000000000000..925b7febf329
--- /dev/null
+++ b/packages/babel-parser/test/fixtures/flow/this-annotation/declare-function/output.json
@@ -0,0 +1,212 @@
+{
+  "type": "File",
+  "start":0,"end":210,"loc":{"start":{"line":1,"column":0},"end":{"line":7,"column":41}},
+  "program": {
+    "type": "Program",
+    "start":0,"end":210,"loc":{"start":{"line":1,"column":0},"end":{"line":7,"column":41}},
+    "sourceType": "module",
+    "interpreter": null,
+    "body": [
+      {
+        "type": "DeclareFunction",
+        "start":0,"end":67,"loc":{"start":{"line":1,"column":0},"end":{"line":1,"column":67}},
+        "id": {
+          "type": "Identifier",
+          "start":17,"end":67,"loc":{"start":{"line":1,"column":17},"end":{"line":1,"column":67},"identifierName":"foo"},
+          "name": "foo",
+          "typeAnnotation": {
+            "type": "TypeAnnotation",
+            "start":21,"end":67,"loc":{"start":{"line":1,"column":21},"end":{"line":1,"column":67}},
+            "typeAnnotation": {
+              "type": "FunctionTypeAnnotation",
+              "start":21,"end":67,"loc":{"start":{"line":1,"column":21},"end":{"line":1,"column":67}},
+              "typeParameters": null,
+              "params": [
+                {
+                  "type": "FunctionTypeParam",
+                  "start":37,"end":47,"loc":{"start":{"line":1,"column":37},"end":{"line":1,"column":47}},
+                  "name": {
+                    "type": "Identifier",
+                    "start":37,"end":38,"loc":{"start":{"line":1,"column":37},"end":{"line":1,"column":38},"identifierName":"a"},
+                    "name": "a"
+                  },
+                  "optional": false,
+                  "typeAnnotation": {
+                    "type": "StringTypeAnnotation",
+                    "start":41,"end":47,"loc":{"start":{"line":1,"column":41},"end":{"line":1,"column":47}}
+                  }
+                },
+                {
+                  "type": "FunctionTypeParam",
+                  "start":49,"end":59,"loc":{"start":{"line":1,"column":49},"end":{"line":1,"column":59}},
+                  "name": {
+                    "type": "Identifier",
+                    "start":49,"end":50,"loc":{"start":{"line":1,"column":49},"end":{"line":1,"column":50},"identifierName":"b"},
+                    "name": "b"
+                  },
+                  "optional": false,
+                  "typeAnnotation": {
+                    "type": "NumberTypeAnnotation",
+                    "start":53,"end":59,"loc":{"start":{"line":1,"column":53},"end":{"line":1,"column":59}}
+                  }
+                }
+              ],
+              "rest": null,
+              "this": {
+                "type": "FunctionTypeParam",
+                "start":22,"end":35,"loc":{"start":{"line":1,"column":22},"end":{"line":1,"column":35}},
+                "name": null,
+                "optional": false,
+                "typeAnnotation": {
+                  "type": "NumberTypeAnnotation",
+                  "start":29,"end":35,"loc":{"start":{"line":1,"column":29},"end":{"line":1,"column":35}}
+                }
+              },
+              "returnType": {
+                "type": "VoidTypeAnnotation",
+                "start":63,"end":67,"loc":{"start":{"line":1,"column":63},"end":{"line":1,"column":67}}
+              }
+            }
+          }
+        },
+        "predicate": null
+      },
+      {
+        "type": "DeclareFunction",
+        "start":69,"end":111,"loc":{"start":{"line":3,"column":0},"end":{"line":3,"column":42}},
+        "id": {
+          "type": "Identifier",
+          "start":86,"end":111,"loc":{"start":{"line":3,"column":17},"end":{"line":3,"column":42},"identifierName":"bar"},
+          "name": "bar",
+          "typeAnnotation": {
+            "type": "TypeAnnotation",
+            "start":90,"end":111,"loc":{"start":{"line":3,"column":21},"end":{"line":3,"column":42}},
+            "typeAnnotation": {
+              "type": "FunctionTypeAnnotation",
+              "start":90,"end":111,"loc":{"start":{"line":3,"column":21},"end":{"line":3,"column":42}},
+              "typeParameters": null,
+              "params": [],
+              "rest": null,
+              "this": {
+                "type": "FunctionTypeParam",
+                "start":91,"end":104,"loc":{"start":{"line":3,"column":22},"end":{"line":3,"column":35}},
+                "name": null,
+                "optional": false,
+                "typeAnnotation": {
+                  "type": "NumberTypeAnnotation",
+                  "start":98,"end":104,"loc":{"start":{"line":3,"column":29},"end":{"line":3,"column":35}}
+                }
+              },
+              "returnType": {
+                "type": "VoidTypeAnnotation",
+                "start":107,"end":111,"loc":{"start":{"line":3,"column":38},"end":{"line":3,"column":42}}
+              }
+            }
+          }
+        },
+        "predicate": null
+      },
+      {
+        "type": "DeclareFunction",
+        "start":113,"end":167,"loc":{"start":{"line":5,"column":0},"end":{"line":5,"column":54}},
+        "id": {
+          "type": "Identifier",
+          "start":130,"end":167,"loc":{"start":{"line":5,"column":17},"end":{"line":5,"column":54},"identifierName":"baz"},
+          "name": "baz",
+          "typeAnnotation": {
+            "type": "TypeAnnotation",
+            "start":134,"end":167,"loc":{"start":{"line":5,"column":21},"end":{"line":5,"column":54}},
+            "typeAnnotation": {
+              "type": "FunctionTypeAnnotation",
+              "start":134,"end":167,"loc":{"start":{"line":5,"column":21},"end":{"line":5,"column":54}},
+              "typeParameters": null,
+              "params": [],
+              "rest": {
+                "type": "FunctionTypeParam",
+                "start":153,"end":160,"loc":{"start":{"line":5,"column":40},"end":{"line":5,"column":47}},
+                "name": {
+                  "type": "Identifier",
+                  "start":153,"end":154,"loc":{"start":{"line":5,"column":40},"end":{"line":5,"column":41},"identifierName":"a"},
+                  "name": "a"
+                },
+                "optional": false,
+                "typeAnnotation": {
+                  "type": "AnyTypeAnnotation",
+                  "start":157,"end":160,"loc":{"start":{"line":5,"column":44},"end":{"line":5,"column":47}}
+                }
+              },
+              "this": {
+                "type": "FunctionTypeParam",
+                "start":135,"end":148,"loc":{"start":{"line":5,"column":22},"end":{"line":5,"column":35}},
+                "name": null,
+                "optional": false,
+                "typeAnnotation": {
+                  "type": "NumberTypeAnnotation",
+                  "start":142,"end":148,"loc":{"start":{"line":5,"column":29},"end":{"line":5,"column":35}}
+                }
+              },
+              "returnType": {
+                "type": "VoidTypeAnnotation",
+                "start":163,"end":167,"loc":{"start":{"line":5,"column":50},"end":{"line":5,"column":54}}
+              }
+            }
+          }
+        },
+        "predicate": null
+      },
+      {
+        "type": "DeclareFunction",
+        "start":169,"end":210,"loc":{"start":{"line":7,"column":0},"end":{"line":7,"column":41}},
+        "id": {
+          "type": "Identifier",
+          "start":186,"end":210,"loc":{"start":{"line":7,"column":17},"end":{"line":7,"column":41},"identifierName":"qux"},
+          "name": "qux",
+          "typeAnnotation": {
+            "type": "TypeAnnotation",
+            "start":189,"end":210,"loc":{"start":{"line":7,"column":20},"end":{"line":7,"column":41}},
+            "typeAnnotation": {
+              "type": "FunctionTypeAnnotation",
+              "start":189,"end":210,"loc":{"start":{"line":7,"column":20},"end":{"line":7,"column":41}},
+              "typeParameters": {
+                "type": "TypeParameterDeclaration",
+                "start":189,"end":192,"loc":{"start":{"line":7,"column":20},"end":{"line":7,"column":23}},
+                "params": [
+                  {
+                    "type": "TypeParameter",
+                    "start":190,"end":191,"loc":{"start":{"line":7,"column":21},"end":{"line":7,"column":22}},
+                    "name": "T",
+                    "variance": null
+                  }
+                ]
+              },
+              "params": [],
+              "rest": null,
+              "this": {
+                "type": "FunctionTypeParam",
+                "start":194,"end":202,"loc":{"start":{"line":7,"column":25},"end":{"line":7,"column":33}},
+                "name": null,
+                "optional": false,
+                "typeAnnotation": {
+                  "type": "GenericTypeAnnotation",
+                  "start":201,"end":202,"loc":{"start":{"line":7,"column":32},"end":{"line":7,"column":33}},
+                  "typeParameters": null,
+                  "id": {
+                    "type": "Identifier",
+                    "start":201,"end":202,"loc":{"start":{"line":7,"column":32},"end":{"line":7,"column":33},"identifierName":"T"},
+                    "name": "T"
+                  }
+                }
+              },
+              "returnType": {
+                "type": "VoidTypeAnnotation",
+                "start":206,"end":210,"loc":{"start":{"line":7,"column":37},"end":{"line":7,"column":41}}
+              }
+            }
+          }
+        },
+        "predicate": null
+      }
+    ],
+    "directives": []
+  }
+}
\ No newline at end of file
diff --git a/packages/babel-parser/test/fixtures/flow/this-annotation/declare-method/input.js b/packages/babel-parser/test/fixtures/flow/this-annotation/declare-method/input.js
new file mode 100644
index 000000000000..69755c4c5fab
--- /dev/null
+++ b/packages/babel-parser/test/fixtures/flow/this-annotation/declare-method/input.js
@@ -0,0 +1,6 @@
+declare class A {
+    m(this : number, a : number, b : string) : void,
+    n(this : number, ...c : any) : void,
+    o(this : number) : void,
+    p<T>(this : T) : void
+}
diff --git a/packages/babel-parser/test/fixtures/flow/this-annotation/declare-method/output.json b/packages/babel-parser/test/fixtures/flow/this-annotation/declare-method/output.json
new file mode 100644
index 000000000000..b089a3cf4d97
--- /dev/null
+++ b/packages/babel-parser/test/fixtures/flow/this-annotation/declare-method/output.json
@@ -0,0 +1,235 @@
+{
+  "type": "File",
+  "start":0,"end":168,"loc":{"start":{"line":1,"column":0},"end":{"line":6,"column":1}},
+  "program": {
+    "type": "Program",
+    "start":0,"end":168,"loc":{"start":{"line":1,"column":0},"end":{"line":6,"column":1}},
+    "sourceType": "module",
+    "interpreter": null,
+    "body": [
+      {
+        "type": "DeclareClass",
+        "start":0,"end":168,"loc":{"start":{"line":1,"column":0},"end":{"line":6,"column":1}},
+        "id": {
+          "type": "Identifier",
+          "start":14,"end":15,"loc":{"start":{"line":1,"column":14},"end":{"line":1,"column":15},"identifierName":"A"},
+          "name": "A"
+        },
+        "typeParameters": null,
+        "extends": [],
+        "implements": [],
+        "mixins": [],
+        "body": {
+          "type": "ObjectTypeAnnotation",
+          "start":16,"end":168,"loc":{"start":{"line":1,"column":16},"end":{"line":6,"column":1}},
+          "callProperties": [],
+          "properties": [
+            {
+              "type": "ObjectTypeProperty",
+              "start":22,"end":69,"loc":{"start":{"line":2,"column":4},"end":{"line":2,"column":51}},
+              "key": {
+                "type": "Identifier",
+                "start":22,"end":23,"loc":{"start":{"line":2,"column":4},"end":{"line":2,"column":5},"identifierName":"m"},
+                "name": "m"
+              },
+              "static": false,
+              "proto": false,
+              "kind": "init",
+              "method": true,
+              "value": {
+                "type": "FunctionTypeAnnotation",
+                "start":22,"end":69,"loc":{"start":{"line":2,"column":4},"end":{"line":2,"column":51}},
+                "params": [
+                  {
+                    "type": "FunctionTypeParam",
+                    "start":39,"end":49,"loc":{"start":{"line":2,"column":21},"end":{"line":2,"column":31}},
+                    "name": {
+                      "type": "Identifier",
+                      "start":39,"end":40,"loc":{"start":{"line":2,"column":21},"end":{"line":2,"column":22},"identifierName":"a"},
+                      "name": "a"
+                    },
+                    "optional": false,
+                    "typeAnnotation": {
+                      "type": "NumberTypeAnnotation",
+                      "start":43,"end":49,"loc":{"start":{"line":2,"column":25},"end":{"line":2,"column":31}}
+                    }
+                  },
+                  {
+                    "type": "FunctionTypeParam",
+                    "start":51,"end":61,"loc":{"start":{"line":2,"column":33},"end":{"line":2,"column":43}},
+                    "name": {
+                      "type": "Identifier",
+                      "start":51,"end":52,"loc":{"start":{"line":2,"column":33},"end":{"line":2,"column":34},"identifierName":"b"},
+                      "name": "b"
+                    },
+                    "optional": false,
+                    "typeAnnotation": {
+                      "type": "StringTypeAnnotation",
+                      "start":55,"end":61,"loc":{"start":{"line":2,"column":37},"end":{"line":2,"column":43}}
+                    }
+                  }
+                ],
+                "rest": null,
+                "typeParameters": null,
+                "this": {
+                  "type": "FunctionTypeParam",
+                  "start":24,"end":37,"loc":{"start":{"line":2,"column":6},"end":{"line":2,"column":19}},
+                  "name": null,
+                  "optional": false,
+                  "typeAnnotation": {
+                    "type": "NumberTypeAnnotation",
+                    "start":31,"end":37,"loc":{"start":{"line":2,"column":13},"end":{"line":2,"column":19}}
+                  }
+                },
+                "returnType": {
+                  "type": "VoidTypeAnnotation",
+                  "start":65,"end":69,"loc":{"start":{"line":2,"column":47},"end":{"line":2,"column":51}}
+                }
+              },
+              "optional": false
+            },
+            {
+              "type": "ObjectTypeProperty",
+              "start":75,"end":110,"loc":{"start":{"line":3,"column":4},"end":{"line":3,"column":39}},
+              "key": {
+                "type": "Identifier",
+                "start":75,"end":76,"loc":{"start":{"line":3,"column":4},"end":{"line":3,"column":5},"identifierName":"n"},
+                "name": "n"
+              },
+              "static": false,
+              "proto": false,
+              "kind": "init",
+              "method": true,
+              "value": {
+                "type": "FunctionTypeAnnotation",
+                "start":75,"end":110,"loc":{"start":{"line":3,"column":4},"end":{"line":3,"column":39}},
+                "params": [],
+                "rest": {
+                  "type": "FunctionTypeParam",
+                  "start":95,"end":102,"loc":{"start":{"line":3,"column":24},"end":{"line":3,"column":31}},
+                  "name": {
+                    "type": "Identifier",
+                    "start":95,"end":96,"loc":{"start":{"line":3,"column":24},"end":{"line":3,"column":25},"identifierName":"c"},
+                    "name": "c"
+                  },
+                  "optional": false,
+                  "typeAnnotation": {
+                    "type": "AnyTypeAnnotation",
+                    "start":99,"end":102,"loc":{"start":{"line":3,"column":28},"end":{"line":3,"column":31}}
+                  }
+                },
+                "typeParameters": null,
+                "this": {
+                  "type": "FunctionTypeParam",
+                  "start":77,"end":90,"loc":{"start":{"line":3,"column":6},"end":{"line":3,"column":19}},
+                  "name": null,
+                  "optional": false,
+                  "typeAnnotation": {
+                    "type": "NumberTypeAnnotation",
+                    "start":84,"end":90,"loc":{"start":{"line":3,"column":13},"end":{"line":3,"column":19}}
+                  }
+                },
+                "returnType": {
+                  "type": "VoidTypeAnnotation",
+                  "start":106,"end":110,"loc":{"start":{"line":3,"column":35},"end":{"line":3,"column":39}}
+                }
+              },
+              "optional": false
+            },
+            {
+              "type": "ObjectTypeProperty",
+              "start":116,"end":139,"loc":{"start":{"line":4,"column":4},"end":{"line":4,"column":27}},
+              "key": {
+                "type": "Identifier",
+                "start":116,"end":117,"loc":{"start":{"line":4,"column":4},"end":{"line":4,"column":5},"identifierName":"o"},
+                "name": "o"
+              },
+              "static": false,
+              "proto": false,
+              "kind": "init",
+              "method": true,
+              "value": {
