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weswighamweswigham
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node builder should strive to preserve mapped type keyofness (microsoft#23815)
1 parent 1cf1b92 commit eb80e9a

5 files changed

Lines changed: 273 additions & 10 deletions

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‎src/compiler/checker.ts‎

Lines changed: 29 additions & 10 deletions
Original file line numberDiff line numberDiff line change
@@ -3158,7 +3158,16 @@ namespace ts {
31583158
Debug.assert(!!(type.flags & TypeFlags.Object));
31593159
const readonlyToken = type.declaration.readonlyToken ? <ReadonlyToken | PlusToken | MinusToken>createToken(type.declaration.readonlyToken.kind) : undefined;
31603160
const questionToken = type.declaration.questionToken ? <QuestionToken | PlusToken | MinusToken>createToken(type.declaration.questionToken.kind) : undefined;
3161-
const typeParameterNode = typeParameterToDeclaration(getTypeParameterFromMappedType(type), context, getConstraintTypeFromMappedType(type));
3161+
let appropriateConstraintTypeNode: TypeNode;
3162+
if (isMappedTypeWithKeyofConstraintDeclaration(type)) {
3163+
// We have a { [P in keyof T]: X }
3164+
// We do this to ensure we retain the toplevel keyof-ness of the type which may be lost due to keyof distribution during `getConstraintTypeFromMappedType`
3165+
appropriateConstraintTypeNode = createTypeOperatorNode(typeToTypeNodeHelper(getModifiersTypeFromMappedType(type), context));
3166+
}
3167+
else {
3168+
appropriateConstraintTypeNode = typeToTypeNodeHelper(getConstraintTypeFromMappedType(type), context);
3169+
}
3170+
const typeParameterNode = typeParameterToDeclarationWithConstraint(getTypeParameterFromMappedType(type), context, appropriateConstraintTypeNode);
31623171
const templateTypeNode = typeToTypeNodeHelper(getTemplateTypeFromMappedType(type), context);
31633172
const mappedTypeNode = createMappedTypeNode(readonlyToken, typeParameterNode, questionToken, templateTypeNode);
31643173
return setEmitFlags(mappedTypeNode, EmitFlags.SingleLine);
@@ -3534,17 +3543,21 @@ namespace ts {
35343543
return createSignatureDeclaration(kind, typeParameters, parameters, returnTypeNode, typeArguments);
35353544
}
35363545

3537-
function typeParameterToDeclaration(type: TypeParameter, context: NodeBuilderContext, constraint = getConstraintFromTypeParameter(type)): TypeParameterDeclaration {
3546+
function typeParameterToDeclarationWithConstraint(type: TypeParameter, context: NodeBuilderContext, constraintNode: TypeNode): TypeParameterDeclaration {
35383547
const savedContextFlags = context.flags;
35393548
context.flags &= ~NodeBuilderFlags.WriteTypeParametersInQualifiedName; // Avoids potential infinite loop when building for a claimspace with a generic
35403549
const name = symbolToName(type.symbol, context, SymbolFlags.Type, /*expectsIdentifier*/ true);
3541-
const constraintNode = constraint && typeToTypeNodeHelper(constraint, context);
35423550
const defaultParameter = getDefaultFromTypeParameter(type);
35433551
const defaultParameterNode = defaultParameter && typeToTypeNodeHelper(defaultParameter, context);
35443552
context.flags = savedContextFlags;
35453553
return createTypeParameterDeclaration(name, constraintNode, defaultParameterNode);
35463554
}
35473555

