Support interpreting non-literal computed properties in classes as implicit index signatures

src/compiler/emitter.ts

@@ -1163,6 +1163,7 @@ export const notImplementedResolver: EmitResolver = {
     getDeclarationStatementsForSourceFile: notImplemented,
     isImportRequiredByAugmentation: notImplemented,
     isDefinitelyReferenceToGlobalSymbolObject: notImplemented,
+    createLateBoundIndexSignatures: notImplemented,
 };
 
 const enum PipelinePhase {

src/compiler/transformers/declarations.ts

@@ -12,6 +12,7 @@ import {
     canHaveModifiers,
     canProduceDiagnostics,
     ClassDeclaration,
+    ClassElement,
     compact,
     concatenate,
     ConditionalTypeNode,
@@ -1654,7 +1655,8 @@ export function transformDeclarations(context: TransformationContext) {
                         /*initializer*/ undefined,
                     ),
                 ] : undefined;
-                const memberNodes = concatenate(concatenate(privateIdentifier, parameterProperties), visitNodes(input.members, visitDeclarationSubtree, isClassElement));
+                const lateIndexes = resolver.createLateBoundIndexSignatures(input, enclosingDeclaration, declarationEmitNodeBuilderFlags, declarationEmitInternalNodeBuilderFlags, symbolTracker);
+                const memberNodes = concatenate(concatenate(concatenate<ClassElement>(privateIdentifier, lateIndexes), parameterProperties), visitNodes(input.members, visitDeclarationSubtree, isClassElement));
                 const members = factory.createNodeArray(memberNodes);
 
                 const extendsClause = getEffectiveBaseTypeNode(input);

src/compiler/types.ts

@@ -5048,7 +5048,7 @@ export interface TypeChecker {
     /** @internal */ getTypeOfPropertyOfType(type: Type, propertyName: string): Type | undefined;
     getIndexInfoOfType(type: Type, kind: IndexKind): IndexInfo | undefined;
     getIndexInfosOfType(type: Type): readonly IndexInfo[];
-    getIndexInfosOfIndexSymbol: (indexSymbol: Symbol) => IndexInfo[];
+    getIndexInfosOfIndexSymbol: (indexSymbol: Symbol, siblingSymbols?: Symbol[] | undefined) => IndexInfo[];
     getSignaturesOfType(type: Type, kind: SignatureKind): readonly Signature[];
     getIndexTypeOfType(type: Type, kind: IndexKind): Type | undefined;
     /** @internal */ getIndexType(type: Type): Type;
@@ -5866,6 +5866,7 @@ export interface EmitResolver {
     getDeclarationStatementsForSourceFile(node: SourceFile, flags: NodeBuilderFlags, internalFlags: InternalNodeBuilderFlags, tracker: SymbolTracker): Statement[] | undefined;
     isImportRequiredByAugmentation(decl: ImportDeclaration): boolean;
     isDefinitelyReferenceToGlobalSymbolObject(node: Node): boolean;
+    createLateBoundIndexSignatures(cls: ClassLikeDeclaration, enclosingDeclaration: Node, flags: NodeBuilderFlags, internalFlags: InternalNodeBuilderFlags, tracker: SymbolTracker): IndexSignatureDeclaration[] | undefined;
 }
 
 // dprint-ignore

tests/baselines/reference/ES5SymbolProperty2.types

@@ -24,8 +24,8 @@ module M {
 >         : ^^^
     }
     (new C)[Symbol.iterator];
->(new C)[Symbol.iterator] : any
->                         : ^^^
+>(new C)[Symbol.iterator] : () => void
+>                         : ^^^^^^^^^^
 >(new C) : C
 >        : ^
 >new C : C
@@ -41,8 +41,8 @@ module M {
 }
 