+                "type": "FunctionTypeAnnotation",
+                "start":116,"end":139,"loc":{"start":{"line":4,"column":4},"end":{"line":4,"column":27}},
+                "params": [],
+                "rest": null,
+                "typeParameters": null,
+                "this": {
+                  "type": "FunctionTypeParam",
+                  "start":118,"end":131,"loc":{"start":{"line":4,"column":6},"end":{"line":4,"column":19}},
+                  "name": null,
+                  "optional": false,
+                  "typeAnnotation": {
+                    "type": "NumberTypeAnnotation",
+                    "start":125,"end":131,"loc":{"start":{"line":4,"column":13},"end":{"line":4,"column":19}}
+                  }
+                },
+                "returnType": {
+                  "type": "VoidTypeAnnotation",
+                  "start":135,"end":139,"loc":{"start":{"line":4,"column":23},"end":{"line":4,"column":27}}
+                }
+              },
+              "optional": false
+            },
+            {
+              "type": "ObjectTypeProperty",
+              "start":145,"end":166,"loc":{"start":{"line":5,"column":4},"end":{"line":5,"column":25}},
+              "key": {
+                "type": "Identifier",
+                "start":145,"end":146,"loc":{"start":{"line":5,"column":4},"end":{"line":5,"column":5},"identifierName":"p"},
+                "name": "p"
+              },
+              "static": false,
+              "proto": false,
+              "kind": "init",
+              "method": true,
+              "value": {
+                "type": "FunctionTypeAnnotation",
+                "start":145,"end":166,"loc":{"start":{"line":5,"column":4},"end":{"line":5,"column":25}},
+                "params": [],
+                "rest": null,
+                "typeParameters": {
+                  "type": "TypeParameterDeclaration",
+                  "start":146,"end":149,"loc":{"start":{"line":5,"column":5},"end":{"line":5,"column":8}},
+                  "params": [
+                    {
+                      "type": "TypeParameter",
+                      "start":147,"end":148,"loc":{"start":{"line":5,"column":6},"end":{"line":5,"column":7}},
+                      "name": "T",
+                      "variance": null
+                    }
+                  ]
+                },
+                "this": {
+                  "type": "FunctionTypeParam",
+                  "start":150,"end":158,"loc":{"start":{"line":5,"column":9},"end":{"line":5,"column":17}},
+                  "name": null,
+                  "optional": false,
+                  "typeAnnotation": {
+                    "type": "GenericTypeAnnotation",
+                    "start":157,"end":158,"loc":{"start":{"line":5,"column":16},"end":{"line":5,"column":17}},
+                    "typeParameters": null,
+                    "id": {
+                      "type": "Identifier",
+                      "start":157,"end":158,"loc":{"start":{"line":5,"column":16},"end":{"line":5,"column":17},"identifierName":"T"},
+                      "name": "T"
+                    }
+                  }
+                },
+                "returnType": {
+                  "type": "VoidTypeAnnotation",
+                  "start":162,"end":166,"loc":{"start":{"line":5,"column":21},"end":{"line":5,"column":25}}
+                }
+              },
+              "optional": false
+            }
+          ],
+          "indexers": [],
+          "internalSlots": [],
+          "exact": false
+        }
+      }
+    ],
+    "directives": []
+  }
+}
\ No newline at end of file
diff --git a/packages/babel-parser/test/fixtures/flow/this-annotation/default/input.js b/packages/babel-parser/test/fixtures/flow/this-annotation/default/input.js
new file mode 100644
index 000000000000..5c62115ccd84
--- /dev/null
+++ b/packages/babel-parser/test/fixtures/flow/this-annotation/default/input.js
@@ -0,0 +1 @@
+function foo<T> (this : number = 2) {}
diff --git a/packages/babel-parser/test/fixtures/flow/this-annotation/default/output.json b/packages/babel-parser/test/fixtures/flow/this-annotation/default/output.json
new file mode 100644
index 000000000000..594580b04d84
--- /dev/null
+++ b/packages/babel-parser/test/fixtures/flow/this-annotation/default/output.json
@@ -0,0 +1,73 @@
+{
+  "type": "File",
+  "start":0,"end":38,"loc":{"start":{"line":1,"column":0},"end":{"line":1,"column":38}},
+  "errors": [
+    "SyntaxError: The `this` parameter may not have a default value. (1:17)"
+  ],
+  "program": {
+    "type": "Program",
+    "start":0,"end":38,"loc":{"start":{"line":1,"column":0},"end":{"line":1,"column":38}},
+    "sourceType": "module",
+    "interpreter": null,
+    "body": [
+      {
+        "type": "FunctionDeclaration",
+        "start":0,"end":38,"loc":{"start":{"line":1,"column":0},"end":{"line":1,"column":38}},
+        "id": {
+          "type": "Identifier",
+          "start":9,"end":12,"loc":{"start":{"line":1,"column":9},"end":{"line":1,"column":12},"identifierName":"foo"},
+          "name": "foo"
+        },
+        "generator": false,
+        "async": false,
+        "typeParameters": {
+          "type": "TypeParameterDeclaration",
+          "start":12,"end":15,"loc":{"start":{"line":1,"column":12},"end":{"line":1,"column":15}},
+          "params": [
+            {
+              "type": "TypeParameter",
+              "start":13,"end":14,"loc":{"start":{"line":1,"column":13},"end":{"line":1,"column":14}},
+              "name": "T",
+              "variance": null
+            }
+          ]
+        },
+        "params": [
+          {
+            "type": "AssignmentPattern",
+            "start":17,"end":34,"loc":{"start":{"line":1,"column":17},"end":{"line":1,"column":34}},
+            "left": {
+              "type": "Identifier",
+              "start":17,"end":30,"loc":{"start":{"line":1,"column":17},"end":{"line":1,"column":30},"identifierName":"this"},
+              "name": "this",
+              "typeAnnotation": {
+                "type": "TypeAnnotation",
+                "start":22,"end":30,"loc":{"start":{"line":1,"column":22},"end":{"line":1,"column":30}},
+                "typeAnnotation": {
+                  "type": "NumberTypeAnnotation",
+                  "start":24,"end":30,"loc":{"start":{"line":1,"column":24},"end":{"line":1,"column":30}}
+                }
+              }
+            },
+            "right": {
+              "type": "NumericLiteral",
+              "start":33,"end":34,"loc":{"start":{"line":1,"column":33},"end":{"line":1,"column":34}},
+              "extra": {
+                "rawValue": 2,
+                "raw": "2"
+              },
+              "value": 2
+            }
+          }
+        ],
+        "body": {
+          "type": "BlockStatement",
+          "start":36,"end":38,"loc":{"start":{"line":1,"column":36},"end":{"line":1,"column":38}},
+          "body": [],
+          "directives": []
+        }
+      }
+    ],
+    "directives": []
+  }
+}
\ No newline at end of file
diff --git a/packages/babel-parser/test/fixtures/flow/this-annotation/function-declaration/input.js b/packages/babel-parser/test/fixtures/flow/this-annotation/function-declaration/input.js
new file mode 100644
index 000000000000..f2d69ae4f83e
--- /dev/null
+++ b/packages/babel-parser/test/fixtures/flow/this-annotation/function-declaration/input.js
@@ -0,0 +1,7 @@
+function foo (this : number, a : string, b) {}
+
+function bar (this : number) {}
+
+function baz (this : number, ...a) {}
+
+function qux<T> (this : T) {}
diff --git a/packages/babel-parser/test/fixtures/flow/this-annotation/function-declaration/output.json b/packages/babel-parser/test/fixtures/flow/this-annotation/function-declaration/output.json
new file mode 100644
index 000000000000..2c042f9f63fd
--- /dev/null
+++ b/packages/babel-parser/test/fixtures/flow/this-annotation/function-declaration/output.json
@@ -0,0 +1,186 @@
+{
+  "type": "File",
+  "start":0,"end":149,"loc":{"start":{"line":1,"column":0},"end":{"line":7,"column":29}},
+  "program": {
+    "type": "Program",
+    "start":0,"end":149,"loc":{"start":{"line":1,"column":0},"end":{"line":7,"column":29}},
+    "sourceType": "module",
+    "interpreter": null,
+    "body": [
+      {
+        "type": "FunctionDeclaration",
+        "start":0,"end":46,"loc":{"start":{"line":1,"column":0},"end":{"line":1,"column":46}},
+        "id": {
+          "type": "Identifier",
+          "start":9,"end":12,"loc":{"start":{"line":1,"column":9},"end":{"line":1,"column":12},"identifierName":"foo"},
+          "name": "foo"
+        },
+        "generator": false,
+        "async": false,
+        "params": [
+          {
+            "type": "Identifier",
+            "start":14,"end":27,"loc":{"start":{"line":1,"column":14},"end":{"line":1,"column":27},"identifierName":"this"},
+            "name": "this",
+            "typeAnnotation": {
+              "type": "TypeAnnotation",
+              "start":19,"end":27,"loc":{"start":{"line":1,"column":19},"end":{"line":1,"column":27}},
+              "typeAnnotation": {
+                "type": "NumberTypeAnnotation",
+                "start":21,"end":27,"loc":{"start":{"line":1,"column":21},"end":{"line":1,"column":27}}
+              }
+            }
+          },
+          {
+            "type": "Identifier",
+            "start":29,"end":39,"loc":{"start":{"line":1,"column":29},"end":{"line":1,"column":39},"identifierName":"a"},
+            "name": "a",
+            "typeAnnotation": {
+              "type": "TypeAnnotation",
+              "start":31,"end":39,"loc":{"start":{"line":1,"column":31},"end":{"line":1,"column":39}},
+              "typeAnnotation": {
+                "type": "StringTypeAnnotation",
+                "start":33,"end":39,"loc":{"start":{"line":1,"column":33},"end":{"line":1,"column":39}}
+              }
+            }
+          },
+          {
+            "type": "Identifier",
+            "start":41,"end":42,"loc":{"start":{"line":1,"column":41},"end":{"line":1,"column":42},"identifierName":"b"},
+            "name": "b"
+          }
+        ],
+        "body": {
+          "type": "BlockStatement",
+          "start":44,"end":46,"loc":{"start":{"line":1,"column":44},"end":{"line":1,"column":46}},
+          "body": [],
+          "directives": []
+        }
+      },
+      {
+        "type": "FunctionDeclaration",
+        "start":48,"end":79,"loc":{"start":{"line":3,"column":0},"end":{"line":3,"column":31}},
+        "id": {
+          "type": "Identifier",
+          "start":57,"end":60,"loc":{"start":{"line":3,"column":9},"end":{"line":3,"column":12},"identifierName":"bar"},
+          "name": "bar"
+        },
+        "generator": false,
+        "async": false,
+        "params": [
+          {
+            "type": "Identifier",
+            "start":62,"end":75,"loc":{"start":{"line":3,"column":14},"end":{"line":3,"column":27},"identifierName":"this"},
+            "name": "this",
+            "typeAnnotation": {
+              "type": "TypeAnnotation",
+              "start":67,"end":75,"loc":{"start":{"line":3,"column":19},"end":{"line":3,"column":27}},
+              "typeAnnotation": {
+                "type": "NumberTypeAnnotation",
+                "start":69,"end":75,"loc":{"start":{"line":3,"column":21},"end":{"line":3,"column":27}}
+              }
+            }
+          }
+        ],
+        "body": {
+          "type": "BlockStatement",
+          "start":77,"end":79,"loc":{"start":{"line":3,"column":29},"end":{"line":3,"column":31}},
+          "body": [],
+          "directives": []
+        }
+      },
+      {
+        "type": "FunctionDeclaration",
+        "start":81,"end":118,"loc":{"start":{"line":5,"column":0},"end":{"line":5,"column":37}},
+        "id": {
+          "type": "Identifier",
+          "start":90,"end":93,"loc":{"start":{"line":5,"column":9},"end":{"line":5,"column":12},"identifierName":"baz"},
+          "name": "baz"
+        },
+        "generator": false,
+        "async": false,
+        "params": [
+          {
+            "type": "Identifier",
+            "start":95,"end":108,"loc":{"start":{"line":5,"column":14},"end":{"line":5,"column":27},"identifierName":"this"},
+            "name": "this",
+            "typeAnnotation": {
+              "type": "TypeAnnotation",
+              "start":100,"end":108,"loc":{"start":{"line":5,"column":19},"end":{"line":5,"column":27}},
+              "typeAnnotation": {
+                "type": "NumberTypeAnnotation",
+                "start":102,"end":108,"loc":{"start":{"line":5,"column":21},"end":{"line":5,"column":27}}
+              }
+            }
+          },
+          {
+            "type": "RestElement",
+            "start":110,"end":114,"loc":{"start":{"line":5,"column":29},"end":{"line":5,"column":33}},
+            "argument": {
+              "type": "Identifier",
+              "start":113,"end":114,"loc":{"start":{"line":5,"column":32},"end":{"line":5,"column":33},"identifierName":"a"},
+              "name": "a"
+            }
+          }
+        ],
+        "body": {
+          "type": "BlockStatement",
+          "start":116,"end":118,"loc":{"start":{"line":5,"column":35},"end":{"line":5,"column":37}},
+          "body": [],
+          "directives": []
+        }
+      },
+      {
+        "type": "FunctionDeclaration",
+        "start":120,"end":149,"loc":{"start":{"line":7,"column":0},"end":{"line":7,"column":29}},
+        "id": {
+          "type": "Identifier",
+          "start":129,"end":132,"loc":{"start":{"line":7,"column":9},"end":{"line":7,"column":12},"identifierName":"qux"},
+          "name": "qux"
+        },
+        "generator": false,
+        "async": false,
+        "typeParameters": {
+          "type": "TypeParameterDeclaration",
+          "start":132,"end":135,"loc":{"start":{"line":7,"column":12},"end":{"line":7,"column":15}},
+          "params": [
+            {
+              "type": "TypeParameter",
+              "start":133,"end":134,"loc":{"start":{"line":7,"column":13},"end":{"line":7,"column":14}},
+              "name": "T",
+              "variance": null
+            }
+          ]
+        },
+        "params": [
+          {
+            "type": "Identifier",
+            "start":137,"end":145,"loc":{"start":{"line":7,"column":17},"end":{"line":7,"column":25},"identifierName":"this"},
+            "name": "this",
+            "typeAnnotation": {
+              "type": "TypeAnnotation",
+              "start":142,"end":145,"loc":{"start":{"line":7,"column":22},"end":{"line":7,"column":25}},
+              "typeAnnotation": {
+                "type": "GenericTypeAnnotation",
+                "start":144,"end":145,"loc":{"start":{"line":7,"column":24},"end":{"line":7,"column":25}},
+                "typeParameters": null,
+                "id": {
+                  "type": "Identifier",
+                  "start":144,"end":145,"loc":{"start":{"line":7,"column":24},"end":{"line":7,"column":25},"identifierName":"T"},
+                  "name": "T"
+                }
+              }
+            }
+          }
+        ],
+        "body": {
+          "type": "BlockStatement",
+          "start":147,"end":149,"loc":{"start":{"line":7,"column":27},"end":{"line":7,"column":29}},
+          "body": [],
+          "directives": []
+        }
+      }
+    ],
+    "directives": []
+  }
+}
\ No newline at end of file
diff --git a/packages/babel-parser/test/fixtures/flow/this-annotation/function-type/input.js b/packages/babel-parser/test/fixtures/flow/this-annotation/function-type/input.js
new file mode 100644
index 000000000000..0ae4768556fc
--- /dev/null
+++ b/packages/babel-parser/test/fixtures/flow/this-annotation/function-type/input.js
@@ -0,0 +1,7 @@
+type T = (this : number, a : string, b : number) => void
+
+type U = (this : number, ...c : any) => void
+
+type V = (this : number) => void
+
+type Q = <T>(this : T) => void
diff --git a/packages/babel-parser/test/fixtures/flow/this-annotation/function-type/output.json b/packages/babel-parser/test/fixtures/flow/this-annotation/function-type/output.json
new file mode 100644
index 000000000000..b3a6efdfd014
--- /dev/null
+++ b/packages/babel-parser/test/fixtures/flow/this-annotation/function-type/output.json
@@ -0,0 +1,196 @@
+{
+  "type": "File",
+  "start":0,"end":168,"loc":{"start":{"line":1,"column":0},"end":{"line":7,"column":30}},
+  "program": {
+    "type": "Program",
+    "start":0,"end":168,"loc":{"start":{"line":1,"column":0},"end":{"line":7,"column":30}},
+    "sourceType": "module",
+    "interpreter": null,
+    "body": [
+      {
+        "type": "TypeAlias",
+        "start":0,"end":56,"loc":{"start":{"line":1,"column":0},"end":{"line":1,"column":56}},
+        "id": {
+          "type": "Identifier",
+          "start":5,"end":6,"loc":{"start":{"line":1,"column":5},"end":{"line":1,"column":6},"identifierName":"T"},
+          "name": "T"
+        },
+        "typeParameters": null,
+        "right": {
+          "type": "FunctionTypeAnnotation",
+          "start":9,"end":56,"loc":{"start":{"line":1,"column":9},"end":{"line":1,"column":56}},
+          "params": [
+            {
+              "type": "FunctionTypeParam",
+              "start":25,"end":35,"loc":{"start":{"line":1,"column":25},"end":{"line":1,"column":35}},
+              "name": {
+                "type": "Identifier",