3556+
function typeParameterToDeclaration(type: TypeParameter, context: NodeBuilderContext, constraint = getConstraintFromTypeParameter(type)): TypeParameterDeclaration {
3557+
const constraintNode = constraint && typeToTypeNodeHelper(constraint, context);
3558+
return typeParameterToDeclarationWithConstraint(type, context, constraintNode);
3559+
}
3560+
35483561
function symbolToParameterDeclaration(parameterSymbol: Symbol, context: NodeBuilderContext, preserveModifierFlags?: boolean): ParameterDeclaration {
35493562
const parameterDeclaration = getDeclarationOfKind<ParameterDeclaration>(parameterSymbol, SyntaxKind.Parameter);
35503563
Debug.assert(!!parameterDeclaration || isTransientSymbol(parameterSymbol) && !!parameterSymbol.isRestParameter);
@@ -6221,10 +6234,8 @@ namespace ts {
62216234
const templateType = getTemplateTypeFromMappedType(<MappedType>type.target || type);
62226235
const modifiersType = getApparentType(getModifiersTypeFromMappedType(type)); // The 'T' in 'keyof T'
62236236
const templateModifiers = getMappedTypeModifiers(type);
6224-
const constraintDeclaration = type.declaration.typeParameter.constraint;
62256237
const include = keyofStringsOnly ? TypeFlags.StringLiteral : TypeFlags.StringOrNumberLiteralOrUnique;
6226-
if (constraintDeclaration.kind === SyntaxKind.TypeOperator &&
6227-
(<TypeOperatorNode>constraintDeclaration).operator === SyntaxKind.KeyOfKeyword) {
6238+
if (isMappedTypeWithKeyofConstraintDeclaration(type)) {
62286239
// We have a { [P in keyof T]: X }
62296240
for (const prop of getPropertiesOfType(modifiersType)) {
62306241
addMemberForKeyType(getLiteralTypeFromPropertyName(prop, include), /*_index*/ undefined, prop);
@@ -6301,15 +6312,23 @@ namespace ts {
63016312
unknownType);
63026313
}
63036314

6315+
function getConstraintDeclarationForMappedType(type: MappedType) {
6316+
return type.declaration.typeParameter.constraint;
6317+
}
6318+
6319+
function isMappedTypeWithKeyofConstraintDeclaration(type: MappedType) {
6320+
const constraintDeclaration = getConstraintDeclarationForMappedType(type);
6321+
return constraintDeclaration.kind === SyntaxKind.TypeOperator &&
6322+
(<TypeOperatorNode>constraintDeclaration).operator === SyntaxKind.KeyOfKeyword;
6323+
}
6324+
63046325
function getModifiersTypeFromMappedType(type: MappedType) {
63056326
if (!type.modifiersType) {
6306-
const constraintDeclaration = type.declaration.typeParameter.constraint;
6307-
if (constraintDeclaration.kind === SyntaxKind.TypeOperator &&
6308-
(<TypeOperatorNode>constraintDeclaration).operator === SyntaxKind.KeyOfKeyword) {
6327+
if (isMappedTypeWithKeyofConstraintDeclaration(type)) {
63096328
// If the constraint declaration is a 'keyof T' node, the modifiers type is T. We check
63106329
// AST nodes here because, when T is a non-generic type, the logic below eagerly resolves
63116330
// 'keyof T' to a literal union type and we can't recover T from that type.
6312-
type.modifiersType = instantiateType(getTypeFromTypeNode((<TypeOperatorNode>constraintDeclaration).type), type.mapper || identityMapper);
6331+
type.modifiersType = instantiateType(getTypeFromTypeNode((<TypeOperatorNode>getConstraintDeclarationForMappedType(type)).type), type.mapper || identityMapper);
63136332
}
63146333
else {
63156334
// Otherwise, get the declared constraint type, and if the constraint type is a type parameter,

‎tests/baselines/reference/mappedTypeUnionConstraintInferences.js‎

Lines changed: 51 additions & 0 deletions
Original file line numberDiff line numberDiff line change
@@ -0,0 +1,51 @@
1+
//// [mappedTypeUnionConstraintInferences.ts]
2+
export declare type Omit<T, K extends keyof T> = Pick<T, Exclude<keyof T, K>>;
3+
export declare type PartialProperties<T, K extends keyof T> = Partial<Pick<T, K>> & Omit<T, K>;
4+
export function doSomething_Actual<T extends {
5+
prop: string;
6+
}>(a: T) {
7+
const x: { [P in keyof PartialProperties<T, "prop">]: PartialProperties<T, "prop">[P]; } = null as any;
8+
return x;
9+
}
10+
export declare function doSomething_Expected<T extends {
11+
prop: string;
12+
}>(a: T): { [P in keyof PartialProperties<T, "prop">]: PartialProperties<T, "prop">[P]; };
13+
14+
export let a = doSomething_Actual({ prop: "test" });
15+
a = {} // should be fine, equivalent to below
16+
17+
export let b = doSomething_Expected({ prop: "test" });
18+
b = {} // fine
19+
20+
21+
//// [mappedTypeUnionConstraintInferences.js]
22+
"use strict";
23+
exports.__esModule = true;
24+
function doSomething_Actual(a) {
25+
var x = null;
26+
return x;
27+
}
28+
exports.doSomething_Actual = doSomething_Actual;
29+
exports.a = doSomething_Actual({ prop: "test" });
30+
exports.a = {}; // should be fine, equivalent to below
31+
exports.b = doSomething_Expected({ prop: "test" });
32+
exports.b = {}; // fine
33+
34+
35+
//// [mappedTypeUnionConstraintInferences.d.ts]
36+
export declare type Omit<T, K extends keyof T> = Pick<T, Exclude<keyof T, K>>;
37+
export declare type PartialProperties<T, K extends keyof T> = Partial<Pick<T, K>> & Omit<T, K>;
38+
export declare function doSomething_Actual<T extends {
39+
prop: string;
40+
}>(a: T): { [P in keyof PartialProperties<T, "prop">]: PartialProperties<T, "prop">[P]; };
41+
export declare function doSomething_Expected<T extends {
42+
prop: string;
43+
}>(a: T): {
44+
[P in keyof PartialProperties<T, "prop">]: PartialProperties<T, "prop">[P];
45+
};
46+
export declare let a: {
47+
prop?: string;
48+
};
49+
export declare let b: {
50+
prop?: string;
51+
};

