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Merge pull request #40597 from weswigham/allow-instanceof-array-to-narrow-readonly-array

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Handle the mapping between Array and ReadonlyArray in isTypeDerivedFrom
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Wesley Wigham
2020-10-13 15:08:17 -07:00
committed by GitHub
parent 8850e0d83d 081f98232b
commit 84726be01a
5 changed files with 71 additions and 1 deletions
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src/compiler/checker.ts
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@@ -15509,7 +15509,7 @@ namespace ts {
source.flags & TypeFlags.InstantiableNonPrimitive ? isTypeDerivedFrom(getBaseConstraintOfType(source) || unknownType, target) :
target === globalObjectType ? !!(source.flags & (TypeFlags.Object | TypeFlags.NonPrimitive)) :
target === globalFunctionType ? !!(source.flags & TypeFlags.Object) && isFunctionObjectType(source as ObjectType) :
hasBaseType(source, getTargetType(target));
hasBaseType(source, getTargetType(target)) || (isArrayType(target) && !isReadonlyArrayType(target) && isTypeDerivedFrom(source, globalReadonlyArrayType));
}
/**