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Disable unsound T[K] rule in subtype relations #39249

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Jun 25, 2020
Merged

Disable unsound T[K] rule in subtype relations #39249

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60992ca
Disable unsound T[K] rule in subtype relations
ahejlsberg Jun 25, 2020
3bca716
Add test
ahejlsberg Jun 25, 2020
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2 changes: 1 addition & 1 deletion src/compiler/checker.ts
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Original file line number Diff line number Diff line change
Expand Up @@ -16873,7 +16873,7 @@ namespace ts {
else if (target.flags & TypeFlags.IndexedAccess) {
// A type S is related to a type T[K] if S is related to C, where C is the base
// constraint of T[K] for writing.
if (relation !== identityRelation) {
if (relation === assignableRelation || relation === comparableRelation) {
const objectType = (<IndexedAccessType>target).objectType;
const indexType = (<IndexedAccessType>target).indexType;
const baseObjectType = getBaseConstraintOfType(objectType) || objectType;
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32 changes: 19 additions & 13 deletions tests/baselines/reference/variadicTuples1.errors.txt
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@@ -1,26 +1,26 @@
tests/cases/conformance/types/tuple/variadicTuples1.ts(6,48): error TS1256: A rest element must be last in a tuple type.
tests/cases/conformance/types/tuple/variadicTuples1.ts(46,5): error TS2555: Expected at least 3 arguments, but got 2.
tests/cases/conformance/types/tuple/variadicTuples1.ts(47,17): error TS2345: Argument of type '45' is not assignable to parameter of type 'boolean'.
tests/cases/conformance/types/tuple/variadicTuples1.ts(125,9): error TS2344: Type 'V' does not satisfy the constraint 'unknown[]'.
tests/cases/conformance/types/tuple/variadicTuples1.ts(52,5): error TS2555: Expected at least 3 arguments, but got 2.
tests/cases/conformance/types/tuple/variadicTuples1.ts(53,17): error TS2345: Argument of type '45' is not assignable to parameter of type 'boolean'.
tests/cases/conformance/types/tuple/variadicTuples1.ts(131,9): error TS2344: Type 'V' does not satisfy the constraint 'unknown[]'.
The type 'readonly unknown[]' is 'readonly' and cannot be assigned to the mutable type 'unknown[]'.
tests/cases/conformance/types/tuple/variadicTuples1.ts(143,5): error TS2322: Type '[string, ...unknown[]]' is not assignable to type '[string, ...T]'.
tests/cases/conformance/types/tuple/variadicTuples1.ts(149,5): error TS2322: Type '[string, ...unknown[]]' is not assignable to type '[string, ...T]'.
Target requires 2 element(s) but source may have fewer.
tests/cases/conformance/types/tuple/variadicTuples1.ts(145,5): error TS2322: Type '[string, ...unknown[]]' is not assignable to type '[string, ...U]'.
tests/cases/conformance/types/tuple/variadicTuples1.ts(151,5): error TS2322: Type '[string, ...unknown[]]' is not assignable to type '[string, ...U]'.
Target requires 2 element(s) but source may have fewer.
tests/cases/conformance/types/tuple/variadicTuples1.ts(146,5): error TS2322: Type '[string, ...T]' is not assignable to type '[string, ...U]'.
tests/cases/conformance/types/tuple/variadicTuples1.ts(152,5): error TS2322: Type '[string, ...T]' is not assignable to type '[string, ...U]'.
Type 'T' is not assignable to type 'U'.
'T' is assignable to the constraint of type 'U', but 'U' could be instantiated with a different subtype of constraint 'string[]'.
Type 'string[]' is not assignable to type 'U'.
'U' could be instantiated with an arbitrary type which could be unrelated to 'string[]'.
tests/cases/conformance/types/tuple/variadicTuples1.ts(154,5): error TS2322: Type 'readonly [...T]' is not assignable to type 'T'.
tests/cases/conformance/types/tuple/variadicTuples1.ts(160,5): error TS2322: Type 'readonly [...T]' is not assignable to type 'T'.
'T' could be instantiated with an arbitrary type which could be unrelated to 'readonly [...T]'.
tests/cases/conformance/types/tuple/variadicTuples1.ts(156,5): error TS4104: The type 'readonly [...T]' is 'readonly' and cannot be assigned to the mutable type '[...T]'.
tests/cases/conformance/types/tuple/variadicTuples1.ts(163,5): error TS2322: Type 'readonly [...T]' is not assignable to type 'T'.
tests/cases/conformance/types/tuple/variadicTuples1.ts(162,5): error TS4104: The type 'readonly [...T]' is 'readonly' and cannot be assigned to the mutable type '[...T]'.
tests/cases/conformance/types/tuple/variadicTuples1.ts(169,5): error TS2322: Type 'readonly [...T]' is not assignable to type 'T'.
'readonly [...T]' is assignable to the constraint of type 'T', but 'T' could be instantiated with a different subtype of constraint 'readonly unknown[]'.
tests/cases/conformance/types/tuple/variadicTuples1.ts(164,5): error TS2322: Type 'T' is not assignable to type '[...T]'.
tests/cases/conformance/types/tuple/variadicTuples1.ts(170,5): error TS2322: Type 'T' is not assignable to type '[...T]'.
The type 'readonly unknown[]' is 'readonly' and cannot be assigned to the mutable type '[...T]'.
tests/cases/conformance/types/tuple/variadicTuples1.ts(165,5): error TS4104: The type 'readonly [...T]' is 'readonly' and cannot be assigned to the mutable type '[...T]'.
tests/cases/conformance/types/tuple/variadicTuples1.ts(297,14): error TS7019: Rest parameter 'x' implicitly has an 'any[]' type.
tests/cases/conformance/types/tuple/variadicTuples1.ts(171,5): error TS4104: The type 'readonly [...T]' is 'readonly' and cannot be assigned to the mutable type '[...T]'.
tests/cases/conformance/types/tuple/variadicTuples1.ts(303,14): error TS7019: Rest parameter 'x' implicitly has an 'any[]' type.