 (new M.C)[Symbol.iterator];
->(new M.C)[Symbol.iterator] : any
->                           : ^^^
+>(new M.C)[Symbol.iterator] : () => void
+>                           : ^^^^^^^^^^
 >(new M.C) : M.C
 >          : ^^^
 >new M.C : M.C

tests/baselines/reference/ES5SymbolProperty3.types

@@ -19,7 +19,8 @@ class C {
 }
 
 (new C)[Symbol.iterator]
->(new C)[Symbol.iterator] : error
+>(new C)[Symbol.iterator] : () => void
+>                         : ^^^^^^^^^^
 >(new C) : C
 >        : ^
 >new C : C

tests/baselines/reference/ES5SymbolProperty4.types

@@ -23,7 +23,8 @@ class C {
 }
 
 (new C)[Symbol.iterator]
->(new C)[Symbol.iterator] : error
+>(new C)[Symbol.iterator] : () => void
+>                         : ^^^^^^^^^^
 >(new C) : C
 >        : ^
 >new C : C

tests/baselines/reference/ES5SymbolProperty5.errors.txt

@@ -0,0 +1,13 @@
+ES5SymbolProperty5.ts(7,26): error TS2554: Expected 0 arguments, but got 1.
+
+
+==== ES5SymbolProperty5.ts (1 errors) ====
+    var Symbol: { iterator: symbol };
+
+    class C {
+        [Symbol.iterator]() { }
+    }
+
+    (new C)[Symbol.iterator](0) // Should error
+                             ~
+!!! error TS2554: Expected 0 arguments, but got 1.

tests/baselines/reference/ES5SymbolProperty5.types

@@ -23,8 +23,10 @@ class C {
 }
 
 (new C)[Symbol.iterator](0) // Should error
->(new C)[Symbol.iterator](0) : error
->(new C)[Symbol.iterator] : error
+>(new C)[Symbol.iterator](0) : void
+>                            : ^^^^
+>(new C)[Symbol.iterator] : () => void
+>                         : ^^^^^^^^^^
 >(new C) : C
 >        : ^
 >new C : C

tests/baselines/reference/ES5SymbolProperty6.types

@@ -17,8 +17,8 @@ class C {
 }
 
 (new C)[Symbol.iterator]
->(new C)[Symbol.iterator] : any
->                         : ^^^
+>(new C)[Symbol.iterator] : () => void
+>                         : ^^^^^^^^^^
 >(new C) : C
 >        : ^
 >new C : C

tests/baselines/reference/ES5SymbolProperty7.types

@@ -21,7 +21,8 @@ class C {
 }
 
 (new C)[Symbol.iterator]
->(new C)[Symbol.iterator] : error
+>(new C)[Symbol.iterator] : () => void
+>                         : ^^^^^^^^^^
 >(new C) : C
 >        : ^
 >new C : C

tests/baselines/reference/api/typescript.d.ts

@@ -6119,7 +6119,7 @@ declare namespace ts {
         getPrivateIdentifierPropertyOfType(leftType: Type, name: string, location: Node): Symbol | undefined;
         getIndexInfoOfType(type: Type, kind: IndexKind): IndexInfo | undefined;
         getIndexInfosOfType(type: Type): readonly IndexInfo[];
-        getIndexInfosOfIndexSymbol: (indexSymbol: Symbol) => IndexInfo[];
+        getIndexInfosOfIndexSymbol: (indexSymbol: Symbol, siblingSymbols?: Symbol[] | undefined) => IndexInfo[];
         getSignaturesOfType(type: Type, kind: SignatureKind): readonly Signature[];
         getIndexTypeOfType(type: Type, kind: IndexKind): Type | undefined;
         getBaseTypes(type: InterfaceType): BaseType[];

tests/baselines/reference/classNonUniqueSymbolMethodHasSymbolIndexer.js

@@ -0,0 +1,39 @@
+//// [tests/cases/compiler/classNonUniqueSymbolMethodHasSymbolIndexer.ts] ////
+
+//// [classNonUniqueSymbolMethodHasSymbolIndexer.ts]
+declare const a: symbol;
+export class A {
+    [a]() { return 1 };
+}
+declare const e1: A[typeof a]; // no error, `A` has `symbol` index
+
+type Constructor = new (...args: any[]) => {};
+declare function Mix<T extends Constructor>(classish: T): T & (new (...args: any[]) => {mixed: true});
+
+export const Mixer = Mix(class {
+    [a]() { return 1 };
+});
+
+
+//// [classNonUniqueSymbolMethodHasSymbolIndexer.js]
+export class A {
+    [a]() { return 1; }
+    ;
+}
+export const Mixer = Mix(class {
+    [a]() { return 1; }
+    ;
+});
+
+
+//// [classNonUniqueSymbolMethodHasSymbolIndexer.d.ts]
+export declare class A {
+    [x: symbol]: () => number;
+}
+export declare const Mixer: {
+    new (): {
+        [x: symbol]: () => number;
+    };
+} & (new (...args: any[]) => {
+    mixed: true;
+});

