Typed 'this' in object literal methods

src/compiler/types.ts

@@ -519,6 +519,8 @@
         /* @internal */ localSymbol?: Symbol;           // Local symbol declared by node (initialized by binding only for exported nodes)
         /* @internal */ flowNode?: FlowNode;            // Associated FlowNode (initialized by binding)
         /* @internal */ emitNode?: EmitNode;            // Associated EmitNode (initialized by transforms)
+        /* @internal */ contextualType?: Type;          // Used to temporarily assign a contextual type during overload resolution
+        /* @internal */ contextualMapper?: TypeMapper;  // Mapper for contextual type
     }
 
     export interface NodeArray<T extends Node> extends Array<T>, TextRange {
@@ -957,7 +959,6 @@
 
     export interface Expression extends Node {
         _expressionBrand: any;
-        contextualType?: Type;  // Used to temporarily assign a contextual type during overload resolution
     }
 
     export interface OmittedExpression extends Expression {

src/lib/es5.d.ts

@@ -1366,6 +1366,11 @@ type Record<K extends string, T> = {
     [P in K]: T;
 }
 
+/**
+ * Marker for contextual 'this' type
+ */
+interface ThisType<T> { }
+
 /**
   * Represents a raw buffer of binary data, which is used to store data for the
   * different typed arrays. ArrayBuffers cannot be read from or written to directly,

tests/baselines/reference/castTest.symbols

@@ -71,7 +71,13 @@ var p_cast = <Point> ({
 
         return new Point(this.x + dx, this.y + dy);
 >Point : Symbol(Point, Decl(castTest.ts, 11, 37))
+>this.x : Symbol(Point.x, Decl(castTest.ts, 14, 1))
+>this : Symbol(Point, Decl(castTest.ts, 11, 37))
+>x : Symbol(Point.x, Decl(castTest.ts, 14, 1))
 >dx : Symbol(dx, Decl(castTest.ts, 25, 18))
+>this.y : Symbol(Point.y, Decl(castTest.ts, 15, 14))
+>this : Symbol(Point, Decl(castTest.ts, 11, 37))
+>y : Symbol(Point.y, Decl(castTest.ts, 15, 14))
 >dy : Symbol(dy, Decl(castTest.ts, 25, 21))
 
     },

tests/baselines/reference/castTest.types

@@ -91,15 +91,15 @@ var p_cast = <Point> ({
         return new Point(this.x + dx, this.y + dy);
 >new Point(this.x + dx, this.y + dy) : Point
 >Point : typeof Point
->this.x + dx : any
->this.x : any
->this : any
->x : any
+>this.x + dx : number
+>this.x : number
+>this : Point
+>x : number
 >dx : number
->this.y + dy : any
->this.y : any
->this : any
->y : any
+>this.y + dy : number
+>this.y : number
+>this : Point
+>y : number
 >dy : number
 
     },

tests/baselines/reference/commentsOnObjectLiteral3.symbols

@@ -21,13 +21,20 @@ var v = {
 >a : Symbol(a, Decl(commentsOnObjectLiteral3.ts, 8, 13), Decl(commentsOnObjectLiteral3.ts, 12, 18))
 
   return this.prop;
+>this.prop : Symbol(prop, Decl(commentsOnObjectLiteral3.ts, 1, 9))
+>this : Symbol(v, Decl(commentsOnObjectLiteral3.ts, 1, 7))
+>prop : Symbol(prop, Decl(commentsOnObjectLiteral3.ts, 1, 9))
+
  } /*trailing 1*/,
  //setter
  set a(value) {
 >a : Symbol(a, Decl(commentsOnObjectLiteral3.ts, 8, 13), Decl(commentsOnObjectLiteral3.ts, 12, 18))
 >value : Symbol(value, Decl(commentsOnObjectLiteral3.ts, 14, 7))
 
   this.prop = value;
+>this.prop : Symbol(prop, Decl(commentsOnObjectLiteral3.ts, 1, 9))
+>this : Symbol(v, Decl(commentsOnObjectLiteral3.ts, 1, 7))
+>prop : Symbol(prop, Decl(commentsOnObjectLiteral3.ts, 1, 9))
 >value : Symbol(value, Decl(commentsOnObjectLiteral3.ts, 14, 7))
 