+                "start":25,"end":26,"loc":{"start":{"line":1,"column":25},"end":{"line":1,"column":26},"identifierName":"a"},
+                "name": "a"
+              },
+              "optional": false,
+              "typeAnnotation": {
+                "type": "StringTypeAnnotation",
+                "start":29,"end":35,"loc":{"start":{"line":1,"column":29},"end":{"line":1,"column":35}}
+              }
+            },
+            {
+              "type": "FunctionTypeParam",
+              "start":37,"end":47,"loc":{"start":{"line":1,"column":37},"end":{"line":1,"column":47}},
+              "name": {
+                "type": "Identifier",
+                "start":37,"end":38,"loc":{"start":{"line":1,"column":37},"end":{"line":1,"column":38},"identifierName":"b"},
+                "name": "b"
+              },
+              "optional": false,
+              "typeAnnotation": {
+                "type": "NumberTypeAnnotation",
+                "start":41,"end":47,"loc":{"start":{"line":1,"column":41},"end":{"line":1,"column":47}}
+              }
+            }
+          ],
+          "rest": null,
+          "this": {
+            "type": "FunctionTypeParam",
+            "start":10,"end":23,"loc":{"start":{"line":1,"column":10},"end":{"line":1,"column":23}},
+            "name": null,
+            "optional": false,
+            "typeAnnotation": {
+              "type": "NumberTypeAnnotation",
+              "start":17,"end":23,"loc":{"start":{"line":1,"column":17},"end":{"line":1,"column":23}}
+            }
+          },
+          "returnType": {
+            "type": "VoidTypeAnnotation",
+            "start":52,"end":56,"loc":{"start":{"line":1,"column":52},"end":{"line":1,"column":56}}
+          },
+          "typeParameters": null
+        }
+      },
+      {
+        "type": "TypeAlias",
+        "start":58,"end":102,"loc":{"start":{"line":3,"column":0},"end":{"line":3,"column":44}},
+        "id": {
+          "type": "Identifier",
+          "start":63,"end":64,"loc":{"start":{"line":3,"column":5},"end":{"line":3,"column":6},"identifierName":"U"},
+          "name": "U"
+        },
+        "typeParameters": null,
+        "right": {
+          "type": "FunctionTypeAnnotation",
+          "start":67,"end":102,"loc":{"start":{"line":3,"column":9},"end":{"line":3,"column":44}},
+          "params": [],
+          "rest": {
+            "type": "FunctionTypeParam",
+            "start":86,"end":93,"loc":{"start":{"line":3,"column":28},"end":{"line":3,"column":35}},
+            "name": {
+              "type": "Identifier",
+              "start":86,"end":87,"loc":{"start":{"line":3,"column":28},"end":{"line":3,"column":29},"identifierName":"c"},
+              "name": "c"
+            },
+            "optional": false,
+            "typeAnnotation": {
+              "type": "AnyTypeAnnotation",
+              "start":90,"end":93,"loc":{"start":{"line":3,"column":32},"end":{"line":3,"column":35}}
+            }
+          },
+          "this": {
+            "type": "FunctionTypeParam",
+            "start":68,"end":81,"loc":{"start":{"line":3,"column":10},"end":{"line":3,"column":23}},
+            "name": null,
+            "optional": false,
+            "typeAnnotation": {
+              "type": "NumberTypeAnnotation",
+              "start":75,"end":81,"loc":{"start":{"line":3,"column":17},"end":{"line":3,"column":23}}
+            }
+          },
+          "returnType": {
+            "type": "VoidTypeAnnotation",
+            "start":98,"end":102,"loc":{"start":{"line":3,"column":40},"end":{"line":3,"column":44}}
+          },
+          "typeParameters": null
+        }
+      },
+      {
+        "type": "TypeAlias",
+        "start":104,"end":136,"loc":{"start":{"line":5,"column":0},"end":{"line":5,"column":32}},
+        "id": {
+          "type": "Identifier",
+          "start":109,"end":110,"loc":{"start":{"line":5,"column":5},"end":{"line":5,"column":6},"identifierName":"V"},
+          "name": "V"
+        },
+        "typeParameters": null,
+        "right": {
+          "type": "FunctionTypeAnnotation",
+          "start":113,"end":136,"loc":{"start":{"line":5,"column":9},"end":{"line":5,"column":32}},
+          "params": [],
+          "rest": null,
+          "this": {
+            "type": "FunctionTypeParam",
+            "start":114,"end":127,"loc":{"start":{"line":5,"column":10},"end":{"line":5,"column":23}},
+            "name": null,
+            "optional": false,
+            "typeAnnotation": {
+              "type": "NumberTypeAnnotation",
+              "start":121,"end":127,"loc":{"start":{"line":5,"column":17},"end":{"line":5,"column":23}}
+            }
+          },
+          "returnType": {
+            "type": "VoidTypeAnnotation",
+            "start":132,"end":136,"loc":{"start":{"line":5,"column":28},"end":{"line":5,"column":32}}
+          },
+          "typeParameters": null
+        }
+      },
+      {
+        "type": "TypeAlias",
+        "start":138,"end":168,"loc":{"start":{"line":7,"column":0},"end":{"line":7,"column":30}},
+        "id": {
+          "type": "Identifier",
+          "start":143,"end":144,"loc":{"start":{"line":7,"column":5},"end":{"line":7,"column":6},"identifierName":"Q"},
+          "name": "Q"
+        },
+        "typeParameters": null,
+        "right": {
+          "type": "FunctionTypeAnnotation",
+          "start":147,"end":168,"loc":{"start":{"line":7,"column":9},"end":{"line":7,"column":30}},
+          "typeParameters": {
+            "type": "TypeParameterDeclaration",
+            "start":147,"end":150,"loc":{"start":{"line":7,"column":9},"end":{"line":7,"column":12}},
+            "params": [
+              {
+                "type": "TypeParameter",
+                "start":148,"end":149,"loc":{"start":{"line":7,"column":10},"end":{"line":7,"column":11}},
+                "name": "T",
+                "variance": null
+              }
+            ]
+          },
+          "params": [],
+          "rest": null,
+          "this": {
+            "type": "FunctionTypeParam",
+            "start":151,"end":159,"loc":{"start":{"line":7,"column":13},"end":{"line":7,"column":21}},
+            "name": null,
+            "optional": false,
+            "typeAnnotation": {
+              "type": "GenericTypeAnnotation",
+              "start":158,"end":159,"loc":{"start":{"line":7,"column":20},"end":{"line":7,"column":21}},
+              "typeParameters": null,
+              "id": {
+                "type": "Identifier",
+                "start":158,"end":159,"loc":{"start":{"line":7,"column":20},"end":{"line":7,"column":21},"identifierName":"T"},
+                "name": "T"
+              }
+            }
+          },
+          "returnType": {
+            "type": "VoidTypeAnnotation",
+            "start":164,"end":168,"loc":{"start":{"line":7,"column":26},"end":{"line":7,"column":30}}
+          }
+        }
+      }
+    ],
+    "directives": []
+  }
+}
\ No newline at end of file
diff --git a/packages/babel-parser/test/fixtures/flow/this-annotation/method/input.js b/packages/babel-parser/test/fixtures/flow/this-annotation/method/input.js
new file mode 100644
index 000000000000..9b145069abcb
--- /dev/null
+++ b/packages/babel-parser/test/fixtures/flow/this-annotation/method/input.js
@@ -0,0 +1,6 @@
+class A {
+    m(this : number, a : number, b : string) {}
+    n(this : number, ...c) {}
+    o(this : number) {}
+    p<T>(this : T) {}
+}
diff --git a/packages/babel-parser/test/fixtures/flow/this-annotation/method/output.json b/packages/babel-parser/test/fixtures/flow/this-annotation/method/output.json
new file mode 100644
index 000000000000..b972757dedd7
--- /dev/null
+++ b/packages/babel-parser/test/fixtures/flow/this-annotation/method/output.json
@@ -0,0 +1,226 @@
+{
+  "type": "File",
+  "start":0,"end":135,"loc":{"start":{"line":1,"column":0},"end":{"line":6,"column":1}},
+  "program": {
+    "type": "Program",
+    "start":0,"end":135,"loc":{"start":{"line":1,"column":0},"end":{"line":6,"column":1}},
+    "sourceType": "module",
+    "interpreter": null,
+    "body": [
+      {
+        "type": "ClassDeclaration",
+        "start":0,"end":135,"loc":{"start":{"line":1,"column":0},"end":{"line":6,"column":1}},
+        "id": {
+          "type": "Identifier",
+          "start":6,"end":7,"loc":{"start":{"line":1,"column":6},"end":{"line":1,"column":7},"identifierName":"A"},
+          "name": "A"
+        },
+        "superClass": null,
+        "body": {
+          "type": "ClassBody",
+          "start":8,"end":135,"loc":{"start":{"line":1,"column":8},"end":{"line":6,"column":1}},
+          "body": [
+            {
+              "type": "ClassMethod",
+              "start":14,"end":57,"loc":{"start":{"line":2,"column":4},"end":{"line":2,"column":47}},
+              "static": false,
+              "key": {
+                "type": "Identifier",
+                "start":14,"end":15,"loc":{"start":{"line":2,"column":4},"end":{"line":2,"column":5},"identifierName":"m"},
+                "name": "m"
+              },
+              "computed": false,
+              "kind": "method",
+              "id": null,
+              "generator": false,
+              "async": false,
+              "params": [
+                {
+                  "type": "Identifier",
+                  "start":16,"end":29,"loc":{"start":{"line":2,"column":6},"end":{"line":2,"column":19},"identifierName":"this"},
+                  "name": "this",
+                  "typeAnnotation": {
+                    "type": "TypeAnnotation",
+                    "start":21,"end":29,"loc":{"start":{"line":2,"column":11},"end":{"line":2,"column":19}},
+                    "typeAnnotation": {
+                      "type": "NumberTypeAnnotation",
+                      "start":23,"end":29,"loc":{"start":{"line":2,"column":13},"end":{"line":2,"column":19}}
+                    }
+                  }
+                },
+                {
+                  "type": "Identifier",
+                  "start":31,"end":41,"loc":{"start":{"line":2,"column":21},"end":{"line":2,"column":31},"identifierName":"a"},
+                  "name": "a",
+                  "typeAnnotation": {
+                    "type": "TypeAnnotation",
+                    "start":33,"end":41,"loc":{"start":{"line":2,"column":23},"end":{"line":2,"column":31}},
+                    "typeAnnotation": {
+                      "type": "NumberTypeAnnotation",
+                      "start":35,"end":41,"loc":{"start":{"line":2,"column":25},"end":{"line":2,"column":31}}
+                    }
+                  }
+                },
+                {
+                  "type": "Identifier",
+                  "start":43,"end":53,"loc":{"start":{"line":2,"column":33},"end":{"line":2,"column":43},"identifierName":"b"},
+                  "name": "b",
+                  "typeAnnotation": {
+                    "type": "TypeAnnotation",
+                    "start":45,"end":53,"loc":{"start":{"line":2,"column":35},"end":{"line":2,"column":43}},
+                    "typeAnnotation": {
+                      "type": "StringTypeAnnotation",
+                      "start":47,"end":53,"loc":{"start":{"line":2,"column":37},"end":{"line":2,"column":43}}
+                    }
+                  }
+                }
+              ],
+              "body": {
+                "type": "BlockStatement",
+                "start":55,"end":57,"loc":{"start":{"line":2,"column":45},"end":{"line":2,"column":47}},
+                "body": [],
+                "directives": []
+              }
+            },
+            {
+              "type": "ClassMethod",
+              "start":62,"end":87,"loc":{"start":{"line":3,"column":4},"end":{"line":3,"column":29}},
+              "static": false,
+              "key": {
+                "type": "Identifier",
+                "start":62,"end":63,"loc":{"start":{"line":3,"column":4},"end":{"line":3,"column":5},"identifierName":"n"},
+                "name": "n"
+              },
+              "computed": false,
+              "kind": "method",
+              "id": null,
+              "generator": false,
+              "async": false,
+              "params": [
+                {
+                  "type": "Identifier",
+                  "start":64,"end":77,"loc":{"start":{"line":3,"column":6},"end":{"line":3,"column":19},"identifierName":"this"},
+                  "name": "this",
+                  "typeAnnotation": {
+                    "type": "TypeAnnotation",
+                    "start":69,"end":77,"loc":{"start":{"line":3,"column":11},"end":{"line":3,"column":19}},
+                    "typeAnnotation": {
+                      "type": "NumberTypeAnnotation",
+                      "start":71,"end":77,"loc":{"start":{"line":3,"column":13},"end":{"line":3,"column":19}}
+                    }
+                  }
+                },
+                {
+                  "type": "RestElement",
+                  "start":79,"end":83,"loc":{"start":{"line":3,"column":21},"end":{"line":3,"column":25}},
+                  "argument": {
+                    "type": "Identifier",
+                    "start":82,"end":83,"loc":{"start":{"line":3,"column":24},"end":{"line":3,"column":25},"identifierName":"c"},
+                    "name": "c"
+                  }
+                }
+              ],
+              "body": {
+                "type": "BlockStatement",
+                "start":85,"end":87,"loc":{"start":{"line":3,"column":27},"end":{"line":3,"column":29}},
+                "body": [],
+                "directives": []
+              }
+            },
+            {
+              "type": "ClassMethod",
+              "start":92,"end":111,"loc":{"start":{"line":4,"column":4},"end":{"line":4,"column":23}},
+              "static": false,
+              "key": {
+                "type": "Identifier",
+                "start":92,"end":93,"loc":{"start":{"line":4,"column":4},"end":{"line":4,"column":5},"identifierName":"o"},
+                "name": "o"
+              },
+              "computed": false,
+              "kind": "method",
+              "id": null,
+              "generator": false,
+              "async": false,
+              "params": [
+                {
+                  "type": "Identifier",
+                  "start":94,"end":107,"loc":{"start":{"line":4,"column":6},"end":{"line":4,"column":19},"identifierName":"this"},
+                  "name": "this",
+                  "typeAnnotation": {
+                    "type": "TypeAnnotation",
+                    "start":99,"end":107,"loc":{"start":{"line":4,"column":11},"end":{"line":4,"column":19}},
+                    "typeAnnotation": {
+                      "type": "NumberTypeAnnotation",
+                      "start":101,"end":107,"loc":{"start":{"line":4,"column":13},"end":{"line":4,"column":19}}
+                    }
+                  }
+                }
+              ],
+              "body": {
+                "type": "BlockStatement",
+                "start":109,"end":111,"loc":{"start":{"line":4,"column":21},"end":{"line":4,"column":23}},
+                "body": [],
+                "directives": []
+              }
+            },
+            {
+              "type": "ClassMethod",
+              "start":116,"end":133,"loc":{"start":{"line":5,"column":4},"end":{"line":5,"column":21}},
+              "static": false,
+              "key": {
+                "type": "Identifier",
+                "start":116,"end":117,"loc":{"start":{"line":5,"column":4},"end":{"line":5,"column":5},"identifierName":"p"},
+                "name": "p"
+              },
+              "computed": false,
+              "kind": "method",
+              "typeParameters": {
+                "type": "TypeParameterDeclaration",
+                "start":117,"end":120,"loc":{"start":{"line":5,"column":5},"end":{"line":5,"column":8}},
+                "params": [
+                  {
+                    "type": "TypeParameter",
+                    "start":118,"end":119,"loc":{"start":{"line":5,"column":6},"end":{"line":5,"column":7}},
+                    "name": "T",
+                    "variance": null
+                  }
+                ]
+              },
+              "id": null,
+              "generator": false,
+              "async": false,
+              "params": [
+                {
+                  "type": "Identifier",
+                  "start":121,"end":129,"loc":{"start":{"line":5,"column":9},"end":{"line":5,"column":17},"identifierName":"this"},
+                  "name": "this",
+                  "typeAnnotation": {
+                    "type": "TypeAnnotation",
+                    "start":126,"end":129,"loc":{"start":{"line":5,"column":14},"end":{"line":5,"column":17}},
+                    "typeAnnotation": {
+                      "type": "GenericTypeAnnotation",
+                      "start":128,"end":129,"loc":{"start":{"line":5,"column":16},"end":{"line":5,"column":17}},
+                      "typeParameters": null,
+                      "id": {
+                        "type": "Identifier",
+                        "start":128,"end":129,"loc":{"start":{"line":5,"column":16},"end":{"line":5,"column":17},"identifierName":"T"},
+                        "name": "T"
+                      }
+                    }
+                  }
