fix(52594): this incorrectly applies in TS files in typeToString (#52610)

src/compiler/checker.ts

@@ -7307,7 +7307,7 @@ export function createTypeChecker(host: TypeCheckerHost): TypeChecker {
             if (signature.thisParameter) {
                 return symbolToParameterDeclaration(signature.thisParameter, context);
             }
-            if (signature.declaration) {
+            if (signature.declaration && isInJSFile(signature.declaration)) {
                 const thisTag = getJSDocThisTag(signature.declaration);
                 if (thisTag && thisTag.typeExpression) {
                     return factory.createParameterDeclaration(

tests/baselines/reference/quickInfoJsDocThisTag.baseline

@@ -0,0 +1,68 @@
+=== /a.ts ===
+// /** @this {number} */
+// function f() {
+//          ^
+// | ----------------------------------------------------------------------
+// | function f(): void
+// | @this 
+// | ----------------------------------------------------------------------
+//     this
+// }
+
+[
+  {
+    "marker": {
+      "fileName": "/a.ts",
+      "position": 32,
+      "name": ""
+    },
+    "item": {
+      "kind": "function",
+      "kindModifiers": "",
+      "textSpan": {
+        "start": 31,
+        "length": 1
+      },
+      "displayParts": [
+        {
+          "text": "function",
+          "kind": "keyword"
+        },
+        {
+          "text": " ",
+          "kind": "space"
+        },
+        {
+          "text": "f",
+          "kind": "functionName"
+        },
+        {
+          "text": "(",
+          "kind": "punctuation"
+        },
+        {
+          "text": ")",
+          "kind": "punctuation"
+        },
+        {
+          "text": ":",
+          "kind": "punctuation"
+        },
+        {
+          "text": " ",
+          "kind": "space"
+        },
+        {
+          "text": "void",
+          "kind": "keyword"
+        }
+      ],
+      "documentation": [],
+      "tags": [
+        {
+          "name": "this"
+        }
+      ]
+    }
+  }
+]

tests/baselines/reference/thisInFunctionCall.types

@@ -84,7 +84,7 @@ class Test {
 
     /** @this {Test} */
     function (d) {
->function (d) {      console.log(d === this.data.length)    } : (this: Test, d: number) => void
+>function (d) {      console.log(d === this.data.length)    } : (d: number) => void
 >d : number
 
       console.log(d === this.data.length)
@@ -117,7 +117,7 @@ class Test {
 
     /** @this {Test} */
     function (d) {
->function (d) {      return d === this.data.length    } : (this: Test, d: number) => boolean
+>function (d) {      return d === this.data.length    } : (d: number) => boolean
 >d : number
 
       return d === this.data.length

tests/baselines/reference/thisInFunctionCallJs.errors.txt

@@ -0,0 +1,46 @@
+/a.js(9,26): error TS2683: 'this' implicitly has type 'any' because it does not have a type annotation.
+/a.js(15,31): error TS2683: 'this' implicitly has type 'any' because it does not have a type annotation.
+
+
+==== /a.js (2 errors) ====
+    class Test {
+        constructor() {
+            /** @type {number[]} */
+            this.data = [1, 2, 3];
+        }
+    
+        finderRaw() {
+            this.data.find(function (d) {
+                return d === this.data.length
+                             ~~~~
+!!! error TS2683: 'this' implicitly has type 'any' because it does not have a type annotation.
+!!! related TS2738 /a.js:8:24: An outer value of 'this' is shadowed by this container.
+            })
+        }
+    
+        forEacherRaw() {
+            this.data.forEach(function (d) {
+                console.log(d === this.data.length)
+                                  ~~~~
+!!! error TS2683: 'this' implicitly has type 'any' because it does not have a type annotation.
+!!! related TS2738 /a.js:14:27: An outer value of 'this' is shadowed by this container.
+            })
+        }
+    
+        forEacher() {
+            this.data.forEach(
+            /** @this {Test} */
+            function (d) {
+                console.log(d === this.data.length)
+            }, this)
+        }
+    
+        finder() {
+            this.data.find(
+            /** @this {Test} */
+            function (d) {
+                return d === this.data.length
+            }, this)
+        }
+    }
+    

