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RyanCavanaughRyanCavanaugh
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Merge pull request #27254 from weswigham/port-distribution-fix
Distribute indexes of indexed access types first (#27243)
2 parents c48de89 + 317b2c2 commit d715d83

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6 files changed

+154
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‎src/compiler/checker.ts‎

Lines changed: 16 additions & 4 deletions
Original file line numberDiff line numberDiff line change
@@ -9369,12 +9369,24 @@ namespace ts {
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// '{ [P in T]: { [Q in U]: number } }[T][U]' we want to first simplify the inner indexed access type.
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const objectType = getSimplifiedType(type.objectType);
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const indexType = getSimplifiedType(type.indexType);
9372-
if (objectType.flags & TypeFlags.Union) {
9373-
return type.simplified = mapType(objectType, t => getSimplifiedType(getIndexedAccessType(t, indexType)));
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// T[A | B] -> T[A] | T[B]
9373+
if (indexType.flags & TypeFlags.Union) {
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return type.simplified = mapType(indexType, t => getSimplifiedType(getIndexedAccessType(objectType, t)));
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}
9375-
if (objectType.flags & TypeFlags.Intersection) {
9376-
return type.simplified = getIntersectionType(map((objectType as IntersectionType).types, t => getSimplifiedType(getIndexedAccessType(t, indexType))));
9376+
// Only do the inner distributions if the index can no longer be instantiated to cause index distribution again
9377+
if (!(indexType.flags & TypeFlags.Instantiable)) {
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// (T | U)[K] -> T[K] | U[K]
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if (objectType.flags & TypeFlags.Union) {
9380+
return type.simplified = mapType(objectType, t => getSimplifiedType(getIndexedAccessType(t, indexType)));
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}
9382+
// (T & U)[K] -> T[K] & U[K]
9383+
if (objectType.flags & TypeFlags.Intersection) {
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return type.simplified = getIntersectionType(map((objectType as IntersectionType).types, t => getSimplifiedType(getIndexedAccessType(t, indexType))));
9385+
}
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}
9387+
// So ultimately:
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// ((A & B) | C)[K1 | K2] -> ((A & B) | C)[K1] | ((A & B) | C)[K2] -> (A & B)[K1] | C[K1] | (A & B)[K2] | C[K2] -> (A[K1] & B[K1]) | C[K1] | (A[K2] & B[K2]) | C[K2]
9389+
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// If the object type is a mapped type { [P in K]: E }, where K is generic, instantiate E using a mapper
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// that substitutes the index type for P. For example, for an index access { [P in K]: Box<T[P]> }[X], we
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// construct the type Box<T[X]>. We do not further simplify the result because mapped types can be recursive

‎tests/baselines/reference/contextualTypeOfIndexedAccessParameter.js‎

Lines changed: 25 additions & 0 deletions
Original file line numberDiff line numberDiff line change
@@ -0,0 +1,25 @@
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//// [contextualTypeOfIndexedAccessParameter.ts]
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type Keys = "a" | "b";
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type OptionsForKey = { a: { cb: (p: number) => number } } & { b: {} };
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declare function f<K extends Keys>(key: K, options: OptionsForKey[K]): void;
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f("a", {
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cb: p => p,
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});
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function g<
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K extends "a" | "b">(x: ({ a: string } & { b: string })[K], y: string) {
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x = y;
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}
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//// [contextualTypeOfIndexedAccessParameter.js]
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"use strict";
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f("a", {
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cb: function (p) { return p; }
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});
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function g(x, y) {
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x = y;
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}

