Add numeric constraint to type parameter of mapped types with name ty…

…pe and array constraints
microsoft · Sep 18, 2023 · c28fb9e · c28fb9e
1 parent b9b5d16
commit c28fb9e
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Showing 4 changed files with 256 additions and 2 deletions.
diff --git a/src/compiler/checker.ts b/src/compiler/checker.ts
@@ -13583,7 +13583,15 @@ export function createTypeChecker(host: TypeCheckerHost): TypeChecker {
         const include = keyofStringsOnly ? TypeFlags.StringLiteral : TypeFlags.StringOrNumberLiteralOrUnique;
         if (isMappedTypeWithKeyofConstraintDeclaration(type)) {
             // We have a { [P in keyof T]: X }
-            forEachMappedTypePropertyKeyTypeAndIndexSignatureKeyType(modifiersType, include, keyofStringsOnly, addMemberForKeyType);
+            if (nameType && isTupleType(modifiersType)) {
+                forEachType(getUnionType(getElementTypes(modifiersType).map((_, i) => getStringLiteralType("" + i))), addMemberForKeyType);
+            }
+            else if (isArrayType(modifiersType)) {
+                addMemberForKeyType(numberType);
+            }
+            else {
+                forEachMappedTypePropertyKeyTypeAndIndexSignatureKeyType(modifiersType, include, keyofStringsOnly, addMemberForKeyType);
+            }
         }
         else {
             forEachType(getLowerBoundOfKeyType(constraintType), addMemberForKeyType);
@@ -15881,7 +15889,7 @@ export function createTypeChecker(host: TypeCheckerHost): TypeChecker {
             }
             // Given a homomorphic mapped type { [K in keyof T]: XXX }, where T is constrained to an array or tuple type, in the
             // template type XXX, K has an added constraint of number | `${number}`.
-            else if (type.flags & TypeFlags.TypeParameter && parent.kind === SyntaxKind.MappedType && node === (parent as MappedTypeNode).type) {
+            else if (type.flags & TypeFlags.TypeParameter && parent.kind === SyntaxKind.MappedType && (node === (parent as MappedTypeNode).type || node === (parent as MappedTypeNode).nameType)) {
                 const mappedType = getTypeFromTypeNode(parent as TypeNode) as MappedType;
                 if (getTypeParameterFromMappedType(mappedType) === getActualTypeVariable(type)) {
                     const typeParameter = getHomomorphicTypeVariable(mappedType);

diff --git a/tests/baselines/reference/mappedTypeTupleConstraintTypeParameterInNameType.symbols b/tests/baselines/reference/mappedTypeTupleConstraintTypeParameterInNameType.symbols
@@ -0,0 +1,113 @@
+//// [tests/cases/compiler/mappedTypeTupleConstraintTypeParameterInNameType.ts] ////
+
+=== mappedTypeTupleConstraintTypeParameterInNameType.ts ===
+// based on https://github.com/microsoft/TypeScript/issues/55762
+
+declare class Decoder<T> {
+>Decoder : Symbol(Decoder, Decl(mappedTypeTupleConstraintTypeParameterInNameType.ts, 0, 0))
+>T : Symbol(T, Decl(mappedTypeTupleConstraintTypeParameterInNameType.ts, 2, 22))
+
+  decode(arrayBuffer: ArrayBuffer): T;
+>decode : Symbol(Decoder.decode, Decl(mappedTypeTupleConstraintTypeParameterInNameType.ts, 2, 26))
+>arrayBuffer : Symbol(arrayBuffer, Decl(mappedTypeTupleConstraintTypeParameterInNameType.ts, 3, 9))
+>ArrayBuffer : Symbol(ArrayBuffer, Decl(lib.es5.d.ts, --, --), Decl(lib.es5.d.ts, --, --))