tests/baselines/reference/thisInFunctionCallJs.symbols

@@ -0,0 +1,105 @@
+=== /a.js ===
+class Test {
+>Test : Symbol(Test, Decl(a.js, 0, 0))
+
+    constructor() {
+        /** @type {number[]} */
+        this.data = [1, 2, 3];
+>this.data : Symbol(Test.data, Decl(a.js, 1, 19))
+>this : Symbol(Test, Decl(a.js, 0, 0))
+>data : Symbol(Test.data, Decl(a.js, 1, 19))
+    }
+
+    finderRaw() {
+>finderRaw : Symbol(Test.finderRaw, Decl(a.js, 4, 5))
+
+        this.data.find(function (d) {
+>this.data.find : Symbol(Array.find, Decl(lib.es2015.core.d.ts, --, --), Decl(lib.es2015.core.d.ts, --, --))
+>this.data : Symbol(Test.data, Decl(a.js, 1, 19))
+>this : Symbol(Test, Decl(a.js, 0, 0))
+>data : Symbol(Test.data, Decl(a.js, 1, 19))
+>find : Symbol(Array.find, Decl(lib.es2015.core.d.ts, --, --), Decl(lib.es2015.core.d.ts, --, --))
+>d : Symbol(d, Decl(a.js, 7, 33))
+
+            return d === this.data.length
+>d : Symbol(d, Decl(a.js, 7, 33))
+
+        })
+    }
+
+    forEacherRaw() {
+>forEacherRaw : Symbol(Test.forEacherRaw, Decl(a.js, 10, 5))
+
+        this.data.forEach(function (d) {
+>this.data.forEach : Symbol(Array.forEach, Decl(lib.es5.d.ts, --, --))
+>this.data : Symbol(Test.data, Decl(a.js, 1, 19))
+>this : Symbol(Test, Decl(a.js, 0, 0))
+>data : Symbol(Test.data, Decl(a.js, 1, 19))
+>forEach : Symbol(Array.forEach, Decl(lib.es5.d.ts, --, --))
+>d : Symbol(d, Decl(a.js, 13, 36))
+
+            console.log(d === this.data.length)
+>console.log : Symbol(Console.log, Decl(lib.dom.d.ts, --, --))
+>console : Symbol(console, Decl(lib.dom.d.ts, --, --))
+>log : Symbol(Console.log, Decl(lib.dom.d.ts, --, --))
+>d : Symbol(d, Decl(a.js, 13, 36))
+
+        })
+    }
+
+    forEacher() {
+>forEacher : Symbol(Test.forEacher, Decl(a.js, 16, 5))
+
+        this.data.forEach(
+>this.data.forEach : Symbol(Array.forEach, Decl(lib.es5.d.ts, --, --))
+>this.data : Symbol(Test.data, Decl(a.js, 1, 19))
+>this : Symbol(Test, Decl(a.js, 0, 0))
+>data : Symbol(Test.data, Decl(a.js, 1, 19))
+>forEach : Symbol(Array.forEach, Decl(lib.es5.d.ts, --, --))
+
+        /** @this {Test} */
+        function (d) {
+>d : Symbol(d, Decl(a.js, 21, 18))
+
+            console.log(d === this.data.length)
+>console.log : Symbol(Console.log, Decl(lib.dom.d.ts, --, --))
+>console : Symbol(console, Decl(lib.dom.d.ts, --, --))
+>log : Symbol(Console.log, Decl(lib.dom.d.ts, --, --))
+>d : Symbol(d, Decl(a.js, 21, 18))
+>this.data.length : Symbol(Array.length, Decl(lib.es5.d.ts, --, --))
+>this.data : Symbol(Test.data, Decl(a.js, 1, 19))
+>this : Symbol(this)
+>data : Symbol(Test.data, Decl(a.js, 1, 19))
+>length : Symbol(Array.length, Decl(lib.es5.d.ts, --, --))
+
+        }, this)
+>this : Symbol(Test, Decl(a.js, 0, 0))
+    }
+
+    finder() {
+>finder : Symbol(Test.finder, Decl(a.js, 24, 5))
+
+        this.data.find(
+>this.data.find : Symbol(Array.find, Decl(lib.es2015.core.d.ts, --, --), Decl(lib.es2015.core.d.ts, --, --))
+>this.data : Symbol(Test.data, Decl(a.js, 1, 19))
+>this : Symbol(Test, Decl(a.js, 0, 0))
+>data : Symbol(Test.data, Decl(a.js, 1, 19))
+>find : Symbol(Array.find, Decl(lib.es2015.core.d.ts, --, --), Decl(lib.es2015.core.d.ts, --, --))
+
+        /** @this {Test} */
+        function (d) {
+>d : Symbol(d, Decl(a.js, 29, 18))
+
+            return d === this.data.length
+>d : Symbol(d, Decl(a.js, 29, 18))
+>this.data.length : Symbol(Array.length, Decl(lib.es5.d.ts, --, --))
+>this.data : Symbol(Test.data, Decl(a.js, 1, 19))
+>this : Symbol(this)
+>data : Symbol(Test.data, Decl(a.js, 1, 19))
+>length : Symbol(Array.length, Decl(lib.es5.d.ts, --, --))
+
+        }, this)
+>this : Symbol(Test, Decl(a.js, 0, 0))
+    }
+}
+

