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Remove eager resolution of distributive conditional types

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This commit is contained in:
Anders Hejlsberg
2018-05-29 17:55:31 -07:00
parent e98f9a699f
commit 6b1c84e84a
1 changed files with 3 additions and 3 deletions
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6
src/compiler/checker.ts
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@@ -8969,9 +8969,6 @@ namespace ts {
if (checkType === wildcardType || extendsType === wildcardType) {
return wildcardType;
}
if (extendsType.flags & TypeFlags.AnyOrUnknown) {
return instantiateType(root.trueType, mapper);
}
// If this is a distributive conditional type and the check type is generic we need to defer
// resolution of the conditional type such that a later instantiation will properly distribute
// over union types.
@@ -8988,6 +8985,9 @@ namespace ts {
combinedMapper = combineTypeMappers(mapper, context);
}
if (!isDeferred) {
if (extendsType.flags & TypeFlags.AnyOrUnknown) {
return instantiateType(root.trueType, mapper);
}
// Return union of trueType and falseType for 'any' since it matches anything
if (checkType.flags & TypeFlags.Any) {
return getUnionType([instantiateType(root.trueType, combinedMapper || mapper), instantiateType(root.falseType, mapper)]);