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Restructure and back off a little bit more

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This commit is contained in:
Anders Hejlsberg
2022-02-05 07:40:31 -08:00
parent 1312e8a420
commit b82966fbaa
1 changed files with 8 additions and 12 deletions
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src/compiler/checker.ts
+8 -12
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@@ -11823,11 +11823,6 @@ namespace ts {
return hasNonCircularBaseConstraint(type) ? getConstraintFromConditionalType(type) : undefined;
}
function isUnionContainingMultipleObjectLikeTypes(type: Type) {
return !!(type.flags & TypeFlags.Union) &&
countWhere((type as UnionType).types, t => !!(t.flags & (TypeFlags.Object | TypeFlags.Intersection | TypeFlags.Substitution))) >= 2;
}
function getEffectiveConstraintOfIntersection(types: readonly Type[], targetIsUnion: boolean) {
let constraints: Type[] | undefined;
let hasDisjointDomainType = false;
@@ -18357,13 +18352,14 @@ namespace ts {
structuredTypeRelatedTo(source, target, reportErrors, intersectionState | IntersectionState.UnionIntersectionCheck) :
recursiveTypeRelatedTo(source, target, reportErrors, intersectionState | IntersectionState.UnionIntersectionCheck, recursionFlags);
// The ordered decomposition above doesn't handle all cases. Specifically, we also need to handle:
// (1) Source is an intersection of object types { a } & { b } and target is an object type { a, b }.
// (2) Source is an object type { a, b: boolean } and target is a union { a, b: true } | { a, b: false }.
// (3) Source is an intersection { a } & { b: boolean } and target is a union { a, b: true } | { a, b: false }.
// (4) Source is an instantiable type with a union or intersection constraint and target is a union or intersection.
if (!result && (source.flags & TypeFlags.Intersection && target.flags & TypeFlags.Object ||
source.flags & (TypeFlags.Object | TypeFlags.Intersection) && isUnionContainingMultipleObjectLikeTypes(target) ||
source.flags & TypeFlags.Instantiable && target.flags & TypeFlags.UnionOrIntersection)) {
// Source is instantiable (e.g. source has union or intersection constraint).
// Source is an object, target is a union (e.g. { a, b: boolean } <=> { a, b: true } | { a, b: false }).
// Source is an intersection, target is an object (e.g. { a } & { b } <=> { a, b }).
// Source is an intersection, target is a union (e.g. { a } & { b: boolean } <=> { a, b: true } | { a, b: false }).
// Source is an intersection, target instantiable (e.g. string & { tag } <=> T["a"] constrained to string & { tag }).
if (!result && (source.flags & TypeFlags.Instantiable ||
source.flags & TypeFlags.Object && target.flags & TypeFlags.Union ||
source.flags & TypeFlags.Intersection && target.flags & (TypeFlags.Object | TypeFlags.Union | TypeFlags.Instantiable))) {
if (result = recursiveTypeRelatedTo(source, target, reportErrors, intersectionState, recursionFlags)) {
resetErrorInfo(saveErrorInfo);
}