‎tests/baselines/reference/mappedTypeUnionConstraintInferences.symbols‎

Lines changed: 81 additions & 0 deletions
Original file line numberDiff line numberDiff line change
@@ -0,0 +1,81 @@
1+
=== tests/cases/compiler/mappedTypeUnionConstraintInferences.ts ===
2+
export declare type Omit<T, K extends keyof T> = Pick<T, Exclude<keyof T, K>>;
3+
>Omit : Symbol(Omit, Decl(mappedTypeUnionConstraintInferences.ts, 0, 0))
4+
>T : Symbol(T, Decl(mappedTypeUnionConstraintInferences.ts, 0, 25))
5+
>K : Symbol(K, Decl(mappedTypeUnionConstraintInferences.ts, 0, 27))
6+
>T : Symbol(T, Decl(mappedTypeUnionConstraintInferences.ts, 0, 25))
7+
>Pick : Symbol(Pick, Decl(lib.d.ts, --, --))
8+
>T : Symbol(T, Decl(mappedTypeUnionConstraintInferences.ts, 0, 25))
9+
>Exclude : Symbol(Exclude, Decl(lib.d.ts, --, --))
10+
>T : Symbol(T, Decl(mappedTypeUnionConstraintInferences.ts, 0, 25))
11+
>K : Symbol(K, Decl(mappedTypeUnionConstraintInferences.ts, 0, 27))
12+
13+
export declare type PartialProperties<T, K extends keyof T> = Partial<Pick<T, K>> & Omit<T, K>;
14+
>PartialProperties : Symbol(PartialProperties, Decl(mappedTypeUnionConstraintInferences.ts, 0, 78))
15+
>T : Symbol(T, Decl(mappedTypeUnionConstraintInferences.ts, 1, 38))
16+
>K : Symbol(K, Decl(mappedTypeUnionConstraintInferences.ts, 1, 40))
17+
>T : Symbol(T, Decl(mappedTypeUnionConstraintInferences.ts, 1, 38))
18+
>Partial : Symbol(Partial, Decl(lib.d.ts, --, --))
19+
>Pick : Symbol(Pick, Decl(lib.d.ts, --, --))
20+
>T : Symbol(T, Decl(mappedTypeUnionConstraintInferences.ts, 1, 38))
21+
>K : Symbol(K, Decl(mappedTypeUnionConstraintInferences.ts, 1, 40))
22+
>Omit : Symbol(Omit, Decl(mappedTypeUnionConstraintInferences.ts, 0, 0))
23+
>T : Symbol(T, Decl(mappedTypeUnionConstraintInferences.ts, 1, 38))
24+
>K : Symbol(K, Decl(mappedTypeUnionConstraintInferences.ts, 1, 40))
25+
26+
export function doSomething_Actual<T extends {
27+
>doSomething_Actual : Symbol(doSomething_Actual, Decl(mappedTypeUnionConstraintInferences.ts, 1, 95))
28+
>T : Symbol(T, Decl(mappedTypeUnionConstraintInferences.ts, 2, 35))
29+
30+
prop: string;
31+
>prop : Symbol(prop, Decl(mappedTypeUnionConstraintInferences.ts, 2, 46))
32+
33+
}>(a: T) {
34+
>a : Symbol(a, Decl(mappedTypeUnionConstraintInferences.ts, 4, 3))
35+
>T : Symbol(T, Decl(mappedTypeUnionConstraintInferences.ts, 2, 35))
36+
37+
const x: { [P in keyof PartialProperties<T, "prop">]: PartialProperties<T, "prop">[P]; } = null as any;
38+
>x : Symbol(x, Decl(mappedTypeUnionConstraintInferences.ts, 5, 9))
39+