  } // trailing 2

tests/baselines/reference/commentsOnObjectLiteral3.types

@@ -1,8 +1,8 @@
 === tests/cases/compiler/commentsOnObjectLiteral3.ts ===
 
 var v = {
->v : { prop: number; func: () => void; func1(): void; a: any; }
->{ //property prop: 1 /* multiple trailing comments */ /*trailing comments*/, //property func: function () { }, //PropertyName + CallSignature func1() { }, //getter get a() {  return this.prop; } /*trailing 1*/, //setter set a(value) {  this.prop = value; } // trailing 2} : { prop: number; func: () => void; func1(): void; a: any; }
+>v : { prop: number; func: () => void; func1(): void; a: number; }
+>{ //property prop: 1 /* multiple trailing comments */ /*trailing comments*/, //property func: function () { }, //PropertyName + CallSignature func1() { }, //getter get a() {  return this.prop; } /*trailing 1*/, //setter set a(value) {  this.prop = value; } // trailing 2} : { prop: number; func: () => void; func1(): void; a: number; }
 
  //property
  prop: 1 /* multiple trailing comments */ /*trailing comments*/,
@@ -21,25 +21,25 @@ var v = {
 
  //getter
  get a() {
->a : any
+>a : number
 
   return this.prop;
->this.prop : any
->this : any
->prop : any
+>this.prop : number
+>this : { prop: number; func: () => void; func1(): void; a: number; }
+>prop : number
 
  } /*trailing 1*/,
  //setter
  set a(value) {
->a : any
->value : any
+>a : number
+>value : number
 
   this.prop = value;
->this.prop = value : any
->this.prop : any
->this : any
->prop : any
->value : any
+>this.prop = value : number
+>this.prop : number
+>this : { prop: number; func: () => void; func1(): void; a: number; }
+>prop : number
+>value : number
 
  } // trailing 2
 };

tests/baselines/reference/declFileObjectLiteralWithAccessors.symbols

@@ -15,6 +15,9 @@ function /*1*/makePoint(x: number) {
         set x(a: number) { this.b = a; }
 >x : Symbol(x, Decl(declFileObjectLiteralWithAccessors.ts, 3, 14), Decl(declFileObjectLiteralWithAccessors.ts, 4, 30))
 >a : Symbol(a, Decl(declFileObjectLiteralWithAccessors.ts, 5, 14))
+>this.b : Symbol(b, Decl(declFileObjectLiteralWithAccessors.ts, 2, 12))
+>this : Symbol(__object, Decl(declFileObjectLiteralWithAccessors.ts, 2, 10))
+>b : Symbol(b, Decl(declFileObjectLiteralWithAccessors.ts, 2, 12))
 >a : Symbol(a, Decl(declFileObjectLiteralWithAccessors.ts, 5, 14))
 
     };

tests/baselines/reference/declFileObjectLiteralWithAccessors.types

@@ -19,9 +19,9 @@ function /*1*/makePoint(x: number) {
 >x : number
 >a : number
 >this.b = a : number
->this.b : any
->this : any
->b : any
+>this.b : number
+>this : { b: number; x: number; }
+>b : number
 >a : number
 
     };

tests/baselines/reference/declFileObjectLiteralWithOnlySetter.symbols

@@ -11,6 +11,9 @@ function /*1*/makePoint(x: number) {
         set x(a: number) { this.b = a; }
 >x : Symbol(x, Decl(declFileObjectLiteralWithOnlySetter.ts, 3, 14))
 >a : Symbol(a, Decl(declFileObjectLiteralWithOnlySetter.ts, 4, 14))
+>this.b : Symbol(b, Decl(declFileObjectLiteralWithOnlySetter.ts, 2, 12))
+>this : Symbol(__object, Decl(declFileObjectLiteralWithOnlySetter.ts, 2, 10))
+>b : Symbol(b, Decl(declFileObjectLiteralWithOnlySetter.ts, 2, 12))
 >a : Symbol(a, Decl(declFileObjectLiteralWithOnlySetter.ts, 4, 14))
 
     };

tests/baselines/reference/declFileObjectLiteralWithOnlySetter.types

@@ -15,9 +15,9 @@ function /*1*/makePoint(x: number) {
 >x : number
 >a : number
 >this.b = a : number
->this.b : any
->this : any
->b : any
+>this.b : number
+>this : { b: number; x: number; }
+>b : number
 >a : number
 
     };

tests/baselines/reference/declarationEmitThisPredicates02.errors.txt

@@ -13,7 +13,7 @@ tests/cases/conformance/declarationEmit/typePredicates/declarationEmitThisPredic
         m(): this is Foo {
              ~~~~
 !!! error TS2526: A 'this' type is available only in a non-static member of a class or interface.
-            let dis = this as Foo;
+            let dis = this as {} as Foo;
             return dis.a != null && dis.b != null && dis.c != null;
         }
     }

tests/baselines/reference/declarationEmitThisPredicates02.js

@@ -8,7 +8,7 @@ export interface Foo {
 
 export const obj = {
     m(): this is Foo {
-        let dis = this as Foo;
+        let dis = this as {} as Foo;
         return dis.a != null && dis.b != null && dis.c != null;
     }
 }

tests/baselines/reference/declarationEmitThisPredicatesWithPrivateName02.errors.txt