+                }
+              ],
+              "body": {
+                "type": "BlockStatement",
+                "start":131,"end":133,"loc":{"start":{"line":5,"column":19},"end":{"line":5,"column":21}},
+                "body": [],
+                "directives": []
+              }
+            }
+          ]
+        }
+      }
+    ],
+    "directives": []
+  }
+}
\ No newline at end of file
diff --git a/packages/babel-parser/test/fixtures/flow/this-annotation/object-constructor/input.js b/packages/babel-parser/test/fixtures/flow/this-annotation/object-constructor/input.js
new file mode 100644
index 000000000000..903a43ad1cca
--- /dev/null
+++ b/packages/babel-parser/test/fixtures/flow/this-annotation/object-constructor/input.js
@@ -0,0 +1,5 @@
+// @flow
+
+({
+    constructor(this: number){}
+})
diff --git a/packages/babel-parser/test/fixtures/flow/this-annotation/object-constructor/output.json b/packages/babel-parser/test/fixtures/flow/this-annotation/object-constructor/output.json
new file mode 100644
index 000000000000..7736cab5a72c
--- /dev/null
+++ b/packages/babel-parser/test/fixtures/flow/this-annotation/object-constructor/output.json
@@ -0,0 +1,77 @@
+{
+  "type": "File",
+  "start":0,"end":47,"loc":{"start":{"line":1,"column":0},"end":{"line":5,"column":2}},
+  "program": {
+    "type": "Program",
+    "start":0,"end":47,"loc":{"start":{"line":1,"column":0},"end":{"line":5,"column":2}},
+    "sourceType": "module",
+    "interpreter": null,
+    "body": [
+      {
+        "type": "ExpressionStatement",
+        "start":10,"end":47,"loc":{"start":{"line":3,"column":0},"end":{"line":5,"column":2}},
+        "leadingComments": [
+          {
+            "type": "CommentLine",
+            "value": " @flow",
+            "start":0,"end":8,"loc":{"start":{"line":1,"column":0},"end":{"line":1,"column":8}}
+          }
+        ],
+        "expression": {
+          "type": "ObjectExpression",
+          "start":11,"end":46,"loc":{"start":{"line":3,"column":1},"end":{"line":5,"column":1}},
+          "extra": {
+            "parenthesized": true,
+            "parenStart": 10
+          },
+          "properties": [
+            {
+              "type": "ObjectMethod",
+              "start":17,"end":44,"loc":{"start":{"line":4,"column":4},"end":{"line":4,"column":31}},
+              "method": true,
+              "key": {
+                "type": "Identifier",
+                "start":17,"end":28,"loc":{"start":{"line":4,"column":4},"end":{"line":4,"column":15},"identifierName":"constructor"},
+                "name": "constructor"
+              },
+              "computed": false,
+              "kind": "method",
+              "id": null,
+              "generator": false,
+              "async": false,
+              "params": [
+                {
+                  "type": "Identifier",
+                  "start":29,"end":41,"loc":{"start":{"line":4,"column":16},"end":{"line":4,"column":28},"identifierName":"this"},
+                  "name": "this",
+                  "typeAnnotation": {
+                    "type": "TypeAnnotation",
+                    "start":33,"end":41,"loc":{"start":{"line":4,"column":20},"end":{"line":4,"column":28}},
+                    "typeAnnotation": {
+                      "type": "NumberTypeAnnotation",
+                      "start":35,"end":41,"loc":{"start":{"line":4,"column":22},"end":{"line":4,"column":28}}
+                    }
+                  }
+                }
+              ],
+              "body": {
+                "type": "BlockStatement",
+                "start":42,"end":44,"loc":{"start":{"line":4,"column":29},"end":{"line":4,"column":31}},
+                "body": [],
+                "directives": []
+              }
+            }
+          ]
+        }
+      }
+    ],
+    "directives": []
+  },
+  "comments": [
+    {
+      "type": "CommentLine",
+      "value": " @flow",
+      "start":0,"end":8,"loc":{"start":{"line":1,"column":0},"end":{"line":1,"column":8}}
+    }
+  ]
+}
\ No newline at end of file
diff --git a/packages/babel-parser/test/fixtures/flow/this-annotation/object-method-type-this-not-first/input.js b/packages/babel-parser/test/fixtures/flow/this-annotation/object-method-type-this-not-first/input.js
new file mode 100644
index 000000000000..59702554101e
--- /dev/null
+++ b/packages/babel-parser/test/fixtures/flow/this-annotation/object-method-type-this-not-first/input.js
@@ -0,0 +1,3 @@
+type T = {
+    foo(a : number, this : number) : void
+}
diff --git a/packages/babel-parser/test/fixtures/flow/this-annotation/object-method-type-this-not-first/output.json b/packages/babel-parser/test/fixtures/flow/this-annotation/object-method-type-this-not-first/output.json
new file mode 100644
index 000000000000..8a93ef574818
--- /dev/null
+++ b/packages/babel-parser/test/fixtures/flow/this-annotation/object-method-type-this-not-first/output.json
@@ -0,0 +1,92 @@
+{
+  "type": "File",
+  "start":0,"end":54,"loc":{"start":{"line":1,"column":0},"end":{"line":3,"column":1}},
+  "errors": [
+    "SyntaxError: The `this` parameter must be the first function parameter. (2:20)"
+  ],
+  "program": {
+    "type": "Program",
+    "start":0,"end":54,"loc":{"start":{"line":1,"column":0},"end":{"line":3,"column":1}},
+    "sourceType": "module",
+    "interpreter": null,
+    "body": [
+      {
+        "type": "TypeAlias",
+        "start":0,"end":54,"loc":{"start":{"line":1,"column":0},"end":{"line":3,"column":1}},
+        "id": {
+          "type": "Identifier",
+          "start":5,"end":6,"loc":{"start":{"line":1,"column":5},"end":{"line":1,"column":6},"identifierName":"T"},
+          "name": "T"
+        },
+        "typeParameters": null,
+        "right": {
+          "type": "ObjectTypeAnnotation",
+          "start":9,"end":54,"loc":{"start":{"line":1,"column":9},"end":{"line":3,"column":1}},
+          "callProperties": [],
+          "properties": [
+            {
+              "type": "ObjectTypeProperty",
+              "start":15,"end":52,"loc":{"start":{"line":2,"column":4},"end":{"line":2,"column":41}},
+              "key": {
+                "type": "Identifier",
+                "start":15,"end":18,"loc":{"start":{"line":2,"column":4},"end":{"line":2,"column":7},"identifierName":"foo"},
+                "name": "foo"
+              },
+              "static": false,
+              "proto": false,
+              "kind": "init",
+              "method": true,
+              "value": {
+                "type": "FunctionTypeAnnotation",
+                "start":15,"end":52,"loc":{"start":{"line":2,"column":4},"end":{"line":2,"column":41}},
+                "params": [
+                  {
+                    "type": "FunctionTypeParam",
+                    "start":19,"end":29,"loc":{"start":{"line":2,"column":8},"end":{"line":2,"column":18}},
+                    "name": {
+                      "type": "Identifier",
+                      "start":19,"end":20,"loc":{"start":{"line":2,"column":8},"end":{"line":2,"column":9},"identifierName":"a"},
+                      "name": "a"
+                    },
+                    "optional": false,
+                    "typeAnnotation": {
+                      "type": "NumberTypeAnnotation",
+                      "start":23,"end":29,"loc":{"start":{"line":2,"column":12},"end":{"line":2,"column":18}}
+                    }
+                  },
+                  {
+                    "type": "FunctionTypeParam",
+                    "start":31,"end":44,"loc":{"start":{"line":2,"column":20},"end":{"line":2,"column":33}},
+                    "name": {
+                      "type": "Identifier",
+                      "start":31,"end":35,"loc":{"start":{"line":2,"column":20},"end":{"line":2,"column":24},"identifierName":"this"},
+                      "name": "this"
+                    },
+                    "optional": false,
+                    "typeAnnotation": {
+                      "type": "NumberTypeAnnotation",
+                      "start":38,"end":44,"loc":{"start":{"line":2,"column":27},"end":{"line":2,"column":33}}
+                    }
+                  }
+                ],
+                "rest": null,
+                "typeParameters": null,
+                "this": null,
+                "returnType": {
+                  "type": "VoidTypeAnnotation",
+                  "start":48,"end":52,"loc":{"start":{"line":2,"column":37},"end":{"line":2,"column":41}}
+                }
+              },
+              "optional": false
+            }
+          ],
+          "indexers": [],
+          "internalSlots": [],
+          "exact": false,
+          "inexact": false
+        }
+      }
+    ],
+    "directives": []
+  }
+}
\ No newline at end of file
diff --git a/packages/babel-parser/test/fixtures/flow/this-annotation/object-method-type/input.js b/packages/babel-parser/test/fixtures/flow/this-annotation/object-method-type/input.js
new file mode 100644
index 000000000000..46171c399edd
--- /dev/null
+++ b/packages/babel-parser/test/fixtures/flow/this-annotation/object-method-type/input.js
@@ -0,0 +1,3 @@
+type T = {
+    foo(this : number) : void
+}
diff --git a/packages/babel-parser/test/fixtures/flow/this-annotation/object-method-type/output.json b/packages/babel-parser/test/fixtures/flow/this-annotation/object-method-type/output.json
new file mode 100644
index 000000000000..f71f3acee7df
--- /dev/null
+++ b/packages/babel-parser/test/fixtures/flow/this-annotation/object-method-type/output.json
@@ -0,0 +1,69 @@
+{
+  "type": "File",
+  "start":0,"end":42,"loc":{"start":{"line":1,"column":0},"end":{"line":3,"column":1}},
+  "program": {
+    "type": "Program",
+    "start":0,"end":42,"loc":{"start":{"line":1,"column":0},"end":{"line":3,"column":1}},
+    "sourceType": "module",
+    "interpreter": null,
+    "body": [
+      {
+        "type": "TypeAlias",
+        "start":0,"end":42,"loc":{"start":{"line":1,"column":0},"end":{"line":3,"column":1}},
+        "id": {
+          "type": "Identifier",
+          "start":5,"end":6,"loc":{"start":{"line":1,"column":5},"end":{"line":1,"column":6},"identifierName":"T"},
+          "name": "T"
+        },
+        "typeParameters": null,
+        "right": {
+          "type": "ObjectTypeAnnotation",
+          "start":9,"end":42,"loc":{"start":{"line":1,"column":9},"end":{"line":3,"column":1}},
+          "callProperties": [],
+          "properties": [
+            {
+              "type": "ObjectTypeProperty",
+              "start":15,"end":40,"loc":{"start":{"line":2,"column":4},"end":{"line":2,"column":29}},
+              "key": {
+                "type": "Identifier",
+                "start":15,"end":18,"loc":{"start":{"line":2,"column":4},"end":{"line":2,"column":7},"identifierName":"foo"},
+                "name": "foo"
+              },
+              "static": false,
+              "proto": false,
+              "kind": "init",
+              "method": true,
+              "value": {
+                "type": "FunctionTypeAnnotation",
+                "start":15,"end":40,"loc":{"start":{"line":2,"column":4},"end":{"line":2,"column":29}},
+                "params": [],
+                "rest": null,
+                "typeParameters": null,
+                "this": {
+                  "type": "FunctionTypeParam",
+                  "start":19,"end":32,"loc":{"start":{"line":2,"column":8},"end":{"line":2,"column":21}},
+                  "name": null,
+                  "optional": false,
+                  "typeAnnotation": {
+                    "type": "NumberTypeAnnotation",
+                    "start":26,"end":32,"loc":{"start":{"line":2,"column":15},"end":{"line":2,"column":21}}
+                  }
+                },
+                "returnType": {
+                  "type": "VoidTypeAnnotation",
+                  "start":36,"end":40,"loc":{"start":{"line":2,"column":25},"end":{"line":2,"column":29}}
+                }
+              },
+              "optional": false
+            }
+          ],
+          "indexers": [],
+          "internalSlots": [],
+          "exact": false,
+          "inexact": false
+        }
+      }
+    ],
+    "directives": []
+  }
+}
\ No newline at end of file
diff --git a/packages/babel-parser/test/fixtures/flow/this-annotation/object-type-constructor/input.js b/packages/babel-parser/test/fixtures/flow/this-annotation/object-type-constructor/input.js
new file mode 100644
index 000000000000..7993687854c8
--- /dev/null
+++ b/packages/babel-parser/test/fixtures/flow/this-annotation/object-type-constructor/input.js
@@ -0,0 +1,5 @@
+// @flow
+
+type T = {
+    constructor(this : number) : void
+}
diff --git a/packages/babel-parser/test/fixtures/flow/this-annotation/object-type-constructor/output.json b/packages/babel-parser/test/fixtures/flow/this-annotation/object-type-constructor/output.json
new file mode 100644
index 000000000000..8555aed34e47
--- /dev/null
+++ b/packages/babel-parser/test/fixtures/flow/this-annotation/object-type-constructor/output.json
@@ -0,0 +1,83 @@
+{
+  "type": "File",
+  "start":0,"end":60,"loc":{"start":{"line":1,"column":0},"end":{"line":5,"column":1}},
+  "program": {
+    "type": "Program",
+    "start":0,"end":60,"loc":{"start":{"line":1,"column":0},"end":{"line":5,"column":1}},
+    "sourceType": "module",
+    "interpreter": null,
+    "body": [
+      {
+        "type": "TypeAlias",
+        "start":10,"end":60,"loc":{"start":{"line":3,"column":0},"end":{"line":5,"column":1}},
+        "leadingComments": [
+          {
+            "type": "CommentLine",
+            "value": " @flow",
+            "start":0,"end":8,"loc":{"start":{"line":1,"column":0},"end":{"line":1,"column":8}}
+          }
+        ],
+        "id": {
+          "type": "Identifier",
+          "start":15,"end":16,"loc":{"start":{"line":3,"column":5},"end":{"line":3,"column":6},"identifierName":"T"},
+          "name": "T"
+        },
+        "typeParameters": null,
+        "right": {
+          "type": "ObjectTypeAnnotation",
+          "start":19,"end":60,"loc":{"start":{"line":3,"column":9},"end":{"line":5,"column":1}},
+          "callProperties": [],
+          "properties": [
+            {
+              "type": "ObjectTypeProperty",
+              "start":25,"end":58,"loc":{"start":{"line":4,"column":4},"end":{"line":4,"column":37}},
+              "key": {
+                "type": "Identifier",
+                "start":25,"end":36,"loc":{"start":{"line":4,"column":4},"end":{"line":4,"column":15},"identifierName":"constructor"},
+                "name": "constructor"
+              },
+              "static": false,
+              "proto": false,
+              "kind": "init",
+              "method": true,
+              "value": {
+                "type": "FunctionTypeAnnotation",
+                "start":25,"end":58,"loc":{"start":{"line":4,"column":4},"end":{"line":4,"column":37}},
+                "params": [],
+                "rest": null,
+                "typeParameters": null,
+                "this": {
+                  "type": "FunctionTypeParam",
+                  "start":37,"end":50,"loc":{"start":{"line":4,"column":16},"end":{"line":4,"column":29}},
+                  "name": null,
+                  "optional": false,
+                  "typeAnnotation": {
+                    "type": "NumberTypeAnnotation",
+                    "start":44,"end":50,"loc":{"start":{"line":4,"column":23},"end":{"line":4,"column":29}}
+                  }
+                },
+                "returnType": {
+                  "type": "VoidTypeAnnotation",
+                  "start":54,"end":58,"loc":{"start":{"line":4,"column":33},"end":{"line":4,"column":37}}
+                }
+              },
+              "optional": false
+            }
+          ],
+          "indexers": [],
+          "internalSlots": [],
+          "exact": false,
+          "inexact": false
+        }
+      }
+    ],
+    "directives": []
+  },
+  "comments": [
+    {
+      "type": "CommentLine",
+      "value": " @flow",
+      "start":0,"end":8,"loc":{"start":{"line":1,"column":0},"end":{"line":1,"column":8}}
+    }
+  ]
+}
\ No newline at end of file
diff --git a/packages/babel-parser/test/fixtures/flow/this-annotation/this-arrow-function/input.js b/packages/babel-parser/test/fixtures/flow/this-annotation/this-arrow-function/input.js
new file mode 100644
index 000000000000..cb37e78f7046
--- /dev/null
+++ b/packages/babel-parser/test/fixtures/flow/this-annotation/this-arrow-function/input.js
@@ -0,0 +1 @@
+let x = (this : number) => 0
diff --git a/packages/babel-parser/test/fixtures/flow/this-annotation/this-arrow-function/output.json b/packages/babel-parser/test/fixtures/flow/this-annotation/this-arrow-function/output.json
new file mode 100644
index 000000000000..954fd71984d6
--- /dev/null
+++ b/packages/babel-parser/test/fixtures/flow/this-annotation/this-arrow-function/output.json
@@ -0,0 +1,62 @@
+{
+  "type": "File",
+  "start":0,"end":28,"loc":{"start":{"line":1,"column":0},"end":{"line":1,"column":28}},
+  "errors": [
+    "SyntaxError: Binding invalid left-hand side in function parameter list (1:9)"
+  ],
+  "program": {
+    "type": "Program",
+    "start":0,"end":28,"loc":{"start":{"line":1,"column":0},"end":{"line":1,"column":28}},
+    "sourceType": "module",
+    "interpreter": null,
+    "body": [
+      {
+        "type": "VariableDeclaration",
