Enable the noImplicitThis tsc option (#14545)

* enable noImplicitThis

* refactor: cache type annotation in path.data

* update test fixtures

packages/babel-core/src/config/full.ts

@@ -494,7 +494,7 @@ function chain(a, b) {
   const fns = [a, b].filter(Boolean);
   if (fns.length <= 1) return fns[0];
 
-  return function (...args) {
+  return function (this: unknown, ...args) {
     for (const fn of fns) {
       fn.apply(this, args);
     }

packages/babel-generator/src/generators/classes.ts

@@ -199,7 +199,7 @@ export function _classMethodHead(this: Printer, node) {
   this._methodHead(node);
 }
 
-export function StaticBlock(node: t.StaticBlock) {
+export function StaticBlock(this: Printer, node: t.StaticBlock) {
   this.word("static");
   this.space();
   this.token("{");

packages/babel-generator/src/generators/expressions.ts

@@ -219,7 +219,7 @@ export function Import(this: Printer) {
 }
 
 function buildYieldAwait(keyword: string) {
-  return function (node: any) {
+  return function (this: Printer, node: any) {
     this.word(keyword);
 
     if (node.delegate) {
@@ -348,7 +348,7 @@ export function V8IntrinsicIdentifier(
   this.word(node.name);
 }
 
-export function ModuleExpression(node: t.ModuleExpression) {
+export function ModuleExpression(this: Printer, node: t.ModuleExpression) {
   this.word("module");
   this.space();
   this.token("{");

packages/babel-generator/src/generators/flow.ts

@@ -68,7 +68,7 @@ export function DeclareFunction(
   this.semicolon();
 }
 
-export function InferredPredicate(/*node: Object*/) {
+export function InferredPredicate(this: Printer) {
   this.token("%");
   this.word("checks");
 }
@@ -159,7 +159,7 @@ export function DeclareExportDeclaration(
   FlowExportDeclaration.apply(this, arguments);
 }
 
-export function DeclareExportAllDeclaration(/*node: Object*/) {
+export function DeclareExportAllDeclaration(this: Printer) {
   this.word("declare");
   this.space();
   ExportAllDeclaration.apply(this, arguments);
@@ -258,7 +258,7 @@ export function EnumStringMember(this: Printer, node: t.EnumStringMember) {
   enumInitializedMember(this, node);
 }
 
-function FlowExportDeclaration(node: any) {
+function FlowExportDeclaration(this: Printer, node: any) {
   if (node.declaration) {
     const declar = node.declaration;
     this.print(declar, node);
@@ -403,7 +403,7 @@ export function InterfaceDeclaration(
   this._interfaceish(node);
 }
 
-function andSeparator() {
+function andSeparator(this: Printer) {
   this.space();
   this.token("&");
   this.space();
@@ -707,7 +707,7 @@ export function SymbolTypeAnnotation(this: Printer) {
   this.word("symbol");
 }
 
-function orSeparator() {
+function orSeparator(this: Printer) {
   this.space();
   this.token("|");
   this.space();

packages/babel-generator/src/generators/jsx.ts

@@ -75,7 +75,7 @@ export function JSXElement(this: Printer, node: t.JSXElement) {
   this.print(node.closingElement, node);
 }
 
-function spaceSeparator() {
+function spaceSeparator(this: Printer) {
   this.space();
 }
 

packages/babel-generator/src/generators/modules.ts

@@ -119,7 +119,7 @@ export function ExportDefaultDeclaration(
   ExportDeclaration.apply(this, arguments);
 }
 
-function ExportDeclaration(node: any) {
+function ExportDeclaration(this: Printer, node: any) {
   if (node.declaration) {
     const declar = node.declaration;
     this.print(declar, node);

packages/babel-generator/src/generators/statements.ts

@@ -90,7 +90,7 @@ export function WhileStatement(this: Printer, node: t.WhileStatement) {
 }
 
 const buildForXStatement = function (op) {
-  return function (node: any) {
+  return function (this: Printer, node: any) {
     this.word("for");
     this.space();
     if (op === "of" && node.await) {
@@ -125,7 +125,7 @@ export function DoWhileStatement(this: Printer, node: t.DoWhileStatement) {
 }
 
 function buildLabelStatement(prefix, key = "label") {
-  return function (node: any) {
+  return function (this: Printer, node: any) {
     this.word(prefix);
 
     const label = node[key];
@@ -232,7 +232,7 @@ export function DebuggerStatement(this: Printer) {
   this.semicolon();
 }
 
