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Enum literal type is assignable to regular literal type with same value

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This commit is contained in:
Anders Hejlsberg
2017-04-29 17:57:12 -07:00
parent 72e77a80e8
commit 106214a0e4
1 changed files with 11 additions and 1 deletions
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12
src/compiler/checker.ts
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@@ -8432,7 +8432,13 @@ namespace ts {
if (target.flags & TypeFlags.Never) return false;
if (target.flags & TypeFlags.Any || source.flags & TypeFlags.Never) return true;
if (source.flags & TypeFlags.StringLike && target.flags & TypeFlags.String) return true;
if (source.flags & TypeFlags.StringLiteral && source.flags & TypeFlags.EnumLiteral &&
target.flags & TypeFlags.StringLiteral && !(target.flags & TypeFlags.EnumLiteral) &&
(<LiteralType>source).value === (<LiteralType>target).value) return true;
if (source.flags & TypeFlags.NumberLike && target.flags & TypeFlags.Number) return true;
if (source.flags & TypeFlags.NumberLiteral && source.flags & TypeFlags.EnumLiteral &&
target.flags & TypeFlags.NumberLiteral && !(target.flags & TypeFlags.EnumLiteral) &&
(<LiteralType>source).value === (<LiteralType>target).value) return true;
if (source.flags & TypeFlags.BooleanLike && target.flags & TypeFlags.Boolean) return true;
if (source.flags & TypeFlags.Enum && target.flags & TypeFlags.Enum && isEnumTypeRelatedTo(source.symbol, target.symbol, errorReporter)) return true;
if (source.flags & TypeFlags.EnumLiteral && target.flags & TypeFlags.EnumLiteral) {
@@ -8446,7 +8452,11 @@ namespace ts {
if (source.flags & TypeFlags.Object && target.flags & TypeFlags.NonPrimitive) return true;
if (relation === assignableRelation || relation === comparableRelation) {
if (source.flags & TypeFlags.Any) return true;
if (source.flags & (TypeFlags.Number | TypeFlags.NumberLiteral) && !(source.flags & TypeFlags.EnumLiteral) && target.flags & TypeFlags.EnumLike) return true;
// Type number or any numeric literal type is assignable to any numeric enum type or any
// numeric enum literal type. This rule exists for backwards compatibility reasons because
// bit-flag enum types sometimes look like literal enum types with numeric literal values.
if (source.flags & (TypeFlags.Number | TypeFlags.NumberLiteral) && !(source.flags & TypeFlags.EnumLiteral) && (
target.flags & TypeFlags.Enum || target.flags & TypeFlags.NumberLiteral && target.flags & TypeFlags.EnumLiteral)) return true;
}
return false;
}