+        "start":0,"end":28,"loc":{"start":{"line":1,"column":0},"end":{"line":1,"column":28}},
+        "declarations": [
+          {
+            "type": "VariableDeclarator",
+            "start":4,"end":28,"loc":{"start":{"line":1,"column":4},"end":{"line":1,"column":28}},
+            "id": {
+              "type": "Identifier",
+              "start":4,"end":5,"loc":{"start":{"line":1,"column":4},"end":{"line":1,"column":5},"identifierName":"x"},
+              "name": "x"
+            },
+            "init": {
+              "type": "ArrowFunctionExpression",
+              "start":8,"end":28,"loc":{"start":{"line":1,"column":8},"end":{"line":1,"column":28}},
+              "id": null,
+              "generator": false,
+              "async": false,
+              "params": [
+                {
+                  "type": "ThisExpression",
+                  "start":9,"end":22,"loc":{"start":{"line":1,"column":9},"end":{"line":1,"column":22}},
+                  "typeAnnotation": {
+                    "type": "TypeAnnotation",
+                    "start":14,"end":22,"loc":{"start":{"line":1,"column":14},"end":{"line":1,"column":22}},
+                    "typeAnnotation": {
+                      "type": "NumberTypeAnnotation",
+                      "start":16,"end":22,"loc":{"start":{"line":1,"column":16},"end":{"line":1,"column":22}}
+                    }
+                  }
+                }
+              ],
+              "body": {
+                "type": "NumericLiteral",
+                "start":27,"end":28,"loc":{"start":{"line":1,"column":27},"end":{"line":1,"column":28}},
+                "extra": {
+                  "rawValue": 0,
+                  "raw": "0"
+                },
+                "value": 0
+              }
+            }
+          }
+        ],
+        "kind": "let"
+      }
+    ],
+    "directives": []
+  }
+}
\ No newline at end of file
diff --git a/packages/babel-parser/test/fixtures/flow/this-annotation/this-constructor-declare/input.js b/packages/babel-parser/test/fixtures/flow/this-annotation/this-constructor-declare/input.js
new file mode 100644
index 000000000000..6e9a7ca40c96
--- /dev/null
+++ b/packages/babel-parser/test/fixtures/flow/this-annotation/this-constructor-declare/input.js
@@ -0,0 +1,3 @@
+declare class A {
+    constructor(this : number) : A;
+}
diff --git a/packages/babel-parser/test/fixtures/flow/this-annotation/this-constructor-declare/output.json b/packages/babel-parser/test/fixtures/flow/this-annotation/this-constructor-declare/output.json
new file mode 100644
index 000000000000..d3461e69afbc
--- /dev/null
+++ b/packages/babel-parser/test/fixtures/flow/this-annotation/this-constructor-declare/output.json
@@ -0,0 +1,80 @@
+{
+  "type": "File",
+  "start":0,"end":55,"loc":{"start":{"line":1,"column":0},"end":{"line":3,"column":1}},
+  "errors": [
+    "SyntaxError: Constructors cannot have a `this` parameter; constructors don't bind `this` like other functions. (2:16)"
+  ],
+  "program": {
+    "type": "Program",
+    "start":0,"end":55,"loc":{"start":{"line":1,"column":0},"end":{"line":3,"column":1}},
+    "sourceType": "module",
+    "interpreter": null,
+    "body": [
+      {
+        "type": "DeclareClass",
+        "start":0,"end":55,"loc":{"start":{"line":1,"column":0},"end":{"line":3,"column":1}},
+        "id": {
+          "type": "Identifier",
+          "start":14,"end":15,"loc":{"start":{"line":1,"column":14},"end":{"line":1,"column":15},"identifierName":"A"},
+          "name": "A"
+        },
+        "typeParameters": null,
+        "extends": [],
+        "implements": [],
+        "mixins": [],
+        "body": {
+          "type": "ObjectTypeAnnotation",
+          "start":16,"end":55,"loc":{"start":{"line":1,"column":16},"end":{"line":3,"column":1}},
+          "callProperties": [],
+          "properties": [
+            {
+              "type": "ObjectTypeProperty",
+              "start":22,"end":52,"loc":{"start":{"line":2,"column":4},"end":{"line":2,"column":34}},
+              "key": {
+                "type": "Identifier",
+                "start":22,"end":33,"loc":{"start":{"line":2,"column":4},"end":{"line":2,"column":15},"identifierName":"constructor"},
+                "name": "constructor"
+              },
+              "static": false,
+              "proto": false,
+              "kind": "init",
+              "method": true,
+              "value": {
+                "type": "FunctionTypeAnnotation",
+                "start":22,"end":52,"loc":{"start":{"line":2,"column":4},"end":{"line":2,"column":34}},
+                "params": [],
+                "rest": null,
+                "typeParameters": null,
+                "this": {
+                  "type": "FunctionTypeParam",
+                  "start":34,"end":47,"loc":{"start":{"line":2,"column":16},"end":{"line":2,"column":29}},
+                  "name": null,
+                  "optional": false,
+                  "typeAnnotation": {
+                    "type": "NumberTypeAnnotation",
+                    "start":41,"end":47,"loc":{"start":{"line":2,"column":23},"end":{"line":2,"column":29}}
+                  }
+                },
+                "returnType": {
+                  "type": "GenericTypeAnnotation",
+                  "start":51,"end":52,"loc":{"start":{"line":2,"column":33},"end":{"line":2,"column":34}},
+                  "typeParameters": null,
+                  "id": {
+                    "type": "Identifier",
+                    "start":51,"end":52,"loc":{"start":{"line":2,"column":33},"end":{"line":2,"column":34},"identifierName":"A"},
+                    "name": "A"
+                  }
+                }
+              },
+              "optional": false
+            }
+          ],
+          "indexers": [],
+          "internalSlots": [],
+          "exact": false
+        }
+      }
+    ],
+    "directives": []
+  }
+}
\ No newline at end of file
diff --git a/packages/babel-parser/test/fixtures/flow/this-annotation/this-constructor/input.js b/packages/babel-parser/test/fixtures/flow/this-annotation/this-constructor/input.js
new file mode 100644
index 000000000000..69517defe8d1
--- /dev/null
+++ b/packages/babel-parser/test/fixtures/flow/this-annotation/this-constructor/input.js
@@ -0,0 +1,3 @@
+class A {
+  constructor(this: string) {}
+}
diff --git a/packages/babel-parser/test/fixtures/flow/this-annotation/this-constructor/output.json b/packages/babel-parser/test/fixtures/flow/this-annotation/this-constructor/output.json
new file mode 100644
index 000000000000..3ed70ed007b6
--- /dev/null
+++ b/packages/babel-parser/test/fixtures/flow/this-annotation/this-constructor/output.json
@@ -0,0 +1,68 @@
+{
+  "type": "File",
+  "start":0,"end":42,"loc":{"start":{"line":1,"column":0},"end":{"line":3,"column":1}},
+  "errors": [
+    "SyntaxError: Constructors cannot have a `this` parameter; constructors don't bind `this` like other functions. (2:2)"
+  ],
+  "program": {
+    "type": "Program",
+    "start":0,"end":42,"loc":{"start":{"line":1,"column":0},"end":{"line":3,"column":1}},
+    "sourceType": "module",
+    "interpreter": null,
+    "body": [
+      {
+        "type": "ClassDeclaration",
+        "start":0,"end":42,"loc":{"start":{"line":1,"column":0},"end":{"line":3,"column":1}},
+        "id": {
+          "type": "Identifier",
+          "start":6,"end":7,"loc":{"start":{"line":1,"column":6},"end":{"line":1,"column":7},"identifierName":"A"},
+          "name": "A"
+        },
+        "superClass": null,
+        "body": {
+          "type": "ClassBody",
+          "start":8,"end":42,"loc":{"start":{"line":1,"column":8},"end":{"line":3,"column":1}},
+          "body": [
+            {
+              "type": "ClassMethod",
+              "start":12,"end":40,"loc":{"start":{"line":2,"column":2},"end":{"line":2,"column":30}},
+              "static": false,
+              "key": {
+                "type": "Identifier",
+                "start":12,"end":23,"loc":{"start":{"line":2,"column":2},"end":{"line":2,"column":13},"identifierName":"constructor"},
+                "name": "constructor"
+              },
+              "computed": false,
+              "kind": "constructor",
+              "id": null,
+              "generator": false,
+              "async": false,
+              "params": [
+                {
+                  "type": "Identifier",
+                  "start":24,"end":36,"loc":{"start":{"line":2,"column":14},"end":{"line":2,"column":26},"identifierName":"this"},
+                  "name": "this",
+                  "typeAnnotation": {
+                    "type": "TypeAnnotation",
+                    "start":28,"end":36,"loc":{"start":{"line":2,"column":18},"end":{"line":2,"column":26}},
+                    "typeAnnotation": {
+                      "type": "StringTypeAnnotation",
+                      "start":30,"end":36,"loc":{"start":{"line":2,"column":20},"end":{"line":2,"column":26}}
+                    }
+                  }
+                }
+              ],
+              "body": {
+                "type": "BlockStatement",
+                "start":38,"end":40,"loc":{"start":{"line":2,"column":28},"end":{"line":2,"column":30}},
+                "body": [],
+                "directives": []
+              }
+            }
+          ]
+        }
+      }
+    ],
+    "directives": []
+  }
+}
\ No newline at end of file
diff --git a/packages/babel-parser/test/fixtures/flow/this-annotation/this-getter-type/input.js b/packages/babel-parser/test/fixtures/flow/this-annotation/this-getter-type/input.js
new file mode 100644
index 000000000000..da0c98c60f2c
--- /dev/null
+++ b/packages/babel-parser/test/fixtures/flow/this-annotation/this-getter-type/input.js
@@ -0,0 +1,3 @@
+type T = {
+  get foo(this: string) : void
+}
diff --git a/packages/babel-parser/test/fixtures/flow/this-annotation/this-getter-type/output.json b/packages/babel-parser/test/fixtures/flow/this-annotation/this-getter-type/output.json
new file mode 100644
index 000000000000..1d448d6fd698
--- /dev/null
+++ b/packages/babel-parser/test/fixtures/flow/this-annotation/this-getter-type/output.json
@@ -0,0 +1,72 @@
+{
+  "type": "File",
+  "start":0,"end":43,"loc":{"start":{"line":1,"column":0},"end":{"line":3,"column":1}},
+  "errors": [
+    "SyntaxError: A getter cannot have a `this` parameter. (2:10)"
+  ],
+  "program": {
+    "type": "Program",
+    "start":0,"end":43,"loc":{"start":{"line":1,"column":0},"end":{"line":3,"column":1}},
+    "sourceType": "module",
+    "interpreter": null,
+    "body": [
+      {
+        "type": "TypeAlias",
+        "start":0,"end":43,"loc":{"start":{"line":1,"column":0},"end":{"line":3,"column":1}},
+        "id": {
+          "type": "Identifier",
+          "start":5,"end":6,"loc":{"start":{"line":1,"column":5},"end":{"line":1,"column":6},"identifierName":"T"},
+          "name": "T"
+        },
+        "typeParameters": null,
+        "right": {
+          "type": "ObjectTypeAnnotation",
+          "start":9,"end":43,"loc":{"start":{"line":1,"column":9},"end":{"line":3,"column":1}},
+          "callProperties": [],
+          "properties": [
+            {
+              "type": "ObjectTypeProperty",
+              "start":13,"end":41,"loc":{"start":{"line":2,"column":2},"end":{"line":2,"column":30}},
+              "key": {
+                "type": "Identifier",
+                "start":17,"end":20,"loc":{"start":{"line":2,"column":6},"end":{"line":2,"column":9},"identifierName":"foo"},
+                "name": "foo"
+              },
+              "static": false,
+              "proto": false,
+              "kind": "get",
+              "method": true,
+              "value": {
+                "type": "FunctionTypeAnnotation",
+                "start":13,"end":41,"loc":{"start":{"line":2,"column":2},"end":{"line":2,"column":30}},
+                "params": [],
+                "rest": null,
+                "typeParameters": null,
+                "this": {
+                  "type": "FunctionTypeParam",
+                  "start":21,"end":33,"loc":{"start":{"line":2,"column":10},"end":{"line":2,"column":22}},
+                  "name": null,
+                  "optional": false,
+                  "typeAnnotation": {
+                    "type": "StringTypeAnnotation",
+                    "start":27,"end":33,"loc":{"start":{"line":2,"column":16},"end":{"line":2,"column":22}}
+                  }
+                },
+                "returnType": {
+                  "type": "VoidTypeAnnotation",
+                  "start":37,"end":41,"loc":{"start":{"line":2,"column":26},"end":{"line":2,"column":30}}
+                }
+              },
+              "optional": false
+            }
+          ],
+          "indexers": [],
+          "internalSlots": [],
+          "exact": false,
+          "inexact": false
+        }
+      }
+    ],
+    "directives": []
+  }
+}
\ No newline at end of file
diff --git a/packages/babel-parser/test/fixtures/flow/this-annotation/this-getter/input.js b/packages/babel-parser/test/fixtures/flow/this-annotation/this-getter/input.js
new file mode 100644
index 000000000000..b822a1766aaa
--- /dev/null
+++ b/packages/babel-parser/test/fixtures/flow/this-annotation/this-getter/input.js
@@ -0,0 +1,3 @@
+class Foo {
+  get foo(this: string) {}
+}
diff --git a/packages/babel-parser/test/fixtures/flow/this-annotation/this-getter/output.json b/packages/babel-parser/test/fixtures/flow/this-annotation/this-getter/output.json
new file mode 100644
index 000000000000..320f898c90e4
--- /dev/null
+++ b/packages/babel-parser/test/fixtures/flow/this-annotation/this-getter/output.json
@@ -0,0 +1,69 @@
+{
+  "type": "File",
+  "start":0,"end":40,"loc":{"start":{"line":1,"column":0},"end":{"line":3,"column":1}},
+  "errors": [
+    "SyntaxError: getter must not have any formal parameters (2:2)",
+    "SyntaxError: A getter cannot have a `this` parameter. (2:10)"
+  ],
+  "program": {
+    "type": "Program",
+    "start":0,"end":40,"loc":{"start":{"line":1,"column":0},"end":{"line":3,"column":1}},
+    "sourceType": "module",
+    "interpreter": null,
+    "body": [
+      {
+        "type": "ClassDeclaration",
+        "start":0,"end":40,"loc":{"start":{"line":1,"column":0},"end":{"line":3,"column":1}},
+        "id": {
+          "type": "Identifier",
+          "start":6,"end":9,"loc":{"start":{"line":1,"column":6},"end":{"line":1,"column":9},"identifierName":"Foo"},
+          "name": "Foo"
+        },
+        "superClass": null,
+        "body": {
+          "type": "ClassBody",
+          "start":10,"end":40,"loc":{"start":{"line":1,"column":10},"end":{"line":3,"column":1}},
+          "body": [
+            {
+              "type": "ClassMethod",
+              "start":14,"end":38,"loc":{"start":{"line":2,"column":2},"end":{"line":2,"column":26}},
+              "static": false,
+              "key": {
+                "type": "Identifier",
+                "start":18,"end":21,"loc":{"start":{"line":2,"column":6},"end":{"line":2,"column":9},"identifierName":"foo"},
+                "name": "foo"
+              },
+              "computed": false,
+              "kind": "get",
+              "id": null,
+              "generator": false,
+              "async": false,
+              "params": [
+                {
+                  "type": "Identifier",
+                  "start":22,"end":34,"loc":{"start":{"line":2,"column":10},"end":{"line":2,"column":22},"identifierName":"this"},
+                  "name": "this",
+                  "typeAnnotation": {
+                    "type": "TypeAnnotation",
+                    "start":26,"end":34,"loc":{"start":{"line":2,"column":14},"end":{"line":2,"column":22}},
+                    "typeAnnotation": {
+                      "type": "StringTypeAnnotation",
+                      "start":28,"end":34,"loc":{"start":{"line":2,"column":16},"end":{"line":2,"column":22}}
+                    }
+                  }
+                }
+              ],
+              "body": {
+                "type": "BlockStatement",
+                "start":36,"end":38,"loc":{"start":{"line":2,"column":24},"end":{"line":2,"column":26}},
+                "body": [],
+                "directives": []
+              }
+            }
+          ]
+        }
+      }
+    ],
+    "directives": []
+  }
+}
\ No newline at end of file
diff --git a/packages/babel-parser/test/fixtures/flow/this-annotation/this-no-annot/input.js b/packages/babel-parser/test/fixtures/flow/this-annotation/this-no-annot/input.js
new file mode 100644
index 000000000000..270cd80bc8b2
--- /dev/null
+++ b/packages/babel-parser/test/fixtures/flow/this-annotation/this-no-annot/input.js
@@ -0,0 +1 @@
+function foo (this) {}
diff --git a/packages/babel-parser/test/fixtures/flow/this-annotation/this-no-annot/output.json b/packages/babel-parser/test/fixtures/flow/this-annotation/this-no-annot/output.json
new file mode 100644
index 000000000000..dbbbe1ef2f31
--- /dev/null
+++ b/packages/babel-parser/test/fixtures/flow/this-annotation/this-no-annot/output.json
@@ -0,0 +1,40 @@
+{
+  "type": "File",
+  "start":0,"end":22,"loc":{"start":{"line":1,"column":0},"end":{"line":1,"column":22}},
+  "errors": [
+    "SyntaxError: A type annotation is required for the `this` parameter. (1:14)"
+  ],
+  "program": {
+    "type": "Program",