-function variableDeclarationIndent() {
+function variableDeclarationIndent(this: Printer) {
   // "let " or "var " indentation.
   this.token(",");
   this.newline();
@@ -241,7 +241,7 @@ function variableDeclarationIndent() {
   }
 }
 
-function constDeclarationIndent() {
+function constDeclarationIndent(this: Printer) {
   // "const " indentation.
   this.token(",");
   this.newline();

packages/babel-generator/src/generators/typescript.ts

@@ -208,7 +208,7 @@ export function TSNullKeyword(this: Printer) {
 export function TSNeverKeyword(this: Printer) {
   this.word("never");
 }
-export function TSIntrinsicKeyword() {
+export function TSIntrinsicKeyword(this: Printer) {
   this.word("intrinsic");
 }
 

packages/babel-generator/src/printer.ts

@@ -720,7 +720,7 @@ type GeneratorFunctions = typeof generatorFunctions;
 interface Printer extends GeneratorFunctions {}
 export default Printer;
 
-function commaSeparator() {
+function commaSeparator(this: Printer) {
   this.token(",");
   this.space();
 }

packages/babel-helper-replace-supers/src/index.ts

@@ -16,6 +16,7 @@ import {
   thisExpression,
 } from "@babel/types";
 import type * as t from "@babel/types";
+import type { File } from "@babel/core";
 
 // TODO (Babel 8): Don't export this.
 export {
@@ -72,8 +73,32 @@ const unshadowSuperBindingVisitor = traverse.visitors.merge<{
   },
 ]);
 
+type SharedState = {
+  file: File;
+  scope: Scope;
+  isDerivedConstructor: boolean;
+  isStatic: boolean;
+  isPrivateMethod: boolean;
+  getObjectRef: Function;
+  getSuperRef: Function;
+  // we dont need boundGet here, but memberExpressionToFunctions handler needs it.
+  boundGet: HandlerState["get"];
+};
+
+type Handler = HandlerState<SharedState> & SharedState;
+type SuperMember = NodePath<
+  | t.MemberExpression & {
+      object: t.Super;
+      property: Exclude<t.MemberExpression["property"], t.PrivateName>;
+    }
+>;
+
 const specHandlers = {
-  memoise(superMember, count) {
+  memoise(
+    this: Handler & typeof specHandlers,
+    superMember: SuperMember,
+    count,
+  ) {
     const { scope, node } = superMember;
     const { computed, property } = node;
     if (!computed) {
@@ -88,7 +113,7 @@ const specHandlers = {
     this.memoiser.set(property, memo, count);
   },
 
-  prop(superMember) {
+  prop(this: Handler & typeof specHandlers, superMember: SuperMember) {
     const { computed, property } = superMember.node;
     if (this.memoiser.has(property)) {
       return cloneNode(this.memoiser.get(property));
@@ -98,14 +123,18 @@ const specHandlers = {
       return cloneNode(property);
     }
 
-    return stringLiteral(property.name);
+    return stringLiteral((property as t.Identifier).name);
   },
 
-  get(superMember) {
+  get(this: Handler & typeof specHandlers, superMember: SuperMember) {
     return this._get(superMember, this._getThisRefs());
   },
 
-  _get(superMember, thisRefs) {
+  _get(
+    this: Handler & typeof specHandlers,
+    superMember: SuperMember,
+    thisRefs,
+  ) {
     const proto = getPrototypeOfExpression(
       this.getObjectRef(),
       this.isStatic,
@@ -119,7 +148,7 @@ const specHandlers = {
     ]);
   },
 
-  _getThisRefs() {
+  _getThisRefs(this: Handler & typeof specHandlers) {
     if (!this.isDerivedConstructor) {
       return { this: thisExpression() };
     }
@@ -130,7 +159,7 @@ const specHandlers = {
     };
   },
 
-  set(superMember, value) {
+  set(this: Handler & typeof specHandlers, superMember: SuperMember, value) {
     const thisRefs = this._getThisRefs();
     const proto = getPrototypeOfExpression(
       this.getObjectRef(),
@@ -147,13 +176,16 @@ const specHandlers = {
     ]);
   },
 
-  destructureSet(superMember) {
+  destructureSet(
+    this: Handler & typeof specHandlers,
+    superMember: SuperMember,
+  ) {
     throw superMember.buildCodeFrameError(
       `Destructuring to a super field is not supported yet.`,
     );
   },
 