@@ -16,7 +16,7 @@ tests/cases/conformance/declarationEmit/typePredicates/declarationEmitThisPredic
         m(): this is Foo {
              ~~~~
 !!! error TS2526: A 'this' type is available only in a non-static member of a class or interface.
-            let dis = this as Foo;
+            let dis = this as {} as Foo;
             return dis.a != null && dis.b != null && dis.c != null;
         }
     }

tests/baselines/reference/declarationEmitThisPredicatesWithPrivateName02.js

@@ -8,7 +8,7 @@ interface Foo {
 
 export const obj = {
     m(): this is Foo {
-        let dis = this as Foo;
+        let dis = this as {} as Foo;
         return dis.a != null && dis.b != null && dis.c != null;
     }
 }

tests/baselines/reference/emitCompoundExponentiationAssignmentWithIndexingOnLHS3.symbols

@@ -8,11 +8,18 @@ var object = {
 
     get 0() {
         return this._0;
+>this._0 : Symbol(_0, Decl(emitCompoundExponentiationAssignmentWithIndexingOnLHS3.ts, 1, 14))
+>this : Symbol(object, Decl(emitCompoundExponentiationAssignmentWithIndexingOnLHS3.ts, 1, 12))
+>_0 : Symbol(_0, Decl(emitCompoundExponentiationAssignmentWithIndexingOnLHS3.ts, 1, 14))
+
     },
     set 0(x: number) {
 >x : Symbol(x, Decl(emitCompoundExponentiationAssignmentWithIndexingOnLHS3.ts, 6, 10))
 
         this._0 = x;
+>this._0 : Symbol(_0, Decl(emitCompoundExponentiationAssignmentWithIndexingOnLHS3.ts, 1, 14))
+>this : Symbol(object, Decl(emitCompoundExponentiationAssignmentWithIndexingOnLHS3.ts, 1, 12))
+>_0 : Symbol(_0, Decl(emitCompoundExponentiationAssignmentWithIndexingOnLHS3.ts, 1, 14))
 >x : Symbol(x, Decl(emitCompoundExponentiationAssignmentWithIndexingOnLHS3.ts, 6, 10))
 
     },

tests/baselines/reference/emitCompoundExponentiationAssignmentWithIndexingOnLHS3.types

@@ -10,19 +10,19 @@ var object = {
 
     get 0() {
         return this._0;
->this._0 : any
->this : any
->_0 : any
+>this._0 : number
+>this : { _0: number; 0: number; }
+>_0 : number
 
     },
     set 0(x: number) {
 >x : number
 
         this._0 = x;
 >this._0 = x : number
->this._0 : any
->this : any
->_0 : any
+>this._0 : number
+>this : { _0: number; 0: number; }
+>_0 : number
 >x : number
 
     },

tests/baselines/reference/fatarrowfunctions.symbols

@@ -163,6 +163,11 @@ var messenger = {
 
         setTimeout(() => { this.message.toString(); }, 3000);
 >setTimeout : Symbol(setTimeout, Decl(fatarrowfunctions.ts, 34, 1))
+>this.message.toString : Symbol(String.toString, Decl(lib.d.ts, --, --))
+>this.message : Symbol(message, Decl(fatarrowfunctions.ts, 38, 17))
+>this : Symbol(messenger, Decl(fatarrowfunctions.ts, 38, 15))
+>message : Symbol(message, Decl(fatarrowfunctions.ts, 38, 17))
+>toString : Symbol(String.toString, Decl(lib.d.ts, --, --))
     }
 };
 

tests/baselines/reference/fatarrowfunctions.types

@@ -234,12 +234,12 @@ var messenger = {
 >setTimeout(() => { this.message.toString(); }, 3000) : number
 >setTimeout : (expression: any, msec?: number, language?: any) => number
 >() => { this.message.toString(); } : () => void
->this.message.toString() : any
->this.message.toString : any
->this.message : any
->this : any
->message : any
->toString : any
+>this.message.toString() : string
+>this.message.toString : () => string
+>this.message : string
+>this : { message: string; start: () => void; }
+>message : string
+>toString : () => string
 >3000 : 3000
     }
 };

tests/baselines/reference/fatarrowfunctionsInFunctions.symbols

@@ -16,12 +16,17 @@ var messenger = {
 
         var _self = this;
 >_self : Symbol(_self, Decl(fatarrowfunctionsInFunctions.ts, 5, 11))
+>this : Symbol(messenger, Decl(fatarrowfunctionsInFunctions.ts, 2, 15))
 
         setTimeout(function() {
 >setTimeout : Symbol(setTimeout, Decl(fatarrowfunctionsInFunctions.ts, 0, 0))
 
