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Add depth limiter to isConstTypeVariable function (#54624)

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Anders Hejlsberg 2023-06-16 12:48:44 -07:00 committed by GitHub
parent e1a9290051
commit 84d8429fb6
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5 changed files with 116 additions and 7 deletions
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14
src/compiler/checker.ts
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@ -13538,14 +13538,14 @@ export function createTypeChecker(host: TypeCheckerHost): TypeChecker {
return hasNonCircularBaseConstraint(typeParameter) ? getConstraintFromTypeParameter(typeParameter) : undefined;
}
function isConstTypeVariable(type: Type | undefined): boolean {
return !!(type && (
function isConstTypeVariable(type: Type | undefined, depth = 0): boolean {
return depth < 5 && !!(type && (
type.flags & TypeFlags.TypeParameter && some((type as TypeParameter).symbol?.declarations, d => hasSyntacticModifier(d, ModifierFlags.Const)) ||
type.flags & TypeFlags.Union && some((type as UnionType).types, isConstTypeVariable) ||
type.flags & TypeFlags.IndexedAccess && isConstTypeVariable((type as IndexedAccessType).objectType) ||
type.flags & TypeFlags.Conditional && isConstTypeVariable(getConstraintOfConditionalType(type as ConditionalType)) ||
type.flags & TypeFlags.Substitution && isConstTypeVariable((type as SubstitutionType).baseType) ||
isGenericTupleType(type) && findIndex(getElementTypes(type), (t, i) => !!(type.target.elementFlags[i] & ElementFlags.Variadic) && isConstTypeVariable(t)) >= 0));
type.flags & TypeFlags.Union && some((type as UnionType).types, t => isConstTypeVariable(t, depth)) ||
type.flags & TypeFlags.IndexedAccess && isConstTypeVariable((type as IndexedAccessType).objectType, depth + 1) ||
type.flags & TypeFlags.Conditional && isConstTypeVariable(getConstraintOfConditionalType(type as ConditionalType), depth + 1) ||
type.flags & TypeFlags.Substitution && isConstTypeVariable((type as SubstitutionType).baseType, depth) ||
isGenericTupleType(type) && findIndex(getElementTypes(type), (t, i) => !!(type.target.elementFlags[i] & ElementFlags.Variadic) && isConstTypeVariable(t, depth)) >= 0));
}
function getConstraintOfIndexedAccess(type: IndexedAccessType) {

22
tests/baselines/reference/circularBaseConstraint.errors.txt Normal file
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@ -0,0 +1,22 @@
circularBaseConstraint.ts(14,8): error TS2304: Cannot find name 'a'.
==== circularBaseConstraint.ts (1 errors) ====
// Repro from #54610
type A<T> = T;
type B<T> = T extends any[]
? never
: A<T> extends infer key
? key extends keyof T
? B<T[key]>
: never
: never;
function foo<T>() {
`${a}` as B<T>;
~
!!! error TS2304: Cannot find name 'a'.
}

42
tests/baselines/reference/circularBaseConstraint.symbols Normal file
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@ -0,0 +1,42 @@
//// [tests/cases/compiler/circularBaseConstraint.ts] ////
=== circularBaseConstraint.ts ===
// Repro from #54610
type A<T> = T;
>A : Symbol(A, Decl(circularBaseConstraint.ts, 0, 0))
>T : Symbol(T, Decl(circularBaseConstraint.ts, 2, 7))
>T : Symbol(T, Decl(circularBaseConstraint.ts, 2, 7))
type B<T> = T extends any[]
>B : Symbol(B, Decl(circularBaseConstraint.ts, 2, 14))
>T : Symbol(T, Decl(circularBaseConstraint.ts, 4, 7))
>T : Symbol(T, Decl(circularBaseConstraint.ts, 4, 7))
? never
: A<T> extends infer key
>A : Symbol(A, Decl(circularBaseConstraint.ts, 0, 0))
>T : Symbol(T, Decl(circularBaseConstraint.ts, 4, 7))
>key : Symbol(key, Decl(circularBaseConstraint.ts, 6, 24))
? key extends keyof T
>key : Symbol(key, Decl(circularBaseConstraint.ts, 6, 24))
>T : Symbol(T, Decl(circularBaseConstraint.ts, 4, 7))
? B<T[key]>
>B : Symbol(B, Decl(circularBaseConstraint.ts, 2, 14))
>T : Symbol(T, Decl(circularBaseConstraint.ts, 4, 7))
>key : Symbol(key, Decl(circularBaseConstraint.ts, 6, 24))
: never
: never;
function foo<T>() {
>foo : Symbol(foo, Decl(circularBaseConstraint.ts, 10, 12))
>T : Symbol(T, Decl(circularBaseConstraint.ts, 12, 13))
`${a}` as B<T>;
>B : Symbol(B, Decl(circularBaseConstraint.ts, 2, 14))
>T : Symbol(T, Decl(circularBaseConstraint.ts, 12, 13))
}

27
tests/baselines/reference/circularBaseConstraint.types Normal file
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@ -0,0 +1,27 @@
//// [tests/cases/compiler/circularBaseConstraint.ts] ////
=== circularBaseConstraint.ts ===
// Repro from #54610
type A<T> = T;
>A : T
type B<T> = T extends any[]
>B : B<T>
? never
: A<T> extends infer key
? key extends keyof T
? B<T[key]>
: never
: never;
function foo<T>() {
>foo : <T>() => void
`${a}` as B<T>;
>`${a}` as B<T> : B<T>
>`${a}` : string
>a : any
}

18
tests/cases/compiler/circularBaseConstraint.ts Normal file
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@ -0,0 +1,18 @@
// @strict: true
// @noEmit: true
// Repro from #54610
type A<T> = T;
type B<T> = T extends any[]
? never
: A<T> extends infer key
? key extends keyof T
? B<T[key]>
: never
: never;
function foo<T>() {
`${a}` as B<T>;
}