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Fix higher order inference on indexed access types (microsoft#20165)
1 parent 00450f0 commit 7ad0d7b

5 files changed

Lines changed: 171 additions & 1 deletion

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‎src/compiler/checker.ts‎

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@@ -11400,7 +11400,7 @@ namespace ts {
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return;
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}
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}
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else if (getObjectFlags(source) & ObjectFlags.Reference && getObjectFlags(target) & ObjectFlags.Reference && (<TypeReference>source).target === (<TypeReference>target).target) {
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if (getObjectFlags(source) & ObjectFlags.Reference && getObjectFlags(target) & ObjectFlags.Reference && (<TypeReference>source).target === (<TypeReference>target).target) {
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// If source and target are references to the same generic type, infer from type arguments
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const sourceTypes = (<TypeReference>source).typeArguments || emptyArray;
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const targetTypes = (<TypeReference>target).typeArguments || emptyArray;

‎tests/baselines/reference/indexedAccessCanBeHighOrder.js‎

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//// [indexedAccessCanBeHighOrder.ts]
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declare function get<U, Y extends keyof U>(x: U, y: Y): U[Y];
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declare function find<T, K extends keyof T>(o: T[K]): [T, K];
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function impl<A, B extends keyof A>(a: A, b: B) {
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const item = get(a, b);
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return find(item);
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}
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const o = {x: 42};
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const r = impl(o, "x");
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r[0][r[1]] = o[r[1]];
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//// [indexedAccessCanBeHighOrder.js]
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function impl(a, b) {
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var item = get(a, b);
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return find(item);
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}
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var o = { x: 42 };
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var r = impl(o, "x");
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r[0][r[1]] = o[r[1]];

‎tests/baselines/reference/indexedAccessCanBeHighOrder.symbols‎

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=== tests/cases/compiler/indexedAccessCanBeHighOrder.ts ===
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declare function get<U, Y extends keyof U>(x: U, y: Y): U[Y];
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>get : Symbol(get, Decl(indexedAccessCanBeHighOrder.ts, 0, 0))
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>U : Symbol(U, Decl(indexedAccessCanBeHighOrder.ts, 0, 21))
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>Y : Symbol(Y, Decl(indexedAccessCanBeHighOrder.ts, 0, 23))
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>U : Symbol(U, Decl(indexedAccessCanBeHighOrder.ts, 0, 21))
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>x : Symbol(x, Decl(indexedAccessCanBeHighOrder.ts, 0, 43))
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>U : Symbol(U, Decl(indexedAccessCanBeHighOrder.ts, 0, 21))
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>y : Symbol(y, Decl(indexedAccessCanBeHighOrder.ts, 0, 48))
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>Y : Symbol(Y, Decl(indexedAccessCanBeHighOrder.ts, 0, 23))
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>U : Symbol(U, Decl(indexedAccessCanBeHighOrder.ts, 0, 21))
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>Y : Symbol(Y, Decl(indexedAccessCanBeHighOrder.ts, 0, 23))
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declare function find<T, K extends keyof T>(o: T[K]): [T, K];
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>find : Symbol(find, Decl(indexedAccessCanBeHighOrder.ts, 0, 61))
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>T : Symbol(T, Decl(indexedAccessCanBeHighOrder.ts, 1, 22))
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>K : Symbol(K, Decl(indexedAccessCanBeHighOrder.ts, 1, 24))
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>T : Symbol(T, Decl(indexedAccessCanBeHighOrder.ts, 1, 22))
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>o : Symbol(o, Decl(indexedAccessCanBeHighOrder.ts, 1, 44))
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>T : Symbol(T, Decl(indexedAccessCanBeHighOrder.ts, 1, 22))
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>K : Symbol(K, Decl(indexedAccessCanBeHighOrder.ts, 1, 24))
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>T : Symbol(T, Decl(indexedAccessCanBeHighOrder.ts, 1, 22))
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>K : Symbol(K, Decl(indexedAccessCanBeHighOrder.ts, 1, 24))
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function impl<A, B extends keyof A>(a: A, b: B) {
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>impl : Symbol(impl, Decl(indexedAccessCanBeHighOrder.ts, 1, 61))
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>A : Symbol(A, Decl(indexedAccessCanBeHighOrder.ts, 3, 14))
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>B : Symbol(B, Decl(indexedAccessCanBeHighOrder.ts, 3, 16))
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>A : Symbol(A, Decl(indexedAccessCanBeHighOrder.ts, 3, 14))
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>a : Symbol(a, Decl(indexedAccessCanBeHighOrder.ts, 3, 36))
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>A : Symbol(A, Decl(indexedAccessCanBeHighOrder.ts, 3, 14))
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>b : Symbol(b, Decl(indexedAccessCanBeHighOrder.ts, 3, 41))
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>B : Symbol(B, Decl(indexedAccessCanBeHighOrder.ts, 3, 16))
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const item = get(a, b);
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>item : Symbol(item, Decl(indexedAccessCanBeHighOrder.ts, 4, 9))
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>get : Symbol(get, Decl(indexedAccessCanBeHighOrder.ts, 0, 0))
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>a : Symbol(a, Decl(indexedAccessCanBeHighOrder.ts, 3, 36))
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>b : Symbol(b, Decl(indexedAccessCanBeHighOrder.ts, 3, 41))
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return find(item);
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>find : Symbol(find, Decl(indexedAccessCanBeHighOrder.ts, 0, 61))
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>item : Symbol(item, Decl(indexedAccessCanBeHighOrder.ts, 4, 9))
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}
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const o = {x: 42};
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>o : Symbol(o, Decl(indexedAccessCanBeHighOrder.ts, 8, 5))
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>x : Symbol(x, Decl(indexedAccessCanBeHighOrder.ts, 8, 11))
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const r = impl(o, "x");
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>r : Symbol(r, Decl(indexedAccessCanBeHighOrder.ts, 9, 5))
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>impl : Symbol(impl, Decl(indexedAccessCanBeHighOrder.ts, 1, 61))
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>o : Symbol(o, Decl(indexedAccessCanBeHighOrder.ts, 8, 5))
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r[0][r[1]] = o[r[1]];
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>r : Symbol(r, Decl(indexedAccessCanBeHighOrder.ts, 9, 5))
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>0 : Symbol(0)
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>r : Symbol(r, Decl(indexedAccessCanBeHighOrder.ts, 9, 5))
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>1 : Symbol(1)
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>o : Symbol(o, Decl(indexedAccessCanBeHighOrder.ts, 8, 5))
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>r : Symbol(r, Decl(indexedAccessCanBeHighOrder.ts, 9, 5))
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>1 : Symbol(1)
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‎tests/baselines/reference/indexedAccessCanBeHighOrder.types‎