‎tests/baselines/reference/contextualTypeOfIndexedAccessParameter.symbols‎

Lines changed: 47 additions & 0 deletions
Original file line numberDiff line numberDiff line change
@@ -0,0 +1,47 @@
1+
=== tests/cases/compiler/contextualTypeOfIndexedAccessParameter.ts ===
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type Keys = "a" | "b";
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>Keys : Symbol(Keys, Decl(contextualTypeOfIndexedAccessParameter.ts, 0, 0))
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type OptionsForKey = { a: { cb: (p: number) => number } } & { b: {} };
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>OptionsForKey : Symbol(OptionsForKey, Decl(contextualTypeOfIndexedAccessParameter.ts, 0, 22))
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>a : Symbol(a, Decl(contextualTypeOfIndexedAccessParameter.ts, 2, 22))
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>cb : Symbol(cb, Decl(contextualTypeOfIndexedAccessParameter.ts, 2, 27))
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>p : Symbol(p, Decl(contextualTypeOfIndexedAccessParameter.ts, 2, 33))
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>b : Symbol(b, Decl(contextualTypeOfIndexedAccessParameter.ts, 2, 61))
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declare function f<K extends Keys>(key: K, options: OptionsForKey[K]): void;
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>f : Symbol(f, Decl(contextualTypeOfIndexedAccessParameter.ts, 2, 70))
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>K : Symbol(K, Decl(contextualTypeOfIndexedAccessParameter.ts, 4, 19))
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>Keys : Symbol(Keys, Decl(contextualTypeOfIndexedAccessParameter.ts, 0, 0))
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>key : Symbol(key, Decl(contextualTypeOfIndexedAccessParameter.ts, 4, 35))
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>K : Symbol(K, Decl(contextualTypeOfIndexedAccessParameter.ts, 4, 19))
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>options : Symbol(options, Decl(contextualTypeOfIndexedAccessParameter.ts, 4, 42))
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>OptionsForKey : Symbol(OptionsForKey, Decl(contextualTypeOfIndexedAccessParameter.ts, 0, 22))
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>K : Symbol(K, Decl(contextualTypeOfIndexedAccessParameter.ts, 4, 19))
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f("a", {
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>f : Symbol(f, Decl(contextualTypeOfIndexedAccessParameter.ts, 2, 70))
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cb: p => p,
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>cb : Symbol(cb, Decl(contextualTypeOfIndexedAccessParameter.ts, 6, 8))
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>p : Symbol(p, Decl(contextualTypeOfIndexedAccessParameter.ts, 7, 7))
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>p : Symbol(p, Decl(contextualTypeOfIndexedAccessParameter.ts, 7, 7))
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});
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function g<
33+
>g : Symbol(g, Decl(contextualTypeOfIndexedAccessParameter.ts, 8, 3))
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K extends "a" | "b">(x: ({ a: string } & { b: string })[K], y: string) {
36+
>K : Symbol(K, Decl(contextualTypeOfIndexedAccessParameter.ts, 10, 11))
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>x : Symbol(x, Decl(contextualTypeOfIndexedAccessParameter.ts, 11, 25))
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>a : Symbol(a, Decl(contextualTypeOfIndexedAccessParameter.ts, 11, 30))
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>b : Symbol(b, Decl(contextualTypeOfIndexedAccessParameter.ts, 11, 46))
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>K : Symbol(K, Decl(contextualTypeOfIndexedAccessParameter.ts, 10, 11))
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>y : Symbol(y, Decl(contextualTypeOfIndexedAccessParameter.ts, 11, 63))
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x = y;
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>x : Symbol(x, Decl(contextualTypeOfIndexedAccessParameter.ts, 11, 25))
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>y : Symbol(y, Decl(contextualTypeOfIndexedAccessParameter.ts, 11, 63))
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}
47+

‎tests/baselines/reference/contextualTypeOfIndexedAccessParameter.types‎

Lines changed: 45 additions & 0 deletions
Original file line numberDiff line numberDiff line change
@@ -0,0 +1,45 @@
1+
=== tests/cases/compiler/contextualTypeOfIndexedAccessParameter.ts ===
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type Keys = "a" | "b";
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>Keys : Keys
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type OptionsForKey = { a: { cb: (p: number) => number } } & { b: {} };
6+
>OptionsForKey : OptionsForKey
7+
>a : { cb: (p: number) => number; }
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>cb : (p: number) => number
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>p : number
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>b : {}
11+
12+
declare function f<K extends Keys>(key: K, options: OptionsForKey[K]): void;
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>f : <K extends Keys>(key: K, options: OptionsForKey[K]) => void
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>key : K
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>options : OptionsForKey[K]
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f("a", {
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>f("a", { cb: p => p,}) : void
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>f : <K extends Keys>(key: K, options: OptionsForKey[K]) => void
20+
>"a" : "a"
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>{ cb: p => p,} : { cb: (p: number) => number; }
22+
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cb: p => p,
24+
>cb : (p: number) => number
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>p => p : (p: number) => number
26+
>p : number
27+
>p : number
28+
29+
});
30+
31+
function g<
32+
>g : <K extends Keys>(x: ({ a: string; } & { b: string; })[K], y: string) => void
33+
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K extends "a" | "b">(x: ({ a: string } & { b: string })[K], y: string) {
35+
>x : ({ a: string; } & { b: string; })[K]
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>a : string
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>b : string
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>y : string
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x = y;
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>x = y : string
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>x : ({ a: string; } & { b: string; })[K]
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>y : string
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}
45+

