typescript-eslint · bradzacher · Jun 27, 2022 · Jan 1, 2022 · Jan 4, 2022 · Apr 25, 2022
diff --git a/packages/ast-spec/src/unions/EntityName.ts b/packages/ast-spec/src/unions/EntityName.ts
@@ -1,4 +1,5 @@
 import type { Identifier } from '../expression/Identifier/spec';
+import type { ThisExpression } from '../expression/ThisExpression/spec';
 import type { TSQualifiedName } from '../type/TSQualifiedName/spec';
 
-export type EntityName = Identifier | TSQualifiedName;
+export type EntityName = Identifier | ThisExpression | TSQualifiedName;
diff --git a/packages/eslint-plugin/tests/eslint-rules/no-undef.test.ts b/packages/eslint-plugin/tests/eslint-rules/no-undef.test.ts
@@ -248,6 +248,16 @@ class Foo {}
     `
 export type AppState = typeof import('./src/store/reducers').default;
     `,
+    `
+let self: typeof this;
+let foo: typeof this.foo;
+const obj = {
+  foo: '',
+  bar() {
+    let self: typeof this;
+  },
+};
+    `,
   ],
   invalid: [
     {

diff --git a/packages/scope-manager/src/referencer/ClassVisitor.ts b/packages/scope-manager/src/referencer/ClassVisitor.ts
@@ -293,21 +293,23 @@ class ClassVisitor extends Visitor {
       node.typeAnnotation.type === AST_NODE_TYPES.TSTypeReference &&
       this.#emitDecoratorMetadata
     ) {
-      let identifier: TSESTree.Identifier;
+      let entityName: TSESTree.Identifier | TSESTree.ThisExpression;
       if (
         node.typeAnnotation.typeName.type === AST_NODE_TYPES.TSQualifiedName
       ) {
         let iter = node.typeAnnotation.typeName;
         while (iter.left.type === AST_NODE_TYPES.TSQualifiedName) {
           iter = iter.left;
         }
-        identifier = iter.left;
+        entityName = iter.left;
       } else {
-        identifier = node.typeAnnotation.typeName;
+        entityName = node.typeAnnotation.typeName;
       }
 
       if (withDecorators) {
-        this.#referencer.currentScope().referenceDualValueType(identifier);
+        if (entityName.type === AST_NODE_TYPES.Identifier) {
+          this.#referencer.currentScope().referenceDualValueType(entityName);
+        }
 
         if (node.typeAnnotation.typeParameters) {
           this.visitType(node.typeAnnotation.typeParameters);

diff --git a/packages/scope-manager/src/referencer/TypeVisitor.ts b/packages/scope-manager/src/referencer/TypeVisitor.ts
@@ -256,15 +256,20 @@ class TypeVisitor extends Visitor {
 
   // a type query `typeof foo` is a special case that references a _non-type_ variable,
   protected TSTypeQuery(node: TSESTree.TSTypeQuery): void {
-    if (node.exprName.type === AST_NODE_TYPES.Identifier) {
-      this.#referencer.currentScope().referenceValue(node.exprName);
-    } else {
-      let expr = node.exprName.left;
-      while (expr.type !== AST_NODE_TYPES.Identifier) {
-        expr = expr.left;
+    let entityName: TSESTree.Identifier | TSESTree.ThisExpression;
+    if (node.exprName.type === AST_NODE_TYPES.TSQualifiedName) {
+      let iter = node.exprName;
+      while (iter.left.type === AST_NODE_TYPES.TSQualifiedName) {
+        iter = iter.left;
       }
-      this.#referencer.currentScope().referenceValue(expr);
+      entityName = iter.left;
+    } else {
+      entityName = node.exprName;
     }
+    if (entityName.type === AST_NODE_TYPES.Identifier) {
+      this.#referencer.currentScope().referenceValue(entityName);
+    }
+
     this.visit(node.typeParameters);
   }
 