tests/baselines/reference/classNonUniqueSymbolMethodHasSymbolIndexer.symbols

@@ -0,0 +1,42 @@
+//// [tests/cases/compiler/classNonUniqueSymbolMethodHasSymbolIndexer.ts] ////
+
+=== classNonUniqueSymbolMethodHasSymbolIndexer.ts ===
+declare const a: symbol;
+>a : Symbol(a, Decl(classNonUniqueSymbolMethodHasSymbolIndexer.ts, 0, 13))
+
+export class A {
+>A : Symbol(A, Decl(classNonUniqueSymbolMethodHasSymbolIndexer.ts, 0, 24))
+
+    [a]() { return 1 };
+>[a] : Symbol(A[a], Decl(classNonUniqueSymbolMethodHasSymbolIndexer.ts, 1, 16))
+>a : Symbol(a, Decl(classNonUniqueSymbolMethodHasSymbolIndexer.ts, 0, 13))
+}
+declare const e1: A[typeof a]; // no error, `A` has `symbol` index
+>e1 : Symbol(e1, Decl(classNonUniqueSymbolMethodHasSymbolIndexer.ts, 4, 13))
+>A : Symbol(A, Decl(classNonUniqueSymbolMethodHasSymbolIndexer.ts, 0, 24))
+>a : Symbol(a, Decl(classNonUniqueSymbolMethodHasSymbolIndexer.ts, 0, 13))
+
+type Constructor = new (...args: any[]) => {};
+>Constructor : Symbol(Constructor, Decl(classNonUniqueSymbolMethodHasSymbolIndexer.ts, 4, 30))
+>args : Symbol(args, Decl(classNonUniqueSymbolMethodHasSymbolIndexer.ts, 6, 24))
+
+declare function Mix<T extends Constructor>(classish: T): T & (new (...args: any[]) => {mixed: true});
+>Mix : Symbol(Mix, Decl(classNonUniqueSymbolMethodHasSymbolIndexer.ts, 6, 46))
+>T : Symbol(T, Decl(classNonUniqueSymbolMethodHasSymbolIndexer.ts, 7, 21))
+>Constructor : Symbol(Constructor, Decl(classNonUniqueSymbolMethodHasSymbolIndexer.ts, 4, 30))
+>classish : Symbol(classish, Decl(classNonUniqueSymbolMethodHasSymbolIndexer.ts, 7, 44))
+>T : Symbol(T, Decl(classNonUniqueSymbolMethodHasSymbolIndexer.ts, 7, 21))
+>T : Symbol(T, Decl(classNonUniqueSymbolMethodHasSymbolIndexer.ts, 7, 21))
+>args : Symbol(args, Decl(classNonUniqueSymbolMethodHasSymbolIndexer.ts, 7, 68))
+>mixed : Symbol(mixed, Decl(classNonUniqueSymbolMethodHasSymbolIndexer.ts, 7, 88))
+
+export const Mixer = Mix(class {
+>Mixer : Symbol(Mixer, Decl(classNonUniqueSymbolMethodHasSymbolIndexer.ts, 9, 12))
+>Mix : Symbol(Mix, Decl(classNonUniqueSymbolMethodHasSymbolIndexer.ts, 6, 46))
+
+    [a]() { return 1 };
+>[a] : Symbol((Anonymous class)[a], Decl(classNonUniqueSymbolMethodHasSymbolIndexer.ts, 9, 32))
+>a : Symbol(a, Decl(classNonUniqueSymbolMethodHasSymbolIndexer.ts, 0, 13))
+
+});
+