+>T : Symbol(T, Decl(mappedTypeTupleConstraintTypeParameterInNameType.ts, 2, 22))
+}
+
+type ValueTypeOf<T extends Decoder<any>> = T extends Decoder<infer R>
+>ValueTypeOf : Symbol(ValueTypeOf, Decl(mappedTypeTupleConstraintTypeParameterInNameType.ts, 4, 1))
+>T : Symbol(T, Decl(mappedTypeTupleConstraintTypeParameterInNameType.ts, 6, 17))
+>Decoder : Symbol(Decoder, Decl(mappedTypeTupleConstraintTypeParameterInNameType.ts, 0, 0))
+>T : Symbol(T, Decl(mappedTypeTupleConstraintTypeParameterInNameType.ts, 6, 17))
+>Decoder : Symbol(Decoder, Decl(mappedTypeTupleConstraintTypeParameterInNameType.ts, 0, 0))
+>R : Symbol(R, Decl(mappedTypeTupleConstraintTypeParameterInNameType.ts, 6, 66))
+
+  ? R
+>R : Symbol(R, Decl(mappedTypeTupleConstraintTypeParameterInNameType.ts, 6, 66))
+
+  : never;
+
+type StructDescriptor = ReadonlyArray<
+>StructDescriptor : Symbol(StructDescriptor, Decl(mappedTypeTupleConstraintTypeParameterInNameType.ts, 8, 10))
+>ReadonlyArray : Symbol(ReadonlyArray, Decl(lib.es5.d.ts, --, --))
+
+  readonly [key: string, type: Decoder<any>]
+>Decoder : Symbol(Decoder, Decl(mappedTypeTupleConstraintTypeParameterInNameType.ts, 0, 0))
+
+>;
+
+type StructTypeFor<Descriptor extends StructDescriptor> = {
+>StructTypeFor : Symbol(StructTypeFor, Decl(mappedTypeTupleConstraintTypeParameterInNameType.ts, 12, 2))
+>Descriptor : Symbol(Descriptor, Decl(mappedTypeTupleConstraintTypeParameterInNameType.ts, 14, 19))
+>StructDescriptor : Symbol(StructDescriptor, Decl(mappedTypeTupleConstraintTypeParameterInNameType.ts, 8, 10))
+
+  [K in keyof Descriptor as Descriptor[K][0]]: ValueTypeOf<Descriptor[K][1]>;
+>K : Symbol(K, Decl(mappedTypeTupleConstraintTypeParameterInNameType.ts, 15, 3))
+>Descriptor : Symbol(Descriptor, Decl(mappedTypeTupleConstraintTypeParameterInNameType.ts, 14, 19))
+>Descriptor : Symbol(Descriptor, Decl(mappedTypeTupleConstraintTypeParameterInNameType.ts, 14, 19))
+>K : Symbol(K, Decl(mappedTypeTupleConstraintTypeParameterInNameType.ts, 15, 3))
+>ValueTypeOf : Symbol(ValueTypeOf, Decl(mappedTypeTupleConstraintTypeParameterInNameType.ts, 4, 1))
+>Descriptor : Symbol(Descriptor, Decl(mappedTypeTupleConstraintTypeParameterInNameType.ts, 14, 19))
+>K : Symbol(K, Decl(mappedTypeTupleConstraintTypeParameterInNameType.ts, 15, 3))
+
+};
+
+class StructDecoder<const Descriptor extends StructDescriptor> extends Decoder<
+>StructDecoder : Symbol(StructDecoder, Decl(mappedTypeTupleConstraintTypeParameterInNameType.ts, 16, 2))
+>Descriptor : Symbol(Descriptor, Decl(mappedTypeTupleConstraintTypeParameterInNameType.ts, 18, 20))
+>StructDescriptor : Symbol(StructDescriptor, Decl(mappedTypeTupleConstraintTypeParameterInNameType.ts, 8, 10))
+>Decoder : Symbol(Decoder, Decl(mappedTypeTupleConstraintTypeParameterInNameType.ts, 0, 0))
+
+  StructTypeFor<Descriptor>
+>StructTypeFor : Symbol(StructTypeFor, Decl(mappedTypeTupleConstraintTypeParameterInNameType.ts, 12, 2))
+>Descriptor : Symbol(Descriptor, Decl(mappedTypeTupleConstraintTypeParameterInNameType.ts, 18, 20))
+
+> {
+  constructor(descriptor: Descriptor) {
+>descriptor : Symbol(descriptor, Decl(mappedTypeTupleConstraintTypeParameterInNameType.ts, 21, 14))
+>Descriptor : Symbol(Descriptor, Decl(mappedTypeTupleConstraintTypeParameterInNameType.ts, 18, 20))
+
+    super();
+>super : Symbol(Decoder, Decl(mappedTypeTupleConstraintTypeParameterInNameType.ts, 0, 0))
