Flow opaque type alias backport

src/plugins/flow.js

@@ -119,13 +119,31 @@ pp.flowParseDeclare = function (node) {
     }
   } else if (this.isContextual("type")) {
     return this.flowParseDeclareTypeAlias(node);
+  } else if (this.isContextual("opaque")) {
+    return this.flowParseDeclareOpaqueType(node);
   } else if (this.isContextual("interface")) {
     return this.flowParseDeclareInterface(node);
+  } else if (this.match(tt._export)) {
+    return this.flowParseDeclareExportDeclaration(node);
   } else {
     this.unexpected();
   }
 };
 
+pp.flowParseDeclareExportDeclaration = function (node) {
+  this.expect(tt._export);
+  if (
+    this.isContextual("opaque") // declare export opaque ...
+  ) {
+    node.declaration = this.flowParseDeclare(this.startNode());
+    node.default = false;
+
+    return this.finishNode(node, "DeclareExportDeclaration");
+  }
+
+  throw this.unexpected();
+};
+
 pp.flowParseDeclareVariable = function (node) {
   this.next();
   node.id = this.flowParseTypeAnnotatableIdentifier();
@@ -185,6 +203,13 @@ pp.flowParseDeclareTypeAlias = function (node) {
   return this.finishNode(node, "DeclareTypeAlias");
 };
 
+pp.flowParseDeclareOpaqueType = function (node) {
+  this.next();
+  this.flowParseOpaqueType(node, true);
+  return this.finishNode(node, "DeclareOpaqueType");
+};
+
+
 pp.flowParseDeclareInterface = function (node) {
   this.next();
   this.flowParseInterfaceish(node);
@@ -264,6 +289,33 @@ pp.flowParseTypeAlias = function (node) {
   return this.finishNode(node, "TypeAlias");
 };
 
+// Opaque type aliases
+
+pp.flowParseOpaqueType = function (node, declare) {
+  this.expectContextual("type");
+  node.id = this.flowParseRestrictedIdentifier();
+
+  if (this.isRelational("<")) {
+    node.typeParameters = this.flowParseTypeParameterDeclaration();
+  } else {
+    node.typeParameters = null;
+  }
+
+  // Parse the supertype
+  node.supertype = null;
+  if (this.match(tt.colon)) {
+    node.supertype = this.flowParseTypeInitialiser(tt.colon);
+  }
+
+  node.impltype = null;
+  if (!declare) {
+    node.impltype = this.flowParseTypeInitialiser(tt.eq);
+  }
+  this.semicolon();
+
+  return this.finishNode(node, "OpaqueType");
+};
+
 // Type annotations
 
 pp.flowParseTypeParameter = function () {
@@ -905,14 +957,21 @@ export default function (instance) {
     return function (node, expr) {
       if (expr.type === "Identifier") {
         if (expr.name === "declare") {
-          if (this.match(tt._class) || this.match(tt.name) || this.match(tt._function) || this.match(tt._var)) {
+          if (this.match(tt._class)
+            || this.match(tt.name)
+            || this.match(tt._function)
+            || this.match(tt._var)
+            || this.match(tt._export)
+          ) {
             return this.flowParseDeclare(node);
           }
         } else if (this.match(tt.name)) {
           if (expr.name === "interface") {
             return this.flowParseInterface(node);
           } else if (expr.name === "type") {
             return this.flowParseTypeAlias(node);
+          } else if (expr.name === "opaque") {
+            return this.flowParseOpaqueType(node, false);
           }
         }
       }
@@ -926,6 +985,7 @@ export default function (instance) {
     return function () {
       return this.isContextual("type")
           || this.isContextual("interface")
+          || this.isContextual("opaque")
           || inner.call(this);
     };
   });
@@ -934,7 +994,9 @@ export default function (instance) {
     return function () {
       if (
         this.match(tt.name) &&
-        (this.state.value === "type" || this.state.value === "interface")
+        (this.state.value === "type"
+        || this.state.value === "interface"
+        || this.state.value === "opaque")
       ) {
         return false;
       }
@@ -1013,6 +1075,13 @@ export default function (instance) {
           // export type Foo = Bar;
           return this.flowParseTypeAlias(declarationNode);
         }
+      } else if (this.isContextual("opaque")) {
+        node.exportKind = "type";
+
+        const declarationNode = this.startNode();
+        this.next();
+        // export opaque type Foo = Bar;
+        return this.flowParseOpaqueType(declarationNode, false);
       } else if (this.isContextual("interface")) {
         node.exportKind = "type";
         const declarationNode = this.startNode();

test/fixtures/flow/opaque-type-aliases/declare_opaque/actual.js

@@ -0,0 +1 @@
+declare opaque type ID = number;

test/fixtures/flow/opaque-type-aliases/declare_opaque/options.json

@@ -0,0 +1,3 @@
+{
+  "throws": "Unexpected token, expected ; (1:23)"
+}

test/fixtures/flow/opaque-type-aliases/opaque_collision/actual.js

@@ -0,0 +1,2 @@
+opaque type opaque = number;
+opaque type not_transparent = opaque;

