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Merge pull request #22850 from Microsoft/tupleTypeInference
Only make inferences from tuple types of right arity
2 parents fdc4689 + 63f98de commit d7df84d

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+275
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Diff for: ‎src/compiler/checker.ts

+9-3
Original file line numberDiff line numberDiff line change
@@ -11603,6 +11603,13 @@ namespace ts {
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return undefined;
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}
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function typesDefinitelyUnrelated(source: Type, target: Type) {
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// Two tuple types with different arity are definitely unrelated.
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// Two object types that each have a property that is unmatched in the other are definitely unrelated.
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return isTupleType(source) && isTupleType(target) && getTypeReferenceArity(<TypeReference>source) !== getTypeReferenceArity(<TypeReference>target) ||
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!!getUnmatchedProperty(source, target, /*requireOptionalProperties*/ false) && !!getUnmatchedProperty(target, source, /*requireOptionalProperties*/ false);
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}
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function getTypeFromInference(inference: InferenceInfo) {
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return inference.candidates ? getUnionType(inference.candidates, UnionReduction.Subtype) :
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inference.contraCandidates ? getIntersectionType(inference.contraCandidates) :
@@ -11873,9 +11880,8 @@ namespace ts {
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return;
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}
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}
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// Infer from the members of source and target only if the two types are possibly related. We check
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// in both directions because we may be inferring for a co-variant or a contra-variant position.
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if (!getUnmatchedProperty(source, target, /*requireOptionalProperties*/ false) || !getUnmatchedProperty(target, source, /*requireOptionalProperties*/ false)) {
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// Infer from the members of source and target only if the two types are possibly related
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if (!typesDefinitelyUnrelated(source, target)) {
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inferFromProperties(source, target);
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inferFromSignatures(source, target, SignatureKind.Call);
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inferFromSignatures(source, target, SignatureKind.Construct);

Diff for: ‎tests/baselines/reference/tupleTypeInference2.js

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@@ -0,0 +1,35 @@
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//// [tupleTypeInference2.ts]
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// Repro from #22564
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type A<R> = [R] | [R, string];
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declare function f<T>(x: A<T>): T;
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f([undefined, ''] as [never, string]); // T: never
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f([undefined, ''] as [void, string]); // T: void
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// Repro from #22563
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type B<R, S> = [R] | [R, S];
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declare function g<T, U>(f: B<T, U>): U;
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g([[]] as [void[]]); // U: {}
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type C<R, S> = [R[]] | [R[], S];
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declare function h<T, U>(f: C<T, U>): U;
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h([[]] as [void[]]); // U: {}
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// Repro from #22562
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type C2<R> = [R[]] | [R[], void];
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declare function h2<T>(f: C2<T>): T;
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h2([[]] as [never[]]); // T: never
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h2([[]] as [void[]]); // T: void
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//// [tupleTypeInference2.js]
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"use strict";
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// Repro from #22564
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f([undefined, '']); // T: never
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f([undefined, '']); // T: void
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g([[]]); // U: {}
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h([[]]); // U: {}
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h2([[]]); // T: never
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h2([[]]); // T: void