+    "start":0,"end":22,"loc":{"start":{"line":1,"column":0},"end":{"line":1,"column":22}},
+    "sourceType": "module",
+    "interpreter": null,
+    "body": [
+      {
+        "type": "FunctionDeclaration",
+        "start":0,"end":22,"loc":{"start":{"line":1,"column":0},"end":{"line":1,"column":22}},
+        "id": {
+          "type": "Identifier",
+          "start":9,"end":12,"loc":{"start":{"line":1,"column":9},"end":{"line":1,"column":12},"identifierName":"foo"},
+          "name": "foo"
+        },
+        "generator": false,
+        "async": false,
+        "params": [
+          {
+            "type": "Identifier",
+            "start":14,"end":18,"loc":{"start":{"line":1,"column":14},"end":{"line":1,"column":18},"identifierName":"this"},
+            "name": "this"
+          }
+        ],
+        "body": {
+          "type": "BlockStatement",
+          "start":20,"end":22,"loc":{"start":{"line":1,"column":20},"end":{"line":1,"column":22}},
+          "body": [],
+          "directives": []
+        }
+      }
+    ],
+    "directives": []
+  }
+}
\ No newline at end of file
diff --git a/packages/babel-parser/test/fixtures/flow/this-annotation/this-not-first-type/input.js b/packages/babel-parser/test/fixtures/flow/this-annotation/this-not-first-type/input.js
new file mode 100644
index 000000000000..09ab5a69ee04
--- /dev/null
+++ b/packages/babel-parser/test/fixtures/flow/this-annotation/this-not-first-type/input.js
@@ -0,0 +1 @@
+type T = (a : string, this : number) => void
diff --git a/packages/babel-parser/test/fixtures/flow/this-annotation/this-not-first-type/output.json b/packages/babel-parser/test/fixtures/flow/this-annotation/this-not-first-type/output.json
new file mode 100644
index 000000000000..e903a001115c
--- /dev/null
+++ b/packages/babel-parser/test/fixtures/flow/this-annotation/this-not-first-type/output.json
@@ -0,0 +1,67 @@
+{
+  "type": "File",
+  "start":0,"end":44,"loc":{"start":{"line":1,"column":0},"end":{"line":1,"column":44}},
+  "errors": [
+    "SyntaxError: The `this` parameter must be the first function parameter. (1:22)"
+  ],
+  "program": {
+    "type": "Program",
+    "start":0,"end":44,"loc":{"start":{"line":1,"column":0},"end":{"line":1,"column":44}},
+    "sourceType": "module",
+    "interpreter": null,
+    "body": [
+      {
+        "type": "TypeAlias",
+        "start":0,"end":44,"loc":{"start":{"line":1,"column":0},"end":{"line":1,"column":44}},
+        "id": {
+          "type": "Identifier",
+          "start":5,"end":6,"loc":{"start":{"line":1,"column":5},"end":{"line":1,"column":6},"identifierName":"T"},
+          "name": "T"
+        },
+        "typeParameters": null,
+        "right": {
+          "type": "FunctionTypeAnnotation",
+          "start":9,"end":44,"loc":{"start":{"line":1,"column":9},"end":{"line":1,"column":44}},
+          "params": [
+            {
+              "type": "FunctionTypeParam",
+              "start":10,"end":20,"loc":{"start":{"line":1,"column":10},"end":{"line":1,"column":20}},
+              "name": {
+                "type": "Identifier",
+                "start":10,"end":11,"loc":{"start":{"line":1,"column":10},"end":{"line":1,"column":11},"identifierName":"a"},
+                "name": "a"
+              },
+              "optional": false,
+              "typeAnnotation": {
+                "type": "StringTypeAnnotation",
+                "start":14,"end":20,"loc":{"start":{"line":1,"column":14},"end":{"line":1,"column":20}}
+              }
+            },
+            {
+              "type": "FunctionTypeParam",
+              "start":22,"end":35,"loc":{"start":{"line":1,"column":22},"end":{"line":1,"column":35}},
+              "name": {
+                "type": "Identifier",
+                "start":22,"end":26,"loc":{"start":{"line":1,"column":22},"end":{"line":1,"column":26},"identifierName":"this"},
+                "name": "this"
+              },
+              "optional": false,
+              "typeAnnotation": {
+                "type": "NumberTypeAnnotation",
+                "start":29,"end":35,"loc":{"start":{"line":1,"column":29},"end":{"line":1,"column":35}}
+              }
+            }
+          ],
+          "rest": null,
+          "this": null,
+          "returnType": {
+            "type": "VoidTypeAnnotation",
+            "start":40,"end":44,"loc":{"start":{"line":1,"column":40},"end":{"line":1,"column":44}}
+          },
+          "typeParameters": null
+        }
+      }
+    ],
+    "directives": []
+  }
+}
\ No newline at end of file
diff --git a/packages/babel-parser/test/fixtures/flow/this-annotation/this-not-first/input.js b/packages/babel-parser/test/fixtures/flow/this-annotation/this-not-first/input.js
new file mode 100644
index 000000000000..69e929f34f1f
--- /dev/null
+++ b/packages/babel-parser/test/fixtures/flow/this-annotation/this-not-first/input.js
@@ -0,0 +1 @@
+function foo (a : string, this : number) {}
diff --git a/packages/babel-parser/test/fixtures/flow/this-annotation/this-not-first/output.json b/packages/babel-parser/test/fixtures/flow/this-annotation/this-not-first/output.json
new file mode 100644
index 000000000000..02b00d783712
--- /dev/null
+++ b/packages/babel-parser/test/fixtures/flow/this-annotation/this-not-first/output.json
@@ -0,0 +1,61 @@
+{
+  "type": "File",
+  "start":0,"end":43,"loc":{"start":{"line":1,"column":0},"end":{"line":1,"column":43}},
+  "errors": [
+    "SyntaxError: The `this` parameter must be the first function parameter. (1:26)"
+  ],
+  "program": {
+    "type": "Program",
+    "start":0,"end":43,"loc":{"start":{"line":1,"column":0},"end":{"line":1,"column":43}},
+    "sourceType": "module",
+    "interpreter": null,
+    "body": [
+      {
+        "type": "FunctionDeclaration",
+        "start":0,"end":43,"loc":{"start":{"line":1,"column":0},"end":{"line":1,"column":43}},
+        "id": {
+          "type": "Identifier",
+          "start":9,"end":12,"loc":{"start":{"line":1,"column":9},"end":{"line":1,"column":12},"identifierName":"foo"},
+          "name": "foo"
+        },
+        "generator": false,
+        "async": false,
+        "params": [
+          {
+            "type": "Identifier",
+            "start":14,"end":24,"loc":{"start":{"line":1,"column":14},"end":{"line":1,"column":24},"identifierName":"a"},
+            "name": "a",
+            "typeAnnotation": {
+              "type": "TypeAnnotation",
+              "start":16,"end":24,"loc":{"start":{"line":1,"column":16},"end":{"line":1,"column":24}},
+              "typeAnnotation": {
+                "type": "StringTypeAnnotation",
+                "start":18,"end":24,"loc":{"start":{"line":1,"column":18},"end":{"line":1,"column":24}}
+              }
+            }
+          },
+          {
+            "type": "Identifier",
+            "start":26,"end":39,"loc":{"start":{"line":1,"column":26},"end":{"line":1,"column":39},"identifierName":"this"},
+            "name": "this",
+            "typeAnnotation": {
+              "type": "TypeAnnotation",
+              "start":31,"end":39,"loc":{"start":{"line":1,"column":31},"end":{"line":1,"column":39}},
+              "typeAnnotation": {
+                "type": "NumberTypeAnnotation",
+                "start":33,"end":39,"loc":{"start":{"line":1,"column":33},"end":{"line":1,"column":39}}
+              }
+            }
+          }
+        ],
+        "body": {
+          "type": "BlockStatement",
+          "start":41,"end":43,"loc":{"start":{"line":1,"column":41},"end":{"line":1,"column":43}},
+          "body": [],
+          "directives": []
+        }
+      }
+    ],
+    "directives": []
+  }
+}
\ No newline at end of file
diff --git a/packages/babel-parser/test/fixtures/flow/this-annotation/this-optional-type/input.js b/packages/babel-parser/test/fixtures/flow/this-annotation/this-optional-type/input.js
new file mode 100644
index 000000000000..0c28bd181dc2
--- /dev/null
+++ b/packages/babel-parser/test/fixtures/flow/this-annotation/this-optional-type/input.js
@@ -0,0 +1 @@
+type T = (this? : number) => void
diff --git a/packages/babel-parser/test/fixtures/flow/this-annotation/this-optional-type/output.json b/packages/babel-parser/test/fixtures/flow/this-annotation/this-optional-type/output.json
new file mode 100644
index 000000000000..6e19b60a59cb
--- /dev/null
+++ b/packages/babel-parser/test/fixtures/flow/this-annotation/this-optional-type/output.json
@@ -0,0 +1,47 @@
+{
+  "type": "File",
+  "start":0,"end":33,"loc":{"start":{"line":1,"column":0},"end":{"line":1,"column":33}},
+  "errors": [
+    "SyntaxError: The `this` parameter cannot be optional. (1:10)"
+  ],
+  "program": {
+    "type": "Program",
+    "start":0,"end":33,"loc":{"start":{"line":1,"column":0},"end":{"line":1,"column":33}},
+    "sourceType": "module",
+    "interpreter": null,
+    "body": [
+      {
+        "type": "TypeAlias",
+        "start":0,"end":33,"loc":{"start":{"line":1,"column":0},"end":{"line":1,"column":33}},
+        "id": {
+          "type": "Identifier",
+          "start":5,"end":6,"loc":{"start":{"line":1,"column":5},"end":{"line":1,"column":6},"identifierName":"T"},
+          "name": "T"
+        },
+        "typeParameters": null,
+        "right": {
+          "type": "FunctionTypeAnnotation",
+          "start":9,"end":33,"loc":{"start":{"line":1,"column":9},"end":{"line":1,"column":33}},
+          "params": [],
+          "rest": null,
+          "this": {
+            "type": "FunctionTypeParam",
+            "start":10,"end":24,"loc":{"start":{"line":1,"column":10},"end":{"line":1,"column":24}},
+            "name": null,
+            "optional": true,
+            "typeAnnotation": {
+              "type": "NumberTypeAnnotation",
+              "start":18,"end":24,"loc":{"start":{"line":1,"column":18},"end":{"line":1,"column":24}}
+            }
+          },
+          "returnType": {
+            "type": "VoidTypeAnnotation",
+            "start":29,"end":33,"loc":{"start":{"line":1,"column":29},"end":{"line":1,"column":33}}
+          },
+          "typeParameters": null
+        }
+      }
+    ],
+    "directives": []
+  }
+}
\ No newline at end of file
diff --git a/packages/babel-parser/test/fixtures/flow/this-annotation/this-optional/input.js b/packages/babel-parser/test/fixtures/flow/this-annotation/this-optional/input.js
new file mode 100644
index 000000000000..4b5c4782dff2
--- /dev/null
+++ b/packages/babel-parser/test/fixtures/flow/this-annotation/this-optional/input.js
@@ -0,0 +1 @@
+function foo(this? : number) {}
diff --git a/packages/babel-parser/test/fixtures/flow/this-annotation/this-optional/output.json b/packages/babel-parser/test/fixtures/flow/this-annotation/this-optional/output.json
new file mode 100644
index 000000000000..33bd48751feb
--- /dev/null
+++ b/packages/babel-parser/test/fixtures/flow/this-annotation/this-optional/output.json
@@ -0,0 +1,49 @@
+{
+  "type": "File",
+  "start":0,"end":31,"loc":{"start":{"line":1,"column":0},"end":{"line":1,"column":31}},
+  "errors": [
+    "SyntaxError: The `this` parameter cannot be optional. (1:13)"
+  ],
+  "program": {
+    "type": "Program",
+    "start":0,"end":31,"loc":{"start":{"line":1,"column":0},"end":{"line":1,"column":31}},
+    "sourceType": "module",
+    "interpreter": null,
+    "body": [
+      {
+        "type": "FunctionDeclaration",
+        "start":0,"end":31,"loc":{"start":{"line":1,"column":0},"end":{"line":1,"column":31}},
+        "id": {
+          "type": "Identifier",
+          "start":9,"end":12,"loc":{"start":{"line":1,"column":9},"end":{"line":1,"column":12},"identifierName":"foo"},
+          "name": "foo"
+        },
+        "generator": false,
+        "async": false,
+        "params": [
+          {
+            "type": "Identifier",
+            "start":13,"end":27,"loc":{"start":{"line":1,"column":13},"end":{"line":1,"column":27},"identifierName":"this"},
+            "name": "this",
+            "optional": true,
+            "typeAnnotation": {
+              "type": "TypeAnnotation",
+              "start":19,"end":27,"loc":{"start":{"line":1,"column":19},"end":{"line":1,"column":27}},
+              "typeAnnotation": {
+                "type": "NumberTypeAnnotation",
+                "start":21,"end":27,"loc":{"start":{"line":1,"column":21},"end":{"line":1,"column":27}}
+              }
+            }
+          }
+        ],
+        "body": {
+          "type": "BlockStatement",
+          "start":29,"end":31,"loc":{"start":{"line":1,"column":29},"end":{"line":1,"column":31}},
+          "body": [],
+          "directives": []
+        }
+      }
+    ],
+    "directives": []
+  }
+}
\ No newline at end of file
diff --git a/packages/babel-parser/test/fixtures/flow/this-annotation/this-setter-type/input.js b/packages/babel-parser/test/fixtures/flow/this-annotation/this-setter-type/input.js
new file mode 100644
index 000000000000..a1f5eeb702d5
--- /dev/null
+++ b/packages/babel-parser/test/fixtures/flow/this-annotation/this-setter-type/input.js
@@ -0,0 +1,3 @@
+type T = {
+  set foo(this: string) : void
+}
diff --git a/packages/babel-parser/test/fixtures/flow/this-annotation/this-setter-type/output.json b/packages/babel-parser/test/fixtures/flow/this-annotation/this-setter-type/output.json
new file mode 100644
index 000000000000..06408c4054a1
--- /dev/null
+++ b/packages/babel-parser/test/fixtures/flow/this-annotation/this-setter-type/output.json
@@ -0,0 +1,73 @@
+{
+  "type": "File",
+  "start":0,"end":43,"loc":{"start":{"line":1,"column":0},"end":{"line":3,"column":1}},
+  "errors": [
+    "SyntaxError: A setter cannot have a `this` parameter. (2:10)",
+    "SyntaxError: setter must have exactly one formal parameter (2:2)"
+  ],
+  "program": {
+    "type": "Program",
+    "start":0,"end":43,"loc":{"start":{"line":1,"column":0},"end":{"line":3,"column":1}},
+    "sourceType": "module",
+    "interpreter": null,
+    "body": [
+      {
+        "type": "TypeAlias",
+        "start":0,"end":43,"loc":{"start":{"line":1,"column":0},"end":{"line":3,"column":1}},
+        "id": {
+          "type": "Identifier",
+          "start":5,"end":6,"loc":{"start":{"line":1,"column":5},"end":{"line":1,"column":6},"identifierName":"T"},
+          "name": "T"
+        },
+        "typeParameters": null,
+        "right": {
+          "type": "ObjectTypeAnnotation",
+          "start":9,"end":43,"loc":{"start":{"line":1,"column":9},"end":{"line":3,"column":1}},
+          "callProperties": [],
+          "properties": [
+            {
+              "type": "ObjectTypeProperty",
+              "start":13,"end":41,"loc":{"start":{"line":2,"column":2},"end":{"line":2,"column":30}},
+              "key": {
+                "type": "Identifier",
+                "start":17,"end":20,"loc":{"start":{"line":2,"column":6},"end":{"line":2,"column":9},"identifierName":"foo"},
+                "name": "foo"
+              },
+              "static": false,
+              "proto": false,
+              "kind": "set",
+              "method": true,
+              "value": {
+                "type": "FunctionTypeAnnotation",
+                "start":13,"end":41,"loc":{"start":{"line":2,"column":2},"end":{"line":2,"column":30}},
+                "params": [],
+                "rest": null,
+                "typeParameters": null,
+                "this": {
+                  "type": "FunctionTypeParam",
+                  "start":21,"end":33,"loc":{"start":{"line":2,"column":10},"end":{"line":2,"column":22}},
+                  "name": null,
+                  "optional": false,
+                  "typeAnnotation": {
+                    "type": "StringTypeAnnotation",
+                    "start":27,"end":33,"loc":{"start":{"line":2,"column":16},"end":{"line":2,"column":22}}
+                  }
+                },
+                "returnType": {
+                  "type": "VoidTypeAnnotation",
+                  "start":37,"end":41,"loc":{"start":{"line":2,"column":26},"end":{"line":2,"column":30}}
+                }
+              },
+              "optional": false
+            }
+          ],
+          "indexers": [],
+          "internalSlots": [],
+          "exact": false,
+          "inexact": false
+        }
+      }
+    ],
+    "directives": []
+  }
+}
\ No newline at end of file
diff --git a/packages/babel-parser/test/fixtures/flow/this-annotation/this-setter/input.js b/packages/babel-parser/test/fixtures/flow/this-annotation/this-setter/input.js
new file mode 100644
index 000000000000..4bada6fc7903
--- /dev/null
+++ b/packages/babel-parser/test/fixtures/flow/this-annotation/this-setter/input.js
@@ -0,0 +1,3 @@
+class Foo {
+  set foo(this: string) {}
+}
diff --git a/packages/babel-parser/test/fixtures/flow/this-annotation/this-setter/output.json b/packages/babel-parser/test/fixtures/flow/this-annotation/this-setter/output.json
new file mode 100644
index 000000000000..b71169d3ea5d
--- /dev/null
+++ b/packages/babel-parser/test/fixtures/flow/this-annotation/this-setter/output.json
@@ -0,0 +1,68 @@
+{
+  "type": "File",
+  "start":0,"end":40,"loc":{"start":{"line":1,"column":0},"end":{"line":3,"column":1}},
+  "errors": [
+    "SyntaxError: A setter cannot have a `this` parameter. (2:10)"
+  ],
+  "program": {
+    "type": "Program",
+    "start":0,"end":40,"loc":{"start":{"line":1,"column":0},"end":{"line":3,"column":1}},
+    "sourceType": "module",
+    "interpreter": null,
+    "body": [
+      {
+        "type": "ClassDeclaration",