‎tests/baselines/reference/infiniteConstraints.errors.txt‎

Lines changed: 6 additions & 2 deletions
Original file line numberDiff line numberDiff line change
@@ -1,4 +1,6 @@
1-
error TS2321: Excessive stack depth comparing types 'Extract<T[Exclude<keyof T, string | number | symbol>], Record<"val", string>>["val"]' and 'Extract<T[Exclude<keyof T, Exclude<keyof T, string | number | symbol>>], Record<"val", string>>["val"]'.
1+
error TS2321: Excessive stack depth comparing types 'Extract<T[Exclude<keyof T, number>], Record<"val", string>>["val"]' and 'Extract<T[Exclude<keyof T, Exclude<keyof T, number>>], Record<"val", string>>["val"]'.
2+
error TS2321: Excessive stack depth comparing types 'Extract<T[Exclude<keyof T, string>], Record<"val", string>>["val"]' and 'Extract<T[Exclude<keyof T, Exclude<keyof T, string>>], Record<"val", string>>["val"]'.
3+
error TS2321: Excessive stack depth comparing types 'Extract<T[Exclude<keyof T, symbol>], Record<"val", string>>["val"]' and 'Extract<T[Exclude<keyof T, Exclude<keyof T, symbol>>], Record<"val", string>>["val"]'.
24
tests/cases/compiler/infiniteConstraints.ts(4,37): error TS2536: Type '"val"' cannot be used to index type 'B[Exclude<keyof B, K>]'.
35
tests/cases/compiler/infiniteConstraints.ts(27,37): error TS2322: Type 'Record<"val", "test">' is not assignable to type 'never'.
46
tests/cases/compiler/infiniteConstraints.ts(27,58): error TS2322: Type 'Record<"val", "test2">' is not assignable to type 'never'.
@@ -8,7 +10,9 @@ tests/cases/compiler/infiniteConstraints.ts(31,63): error TS2322: Type 'Record<"
810
tests/cases/compiler/infiniteConstraints.ts(36,71): error TS2536: Type '"foo"' cannot be used to index type 'T[keyof T]'.
911

1012

11-
!!! error TS2321: Excessive stack depth comparing types 'Extract<T[Exclude<keyof T, string | number | symbol>], Record<"val", string>>["val"]' and 'Extract<T[Exclude<keyof T, Exclude<keyof T, string | number | symbol>>], Record<"val", string>>["val"]'.
13+
!!! error TS2321: Excessive stack depth comparing types 'Extract<T[Exclude<keyof T, number>], Record<"val", string>>["val"]' and 'Extract<T[Exclude<keyof T, Exclude<keyof T, number>>], Record<"val", string>>["val"]'.
14+
!!! error TS2321: Excessive stack depth comparing types 'Extract<T[Exclude<keyof T, string>], Record<"val", string>>["val"]' and 'Extract<T[Exclude<keyof T, Exclude<keyof T, string>>], Record<"val", string>>["val"]'.
15+
!!! error TS2321: Excessive stack depth comparing types 'Extract<T[Exclude<keyof T, symbol>], Record<"val", string>>["val"]' and 'Extract<T[Exclude<keyof T, Exclude<keyof T, symbol>>], Record<"val", string>>["val"]'.
1216
==== tests/cases/compiler/infiniteConstraints.ts (7 errors) ====
1317
// Both of the following types trigger the recursion limiter in getImmediateBaseConstraint
1418

‎tests/cases/compiler/contextualTypeOfIndexedAccessParameter.ts‎

Lines changed: 15 additions & 0 deletions
Original file line numberDiff line numberDiff line change
@@ -0,0 +1,15 @@
1+
// @strict: true
2+
type Keys = "a" | "b";
3+
4+
type OptionsForKey = { a: { cb: (p: number) => number } } & { b: {} };
5+
6+
declare function f<K extends Keys>(key: K, options: OptionsForKey[K]): void;
7+
8+
f("a", {
9+
cb: p => p,
10+
});
11+
12+
function g<
13+
K extends "a" | "b">(x: ({ a: string } & { b: string })[K], y: string) {
14+
x = y;
15+
}

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