>P : Symbol(P, Decl(mappedTypeUnionConstraintInferences.ts, 5, 16))
40+
>PartialProperties : Symbol(PartialProperties, Decl(mappedTypeUnionConstraintInferences.ts, 0, 78))
41+
>T : Symbol(T, Decl(mappedTypeUnionConstraintInferences.ts, 2, 35))
42+
>PartialProperties : Symbol(PartialProperties, Decl(mappedTypeUnionConstraintInferences.ts, 0, 78))
43+
>T : Symbol(T, Decl(mappedTypeUnionConstraintInferences.ts, 2, 35))
44+
>P : Symbol(P, Decl(mappedTypeUnionConstraintInferences.ts, 5, 16))
45+
46+
return x;
47+
>x : Symbol(x, Decl(mappedTypeUnionConstraintInferences.ts, 5, 9))
48+
}
49+
export declare function doSomething_Expected<T extends {
50+
>doSomething_Expected : Symbol(doSomething_Expected, Decl(mappedTypeUnionConstraintInferences.ts, 7, 1))
51+
>T : Symbol(T, Decl(mappedTypeUnionConstraintInferences.ts, 8, 45))
52+
53+
prop: string;
54+
>prop : Symbol(prop, Decl(mappedTypeUnionConstraintInferences.ts, 8, 56))
55+
56+
}>(a: T): { [P in keyof PartialProperties<T, "prop">]: PartialProperties<T, "prop">[P]; };
57+
>a : Symbol(a, Decl(mappedTypeUnionConstraintInferences.ts, 10, 3))
58+
>T : Symbol(T, Decl(mappedTypeUnionConstraintInferences.ts, 8, 45))
59+
>P : Symbol(P, Decl(mappedTypeUnionConstraintInferences.ts, 10, 13))
60+
>PartialProperties : Symbol(PartialProperties, Decl(mappedTypeUnionConstraintInferences.ts, 0, 78))
61+
>T : Symbol(T, Decl(mappedTypeUnionConstraintInferences.ts, 8, 45))
62+
>PartialProperties : Symbol(PartialProperties, Decl(mappedTypeUnionConstraintInferences.ts, 0, 78))
63+
>T : Symbol(T, Decl(mappedTypeUnionConstraintInferences.ts, 8, 45))
64+
>P : Symbol(P, Decl(mappedTypeUnionConstraintInferences.ts, 10, 13))
65+
66+
export let a = doSomething_Actual({ prop: "test" });
67+
>a : Symbol(a, Decl(mappedTypeUnionConstraintInferences.ts, 12, 10))
68+
>doSomething_Actual : Symbol(doSomething_Actual, Decl(mappedTypeUnionConstraintInferences.ts, 1, 95))
69+
>prop : Symbol(prop, Decl(mappedTypeUnionConstraintInferences.ts, 12, 35))
70+
71+
a = {} // should be fine, equivalent to below
72+
>a : Symbol(a, Decl(mappedTypeUnionConstraintInferences.ts, 12, 10))
73+
74+
export let b = doSomething_Expected({ prop: "test" });
75+
>b : Symbol(b, Decl(mappedTypeUnionConstraintInferences.ts, 15, 10))
76+
>doSomething_Expected : Symbol(doSomething_Expected, Decl(mappedTypeUnionConstraintInferences.ts, 7, 1))
77+
>prop : Symbol(prop, Decl(mappedTypeUnionConstraintInferences.ts, 15, 37))
78+
79+
b = {} // fine
80+
>b : Symbol(b, Decl(mappedTypeUnionConstraintInferences.ts, 15, 10))
81+