+        "start":0,"end":40,"loc":{"start":{"line":1,"column":0},"end":{"line":3,"column":1}},
+        "id": {
+          "type": "Identifier",
+          "start":6,"end":9,"loc":{"start":{"line":1,"column":6},"end":{"line":1,"column":9},"identifierName":"Foo"},
+          "name": "Foo"
+        },
+        "superClass": null,
+        "body": {
+          "type": "ClassBody",
+          "start":10,"end":40,"loc":{"start":{"line":1,"column":10},"end":{"line":3,"column":1}},
+          "body": [
+            {
+              "type": "ClassMethod",
+              "start":14,"end":38,"loc":{"start":{"line":2,"column":2},"end":{"line":2,"column":26}},
+              "static": false,
+              "key": {
+                "type": "Identifier",
+                "start":18,"end":21,"loc":{"start":{"line":2,"column":6},"end":{"line":2,"column":9},"identifierName":"foo"},
+                "name": "foo"
+              },
+              "computed": false,
+              "kind": "set",
+              "id": null,
+              "generator": false,
+              "async": false,
+              "params": [
+                {
+                  "type": "Identifier",
+                  "start":22,"end":34,"loc":{"start":{"line":2,"column":10},"end":{"line":2,"column":22},"identifierName":"this"},
+                  "name": "this",
+                  "typeAnnotation": {
+                    "type": "TypeAnnotation",
+                    "start":26,"end":34,"loc":{"start":{"line":2,"column":14},"end":{"line":2,"column":22}},
+                    "typeAnnotation": {
+                      "type": "StringTypeAnnotation",
+                      "start":28,"end":34,"loc":{"start":{"line":2,"column":16},"end":{"line":2,"column":22}}
+                    }
+                  }
+                }
+              ],
+              "body": {
+                "type": "BlockStatement",
+                "start":36,"end":38,"loc":{"start":{"line":2,"column":24},"end":{"line":2,"column":26}},
+                "body": [],
+                "directives": []
+              }
+            }
+          ]
+        }
+      }
+    ],
+    "directives": []
+  }
+}
\ No newline at end of file
diff --git a/packages/babel-parser/test/fixtures/flow/this-annotation/this-string-literal-constructor/input.js b/packages/babel-parser/test/fixtures/flow/this-annotation/this-string-literal-constructor/input.js
new file mode 100644
index 000000000000..5d2c3936713b
--- /dev/null
+++ b/packages/babel-parser/test/fixtures/flow/this-annotation/this-string-literal-constructor/input.js
@@ -0,0 +1,3 @@
+class A {
+  "constructor"(this: string) {}
+}
diff --git a/packages/babel-parser/test/fixtures/flow/this-annotation/this-string-literal-constructor/output.json b/packages/babel-parser/test/fixtures/flow/this-annotation/this-string-literal-constructor/output.json
new file mode 100644
index 000000000000..c9c0891bdef7
--- /dev/null
+++ b/packages/babel-parser/test/fixtures/flow/this-annotation/this-string-literal-constructor/output.json
@@ -0,0 +1,72 @@
+{
+  "type": "File",
+  "start":0,"end":44,"loc":{"start":{"line":1,"column":0},"end":{"line":3,"column":1}},
+  "errors": [
+    "SyntaxError: Constructors cannot have a `this` parameter; constructors don't bind `this` like other functions. (2:2)"
+  ],
+  "program": {
+    "type": "Program",
+    "start":0,"end":44,"loc":{"start":{"line":1,"column":0},"end":{"line":3,"column":1}},
+    "sourceType": "module",
+    "interpreter": null,
+    "body": [
+      {
+        "type": "ClassDeclaration",
+        "start":0,"end":44,"loc":{"start":{"line":1,"column":0},"end":{"line":3,"column":1}},
+        "id": {
+          "type": "Identifier",
+          "start":6,"end":7,"loc":{"start":{"line":1,"column":6},"end":{"line":1,"column":7},"identifierName":"A"},
+          "name": "A"
+        },
+        "superClass": null,
+        "body": {
+          "type": "ClassBody",
+          "start":8,"end":44,"loc":{"start":{"line":1,"column":8},"end":{"line":3,"column":1}},
+          "body": [
+            {
+              "type": "ClassMethod",
+              "start":12,"end":42,"loc":{"start":{"line":2,"column":2},"end":{"line":2,"column":32}},
+              "static": false,
+              "key": {
+                "type": "StringLiteral",
+                "start":12,"end":25,"loc":{"start":{"line":2,"column":2},"end":{"line":2,"column":15}},
+                "extra": {
+                  "rawValue": "constructor",
+                  "raw": "\"constructor\""
+                },
+                "value": "constructor"
+              },
+              "computed": false,
+              "kind": "constructor",
+              "id": null,
+              "generator": false,
+              "async": false,
+              "params": [
+                {
+                  "type": "Identifier",
+                  "start":26,"end":38,"loc":{"start":{"line":2,"column":16},"end":{"line":2,"column":28},"identifierName":"this"},
+                  "name": "this",
+                  "typeAnnotation": {
+                    "type": "TypeAnnotation",
+                    "start":30,"end":38,"loc":{"start":{"line":2,"column":20},"end":{"line":2,"column":28}},
+                    "typeAnnotation": {
+                      "type": "StringTypeAnnotation",
+                      "start":32,"end":38,"loc":{"start":{"line":2,"column":22},"end":{"line":2,"column":28}}
+                    }
+                  }
+                }
+              ],
+              "body": {
+                "type": "BlockStatement",
+                "start":40,"end":42,"loc":{"start":{"line":2,"column":30},"end":{"line":2,"column":32}},
+                "body": [],
+                "directives": []
+              }
+            }
+          ]
+        }
+      }
+    ],
+    "directives": []
+  }
+}
\ No newline at end of file
diff --git a/packages/babel-parser/test/fixtures/flow/this-annotation/this-type/input.js b/packages/babel-parser/test/fixtures/flow/this-annotation/this-type/input.js
new file mode 100644
index 000000000000..f472d1c0182f
--- /dev/null
+++ b/packages/babel-parser/test/fixtures/flow/this-annotation/this-type/input.js
@@ -0,0 +1,5 @@
+type T = (this, number) => void;
+
+declare class A {
+  fn(this, number): void;
+}
diff --git a/packages/babel-parser/test/fixtures/flow/this-annotation/this-type/output.json b/packages/babel-parser/test/fixtures/flow/this-annotation/this-type/output.json
new file mode 100644
index 000000000000..6e7b440816db
--- /dev/null
+++ b/packages/babel-parser/test/fixtures/flow/this-annotation/this-type/output.json
@@ -0,0 +1,125 @@
+{
+  "type": "File",
+  "start":0,"end":79,"loc":{"start":{"line":1,"column":0},"end":{"line":5,"column":1}},
+  "program": {
+    "type": "Program",
+    "start":0,"end":79,"loc":{"start":{"line":1,"column":0},"end":{"line":5,"column":1}},
+    "sourceType": "module",
+    "interpreter": null,
+    "body": [
+      {
+        "type": "TypeAlias",
+        "start":0,"end":32,"loc":{"start":{"line":1,"column":0},"end":{"line":1,"column":32}},
+        "id": {
+          "type": "Identifier",
+          "start":5,"end":6,"loc":{"start":{"line":1,"column":5},"end":{"line":1,"column":6},"identifierName":"T"},
+          "name": "T"
+        },
+        "typeParameters": null,
+        "right": {
+          "type": "FunctionTypeAnnotation",
+          "start":9,"end":31,"loc":{"start":{"line":1,"column":9},"end":{"line":1,"column":31}},
+          "params": [
+            {
+              "type": "FunctionTypeParam",
+              "start":10,"end":15,"loc":{"start":{"line":1,"column":10},"end":{"line":1,"column":15}},
+              "name": null,
+              "optional": false,
+              "typeAnnotation": {
+                "type": "ThisTypeAnnotation",
+                "start":10,"end":14,"loc":{"start":{"line":1,"column":10},"end":{"line":1,"column":14}}
+              }
+            },
+            {
+              "type": "FunctionTypeParam",
+              "start":16,"end":22,"loc":{"start":{"line":1,"column":16},"end":{"line":1,"column":22}},
+              "name": null,
+              "optional": false,
+              "typeAnnotation": {
+                "type": "NumberTypeAnnotation",
+                "start":16,"end":22,"loc":{"start":{"line":1,"column":16},"end":{"line":1,"column":22}}
+              }
+            }
+          ],
+          "rest": null,
+          "this": null,
+          "returnType": {
+            "type": "VoidTypeAnnotation",
+            "start":27,"end":31,"loc":{"start":{"line":1,"column":27},"end":{"line":1,"column":31}}
+          },
+          "typeParameters": null
+        }
+      },
+      {
+        "type": "DeclareClass",
+        "start":34,"end":79,"loc":{"start":{"line":3,"column":0},"end":{"line":5,"column":1}},
+        "id": {
+          "type": "Identifier",
+          "start":48,"end":49,"loc":{"start":{"line":3,"column":14},"end":{"line":3,"column":15},"identifierName":"A"},
+          "name": "A"
+        },
+        "typeParameters": null,
+        "extends": [],
+        "implements": [],
+        "mixins": [],
+        "body": {
+          "type": "ObjectTypeAnnotation",
+          "start":50,"end":79,"loc":{"start":{"line":3,"column":16},"end":{"line":5,"column":1}},
+          "callProperties": [],
+          "properties": [
+            {
+              "type": "ObjectTypeProperty",
+              "start":54,"end":76,"loc":{"start":{"line":4,"column":2},"end":{"line":4,"column":24}},
+              "key": {
+                "type": "Identifier",
+                "start":54,"end":56,"loc":{"start":{"line":4,"column":2},"end":{"line":4,"column":4},"identifierName":"fn"},
+                "name": "fn"
+              },
+              "static": false,
+              "proto": false,
+              "kind": "init",
+              "method": true,
+              "value": {
+                "type": "FunctionTypeAnnotation",
+                "start":54,"end":76,"loc":{"start":{"line":4,"column":2},"end":{"line":4,"column":24}},
+                "params": [
+                  {
+                    "type": "FunctionTypeParam",
+                    "start":63,"end":69,"loc":{"start":{"line":4,"column":11},"end":{"line":4,"column":17}},
+                    "name": null,
+                    "optional": false,
+                    "typeAnnotation": {
+                      "type": "NumberTypeAnnotation",
+                      "start":63,"end":69,"loc":{"start":{"line":4,"column":11},"end":{"line":4,"column":17}}
+                    }
+                  }
+                ],
+                "rest": null,
+                "typeParameters": null,
+                "this": {
+                  "type": "FunctionTypeParam",
+                  "start":57,"end":61,"loc":{"start":{"line":4,"column":5},"end":{"line":4,"column":9}},
+                  "name": null,
+                  "optional": false,
+                  "typeAnnotation": {
+                    "type": "ThisTypeAnnotation",
+                    "start":57,"end":61,"loc":{"start":{"line":4,"column":5},"end":{"line":4,"column":9}}
+                  }
+                },
+                "returnType": {
+                  "type": "VoidTypeAnnotation",
+                  "start":72,"end":76,"loc":{"start":{"line":4,"column":20},"end":{"line":4,"column":24}}
+                }
+              },
+              "optional": false
+            }
+          ],
+          "indexers": [],
+          "internalSlots": [],
+          "exact": false
+        }
+      }
+    ],
+    "directives": []
+  }
+}
\ No newline at end of file
diff --git a/packages/babel-parser/test/fixtures/flow/type-alias/4/output.json b/packages/babel-parser/test/fixtures/flow/type-alias/4/output.json
index 8592d1737fed..228f9b9abfc3 100644
--- a/packages/babel-parser/test/fixtures/flow/type-alias/4/output.json
+++ b/packages/babel-parser/test/fixtures/flow/type-alias/4/output.json
@@ -126,6 +126,7 @@
                 }
               ],
               "rest": null,
+              "this": null,
               "returnType": {
                 "type": "NumberTypeAnnotation",
                 "start":83,"end":89,"loc":{"start":{"line":7,"column":20},"end":{"line":7,"column":26}}
@@ -152,6 +153,7 @@
                 }
               ],
               "rest": null,
+              "this": null,
               "returnType": {
                 "type": "StringTypeAnnotation",
                 "start":111,"end":117,"loc":{"start":{"line":8,"column":20},"end":{"line":8,"column":26}}
diff --git a/packages/babel-parser/test/fixtures/flow/type-annotations/10/output.json b/packages/babel-parser/test/fixtures/flow/type-annotations/10/output.json
index 7a545d1e6536..44873b5d54c2 100644
--- a/packages/babel-parser/test/fixtures/flow/type-annotations/10/output.json
+++ b/packages/babel-parser/test/fixtures/flow/type-annotations/10/output.json
@@ -59,6 +59,7 @@
                   }
                 ],
                 "rest": null,
+                "this": null,
                 "returnType": {
                   "type": "NumberTypeAnnotation",
                   "start":47,"end":53,"loc":{"start":{"line":1,"column":47},"end":{"line":1,"column":53}}
diff --git a/packages/babel-parser/test/fixtures/flow/type-annotations/11/output.json b/packages/babel-parser/test/fixtures/flow/type-annotations/11/output.json
index eff1cf78a25e..68c4fdcd366f 100644
--- a/packages/babel-parser/test/fixtures/flow/type-annotations/11/output.json
+++ b/packages/babel-parser/test/fixtures/flow/type-annotations/11/output.json
@@ -73,6 +73,7 @@
                     }
                   }
                 },
+                "this": null,
                 "returnType": {
                   "type": "NumberTypeAnnotation",
                   "start":58,"end":64,"loc":{"start":{"line":1,"column":58},"end":{"line":1,"column":64}}
diff --git a/packages/babel-parser/test/fixtures/flow/type-annotations/13/output.json b/packages/babel-parser/test/fixtures/flow/type-annotations/13/output.json
index fe45c3c0e5dc..d2601c75d8f6 100644
--- a/packages/babel-parser/test/fixtures/flow/type-annotations/13/output.json
+++ b/packages/babel-parser/test/fixtures/flow/type-annotations/13/output.json
@@ -27,6 +27,7 @@
             "start":15,"end":25,"loc":{"start":{"line":1,"column":15},"end":{"line":1,"column":25}},
             "params": [],
             "rest": null,
+            "this": null,
             "returnType": {
               "type": "VoidTypeAnnotation",
               "start":21,"end":25,"loc":{"start":{"line":1,"column":21},"end":{"line":1,"column":25}}
diff --git a/packages/babel-parser/test/fixtures/flow/type-annotations/14/output.json b/packages/babel-parser/test/fixtures/flow/type-annotations/14/output.json
index 9360adf64e81..eadf167279bf 100644
--- a/packages/babel-parser/test/fixtures/flow/type-annotations/14/output.json
+++ b/packages/babel-parser/test/fixtures/flow/type-annotations/14/output.json
@@ -42,6 +42,7 @@
               }
             ],
             "rest": null,
+            "this": null,
             "returnType": {
               "type": "NumberTypeAnnotation",
               "start":27,"end":33,"loc":{"start":{"line":1,"column":27},"end":{"line":1,"column":33}}
diff --git a/packages/babel-parser/test/fixtures/flow/type-annotations/15/output.json b/packages/babel-parser/test/fixtures/flow/type-annotations/15/output.json
index f74434914038..dcdb5c2b3efb 100644
--- a/packages/babel-parser/test/fixtures/flow/type-annotations/15/output.json
+++ b/packages/babel-parser/test/fixtures/flow/type-annotations/15/output.json
@@ -42,6 +42,7 @@
               }
             ],
             "rest": null,
+            "this": null,
             "returnType": {
               "type": "NumberTypeAnnotation",
               "start":28,"end":34,"loc":{"start":{"line":1,"column":28},"end":{"line":1,"column":34}}
diff --git a/packages/babel-parser/test/fixtures/flow/type-annotations/42/output.json b/packages/babel-parser/test/fixtures/flow/type-annotations/42/output.json
index 3e4e5b09000f..d75964c3119d 100644
--- a/packages/babel-parser/test/fixtures/flow/type-annotations/42/output.json
+++ b/packages/babel-parser/test/fixtures/flow/type-annotations/42/output.json
@@ -87,6 +87,7 @@
                           }
                         },
                         "typeParameters": null,
+                        "this": null,
                         "returnType": {
                           "type": "VoidTypeAnnotation",
                           "start":43,"end":47,"loc":{"start":{"line":1,"column":43},"end":{"line":1,"column":47}}
diff --git a/packages/babel-parser/test/fixtures/flow/type-annotations/43/output.json b/packages/babel-parser/test/fixtures/flow/type-annotations/43/output.json
index 049308dd2a06..89f3442c575b 100644
--- a/packages/babel-parser/test/fixtures/flow/type-annotations/43/output.json
+++ b/packages/babel-parser/test/fixtures/flow/type-annotations/43/output.json
@@ -76,6 +76,7 @@
                             }
                           ]
                         },
+                        "this": null,
                         "returnType": {
                           "type": "GenericTypeAnnotation",
                           "start":22,"end":23,"loc":{"start":{"line":1,"column":22},"end":{"line":1,"column":23}},