+  }
+}
+
+declare const i32Decoder: Decoder<number>;
+>i32Decoder : Symbol(i32Decoder, Decl(mappedTypeTupleConstraintTypeParameterInNameType.ts, 26, 13))
+>Decoder : Symbol(Decoder, Decl(mappedTypeTupleConstraintTypeParameterInNameType.ts, 0, 0))
+
+declare const i64Decoder: Decoder<bigint>;
+>i64Decoder : Symbol(i64Decoder, Decl(mappedTypeTupleConstraintTypeParameterInNameType.ts, 27, 13))
+>Decoder : Symbol(Decoder, Decl(mappedTypeTupleConstraintTypeParameterInNameType.ts, 0, 0))
+
+const structDecoder = new StructDecoder([
+>structDecoder : Symbol(structDecoder, Decl(mappedTypeTupleConstraintTypeParameterInNameType.ts, 29, 5))
+>StructDecoder : Symbol(StructDecoder, Decl(mappedTypeTupleConstraintTypeParameterInNameType.ts, 16, 2))
+
+  ["a", i32Decoder],
+>i32Decoder : Symbol(i32Decoder, Decl(mappedTypeTupleConstraintTypeParameterInNameType.ts, 26, 13))
+
+  ["b", i64Decoder],
+>i64Decoder : Symbol(i64Decoder, Decl(mappedTypeTupleConstraintTypeParameterInNameType.ts, 27, 13))
+
+]);
+
+const struct = structDecoder.decode(new ArrayBuffer(100));
+>struct : Symbol(struct, Decl(mappedTypeTupleConstraintTypeParameterInNameType.ts, 34, 5))
+>structDecoder.decode : Symbol(Decoder.decode, Decl(mappedTypeTupleConstraintTypeParameterInNameType.ts, 2, 26))
+>structDecoder : Symbol(structDecoder, Decl(mappedTypeTupleConstraintTypeParameterInNameType.ts, 29, 5))
+>decode : Symbol(Decoder.decode, Decl(mappedTypeTupleConstraintTypeParameterInNameType.ts, 2, 26))
+>ArrayBuffer : Symbol(ArrayBuffer, Decl(lib.es5.d.ts, --, --), Decl(lib.es5.d.ts, --, --))
+
+const v: number = struct.a;
+>v : Symbol(v, Decl(mappedTypeTupleConstraintTypeParameterInNameType.ts, 36, 5))
+>struct.a : Symbol(a)
+>struct : Symbol(struct, Decl(mappedTypeTupleConstraintTypeParameterInNameType.ts, 34, 5))
+>a : Symbol(a)
+
+const v2: bigint = struct.b;
+>v2 : Symbol(v2, Decl(mappedTypeTupleConstraintTypeParameterInNameType.ts, 37, 5))
+>struct.b : Symbol(b)
+>struct : Symbol(struct, Decl(mappedTypeTupleConstraintTypeParameterInNameType.ts, 34, 5))
+>b : Symbol(b)
+
diff --git a/tests/baselines/reference/mappedTypeTupleConstraintTypeParameterInNameType.types b/tests/baselines/reference/mappedTypeTupleConstraintTypeParameterInNameType.types
@@ -0,0 +1,92 @@
+//// [tests/cases/compiler/mappedTypeTupleConstraintTypeParameterInNameType.ts] ////
+
+=== mappedTypeTupleConstraintTypeParameterInNameType.ts ===
+// based on https://github.com/microsoft/TypeScript/issues/55762
+
+declare class Decoder<T> {
+>Decoder : Decoder<T>
+
+  decode(arrayBuffer: ArrayBuffer): T;
+>decode : (arrayBuffer: ArrayBuffer) => T
+>arrayBuffer : ArrayBuffer
+}
+
+type ValueTypeOf<T extends Decoder<any>> = T extends Decoder<infer R>
+>ValueTypeOf : ValueTypeOf<T>
+
+  ? R
+  : never;
+
+type StructDescriptor = ReadonlyArray<
+>StructDescriptor : readonly (readonly [key: string, type: Decoder<any>])[]
+
+  readonly [key: string, type: Decoder<any>]
+>;
+
+type StructTypeFor<Descriptor extends StructDescriptor> = {
+>StructTypeFor : StructTypeFor<Descriptor>
+
+  [K in keyof Descriptor as Descriptor[K][0]]: ValueTypeOf<Descriptor[K][1]>;
+};
+
+class StructDecoder<const Descriptor extends StructDescriptor> extends Decoder<
+>StructDecoder : StructDecoder<Descriptor>
+>Decoder : Decoder<StructTypeFor<Descriptor>>