‎tests/baselines/reference/mappedTypeUnionConstraintInferences.types‎

Lines changed: 93 additions & 0 deletions
Original file line numberDiff line numberDiff line change
@@ -0,0 +1,93 @@
1+
=== tests/cases/compiler/mappedTypeUnionConstraintInferences.ts ===
2+
export declare type Omit<T, K extends keyof T> = Pick<T, Exclude<keyof T, K>>;
3+
>Omit : Pick<T, Exclude<keyof T, K>>
4+
>T : T
5+
>K : K
6+
>T : T
7+
>Pick : Pick<T, K>
8+
>T : T
9+
>Exclude : Exclude<T, U>
10+
>T : T
11+
>K : K
12+
13+
export declare type PartialProperties<T, K extends keyof T> = Partial<Pick<T, K>> & Omit<T, K>;
14+
>PartialProperties : PartialProperties<T, K>
15+
>T : T
16+
>K : K
17+
>T : T
18+
>Partial : Partial<T>
19+
>Pick : Pick<T, K>
20+
>T : T
21+
>K : K
22+
>Omit : Pick<T, Exclude<keyof T, K>>
23+
>T : T
24+
>K : K
25+
26+
export function doSomething_Actual<T extends {
27+
>doSomething_Actual : <T extends { prop: string; }>(a: T) => { [P in keyof PartialProperties<T, "prop">]: PartialProperties<T, "prop">[P]; }
28+
>T : T
29+
30+
prop: string;
31+
>prop : string
32+
33+
}>(a: T) {
34+
>a : T
35+
>T : T
36+
37+
const x: { [P in keyof PartialProperties<T, "prop">]: PartialProperties<T, "prop">[P]; } = null as any;
38+
>x : { [P in keyof PartialProperties<T, "prop">]: PartialProperties<T, "prop">[P]; }
39+
>P : P
40+
>PartialProperties : PartialProperties<T, K>
41+
>T : T
42+
>PartialProperties : PartialProperties<T, K>
43+
>T : T
44+
>P : P
45+
>null as any : any
46+
>null : null
47+
48+
return x;
49+
>x : { [P in keyof PartialProperties<T, "prop">]: PartialProperties<T, "prop">[P]; }
50+
}
51+
export declare function doSomething_Expected<T extends {
52+
>doSomething_Expected : <T extends { prop: string; }>(a: T) => { [P in keyof PartialProperties<T, "prop">]: PartialProperties<T, "prop">[P]; }
53+
>T : T
54+
55+
prop: string;
56+
>prop : string
57+
58+
}>(a: T): { [P in keyof PartialProperties<T, "prop">]: PartialProperties<T, "prop">[P]; };
59+
>a : T
60+
>T : T
61+
>P : P
62+
>PartialProperties : PartialProperties<T, K>
63+
>T : T
64+
>PartialProperties : PartialProperties<T, K>
65+
>T : T
66+
>P : P
67+
68+
export let a = doSomething_Actual({ prop: "test" });
69+
>a : { prop?: string; }
70+
>doSomething_Actual({ prop: "test" }) : { prop?: string; }
71+
>doSomething_Actual : <T extends { prop: string; }>(a: T) => { [P in keyof PartialProperties<T, "prop">]: PartialProperties<T, "prop">[P]; }
72+
>{ prop: "test" } : { prop: string; }
73+
>prop : string
74+
>"test" : "test"
75+
76+
a = {} // should be fine, equivalent to below
77+
>a = {} : {}
78+
>a : { prop?: string; }
79+
>{} : {}
80+
81+
export let b = doSomething_Expected({ prop: "test" });
82+
>b : { prop?: string; }
83+
>doSomething_Expected({ prop: "test" }) : { prop?: string; }
84+
>doSomething_Expected : <T extends { prop: string; }>(a: T) => { [P in keyof PartialProperties<T, "prop">]: PartialProperties<T, "prop">[P]; }
85+
>{ prop: "test" } : { prop: string; }
86+
>prop : string
87+
>"test" : "test"
88+
89+
b = {} // fine
90+
>b = {} : {}
91+
>b : { prop?: string; }
92+
>{} : {}
93+

‎tests/cases/compiler/mappedTypeUnionConstraintInferences.ts‎

Lines changed: 19 additions & 0 deletions
Original file line numberDiff line numberDiff line change
@@ -0,0 +1,19 @@
1+
// @declaration: true
2+
// @keyofStringsOnly: true
3+
export declare type Omit<T, K extends keyof T> = Pick<T, Exclude<keyof T, K>>;
4+
export declare type PartialProperties<T, K extends keyof T> = Partial<Pick<T, K>> & Omit<T, K>;
5+
export function doSomething_Actual<T extends {
6+
prop: string;
7+
}>(a: T) {
8+
const x: { [P in keyof PartialProperties<T, "prop">]: PartialProperties<T, "prop">[P]; } = null as any;
9+
return x;
10+
}
11+
export declare function doSomething_Expected<T extends {
12+
prop: string;
13+
}>(a: T): { [P in keyof PartialProperties<T, "prop">]: PartialProperties<T, "prop">[P]; };
14+
15+
export let a = doSomething_Actual({ prop: "test" });
16+
a = {} // should be fine, equivalent to below
17+
18+
export let b = doSomething_Expected({ prop: "test" });
19+
b = {} // fine

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