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=== tests/cases/compiler/indexedAccessCanBeHighOrder.ts ===
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declare function get<U, Y extends keyof U>(x: U, y: Y): U[Y];
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>get : <U, Y extends keyof U>(x: U, y: Y) => U[Y]
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>U : U
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>Y : Y
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>U : U
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>x : U
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>U : U
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>y : Y
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>Y : Y
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>U : U
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>Y : Y
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declare function find<T, K extends keyof T>(o: T[K]): [T, K];
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>find : <T, K extends keyof T>(o: T[K]) => [T, K]
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>T : T
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>K : K
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>T : T
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>o : T[K]
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>T : T
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>K : K
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>T : T
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>K : K
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function impl<A, B extends keyof A>(a: A, b: B) {
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>impl : <A, B extends keyof A>(a: A, b: B) => [A, B]
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>A : A
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>B : B
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>A : A
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>a : A
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>A : A
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>b : B
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>B : B
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const item = get(a, b);
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>item : A[B]
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>get(a, b) : A[B]
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>get : <U, Y extends keyof U>(x: U, y: Y) => U[Y]
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>a : A
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>b : B
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return find(item);
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>find(item) : [A, B]
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>find : <T, K extends keyof T>(o: T[K]) => [T, K]
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>item : A[B]
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}
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const o = {x: 42};
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>o : { x: number; }
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>{x: 42} : { x: number; }
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>x : number
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>42 : 42
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const r = impl(o, "x");
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>r : [{ x: number; }, "x"]
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>impl(o, "x") : [{ x: number; }, "x"]
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>impl : <A, B extends keyof A>(a: A, b: B) => [A, B]
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>o : { x: number; }
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>"x" : "x"
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r[0][r[1]] = o[r[1]];
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>r[0][r[1]] = o[r[1]] : number
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>r[0][r[1]] : number
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>r[0] : { x: number; }
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>r : [{ x: number; }, "x"]
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>0 : 0
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>r[1] : "x"
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>r : [{ x: number; }, "x"]
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>1 : 1
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>o[r[1]] : number
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>o : { x: number; }
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>r[1] : "x"
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>r : [{ x: number; }, "x"]
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>1 : 1
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‎tests/cases/compiler/indexedAccessCanBeHighOrder.ts‎

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declare function get<U, Y extends keyof U>(x: U, y: Y): U[Y];
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declare function find<T, K extends keyof T>(o: T[K]): [T, K];
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function impl<A, B extends keyof A>(a: A, b: B) {
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const item = get(a, b);
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return find(item);
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}
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const o = {x: 42};
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const r = impl(o, "x");
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r[0][r[1]] = o[r[1]];

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