Diff for: ‎tests/baselines/reference/tupleTypeInference2.symbols

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@@ -0,0 +1,91 @@
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=== tests/cases/compiler/tupleTypeInference2.ts ===
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// Repro from #22564
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type A<R> = [R] | [R, string];
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>A : Symbol(A, Decl(tupleTypeInference2.ts, 0, 0))
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>R : Symbol(R, Decl(tupleTypeInference2.ts, 2, 7))
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>R : Symbol(R, Decl(tupleTypeInference2.ts, 2, 7))
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>R : Symbol(R, Decl(tupleTypeInference2.ts, 2, 7))
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declare function f<T>(x: A<T>): T;
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>f : Symbol(f, Decl(tupleTypeInference2.ts, 2, 30))
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>T : Symbol(T, Decl(tupleTypeInference2.ts, 3, 19))
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>x : Symbol(x, Decl(tupleTypeInference2.ts, 3, 22))
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>A : Symbol(A, Decl(tupleTypeInference2.ts, 0, 0))
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>T : Symbol(T, Decl(tupleTypeInference2.ts, 3, 19))
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>T : Symbol(T, Decl(tupleTypeInference2.ts, 3, 19))
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f([undefined, ''] as [never, string]); // T: never
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>f : Symbol(f, Decl(tupleTypeInference2.ts, 2, 30))
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>undefined : Symbol(undefined)
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f([undefined, ''] as [void, string]); // T: void
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>f : Symbol(f, Decl(tupleTypeInference2.ts, 2, 30))
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>undefined : Symbol(undefined)
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// Repro from #22563
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type B<R, S> = [R] | [R, S];
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>B : Symbol(B, Decl(tupleTypeInference2.ts, 5, 37))
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>R : Symbol(R, Decl(tupleTypeInference2.ts, 9, 7))
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>S : Symbol(S, Decl(tupleTypeInference2.ts, 9, 9))
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>R : Symbol(R, Decl(tupleTypeInference2.ts, 9, 7))
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>R : Symbol(R, Decl(tupleTypeInference2.ts, 9, 7))
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>S : Symbol(S, Decl(tupleTypeInference2.ts, 9, 9))
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declare function g<T, U>(f: B<T, U>): U;
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>g : Symbol(g, Decl(tupleTypeInference2.ts, 9, 28))
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>T : Symbol(T, Decl(tupleTypeInference2.ts, 10, 19))
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>U : Symbol(U, Decl(tupleTypeInference2.ts, 10, 21))
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>f : Symbol(f, Decl(tupleTypeInference2.ts, 10, 25))
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>B : Symbol(B, Decl(tupleTypeInference2.ts, 5, 37))
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>T : Symbol(T, Decl(tupleTypeInference2.ts, 10, 19))
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>U : Symbol(U, Decl(tupleTypeInference2.ts, 10, 21))
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>U : Symbol(U, Decl(tupleTypeInference2.ts, 10, 21))
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g([[]] as [void[]]); // U: {}
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>g : Symbol(g, Decl(tupleTypeInference2.ts, 9, 28))
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type C<R, S> = [R[]] | [R[], S];
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>C : Symbol(C, Decl(tupleTypeInference2.ts, 11, 20))
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>R : Symbol(R, Decl(tupleTypeInference2.ts, 13, 7))
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>S : Symbol(S, Decl(tupleTypeInference2.ts, 13, 9))
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>R : Symbol(R, Decl(tupleTypeInference2.ts, 13, 7))
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>R : Symbol(R, Decl(tupleTypeInference2.ts, 13, 7))
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>S : Symbol(S, Decl(tupleTypeInference2.ts, 13, 9))
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declare function h<T, U>(f: C<T, U>): U;
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>h : Symbol(h, Decl(tupleTypeInference2.ts, 13, 32))
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>T : Symbol(T, Decl(tupleTypeInference2.ts, 14, 19))
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>U : Symbol(U, Decl(tupleTypeInference2.ts, 14, 21))
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>f : Symbol(f, Decl(tupleTypeInference2.ts, 14, 25))
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>C : Symbol(C, Decl(tupleTypeInference2.ts, 11, 20))
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>T : Symbol(T, Decl(tupleTypeInference2.ts, 14, 19))
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>U : Symbol(U, Decl(tupleTypeInference2.ts, 14, 21))
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>U : Symbol(U, Decl(tupleTypeInference2.ts, 14, 21))
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h([[]] as [void[]]); // U: {}
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>h : Symbol(h, Decl(tupleTypeInference2.ts, 13, 32))
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// Repro from #22562
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type C2<R> = [R[]] | [R[], void];
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>C2 : Symbol(C2, Decl(tupleTypeInference2.ts, 15, 20))
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>R : Symbol(R, Decl(tupleTypeInference2.ts, 19, 8))
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>R : Symbol(R, Decl(tupleTypeInference2.ts, 19, 8))
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>R : Symbol(R, Decl(tupleTypeInference2.ts, 19, 8))
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declare function h2<T>(f: C2<T>): T;
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>h2 : Symbol(h2, Decl(tupleTypeInference2.ts, 19, 33))
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>T : Symbol(T, Decl(tupleTypeInference2.ts, 20, 20))
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>f : Symbol(f, Decl(tupleTypeInference2.ts, 20, 23))
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>C2 : Symbol(C2, Decl(tupleTypeInference2.ts, 15, 20))
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>T : Symbol(T, Decl(tupleTypeInference2.ts, 20, 20))
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>T : Symbol(T, Decl(tupleTypeInference2.ts, 20, 20))
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h2([[]] as [never[]]); // T: never
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>h2 : Symbol(h2, Decl(tupleTypeInference2.ts, 19, 33))
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h2([[]] as [void[]]); // T: void
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>h2 : Symbol(h2, Decl(tupleTypeInference2.ts, 19, 33))
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Diff for: ‎tests/baselines/reference/tupleTypeInference2.types