test/fixtures/flow/opaque-type-aliases/opaque_collision/expected.json

@@ -0,0 +1,150 @@
+{
+  "type": "File",
+  "start": 0,
+  "end": 66,
+  "loc": {
+    "start": {
+      "line": 1,
+      "column": 0
+    },
+    "end": {
+      "line": 2,
+      "column": 37
+    }
+  },
+  "program": {
+    "type": "Program",
+    "start": 0,
+    "end": 66,
+    "loc": {
+      "start": {
+        "line": 1,
+        "column": 0
+      },
+      "end": {
+        "line": 2,
+        "column": 37
+      }
+    },
+    "sourceType": "module",
+    "body": [
+      {
+        "type": "OpaqueType",
+        "start": 0,
+        "end": 28,
+        "loc": {
+          "start": {
+            "line": 1,
+            "column": 0
+          },
+          "end": {
+            "line": 1,
+            "column": 28
+          }
+        },
+        "id": {
+          "type": "Identifier",
+          "start": 12,
+          "end": 18,
+          "loc": {
+            "start": {
+              "line": 1,
+              "column": 12
+            },
+            "end": {
+              "line": 1,
+              "column": 18
+            },
+            "identifierName": "opaque"
+          },
+          "name": "opaque"
+        },
+        "typeParameters": null,
+        "supertype": null,
+        "impltype": {
+          "type": "NumberTypeAnnotation",
+          "start": 21,
+          "end": 27,
+          "loc": {
+            "start": {
+              "line": 1,
+              "column": 21
+            },
+            "end": {
+              "line": 1,
+              "column": 27
+            }
+          }
+        }
+      },
+      {
+        "type": "OpaqueType",
+        "start": 29,
+        "end": 66,
+        "loc": {
+          "start": {
+            "line": 2,
+            "column": 0
+          },
+          "end": {
+            "line": 2,
+            "column": 37
+          }
+        },
+        "id": {
+          "type": "Identifier",
+          "start": 41,
+          "end": 56,
+          "loc": {
+            "start": {
+              "line": 2,
+              "column": 12
+            },
+            "end": {
+              "line": 2,
+              "column": 27
+            },
+            "identifierName": "not_transparent"
+          },
+          "name": "not_transparent"
+        },
+        "typeParameters": null,
+        "supertype": null,
+        "impltype": {
+          "type": "GenericTypeAnnotation",
+          "start": 59,
+          "end": 65,
+          "loc": {
+            "start": {
+              "line": 2,
+              "column": 30
+            },
+            "end": {
+              "line": 2,
+              "column": 36
+            }
+          },
+          "typeParameters": null,
+          "id": {
+            "type": "Identifier",
+            "start": 59,
+            "end": 65,
+            "loc": {
+              "start": {
+                "line": 2,
+                "column": 30
+              },
+              "end": {
+                "line": 2,
+                "column": 36
+              },
+              "identifierName": "opaque"
+            },
+            "name": "opaque"
+          }
+        }
+      }
+    ],
+    "directives": []
+  }
+}

test/fixtures/flow/opaque-type-aliases/opaque_declare_export_neither/actual.js

@@ -0,0 +1 @@
+declare export opaque type Foo

test/fixtures/flow/opaque-type-aliases/opaque_declare_export_neither/expected.json

@@ -0,0 +1,85 @@
+{
+  "type": "File",
+  "start": 0,
+  "end": 30,
+  "loc": {
+    "start": {
+      "line": 1,
+      "column": 0
+    },
+    "end": {
+      "line": 1,
+      "column": 30
+    }
+  },
+  "program": {
+    "type": "Program",
+    "start": 0,
+    "end": 30,
+    "loc": {
+      "start": {
+        "line": 1,
+        "column": 0
+      },
+      "end": {
+        "line": 1,
+        "column": 30
+      }
+    },
+    "sourceType": "module",
+    "body": [
+      {
+        "type": "DeclareExportDeclaration",
+        "start": 0,
+        "end": 30,
+        "loc": {
+          "start": {
+            "line": 1,
+            "column": 0
+          },
+          "end": {
+            "line": 1,
+            "column": 30
+          }
+        },
+        "declaration": {
+          "type": "DeclareOpaqueType",
+          "start": 15,
+          "end": 30,
+          "loc": {
+            "start": {
+              "line": 1,
+              "column": 15
+            },
+            "end": {
+              "line": 1,
+              "column": 30
+            }
+          },
+          "id": {
+            "type": "Identifier",
+            "start": 27,
+            "end": 30,
+            "loc": {
+              "start": {
+                "line": 1,
+                "column": 27
+              },
+              "end": {
+                "line": 1,
+                "column": 30
+              },
+              "identifierName": "Foo"
+            },
+            "name": "Foo"
+          },
+          "typeParameters": null,
+          "supertype": null,
+          "impltype": null
+        },
+        "default": false
+      }
+    ],
+    "directives": []
+  }
+}

test/fixtures/flow/opaque-type-aliases/opaque_declare_export_st_no_t/actual.js

@@ -0,0 +1 @@
+declare export opaque type Foo: Bar