+
+  StructTypeFor<Descriptor>
+> {
+  constructor(descriptor: Descriptor) {
+>descriptor : Descriptor
+
+    super();
+>super() : void
+>super : typeof Decoder
+  }
+}
+
+declare const i32Decoder: Decoder<number>;
+>i32Decoder : Decoder<number>
+
+declare const i64Decoder: Decoder<bigint>;
+>i64Decoder : Decoder<bigint>
+
+const structDecoder = new StructDecoder([
+>structDecoder : StructDecoder<readonly [readonly ["a", Decoder<number>], readonly ["b", Decoder<bigint>]]>
+>new StructDecoder([  ["a", i32Decoder],  ["b", i64Decoder],]) : StructDecoder<readonly [readonly ["a", Decoder<number>], readonly ["b", Decoder<bigint>]]>
+>StructDecoder : typeof StructDecoder
+>[  ["a", i32Decoder],  ["b", i64Decoder],] : [["a", Decoder<number>], ["b", Decoder<bigint>]]
+
+  ["a", i32Decoder],
+>["a", i32Decoder] : ["a", Decoder<number>]
+>"a" : "a"
+>i32Decoder : Decoder<number>
+
+  ["b", i64Decoder],
+>["b", i64Decoder] : ["b", Decoder<bigint>]
+>"b" : "b"
+>i64Decoder : Decoder<bigint>
+
+]);
+
+const struct = structDecoder.decode(new ArrayBuffer(100));
+>struct : StructTypeFor<readonly [readonly ["a", Decoder<number>], readonly ["b", Decoder<bigint>]]>
+>structDecoder.decode(new ArrayBuffer(100)) : StructTypeFor<readonly [readonly ["a", Decoder<number>], readonly ["b", Decoder<bigint>]]>
+>structDecoder.decode : (arrayBuffer: ArrayBuffer) => StructTypeFor<readonly [readonly ["a", Decoder<number>], readonly ["b", Decoder<bigint>]]>
+>structDecoder : StructDecoder<readonly [readonly ["a", Decoder<number>], readonly ["b", Decoder<bigint>]]>
+>decode : (arrayBuffer: ArrayBuffer) => StructTypeFor<readonly [readonly ["a", Decoder<number>], readonly ["b", Decoder<bigint>]]>
+>new ArrayBuffer(100) : ArrayBuffer
+>ArrayBuffer : ArrayBufferConstructor
+>100 : 100
+
+const v: number = struct.a;
+>v : number
+>struct.a : number
+>struct : StructTypeFor<readonly [readonly ["a", Decoder<number>], readonly ["b", Decoder<bigint>]]>
+>a : number
+
+const v2: bigint = struct.b;
+>v2 : bigint
+>struct.b : bigint
+>struct : StructTypeFor<readonly [readonly ["a", Decoder<number>], readonly ["b", Decoder<bigint>]]>
+>b : bigint
+
diff --git a/tests/cases/compiler/mappedTypeTupleConstraintTypeParameterInNameType.ts b/tests/cases/compiler/mappedTypeTupleConstraintTypeParameterInNameType.ts
@@ -0,0 +1,41 @@
+// @strict: true
+// @noEmit: true
+
+// based on https://github.com/microsoft/TypeScript/issues/55762
+
+declare class Decoder<T> {
+  decode(arrayBuffer: ArrayBuffer): T;
+}
+
+type ValueTypeOf<T extends Decoder<any>> = T extends Decoder<infer R>
+  ? R
+  : never;
+
+type StructDescriptor = ReadonlyArray<
+  readonly [key: string, type: Decoder<any>]
+>;
+
+type StructTypeFor<Descriptor extends StructDescriptor> = {
+  [K in keyof Descriptor as Descriptor[K][0]]: ValueTypeOf<Descriptor[K][1]>;
+};
+
+class StructDecoder<const Descriptor extends StructDescriptor> extends Decoder<
+  StructTypeFor<Descriptor>
+> {
+  constructor(descriptor: Descriptor) {
+    super();
+  }
+}
+
+declare const i32Decoder: Decoder<number>;
+declare const i64Decoder: Decoder<bigint>;
+
+const structDecoder = new StructDecoder([
+  ["a", i32Decoder],
+  ["b", i64Decoder],
+]);
+
+const struct = structDecoder.decode(new ArrayBuffer(100));
+
+const v: number = struct.a;
+const v2: bigint = struct.b;