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Less aggressive reduction in second pass union/intersection checks

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This commit is contained in:
Anders Hejlsberg
2022-02-04 15:30:40 -08:00
parent a65794c84d
commit f269f4252c
1 changed files with 3 additions and 8 deletions
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11
src/compiler/checker.ts
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@@ -11823,11 +11823,6 @@ namespace ts {
return hasNonCircularBaseConstraint(type) ? getConstraintFromConditionalType(type) : undefined;
}
function hasStructuredOrInstantiableConstraint(type: Type) {
const constraint = type.flags & TypeFlags.Instantiable ? getConstraintOfType(type) : undefined;
return constraint && !!(constraint.flags & TypeFlags.StructuredOrInstantiable);
}
function isUnionContainingMultipleObjectLikeTypes(type: Type) {
return !!(type.flags & TypeFlags.Union) &&
countWhere((type as UnionType).types, t => !!(t.flags & (TypeFlags.Object | TypeFlags.Intersection | TypeFlags.Substitution))) >= 2;
@@ -18365,10 +18360,10 @@ namespace ts {
// (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 constraint and target is a union.
// (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)) ||
(target.flags & TypeFlags.Union && hasStructuredOrInstantiableConstraint(source)))) {
source.flags & (TypeFlags.Object | TypeFlags.Intersection) && isUnionContainingMultipleObjectLikeTypes(target) ||
source.flags & TypeFlags.Instantiable && target.flags & TypeFlags.UnionOrIntersection)) {
if (result = recursiveTypeRelatedTo(source, target, reportErrors, intersectionState, recursionFlags)) {
resetErrorInfo(saveErrorInfo);
}