             _self.message.toString(); 
+>_self.message.toString : Symbol(String.toString, Decl(lib.d.ts, --, --))
+>_self.message : Symbol(message, Decl(fatarrowfunctionsInFunctions.ts, 2, 17))
 >_self : Symbol(_self, Decl(fatarrowfunctionsInFunctions.ts, 5, 11))
+>message : Symbol(message, Decl(fatarrowfunctionsInFunctions.ts, 2, 17))
+>toString : Symbol(String.toString, Decl(lib.d.ts, --, --))
 
         }, 3000); 
     }

tests/baselines/reference/fatarrowfunctionsInFunctions.types

@@ -18,21 +18,21 @@ var messenger = {
 >function() {        var _self = this;        setTimeout(function() {            _self.message.toString();         }, 3000);     } : () => void
 
         var _self = this;
->_self : any
->this : any
+>_self : { message: string; start: () => void; }
+>this : { message: string; start: () => void; }
 
         setTimeout(function() {
 >setTimeout(function() {            _self.message.toString();         }, 3000) : number
 >setTimeout : (expression: any, msec?: number, language?: any) => number
 >function() {            _self.message.toString();         } : () => void
 
             _self.message.toString(); 
->_self.message.toString() : any
->_self.message.toString : any
->_self.message : any
->_self : any
->message : any
->toString : any
+>_self.message.toString() : string
+>_self.message.toString : () => string
+>_self.message : string
+>_self : { message: string; start: () => void; }
+>message : string
+>toString : () => string
 
         }, 3000); 
 >3000 : 3000

tests/baselines/reference/looseThisTypeInFunctions.errors.txt

@@ -1,12 +1,13 @@
 tests/cases/conformance/types/thisType/looseThisTypeInFunctions.ts(21,1): error TS2322: Type '(this: C, m: number) => number' is not assignable to type '(this: void, m: number) => number'.
   The 'this' types of each signature are incompatible.
     Type 'void' is not assignable to type 'C'.
+tests/cases/conformance/types/thisType/looseThisTypeInFunctions.ts(25,27): error TS2339: Property 'length' does not exist on type 'number'.
 tests/cases/conformance/types/thisType/looseThisTypeInFunctions.ts(33,28): error TS2339: Property 'length' does not exist on type 'number'.
 tests/cases/conformance/types/thisType/looseThisTypeInFunctions.ts(37,9): error TS2684: The 'this' context of type 'void' is not assignable to method's 'this' of type 'I'.
 tests/cases/conformance/types/thisType/looseThisTypeInFunctions.ts(46,20): error TS2339: Property 'length' does not exist on type 'number'.
 
 
-==== tests/cases/conformance/types/thisType/looseThisTypeInFunctions.ts (4 errors) ====
+==== tests/cases/conformance/types/thisType/looseThisTypeInFunctions.ts (5 errors) ====
     interface I {
         n: number;
         explicitThis(this: this, m: number): number;
@@ -36,6 +37,8 @@ tests/cases/conformance/types/thisType/looseThisTypeInFunctions.ts(46,20): error
         n: 101,
         explicitThis: function (m: number) {
             return m + this.n.length; // error, 'length' does not exist on 'number'
+                              ~~~~~~
+!!! error TS2339: Property 'length' does not exist on type 'number'.
         },
         implicitThis(m: number): number { return m; }
     };

tests/baselines/reference/objectSpread.symbols

@@ -200,6 +200,9 @@ let cplus: { p: number, plus(): void } = { ...c, plus() { return this.p + 1; } }
 >plus : Symbol(plus, Decl(objectSpread.ts, 49, 23))
 >c : Symbol(c, Decl(objectSpread.ts, 45, 3))
 >plus : Symbol(plus, Decl(objectSpread.ts, 49, 48))
+>this.p : Symbol(p, Decl(objectSpread.ts, 49, 12))
+>this : Symbol(cplus, Decl(objectSpread.ts, 49, 10))
+>p : Symbol(p, Decl(objectSpread.ts, 49, 12))
 
 cplus.plus();
 >cplus.plus : Symbol(plus, Decl(objectSpread.ts, 49, 23))

tests/baselines/reference/objectSpread.types

@@ -263,13 +263,13 @@ let cplus: { p: number, plus(): void } = { ...c, plus() { return this.p + 1; } }
 >cplus : { p: number; plus(): void; }
 >p : number
 >plus : () => void
->{ ...c, plus() { return this.p + 1; } } : { plus(): any; p: number; }
+>{ ...c, plus() { return this.p + 1; } } : { plus(): number; p: number; }
 >c : C
->plus : () => any
->this.p + 1 : any
->this.p : any
->this : any
->p : any
+>plus : () => number
+>this.p + 1 : number
+>this.p : number
+>this : { p: number; plus(): void; }
+>p : number
 >1 : 1
 
 cplus.plus();