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Defer conditional types with parenthesized multi-element tuple types in extends clause #56271

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Merged
merged 4 commits into from
Dec 8, 2023
Merged

Defer conditional types with parenthesized multi-element tuple types in extends clause #56271

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bc15c38
Defer conditional types with parenthesized multi-element tuple types …
Andarist Oct 31, 2023
ec113c0
revert predicate change
Andarist Oct 31, 2023
3254c17
Merge branch 'main' into pr-56271
jakebailey Dec 8, 2023
55e93bf
Update baseline
jakebailey Dec 8, 2023
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9 changes: 6 additions & 3 deletions src/compiler/checker.ts
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Original file line number Diff line number Diff line change
Expand Up @@ -967,6 +967,7 @@ import {
skipParentheses,
skipTrivia,
skipTypeChecking,
skipTypeParentheses,
some,
SourceFile,
SpreadAssignment,
Expand Down Expand Up @@ -18490,7 +18491,7 @@ export function createTypeChecker(host: TypeCheckerHost): TypeChecker {
return constraint && (isGenericObjectType(constraint) || isGenericIndexType(constraint)) ? cloneTypeParameter(p) : p;
}

function isSimpleTupleType(node: TypeNode) {
function isSimpleTupleType(node: TypeNode): boolean {
return isTupleTypeNode(node) && length(node.elements) > 0 &&
!some(node.elements, e => isOptionalTypeNode(e) || isRestTypeNode(e) || isNamedTupleMember(e) && !!(e.questionToken || e.dotDotDotToken));
}
Expand Down Expand Up @@ -18521,11 +18522,13 @@ export function createTypeChecker(host: TypeCheckerHost): TypeChecker {
if (checkType === wildcardType || extendsType === wildcardType) {
return wildcardType;
}
const checkTypeNode = skipTypeParentheses(root.node.checkType);
const extendsTypeNode = skipTypeParentheses(root.node.extendsType);
// When the check and extends types are simple tuple types of the same arity, we defer resolution of the
// conditional type when any tuple elements are generic. This is such that non-distributable conditional
// types can be written `[X] extends [Y] ? ...` and be deferred similarly to `X extends Y ? ...`.
const checkTuples = isSimpleTupleType(root.node.checkType) && isSimpleTupleType(root.node.extendsType) &&
length((root.node.checkType as TupleTypeNode).elements) === length((root.node.extendsType as TupleTypeNode).elements);
const checkTuples = isSimpleTupleType(checkTypeNode) && isSimpleTupleType(extendsTypeNode) &&
length((checkTypeNode as TupleTypeNode).elements) === length((extendsTypeNode as TupleTypeNode).elements);
const checkTypeDeferred = isDeferredType(checkType, checkTuples);
let combinedMapper: TypeMapper | undefined;
if (root.inferTypeParameters) {
Expand Down
117 changes: 117 additions & 0 deletions tests/baselines/reference/deferredConditionalTypes2.symbols
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@@ -0,0 +1,117 @@
//// [tests/cases/compiler/deferredConditionalTypes2.ts] ////

=== deferredConditionalTypes2.ts ===
// https://github.com/microsoft/TypeScript/issues/56270

type PositiveInfinity = 1e999;
>PositiveInfinity : Symbol(PositiveInfinity, Decl(deferredConditionalTypes2.ts, 0, 0))

type NegativeInfinity = -1e999;
>NegativeInfinity : Symbol(NegativeInfinity, Decl(deferredConditionalTypes2.ts, 2, 30))

export type IsEqual<A, B> = (<G>() => G extends A ? 1 : 2) extends <
>IsEqual : Symbol(IsEqual, Decl(deferredConditionalTypes2.ts, 3, 31))
>A : Symbol(A, Decl(deferredConditionalTypes2.ts, 5, 20))
>B : Symbol(B, Decl(deferredConditionalTypes2.ts, 5, 22))
>G : Symbol(G, Decl(deferredConditionalTypes2.ts, 5, 30))
>G : Symbol(G, Decl(deferredConditionalTypes2.ts, 5, 30))
>A : Symbol(A, Decl(deferredConditionalTypes2.ts, 5, 20))

G,
>G : Symbol(G, Decl(deferredConditionalTypes2.ts, 5, 68))

>() => G extends B ? 1 : 2
>G : Symbol(G, Decl(deferredConditionalTypes2.ts, 5, 68))
>B : Symbol(B, Decl(deferredConditionalTypes2.ts, 5, 22))

? true
: false;

export type Add<A extends number, B extends number> = [
>Add : Symbol(Add, Decl(deferredConditionalTypes2.ts, 9, 10))
>A : Symbol(A, Decl(deferredConditionalTypes2.ts, 11, 16))
>B : Symbol(B, Decl(deferredConditionalTypes2.ts, 11, 33))