tests/baselines/reference/classNonUniqueSymbolMethodHasSymbolIndexer.types

@@ -0,0 +1,63 @@
+//// [tests/cases/compiler/classNonUniqueSymbolMethodHasSymbolIndexer.ts] ////
+
+=== classNonUniqueSymbolMethodHasSymbolIndexer.ts ===
+declare const a: symbol;
+>a : symbol
+>  : ^^^^^^
+
+export class A {
+>A : A
+>  : ^
+
+    [a]() { return 1 };
+>[a] : () => number
+>    : ^^^^^^^^^^^^
+>a : symbol
+>  : ^^^^^^
+>1 : 1
+>  : ^
+}
+declare const e1: A[typeof a]; // no error, `A` has `symbol` index
+>e1 : () => number
+>   : ^^^^^^^^^^^^
+>a : symbol
+>  : ^^^^^^
+
+type Constructor = new (...args: any[]) => {};
+>Constructor : Constructor
+>            : ^^^^^^^^^^^
+>args : any[]
+>     : ^^^^^
+
+declare function Mix<T extends Constructor>(classish: T): T & (new (...args: any[]) => {mixed: true});
+>Mix : <T extends Constructor>(classish: T) => T & (new (...args: any[]) => { mixed: true; })
+>    : ^ ^^^^^^^^^           ^^        ^^ ^^^^^                                              
+>classish : T
+>         : ^
+>args : any[]
+>     : ^^^^^
+>mixed : true
+>      : ^^^^
+>true : true
+>     : ^^^^
+
+export const Mixer = Mix(class {
+>Mixer : typeof (Anonymous class) & (new (...args: any[]) => { mixed: true; })
+>      : ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^    ^^     ^^^^^                ^
+>Mix(class {    [a]() { return 1 };}) : typeof (Anonymous class) & (new (...args: any[]) => { mixed: true; })
+>                                     : ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^    ^^     ^^^^^                ^
+>Mix : <T extends Constructor>(classish: T) => T & (new (...args: any[]) => { mixed: true; })
+>    : ^ ^^^^^^^^^           ^^        ^^ ^^^^^                                              
+>class {    [a]() { return 1 };} : typeof (Anonymous class)
+>                                : ^^^^^^^^^^^^^^^^^^^^^^^^
+
+    [a]() { return 1 };
+>[a] : () => number
+>    : ^^^^^^^^^^^^
+>a : symbol
+>  : ^^^^^^
+>1 : 1
+>  : ^
+
+});
+

tests/baselines/reference/complicatedPrivacy.types

@@ -86,8 +86,8 @@ module m1 {
     export function f4(arg1: 
 >f4 : (arg1: { [number]: C1; }) => void
 >   : ^    ^^                 ^^^^^^^^^
->arg1 : {}
->     : ^^
+>arg1 : { [x: number]: C1; }
+>     : ^^^^^^^^^^^^^^^^^^^^
     {
     [number]: C1; // Used to be indexer, now it is a computed property
 >[number] : C1

tests/baselines/reference/computedPropertyNames12_ES5.errors.txt

@@ -3,12 +3,14 @@ computedPropertyNames12_ES5.ts(6,5): error TS1166: A computed property name in a
 computedPropertyNames12_ES5.ts(7,12): error TS1166: A computed property name in a class property declaration must have a simple literal type or a 'unique symbol' type.
 computedPropertyNames12_ES5.ts(8,5): error TS1166: A computed property name in a class property declaration must have a simple literal type or a 'unique symbol' type.
 computedPropertyNames12_ES5.ts(9,5): error TS1166: A computed property name in a class property declaration must have a simple literal type or a 'unique symbol' type.
+computedPropertyNames12_ES5.ts(9,5): error TS2411: Property '[+s]' of type 'string' is not assignable to 'number' index type 'number'.
+computedPropertyNames12_ES5.ts(9,5): error TS2411: Property '[+s]' of type 'string' is not assignable to 'string' index type 'number'.
 computedPropertyNames12_ES5.ts(12,5): error TS1166: A computed property name in a class property declaration must have a simple literal type or a 'unique symbol' type.
 computedPropertyNames12_ES5.ts(13,12): error TS1166: A computed property name in a class property declaration must have a simple literal type or a 'unique symbol' type.
 computedPropertyNames12_ES5.ts(15,12): error TS1166: A computed property name in a class property declaration must have a simple literal type or a 'unique symbol' type.
 