tests/baselines/reference/thisInFunctionCallJs.types

@@ -0,0 +1,134 @@
+=== /a.js ===
+class Test {
+>Test : Test
+
+    constructor() {
+        /** @type {number[]} */
+        this.data = [1, 2, 3];
+>this.data = [1, 2, 3] : number[]
+>this.data : number[]
+>this : this
+>data : number[]
+>[1, 2, 3] : number[]
+>1 : 1
+>2 : 2
+>3 : 3
+    }
+
+    finderRaw() {
+>finderRaw : () => void
+
+        this.data.find(function (d) {
+>this.data.find(function (d) {            return d === this.data.length        }) : number
+>this.data.find : { <S extends number>(predicate: (value: number, index: number, obj: number[]) => value is S, thisArg?: any): S; (predicate: (value: number, index: number, obj: number[]) => unknown, thisArg?: any): number; }
+>this.data : number[]
+>this : this
+>data : number[]
+>find : { <S extends number>(predicate: (value: number, index: number, obj: number[]) => value is S, thisArg?: any): S; (predicate: (value: number, index: number, obj: number[]) => unknown, thisArg?: any): number; }
+>function (d) {            return d === this.data.length        } : (d: number) => boolean
+>d : number
+
+            return d === this.data.length
+>d === this.data.length : boolean
+>d : number
+>this.data.length : any
+>this.data : any
+>this : any
+>data : any
+>length : any
+
+        })
+    }
+
+    forEacherRaw() {
+>forEacherRaw : () => void
+
+        this.data.forEach(function (d) {
+>this.data.forEach(function (d) {            console.log(d === this.data.length)        }) : void
+>this.data.forEach : (callbackfn: (value: number, index: number, array: number[]) => void, thisArg?: any) => void
+>this.data : number[]
+>this : this
+>data : number[]
+>forEach : (callbackfn: (value: number, index: number, array: number[]) => void, thisArg?: any) => void
+>function (d) {            console.log(d === this.data.length)        } : (d: number) => void
+>d : number
+
+            console.log(d === this.data.length)
+>console.log(d === this.data.length) : void
+>console.log : (...data: any[]) => void
+>console : Console
+>log : (...data: any[]) => void
+>d === this.data.length : boolean
+>d : number
+>this.data.length : any
+>this.data : any
+>this : any
+>data : any
+>length : any
+
+        })
+    }
+
+    forEacher() {
+>forEacher : () => void
+
+        this.data.forEach(
+>this.data.forEach(        /** @this {Test} */        function (d) {            console.log(d === this.data.length)        }, this) : void
+>this.data.forEach : (callbackfn: (value: number, index: number, array: number[]) => void, thisArg?: any) => void
+>this.data : number[]
+>this : this
+>data : number[]
+>forEach : (callbackfn: (value: number, index: number, array: number[]) => void, thisArg?: any) => void
+
+        /** @this {Test} */
+        function (d) {
+>function (d) {            console.log(d === this.data.length)        } : (this: Test, d: number) => void
+>d : number
+
+            console.log(d === this.data.length)
+>console.log(d === this.data.length) : void
+>console.log : (...data: any[]) => void
+>console : Console
+>log : (...data: any[]) => void
+>d === this.data.length : boolean
+>d : number
+>this.data.length : number
+>this.data : number[]
+>this : Test
+>data : number[]
+>length : number
+
+        }, this)
+>this : this
+    }
+
+    finder() {
+>finder : () => void
+
+        this.data.find(
+>this.data.find(        /** @this {Test} */        function (d) {            return d === this.data.length        }, this) : number
+>this.data.find : { <S extends number>(predicate: (value: number, index: number, obj: number[]) => value is S, thisArg?: any): S; (predicate: (value: number, index: number, obj: number[]) => unknown, thisArg?: any): number; }
+>this.data : number[]
+>this : this
+>data : number[]
+>find : { <S extends number>(predicate: (value: number, index: number, obj: number[]) => value is S, thisArg?: any): S; (predicate: (value: number, index: number, obj: number[]) => unknown, thisArg?: any): number; }
+
+        /** @this {Test} */
+        function (d) {
+>function (d) {            return d === this.data.length        } : (this: Test, d: number) => boolean
+>d : number
+
+            return d === this.data.length
+>d === this.data.length : boolean
+>d : number
+>this.data.length : number
+>this.data : number[]
+>this : Test
+>data : number[]
+>length : number
+
+        }, this)
+>this : this
+    }
+}
+

tests/cases/compiler/thisInFunctionCallJs.ts

@@ -0,0 +1,41 @@
+// @target: es2015
+// @allowJs: true
+// @checkJs: true
+// @noEmit: true
+// @noImplicitThis: true
+// @filename: /a.js
+
+class Test {
+    constructor() {
+        /** @type {number[]} */
+        this.data = [1, 2, 3];
+    }
+
+    finderRaw() {
+        this.data.find(function (d) {
+            return d === this.data.length
+        })
+    }
+
+    forEacherRaw() {
+        this.data.forEach(function (d) {
+            console.log(d === this.data.length)
+        })
+    }
+
+    forEacher() {
+        this.data.forEach(
+        /** @this {Test} */
+        function (d) {
+            console.log(d === this.data.length)
+        }, this)
+    }
+
+    finder() {
+        this.data.find(
+        /** @this {Test} */
+        function (d) {
+            return d === this.data.length
+        }, this)
+    }
+}

tests/cases/fourslash/quickInfoJsDocThisTag.ts

@@ -0,0 +1,9 @@
+/// <reference path="fourslash.ts" />
+// @strict: true
+// @filename: /a.ts
+/////** @this {number} */
+////function f/**/() {
+////    this
+////}
+
+verify.baselineQuickInfo();