IsEqual<A, PositiveInfinity>,
>IsEqual : Symbol(IsEqual, Decl(deferredConditionalTypes2.ts, 3, 31))
>A : Symbol(A, Decl(deferredConditionalTypes2.ts, 11, 16))
>PositiveInfinity : Symbol(PositiveInfinity, Decl(deferredConditionalTypes2.ts, 0, 0))

IsEqual<A, NegativeInfinity>,
>IsEqual : Symbol(IsEqual, Decl(deferredConditionalTypes2.ts, 3, 31))
>A : Symbol(A, Decl(deferredConditionalTypes2.ts, 11, 16))
>NegativeInfinity : Symbol(NegativeInfinity, Decl(deferredConditionalTypes2.ts, 2, 30))

IsEqual<B, PositiveInfinity>,
>IsEqual : Symbol(IsEqual, Decl(deferredConditionalTypes2.ts, 3, 31))
>B : Symbol(B, Decl(deferredConditionalTypes2.ts, 11, 33))
>PositiveInfinity : Symbol(PositiveInfinity, Decl(deferredConditionalTypes2.ts, 0, 0))

IsEqual<B, NegativeInfinity>,
>IsEqual : Symbol(IsEqual, Decl(deferredConditionalTypes2.ts, 3, 31))
>B : Symbol(B, Decl(deferredConditionalTypes2.ts, 11, 33))
>NegativeInfinity : Symbol(NegativeInfinity, Decl(deferredConditionalTypes2.ts, 2, 30))

] extends infer R extends [boolean, boolean, boolean, boolean]
>R : Symbol(R, Decl(deferredConditionalTypes2.ts, 16, 15))

? [true, false] extends ([R[0], R[3]])
>R : Symbol(R, Decl(deferredConditionalTypes2.ts, 16, 15))
>R : Symbol(R, Decl(deferredConditionalTypes2.ts, 16, 15))

? PositiveInfinity
>PositiveInfinity : Symbol(PositiveInfinity, Decl(deferredConditionalTypes2.ts, 0, 0))

: "failed"
: never;

export type AddWithoutParentheses<A extends number, B extends number> = [
>AddWithoutParentheses : Symbol(AddWithoutParentheses, Decl(deferredConditionalTypes2.ts, 20, 10))
>A : Symbol(A, Decl(deferredConditionalTypes2.ts, 22, 34))
>B : Symbol(B, Decl(deferredConditionalTypes2.ts, 22, 51))

IsEqual<A, PositiveInfinity>,
>IsEqual : Symbol(IsEqual, Decl(deferredConditionalTypes2.ts, 3, 31))
>A : Symbol(A, Decl(deferredConditionalTypes2.ts, 22, 34))
>PositiveInfinity : Symbol(PositiveInfinity, Decl(deferredConditionalTypes2.ts, 0, 0))

IsEqual<A, NegativeInfinity>,
>IsEqual : Symbol(IsEqual, Decl(deferredConditionalTypes2.ts, 3, 31))
>A : Symbol(A, Decl(deferredConditionalTypes2.ts, 22, 34))
>NegativeInfinity : Symbol(NegativeInfinity, Decl(deferredConditionalTypes2.ts, 2, 30))

IsEqual<B, PositiveInfinity>,
>IsEqual : Symbol(IsEqual, Decl(deferredConditionalTypes2.ts, 3, 31))
>B : Symbol(B, Decl(deferredConditionalTypes2.ts, 22, 51))
>PositiveInfinity : Symbol(PositiveInfinity, Decl(deferredConditionalTypes2.ts, 0, 0))

IsEqual<B, NegativeInfinity>,
>IsEqual : Symbol(IsEqual, Decl(deferredConditionalTypes2.ts, 3, 31))
>B : Symbol(B, Decl(deferredConditionalTypes2.ts, 22, 51))
>NegativeInfinity : Symbol(NegativeInfinity, Decl(deferredConditionalTypes2.ts, 2, 30))

] extends infer R extends [boolean, boolean, boolean, boolean]
>R : Symbol(R, Decl(deferredConditionalTypes2.ts, 27, 15))

? [true, false] extends [R[0], R[3]]
>R : Symbol(R, Decl(deferredConditionalTypes2.ts, 27, 15))
>R : Symbol(R, Decl(deferredConditionalTypes2.ts, 27, 15))

? PositiveInfinity
>PositiveInfinity : Symbol(PositiveInfinity, Decl(deferredConditionalTypes2.ts, 0, 0))