diff --git a/packages/scope-manager/tests/fixtures/decorators/typeof-this.ts b/packages/scope-manager/tests/fixtures/decorators/typeof-this.ts
@@ -0,0 +1,5 @@
+function decorator() {}
+@decorator
+class Foo {
+  bar(baz: typeof this) {}
+}
diff --git a/packages/scope-manager/tests/fixtures/decorators/typeof-this.ts.shot b/packages/scope-manager/tests/fixtures/decorators/typeof-this.ts.shot
@@ -0,0 +1,142 @@
+// Jest Snapshot v1, https://goo.gl/fbAQLP
+
+exports[`decorators typeof-this 1`] = `
+ScopeManager {
+  variables: Array [
+    ImplicitGlobalConstTypeVariable,
+    Variable$2 {
+      defs: Array [
+        FunctionNameDefinition$1 {
+          name: Identifier<"decorator">,
+          node: FunctionDeclaration$1,
+        },
+      ],
+      name: "decorator",
+      references: Array [
+        Reference$1 {
+          identifier: Identifier<"decorator">,
+          isRead: true,
+          isTypeReference: false,
+          isValueReference: true,
+          isWrite: false,
+          resolved: Variable$2,
+        },
+      ],
+      isValueVariable: true,
+      isTypeVariable: false,
+    },
+    Variable$3 {
+      defs: Array [],
+      name: "arguments",
+      references: Array [],
+      isValueVariable: true,
+      isTypeVariable: true,
+    },
+    Variable$4 {
+      defs: Array [
+        ClassNameDefinition$2 {
+          name: Identifier<"Foo">,
+          node: ClassDeclaration$2,
+        },
+      ],
+      name: "Foo",
+      references: Array [],
+      isValueVariable: true,
+      isTypeVariable: true,
+    },
+    Variable$5 {
+      defs: Array [
+        ClassNameDefinition$3 {
+          name: Identifier<"Foo">,
+          node: ClassDeclaration$2,
+        },
+      ],
+      name: "Foo",
+      references: Array [],
+      isValueVariable: true,
+      isTypeVariable: true,
+    },
+    Variable$6 {
+      defs: Array [],
+      name: "arguments",
+      references: Array [],
+      isValueVariable: true,
+      isTypeVariable: true,
+    },
+    Variable$7 {
+      defs: Array [
+        ParameterDefinition$4 {
+          name: Identifier<"baz">,
+          node: FunctionExpression$3,
+        },
+      ],
+      name: "baz",
+      references: Array [],
+      isValueVariable: true,
+      isTypeVariable: false,
+    },
+  ],
+  scopes: Array [
+    GlobalScope$1 {
+      block: Program$4,
+      isStrict: false,
+      references: Array [
+        Reference$1,
+      ],
+      set: Map {
+        "const" => ImplicitGlobalConstTypeVariable,
+        "decorator" => Variable$2,
+        "Foo" => Variable$4,
+      },
+      type: "global",
+      upper: null,
+      variables: Array [
+        ImplicitGlobalConstTypeVariable,
+        Variable$2,
+        Variable$4,
+      ],
+    },
+    FunctionScope$2 {
+      block: FunctionDeclaration$1,
+      isStrict: false,
+      references: Array [],
+      set: Map {
+        "arguments" => Variable$3,
+      },
+      type: "function",
+      upper: GlobalScope$1,
+      variables: Array [
+        Variable$3,
+      ],
+    },
+    ClassScope$3 {
+      block: ClassDeclaration$2,
+      isStrict: true,
+      references: Array [],
+      set: Map {
+        "Foo" => Variable$5,
+      },
+      type: "class",
+      upper: GlobalScope$1,
+      variables: Array [
+        Variable$5,
+      ],
+    },
+    FunctionScope$4 {
+      block: FunctionExpression$3,
+      isStrict: true,
+      references: Array [],
+      set: Map {
+        "arguments" => Variable$6,
+        "baz" => Variable$7,
+      },
+      type: "function",
+      upper: ClassScope$3,
+      variables: Array [
+        Variable$6,
+        Variable$7,
+      ],
+    },
+  ],
+}
+`;
diff --git a/packages/shared-fixtures/fixtures/typescript/types/typeof-this.src.ts b/packages/shared-fixtures/fixtures/typescript/types/typeof-this.src.ts
@@ -0,0 +1,2 @@
+let self: typeof this;
+let foo: typeof this.foo;
diff --git a/packages/typescript-estree/src/convert.ts b/packages/typescript-estree/src/convert.ts
@@ -20,6 +20,7 @@ import {
   isComputedProperty,
   isESTreeClassMember,
   isOptional,
+  isThisInTypeQuery,
   TSError,
   unescapeStringLiteralText,
 } from './node-utils';
@@ -799,6 +800,13 @@ export class Converter {
       }
 
       case SyntaxKind.Identifier: {
+        if (isThisInTypeQuery(node)) {
+          // special case for `typeof this.foo` - TS emits an Identifier for `this`
+          // but we want to treat it as a ThisExpression for consistency
+          return this.createNode<TSESTree.ThisExpression>(node, {
+            type: AST_NODE_TYPES.ThisExpression,
+          });
+        }
         return this.createNode<TSESTree.Identifier>(node, {
           type: AST_NODE_TYPES.Identifier,
           name: node.text,