-  call(superMember, args) {
+  call(this: Handler & typeof specHandlers, superMember: SuperMember, args) {
     const thisRefs = this._getThisRefs();
     return optimiseCall(
       this._get(superMember, thisRefs),
@@ -163,7 +195,11 @@ const specHandlers = {
     );
   },
 
-  optionalCall(superMember, args) {
+  optionalCall(
+    this: Handler & typeof specHandlers,
+    superMember: SuperMember,
+    args,
+  ) {
     const thisRefs = this._getThisRefs();
     return optimiseCall(
       this._get(superMember, thisRefs),
@@ -177,7 +213,7 @@ const specHandlers = {
 const looseHandlers = {
   ...specHandlers,
 
-  prop(superMember) {
+  prop(this: Handler & typeof specHandlers, superMember: SuperMember) {
     const { property } = superMember.node;
     if (this.memoiser.has(property)) {
       return cloneNode(this.memoiser.get(property));
@@ -186,7 +222,7 @@ const looseHandlers = {
     return cloneNode(property);
   },
 
-  get(superMember) {
+  get(this: Handler & typeof specHandlers, superMember: SuperMember) {
     const { isStatic, getSuperRef } = this;
     const { computed } = superMember.node;
     const prop = this.prop(superMember);
@@ -206,7 +242,7 @@ const looseHandlers = {
     return memberExpression(object, prop, computed);
   },
 
-  set(superMember, value) {
+  set(this: Handler & typeof specHandlers, superMember: SuperMember, value) {
     const { computed } = superMember.node;
     const prop = this.prop(superMember);
 
@@ -217,18 +253,25 @@ const looseHandlers = {
     );
   },
 
-  destructureSet(superMember) {
+  destructureSet(
+    this: Handler & typeof specHandlers,
+    superMember: SuperMember,
+  ) {
     const { computed } = superMember.node;
     const prop = this.prop(superMember);
 
     return memberExpression(thisExpression(), prop, computed);
   },
 
-  call(superMember, args) {
+  call(this: Handler & typeof specHandlers, superMember: SuperMember, args) {
     return optimiseCall(this.get(superMember), thisExpression(), args, false);
   },
 
-  optionalCall(superMember, args) {
+  optionalCall(
+    this: Handler & typeof specHandlers,
+    superMember: SuperMember,
+    args,
+  ) {
     return optimiseCall(this.get(superMember), thisExpression(), args, true);
   },
 };

packages/babel-helper-simple-access/src/index.ts

@@ -9,8 +9,15 @@ import {
   sequenceExpression,
   unaryExpression,
 } from "@babel/types";
-import type { NodePath } from "@babel/traverse";
-
+import type * as t from "@babel/types";
+import type { NodePath, Scope, Visitor } from "@babel/traverse";
+
+type State = {
+  scope: Scope;
+  bindingNames: Set<string>;
+  seen: WeakSet<t.Node>;
+  includeUpdateExpression: boolean;
+};
 export default function simplifyAccess(
   path: NodePath,
   bindingNames,
@@ -25,7 +32,7 @@ export default function simplifyAccess(
   });
 }
 
-const simpleAssignmentVisitor = {
+const simpleAssignmentVisitor: Visitor<State> = {
   // TODO(Babel 8): Remove UpdateExpression
   UpdateExpression: {
     exit(path) {
@@ -61,7 +68,7 @@ const simpleAssignmentVisitor = {
             "=",
             identifier(localName),
             binaryExpression(
-              path.node.operator[0],
+              path.node.operator[0] as "+" | "-",
               unaryExpression("+", arg.node),
               numericLiteral(1),
             ),
@@ -76,8 +83,9 @@ const simpleAssignmentVisitor = {
         path.scope.push({ id: old });
 
         const binary = binaryExpression(
-          path.node.operator[0],
+          path.node.operator[0] as "+" | "-",
           identifier(varName),
+          // todo: support bigint
           numericLiteral(1),
         );
 
@@ -126,6 +134,7 @@ const simpleAssignmentVisitor = {
         // (foo &&= bar) => (foo && foo = bar)
         path.replaceWith(
           logicalExpression(
+            // @ts-expect-error Guarded by LOGICAL_OPERATORS.includes
             operator,
             path.node.left,
             assignmentExpression(
@@ -138,6 +147,8 @@ const simpleAssignmentVisitor = {
       } else {
         // (foo += bar) => (foo = foo + bar)
         path.node.right = binaryExpression(
+          // @ts-expect-error An assignment expression operator removing "=" must
+          // be a valid binary operator
           operator,
           cloneNode(path.node.left),
           path.node.right,