: "failed"
: never;

type AddTest0 = Add<PositiveInfinity, PositiveInfinity>;
>AddTest0 : Symbol(AddTest0, Decl(deferredConditionalTypes2.ts, 31, 10))
>Add : Symbol(Add, Decl(deferredConditionalTypes2.ts, 9, 10))
>PositiveInfinity : Symbol(PositiveInfinity, Decl(deferredConditionalTypes2.ts, 0, 0))
>PositiveInfinity : Symbol(PositiveInfinity, Decl(deferredConditionalTypes2.ts, 0, 0))

type AddTest1 = AddWithoutParentheses<PositiveInfinity, PositiveInfinity>;
>AddTest1 : Symbol(AddTest1, Decl(deferredConditionalTypes2.ts, 33, 56))
>AddWithoutParentheses : Symbol(AddWithoutParentheses, Decl(deferredConditionalTypes2.ts, 20, 10))
>PositiveInfinity : Symbol(PositiveInfinity, Decl(deferredConditionalTypes2.ts, 0, 0))
>PositiveInfinity : Symbol(PositiveInfinity, Decl(deferredConditionalTypes2.ts, 0, 0))

62 changes: 62 additions & 0 deletions tests/baselines/reference/deferredConditionalTypes2.types
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@@ -0,0 +1,62 @@
//// [tests/cases/compiler/deferredConditionalTypes2.ts] ////

=== deferredConditionalTypes2.ts ===
// https://github.com/microsoft/TypeScript/issues/56270

type PositiveInfinity = 1e999;
>PositiveInfinity : Infinity

type NegativeInfinity = -1e999;
>NegativeInfinity : -Infinity
>-1e999 : -Infinity
>1e999 : Infinity

export type IsEqual<A, B> = (<G>() => G extends A ? 1 : 2) extends <
>IsEqual : IsEqual<A, B>

G,
>() => G extends B ? 1 : 2
? true
>true : true

: false;
>false : false

export type Add<A extends number, B extends number> = [
>Add : [true, false] extends [IsEqual<A, Infinity>, IsEqual<B, -Infinity>] ? Infinity : "failed"

IsEqual<A, PositiveInfinity>,
IsEqual<A, NegativeInfinity>,
IsEqual<B, PositiveInfinity>,
IsEqual<B, NegativeInfinity>,
] extends infer R extends [boolean, boolean, boolean, boolean]
? [true, false] extends ([R[0], R[3]])
>true : true
>false : false

? PositiveInfinity
: "failed"
: never;

export type AddWithoutParentheses<A extends number, B extends number> = [
>AddWithoutParentheses : [true, false] extends [IsEqual<A, Infinity>, IsEqual<B, -Infinity>] ? Infinity : "failed"

IsEqual<A, PositiveInfinity>,
IsEqual<A, NegativeInfinity>,
IsEqual<B, PositiveInfinity>,
IsEqual<B, NegativeInfinity>,
] extends infer R extends [boolean, boolean, boolean, boolean]
? [true, false] extends [R[0], R[3]]
>true : true
>false : false

? PositiveInfinity
: "failed"
: never;

type AddTest0 = Add<PositiveInfinity, PositiveInfinity>;
>AddTest0 : Infinity

type AddTest1 = AddWithoutParentheses<PositiveInfinity, PositiveInfinity>;
>AddTest1 : Infinity

38 changes: 38 additions & 0 deletions tests/cases/compiler/deferredConditionalTypes2.ts
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@@ -0,0 +1,38 @@
// @strict: true
// @noEmit: true

// https://github.com/microsoft/TypeScript/issues/56270

type PositiveInfinity = 1e999;
type NegativeInfinity = -1e999;

export type IsEqual<A, B> = (<G>() => G extends A ? 1 : 2) extends <
G,
>() => G extends B ? 1 : 2
? true
: false;

export type Add<A extends number, B extends number> = [
IsEqual<A, PositiveInfinity>,
IsEqual<A, NegativeInfinity>,
IsEqual<B, PositiveInfinity>,
IsEqual<B, NegativeInfinity>,
] extends infer R extends [boolean, boolean, boolean, boolean]
? [true, false] extends ([R[0], R[3]])
? PositiveInfinity
: "failed"
: never;

export type AddWithoutParentheses<A extends number, B extends number> = [
IsEqual<A, PositiveInfinity>,
IsEqual<A, NegativeInfinity>,
IsEqual<B, PositiveInfinity>,
IsEqual<B, NegativeInfinity>,
] extends infer R extends [boolean, boolean, boolean, boolean]
? [true, false] extends [R[0], R[3]]
? PositiveInfinity
: "failed"
: never;

type AddTest0 = Add<PositiveInfinity, PositiveInfinity>;
type AddTest1 = AddWithoutParentheses<PositiveInfinity, PositiveInfinity>;