==== tests/cases/conformance/types/tuple/variadicTuples1.ts (13 errors) ====
Expand Down Expand Up @@ -62,6 +62,12 @@ tests/cases/conformance/types/tuple/variadicTuples1.ts(297,14): error TS7019: Re
const tc3 = concat([1, 2, 3], sa);
const tc4 = concat(sa, [1, 2, 3]); // Ideally would be [...string[], number, number, number]

function concat2<T extends readonly unknown[], U extends readonly unknown[]>(t: T, u: U) {
return [...t, ...u]; // (T[number] | U[number])[]
}

const tc5 = concat2([1, 2, 3] as const, [4, 5, 6] as const); // (1 | 2 | 3 | 4 | 5 | 6)[]

// Spread arguments

declare function foo1(a: number, b: string, c: boolean, ...d: number[]): void;
Expand All @@ -74,7 +80,7 @@ tests/cases/conformance/types/tuple/variadicTuples1.ts(297,14): error TS7019: Re
foo1(...t1); // Error
~~~~~~~~~~~
!!! error TS2555: Expected at least 3 arguments, but got 2.
!!! related TS6210 tests/cases/conformance/types/tuple/variadicTuples1.ts:39:45: An argument for 'c' was not provided.
!!! related TS6210 tests/cases/conformance/types/tuple/variadicTuples1.ts:45:45: An argument for 'c' was not provided.
foo1(...t1, 45); // Error
~~
!!! error TS2345: Argument of type '45' is not assignable to parameter of type 'boolean'.
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12 changes: 12 additions & 0 deletions tests/baselines/reference/variadicTuples1.js
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Expand Up @@ -35,6 +35,12 @@ const tc2 = concat(['hello'], [42]);
const tc3 = concat([1, 2, 3], sa);
const tc4 = concat(sa, [1, 2, 3]); // Ideally would be [...string[], number, number, number]

function concat2<T extends readonly unknown[], U extends readonly unknown[]>(t: T, u: U) {
return [...t, ...u]; // (T[number] | U[number])[]
}

const tc5 = concat2([1, 2, 3] as const, [4, 5, 6] as const); // (1 | 2 | 3 | 4 | 5 | 6)[]

// Spread arguments

declare function foo1(a: number, b: string, c: boolean, ...d: number[]): void;
Expand Down Expand Up @@ -320,6 +326,10 @@ var tc1 = concat([], []);
var tc2 = concat(['hello'], [42]);
var tc3 = concat([1, 2, 3], sa);
var tc4 = concat(sa, [1, 2, 3]); // Ideally would be [...string[], number, number, number]
function concat2(t, u) {
return __spreadArrays(t, u); // (T[number] | U[number])[]
}
var tc5 = concat2([1, 2, 3], [4, 5, 6]); // (1 | 2 | 3 | 4 | 5 | 6)[]
function foo2(t1, t2, a1) {
foo1(1, 'abc', true, 42, 43, 44);
foo1.apply(void 0, __spreadArrays(t1, [true, 42, 43, 44]));
Expand Down Expand Up @@ -483,6 +493,8 @@ declare const tc1: [];
declare const tc2: [string, number];
declare const tc3: [number, number, number, ...string[]];
declare const tc4: (string | number)[];
declare function concat2<T extends readonly unknown[], U extends readonly unknown[]>(t: T, u: U): (T[number] | U[number])[];
declare const tc5: (2 | 4 | 1 | 3 | 6 | 5)[];
declare function foo1(a: number, b: string, c: boolean, ...d: number[]): void;
declare function foo2(t1: [number, string], t2: [boolean], a1: number[]): void;
declare function foo3<T extends unknown[]>(x: number, ...args: [...T, number]): T;
Expand Down
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