diff --git a/packages/typescript-estree/src/node-utils.ts b/packages/typescript-estree/src/node-utils.ts
@@ -662,3 +662,29 @@ export function firstDefined<T, U>(
   }
   return undefined;
 }
+
+export function identifierIsThisKeyword(id: ts.Identifier): boolean {
+  return id.originalKeywordKind === SyntaxKind.ThisKeyword;
+}
+
+export function isThisIdentifier(
+  node: ts.Node | undefined,
+): node is ts.Identifier {
+  return (
+    !!node &&
+    node.kind === SyntaxKind.Identifier &&
+    identifierIsThisKeyword(node as ts.Identifier)
+  );
+}
+
+export function isThisInTypeQuery(node: ts.Node): boolean {
+  if (!isThisIdentifier(node)) {
+    return false;
+  }
+
+  while (ts.isQualifiedName(node.parent) && node.parent.left === node) {
+    node = node.parent;
+  }
+
+  return node.parent.kind === SyntaxKind.TypeQuery;
+}
diff --git a/packages/typescript-estree/src/ts-estree/estree-to-ts-node-types.ts b/packages/typescript-estree/src/ts-estree/estree-to-ts-node-types.ts
@@ -149,7 +149,10 @@ export interface EstreeToTsNodeTypes {
   [AST_NODE_TYPES.TemplateLiteral]:
     | ts.NoSubstitutionTemplateLiteral
     | ts.TemplateExpression;
-  [AST_NODE_TYPES.ThisExpression]: ts.ThisExpression | ts.KeywordTypeNode;
+  [AST_NODE_TYPES.ThisExpression]:
+    | ts.ThisExpression
+    | ts.KeywordTypeNode
+    | ts.Identifier;
   [AST_NODE_TYPES.ThrowStatement]: ts.ThrowStatement;
   [AST_NODE_TYPES.TryStatement]: ts.TryStatement;
   [AST_NODE_TYPES.TSAbstractPropertyDefinition]: ts.PropertyDeclaration;

diff --git a/packages/typescript-estree/tests/ast-alignment/utils.ts b/packages/typescript-estree/tests/ast-alignment/utils.ts
@@ -1,6 +1,6 @@
 // babel types are something we don't really care about
 /* eslint-disable @typescript-eslint/no-explicit-any, @typescript-eslint/no-unsafe-assignment, @typescript-eslint/no-unsafe-member-access, @typescript-eslint/restrict-plus-operands */
-import type { File, Program } from '@babel/types';
+import type { File, Identifier, Program, TSTypeQuery } from '@babel/types';
 import { AST_NODE_TYPES, TSESTree } from '../../src/ts-estree';
 import { deeplyCopy, omitDeep } from '../../tools/test-utils';
 
@@ -295,6 +295,30 @@ export function preprocessBabylonAST(ast: File): any {
           delete node.loc.start.index;
         }
       },
+      /**
+       * ts-estree: `this` in `typeof this` has been converted from `Identifier` to `ThisExpression`
+       * @see https://github.com/typescript-eslint/typescript-eslint/pull/4382
+       */
+      TSTypeQuery(node: any) {
+        const { exprName } = node as TSTypeQuery;
+        let identifier: Identifier;
+        if (exprName.type === AST_NODE_TYPES.TSImportType) {
+          return;
+        } else if (exprName.type === AST_NODE_TYPES.TSQualifiedName) {
+          let iter = exprName;
+          while (iter.left.type === AST_NODE_TYPES.TSQualifiedName) {
+            iter = iter.left;
+          }
+          identifier = iter.left;
+        } else {
+          identifier = exprName;
+        }
+
+        if (identifier.name === 'this') {
+          (identifier.type as string) = AST_NODE_TYPES.ThisExpression;
+          delete (identifier as { name?: string }).name;
+        }
+      },
     },
   );
 }

diff --git a/packages/typescript-estree/tests/lib/__snapshots__/semantic-diagnostics-enabled.test.ts.snap b/packages/typescript-estree/tests/lib/__snapshots__/semantic-diagnostics-enabled.test.ts.snap
@@ -2786,6 +2786,8 @@ exports[`Parse all fixtures with "errorOnTypeScriptSyntacticAndSemanticIssues" e
 
 exports[`Parse all fixtures with "errorOnTypeScriptSyntacticAndSemanticIssues" enabled fixtures/typescript/types/typeof.src 1`] = `"TEST OUTPUT: No semantic or syntactic issues found"`;
 
+exports[`Parse all fixtures with "errorOnTypeScriptSyntacticAndSemanticIssues" enabled fixtures/typescript/types/typeof-this.src 1`] = `"TEST OUTPUT: No semantic or syntactic issues found"`;
+
 exports[`Parse all fixtures with "errorOnTypeScriptSyntacticAndSemanticIssues" enabled fixtures/typescript/types/typeof-with-type-parameters.src 1`] = `"TEST OUTPUT: No semantic or syntactic issues found"`;
 
 exports[`Parse all fixtures with "errorOnTypeScriptSyntacticAndSemanticIssues" enabled fixtures/typescript/types/union-intersection.src 1`] = `"TEST OUTPUT: No semantic or syntactic issues found"`;
Original file line number	Diff line number	Diff line change
		@@ -0,0 +1,2 @@
		let self: typeof this;
		let foo: typeof this.foo;