 
-==== computedPropertyNames12_ES5.ts (8 errors) ====
+==== computedPropertyNames12_ES5.ts (10 errors) ====
     var s: string;
     var n: number;
     var a: any;
@@ -28,6 +30,10 @@ computedPropertyNames12_ES5.ts(15,12): error TS1166: A computed property name in
         [+s]: typeof s;
         ~~~~
 !!! error TS1166: A computed property name in a class property declaration must have a simple literal type or a 'unique symbol' type.
+        ~~~~
+!!! error TS2411: Property '[+s]' of type 'string' is not assignable to 'number' index type 'number'.
+        ~~~~
+!!! error TS2411: Property '[+s]' of type 'string' is not assignable to 'string' index type 'number'.
         static [""]: number;
         [0]: number;
         [a]: number;

tests/baselines/reference/computedPropertyNames12_ES6.errors.txt

@@ -3,12 +3,14 @@ computedPropertyNames12_ES6.ts(6,5): error TS1166: A computed property name in a
 computedPropertyNames12_ES6.ts(7,12): error TS1166: A computed property name in a class property declaration must have a simple literal type or a 'unique symbol' type.
 computedPropertyNames12_ES6.ts(8,5): error TS1166: A computed property name in a class property declaration must have a simple literal type or a 'unique symbol' type.
 computedPropertyNames12_ES6.ts(9,5): error TS1166: A computed property name in a class property declaration must have a simple literal type or a 'unique symbol' type.
+computedPropertyNames12_ES6.ts(9,5): error TS2411: Property '[+s]' of type 'string' is not assignable to 'number' index type 'number'.
+computedPropertyNames12_ES6.ts(9,5): error TS2411: Property '[+s]' of type 'string' is not assignable to 'string' index type 'number'.
 computedPropertyNames12_ES6.ts(12,5): error TS1166: A computed property name in a class property declaration must have a simple literal type or a 'unique symbol' type.
 computedPropertyNames12_ES6.ts(13,12): error TS1166: A computed property name in a class property declaration must have a simple literal type or a 'unique symbol' type.
 computedPropertyNames12_ES6.ts(15,12): error TS1166: A computed property name in a class property declaration must have a simple literal type or a 'unique symbol' type.
 
 
-==== computedPropertyNames12_ES6.ts (8 errors) ====
+==== computedPropertyNames12_ES6.ts (10 errors) ====
     var s: string;
     var n: number;
     var a: any;
@@ -28,6 +30,10 @@ computedPropertyNames12_ES6.ts(15,12): error TS1166: A computed property name in
         [+s]: typeof s;
         ~~~~
 !!! error TS1166: A computed property name in a class property declaration must have a simple literal type or a 'unique symbol' type.
+        ~~~~
+!!! error TS2411: Property '[+s]' of type 'string' is not assignable to 'number' index type 'number'.
+        ~~~~
+!!! error TS2411: Property '[+s]' of type 'string' is not assignable to 'string' index type 'number'.
         static [""]: number;
         [0]: number;
         [a]: number;

tests/baselines/reference/declarationEmitAnyComputedPropertyInClass.js

@@ -28,4 +28,5 @@ exports.C = C;
 
 //// [main.d.ts]
 export declare class C {
+    [x: number]: () => void;
 }

tests/baselines/reference/declarationEmitComputedPropertyNameEnum2.types

@@ -4,8 +4,8 @@
 export type Type = { x?: { [Enum.A]: 0 } };
 >Type : Type
 >     : ^^^^
->x : {} | undefined
->  : ^^^^^^^^^^^^^^
+>x : { [x: number]: 0; } | undefined
+>  : ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
 >[Enum.A] : 0
 >         : ^
 >Enum.A : any

tests/baselines/reference/parserComputedPropertyName13.types

@@ -2,8 +2,8 @@
 
 === parserComputedPropertyName13.ts ===
 var v: { [e]: number };
->v : {}
->  : ^^
+>v : { [x: number]: number; }
+>  : ^^^^^^^^^^^^^^^^^^^^^^^^
 >[e] : number
 >    : ^^^^^^
 >e : any

tests/baselines/reference/parserComputedPropertyName14.types

@@ -2,8 +2,8 @@
 
 === parserComputedPropertyName14.ts ===
 var v: { [e](): number };
->v : {}
->  : ^^
+>v : { [x: number]: () => number; }
+>  : ^^^^^^^^^^^^^^^^^^^^^      ^^^
 >[e] : () => number
 >    : ^^^^^^      
 >e : any