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=== tests/cases/compiler/tupleTypeInference2.ts ===
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// Repro from #22564
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type A<R> = [R] | [R, string];
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>A : A<R>
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>R : R
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>R : R
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>R : R
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declare function f<T>(x: A<T>): T;
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>f : <T>(x: A<T>) => T
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>T : T
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>x : A<T>
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>A : A<R>
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>T : T
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>T : T
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f([undefined, ''] as [never, string]); // T: never
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>f([undefined, ''] as [never, string]) : never
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>f : <T>(x: A<T>) => T
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>[undefined, ''] as [never, string] : [never, string]
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>[undefined, ''] : [undefined, string]
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>undefined : undefined
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>'' : ""
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f([undefined, ''] as [void, string]); // T: void
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>f([undefined, ''] as [void, string]) : void
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>f : <T>(x: A<T>) => T
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>[undefined, ''] as [void, string] : [void, string]
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>[undefined, ''] : [undefined, string]
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>undefined : undefined
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>'' : ""
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// Repro from #22563
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type B<R, S> = [R] | [R, S];
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>B : B<R, S>
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>R : R
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>S : S
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>R : R
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>R : R
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>S : S
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declare function g<T, U>(f: B<T, U>): U;
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>g : <T, U>(f: B<T, U>) => U
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>T : T
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>U : U
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>f : B<T, U>
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>B : B<R, S>
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>T : T
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>U : U
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>U : U
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g([[]] as [void[]]); // U: {}
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>g([[]] as [void[]]) : {}
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>g : <T, U>(f: B<T, U>) => U
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>[[]] as [void[]] : [void[]]
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>[[]] : [never[]]
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>[] : never[]
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type C<R, S> = [R[]] | [R[], S];
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>C : C<R, S>
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>R : R
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>S : S
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>R : R
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>R : R
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>S : S
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declare function h<T, U>(f: C<T, U>): U;
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>h : <T, U>(f: C<T, U>) => U
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>T : T
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>U : U
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>f : C<T, U>
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>C : C<R, S>
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>T : T
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>U : U
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>U : U
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h([[]] as [void[]]); // U: {}
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>h([[]] as [void[]]) : {}
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>h : <T, U>(f: C<T, U>) => U
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>[[]] as [void[]] : [void[]]
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>[[]] : [never[]]
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>[] : never[]
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// Repro from #22562
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type C2<R> = [R[]] | [R[], void];
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>C2 : C2<R>
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>R : R
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>R : R
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>R : R
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declare function h2<T>(f: C2<T>): T;
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>h2 : <T>(f: C2<T>) => T
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>T : T
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>f : C2<T>
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>C2 : C2<R>
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>T : T
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>T : T
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h2([[]] as [never[]]); // T: never
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>h2([[]] as [never[]]) : never
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>h2 : <T>(f: C2<T>) => T
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>[[]] as [never[]] : [never[]]
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>[[]] : [never[]]
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>[] : never[]
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h2([[]] as [void[]]); // T: void
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>h2([[]] as [void[]]) : void
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>h2 : <T>(f: C2<T>) => T
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>[[]] as [void[]] : [void[]]
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>[[]] : [never[]]
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>[] : never[]
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Diff for: ‎tests/cases/compiler/tupleTypeInference2.ts

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// @strict: true
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// Repro from #22564
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type A<R> = [R] | [R, string];
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declare function f<T>(x: A<T>): T;
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f([undefined, ''] as [never, string]); // T: never
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f([undefined, ''] as [void, string]); // T: void
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// Repro from #22563
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type B<R, S> = [R] | [R, S];
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declare function g<T, U>(f: B<T, U>): U;
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g([[]] as [void[]]); // U: {}
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type C<R, S> = [R[]] | [R[], S];
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declare function h<T, U>(f: C<T, U>): U;
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h([[]] as [void[]]); // U: {}
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// Repro from #22562
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type C2<R> = [R[]] | [R[], void];
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declare function h2<T>(f: C2<T>): T;
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h2([[]] as [never[]]); // T: never
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h2([[]] as [void[]]); // T: void

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