diff --git a/packages/babel-parser/test/fixtures/flow/type-annotations/57/output.json b/packages/babel-parser/test/fixtures/flow/type-annotations/57/output.json
index b19b04b9728f..817e35c3bbfd 100644
--- a/packages/babel-parser/test/fixtures/flow/type-annotations/57/output.json
+++ b/packages/babel-parser/test/fixtures/flow/type-annotations/57/output.json
@@ -26,6 +26,7 @@
                   "start":8,"end":35,"loc":{"start":{"line":1,"column":8},"end":{"line":1,"column":35}},
                   "params": [],
                   "rest": null,
+                  "this": null,
                   "returnType": {
                     "type": "UnionTypeAnnotation",
                     "start":14,"end":35,"loc":{"start":{"line":1,"column":14},"end":{"line":1,"column":35}},
@@ -39,6 +40,7 @@
                         "start":23,"end":35,"loc":{"start":{"line":1,"column":23},"end":{"line":1,"column":35}},
                         "params": [],
                         "rest": null,
+                        "this": null,
                         "returnType": {
                           "type": "StringTypeAnnotation",
                           "start":29,"end":35,"loc":{"start":{"line":1,"column":29},"end":{"line":1,"column":35}}
diff --git a/packages/babel-parser/test/fixtures/flow/type-annotations/7/output.json b/packages/babel-parser/test/fixtures/flow/type-annotations/7/output.json
index b49204c7f0b3..9cbace9de416 100644
--- a/packages/babel-parser/test/fixtures/flow/type-annotations/7/output.json
+++ b/packages/babel-parser/test/fixtures/flow/type-annotations/7/output.json
@@ -30,6 +30,7 @@
                 "start":23,"end":33,"loc":{"start":{"line":1,"column":23},"end":{"line":1,"column":33}},
                 "params": [],
                 "rest": null,
+                "this": null,
                 "returnType": {
                   "type": "VoidTypeAnnotation",
                   "start":29,"end":33,"loc":{"start":{"line":1,"column":29},"end":{"line":1,"column":33}}
diff --git a/packages/babel-parser/test/fixtures/flow/type-annotations/8/output.json b/packages/babel-parser/test/fixtures/flow/type-annotations/8/output.json
index cbfbdd516663..0527292f0ec7 100644
--- a/packages/babel-parser/test/fixtures/flow/type-annotations/8/output.json
+++ b/packages/babel-parser/test/fixtures/flow/type-annotations/8/output.json
@@ -30,6 +30,7 @@
                 "start":23,"end":35,"loc":{"start":{"line":1,"column":23},"end":{"line":1,"column":35}},
                 "params": [],
                 "rest": null,
+                "this": null,
                 "returnType": {
                   "type": "NumberTypeAnnotation",
                   "start":29,"end":35,"loc":{"start":{"line":1,"column":29},"end":{"line":1,"column":35}}
diff --git a/packages/babel-parser/test/fixtures/flow/type-annotations/86/output.json b/packages/babel-parser/test/fixtures/flow/type-annotations/86/output.json
index 3f525d36038f..52ae1d2ec9dd 100644
--- a/packages/babel-parser/test/fixtures/flow/type-annotations/86/output.json
+++ b/packages/babel-parser/test/fixtures/flow/type-annotations/86/output.json
@@ -54,6 +54,7 @@
                       }
                     }
                   },
+                  "this": null,
                   "returnType": {
                     "type": "NumberTypeAnnotation",
                     "start":33,"end":39,"loc":{"start":{"line":1,"column":33},"end":{"line":1,"column":39}}
diff --git a/packages/babel-parser/test/fixtures/flow/type-annotations/87/output.json b/packages/babel-parser/test/fixtures/flow/type-annotations/87/output.json
index 30d0d42c5f39..1aefc281d409 100644
--- a/packages/babel-parser/test/fixtures/flow/type-annotations/87/output.json
+++ b/packages/babel-parser/test/fixtures/flow/type-annotations/87/output.json
@@ -59,6 +59,7 @@
                     }
                   ],
                   "rest": null,
+                  "this": null,
                   "returnType": {
                     "type": "GenericTypeAnnotation",
                     "start":27,"end":28,"loc":{"start":{"line":1,"column":27},"end":{"line":1,"column":28}},
diff --git a/packages/babel-parser/test/fixtures/flow/type-annotations/88/output.json b/packages/babel-parser/test/fixtures/flow/type-annotations/88/output.json
index 1b22c73f7400..8a5b0ea84ca2 100644
--- a/packages/babel-parser/test/fixtures/flow/type-annotations/88/output.json
+++ b/packages/babel-parser/test/fixtures/flow/type-annotations/88/output.json
@@ -82,6 +82,7 @@
                       }
                     }
                   },
+                  "this": null,
                   "returnType": {
                     "type": "GenericTypeAnnotation",
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index 7cb400a2d942..0ebc8fa0a1fa 100644
--- a/packages/babel-parser/test/fixtures/flow/type-annotations/9/output.json
+++ b/packages/babel-parser/test/fixtures/flow/type-annotations/9/output.json
@@ -45,6 +45,7 @@
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index b8e1ad4ce035..ab63de410053 100644
--- a/packages/babel-parser/test/fixtures/flow/type-annotations/object-type-method/output.json
+++ b/packages/babel-parser/test/fixtures/flow/type-annotations/object-type-method/output.json
@@ -38,6 +38,7 @@
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@@ -97,6 +98,7 @@
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@@ -144,6 +146,7 @@
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@@ -201,6 +204,7 @@
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@@ -238,6 +242,7 @@
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@@ -307,6 +312,7 @@
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@@ -356,6 +362,7 @@
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@@ -404,6 +411,7 @@
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@@ -443,6 +451,7 @@
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@@ -482,6 +491,7 @@
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index fa4b9aa787dd..a65cc3450814 100644
--- a/packages/babel-parser/test/fixtures/flow/type-generics/async-arrow-like/output.json
+++ b/packages/babel-parser/test/fixtures/flow/type-generics/async-arrow-like/output.json
@@ -10,6 +10,18 @@
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+            "value": " This looks A LOT like an async arrow function, but it isn't because",
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+          },
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+            "value": " T + U isn't a valid type parameter.",
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@@ -32,6 +44,10 @@
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@@ -45,6 +61,7 @@
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@@ -57,14 +74,14 @@
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@@ -115,6 +132,10 @@
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@@ -133,10 +154,6 @@
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index 3a4d934f13ec..b5cff2c4e4f4 100644
--- a/packages/babel-parser/test/fixtures/flow/type-generics/async-arrow/output.json
+++ b/packages/babel-parser/test/fixtures/flow/type-generics/async-arrow/output.json
@@ -38,6 +38,7 @@
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index f2ee74dd938a..95b223ebc096 100644
--- a/packages/babel-parser/test/fixtures/flow/type-grouping/2/output.json
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@@ -30,6 +30,7 @@
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@@ -41,6 +42,7 @@
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index 1fcb8935c9e1..4d111fa58260 100644
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+++ b/packages/babel-parser/test/fixtures/flow/type-parameter-declaration/declare-class-method-reserved-word/output.json
@@ -53,6 +53,7 @@
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@@ -89,6 +90,7 @@
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@@ -125,6 +127,7 @@
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@@ -161,6 +164,7 @@
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@@ -197,6 +201,7 @@
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@@ -233,6 +238,7 @@
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@@ -269,6 +275,7 @@
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@@ -305,6 +312,7 @@
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diff --git a/packages/babel-parser/test/fixtures/flow/type-parameter-declaration/declare-interface-method-reserved-word/output.json b/packages/babel-parser/test/fixtures/flow/type-parameter-declaration/declare-interface-method-reserved-word/output.json
index b1a4c4bd1ddc..470c0092b769 100644
--- a/packages/babel-parser/test/fixtures/flow/type-parameter-declaration/declare-interface-method-reserved-word/output.json
+++ b/packages/babel-parser/test/fixtures/flow/type-parameter-declaration/declare-interface-method-reserved-word/output.json
@@ -53,6 +53,7 @@
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@@ -89,6 +90,7 @@
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@@ -125,6 +127,7 @@
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@@ -161,6 +164,7 @@
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index 767a8b87545a..615b9d52168f 100644
--- a/packages/babel-parser/test/fixtures/flow/type-parameter-declaration/default/output.json
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@@ -420,6 +420,10 @@
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@@ -446,10 +450,6 @@
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@@ -459,6 +459,10 @@
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@@ -497,10 +501,6 @@
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@@ -554,10 +558,6 @@
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@@ -615,10 +619,6 @@
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@@ -1140,11 +1144,7 @@
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@@ -1211,6 +1211,10 @@
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@@ -1260,10 +1264,6 @@
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@@ -1317,6 +1317,7 @@
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diff --git a/packages/babel-parser/test/fixtures/flow/type-parameter-declaration/interface-reserved-word/output.json b/packages/babel-parser/test/fixtures/flow/type-parameter-declaration/interface-reserved-word/output.json
index fc8e1f196b8f..6b114cbbac93 100644
--- a/packages/babel-parser/test/fixtures/flow/type-parameter-declaration/interface-reserved-word/output.json
+++ b/packages/babel-parser/test/fixtures/flow/type-parameter-declaration/interface-reserved-word/output.json
@@ -53,6 +53,7 @@
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@@ -89,6 +90,7 @@
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@@ -125,6 +127,7 @@
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@@ -161,6 +164,7 @@
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diff --git a/packages/babel-parser/test/fixtures/flow/type-parameter-declaration/type-object-reserved-word/output.json b/packages/babel-parser/test/fixtures/flow/type-parameter-declaration/type-object-reserved-word/output.json
index 86e2ee528e18..093870a8b238 100644
--- a/packages/babel-parser/test/fixtures/flow/type-parameter-declaration/type-object-reserved-word/output.json
+++ b/packages/babel-parser/test/fixtures/flow/type-parameter-declaration/type-object-reserved-word/output.json
@@ -50,6 +50,7 @@
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@@ -86,6 +87,7 @@
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@@ -122,6 +124,7 @@
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@@ -158,6 +161,7 @@
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diff --git a/packages/babel-parser/test/fixtures/flow/typecasts/3/output.json b/packages/babel-parser/test/fixtures/flow/typecasts/3/output.json
index 0e3ddeef5439..abd3347382a6 100644
--- a/packages/babel-parser/test/fixtures/flow/typecasts/3/output.json
+++ b/packages/babel-parser/test/fixtures/flow/typecasts/3/output.json
@@ -13,6 +13,10 @@
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             "type": "ArrowFunctionExpression",
             "start":1,"end":17,"loc":{"start":{"line":1,"column":1},"end":{"line":1,"column":17}},
@@ -69,16 +73,13 @@
                 }
               ],
               "rest": null,
+              "this": null,
               "returnType": {
                 "type": "NumberTypeAnnotation",
                 "start":36,"end":42,"loc":{"start":{"line":1,"column":36},"end":{"line":1,"column":42}}
               },
               "typeParameters": null
             }
-          },
-          "extra": {
-            "parenthesized": true,
-            "parenStart": 0
           }
         }
       }
diff --git a/packages/babel-plugin-transform-flow-strip-types/src/index.js b/packages/babel-plugin-transform-flow-strip-types/src/index.js
index a5e0fed85d66..5d293ae474aa 100644
--- a/packages/babel-plugin-transform-flow-strip-types/src/index.js
+++ b/packages/babel-plugin-transform-flow-strip-types/src/index.js
@@ -130,6 +130,13 @@ export default declare((api, opts) => {
 
       Function({ node }) {
         if (skipStrip) return;
+        if (
+          node.params.length > 0 &&
+          node.params[0].type === "Identifier" &&
+          node.params[0].name === "this"
+        ) {
+          node.params.shift();
+        }
         for (let i = 0; i < node.params.length; i++) {
           const param = node.params[i];
           param.optional = false;
diff --git a/packages/babel-plugin-transform-flow-strip-types/test/fixtures/strip-types/strip-this-param/input.js b/packages/babel-plugin-transform-flow-strip-types/test/fixtures/strip-types/strip-this-param/input.js
new file mode 100644
index 000000000000..0f879d0068d2
--- /dev/null
+++ b/packages/babel-plugin-transform-flow-strip-types/test/fixtures/strip-types/strip-this-param/input.js
@@ -0,0 +1,26 @@
+function one (this : number) {}
+function two (this : number, a) {}
+function three (this : number, ...a) {}
+function four (this : number, a, b, ...c) {}
+function five<T> (this : T) {}
+
+type six = (this : number) => void
+type seven = { o(this : string) : void }
+declare function eight (this : number) : void
+declare class Nine { m (this : number) : void }
+
+class Ten {
+    m1 (this : number) {}
+    m2 (this : number, a) {}
+    m3 (this : number, ...a) {}
+    m4 (this : number, a, b, ...c) {}
+    m5<T> (this : T) {}
+}
+
+let eleven = {
+    m1 (this : number) {},
+    m2 (this : number, a) {},
+    m3 (this : number, ...a) {},
+    m4 (this : number, a, b, ...c) {},
+    m5<T> (this : T) {}
+}
diff --git a/packages/babel-plugin-transform-flow-strip-types/test/fixtures/strip-types/strip-this-param/output.js b/packages/babel-plugin-transform-flow-strip-types/test/fixtures/strip-types/strip-this-param/output.js
new file mode 100644
index 000000000000..4111c826911e
--- /dev/null
+++ b/packages/babel-plugin-transform-flow-strip-types/test/fixtures/strip-types/strip-this-param/output.js
@@ -0,0 +1,35 @@
+function one() {}
+
+function two(a) {}
+
+function three(...a) {}
+
+function four(a, b, ...c) {}
+
+function five() {}
+
+class Ten {
+  m1() {}
+
+  m2(a) {}
+
+  m3(...a) {}
+
+  m4(a, b, ...c) {}
+
+  m5() {}
+
+}
+
+let eleven = {
+  m1() {},
+
+  m2(a) {},
+
+  m3(...a) {},
+
+  m4(a, b, ...c) {},
+
+  m5() {}
+
+};
diff --git a/packages/babel-plugin-transform-parameters/test/fixtures/parameters/flow-this-param/input.js b/packages/babel-plugin-transform-parameters/test/fixtures/parameters/flow-this-param/input.js
new file mode 100644
index 000000000000..0fc352021e80
--- /dev/null
+++ b/packages/babel-plugin-transform-parameters/test/fixtures/parameters/flow-this-param/input.js
@@ -0,0 +1,3 @@
+function foo (this : number, x : number, y : string, ...z : any) {
+    x + y + z[0];
+}
diff --git a/packages/babel-plugin-transform-parameters/test/fixtures/parameters/flow-this-param/output.js b/packages/babel-plugin-transform-parameters/test/fixtures/parameters/flow-this-param/output.js
new file mode 100644
index 000000000000..79906598b753
--- /dev/null
+++ b/packages/babel-plugin-transform-parameters/test/fixtures/parameters/flow-this-param/output.js
@@ -0,0 +1,3 @@
+function foo(this: number, x: number, y: string) {
+  x + y + (arguments.length <= 2 ? undefined : arguments[2]);
+}
diff --git a/packages/babel-types/src/ast-types/generated/index.ts b/packages/babel-types/src/ast-types/generated/index.ts
index ae461bbae0d0..1fcc394c8cf6 100755
--- a/packages/babel-types/src/ast-types/generated/index.ts
+++ b/packages/babel-types/src/ast-types/generated/index.ts
@@ -1118,6 +1118,7 @@ export interface FunctionTypeAnnotation extends BaseNode {
   params: Array<FunctionTypeParam>;
   rest?: FunctionTypeParam | null;
   returnType: FlowType;
+  this?: FunctionTypeParam | null;
 }
 
 export interface FunctionTypeParam extends BaseNode {
diff --git a/packages/babel-types/src/definitions/flow.ts b/packages/babel-types/src/definitions/flow.ts
index bb1015d18c0c..9204fe10b257 100644
--- a/packages/babel-types/src/definitions/flow.ts
+++ b/packages/babel-types/src/definitions/flow.ts
@@ -173,6 +173,7 @@ defineType("FunctionTypeAnnotation", {
     typeParameters: validateOptionalType("TypeParameterDeclaration"),
     params: validate(arrayOfType("FunctionTypeParam")),
     rest: validateOptionalType("FunctionTypeParam"),
+    this: validateOptionalType("FunctionTypeParam"),
     returnType: validateType("FlowType"),
   },
 });