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Check constraints deeply on singleton types.

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Daniel
2020-05-22 00:40:28 +00:00
parent 8cf2466110
commit a04ecb592c
1 changed files with 16 additions and 11 deletions
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27
src/compiler/checker.ts
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@@ -15764,23 +15764,13 @@ namespace ts {
}
}
if (isLiteralType(source) && !typeCouldHaveNoTopLevelSingletonTypes(target)) {
if (isLiteralType(source) && !typeCouldHaveTopLevelSingletonTypes(target)) {
generalizedSourceType = getTypeNameForErrorDisplay(getBaseTypeOfLiteralType(source));
}
reportError(message, generalizedSourceType, targetType);
}
function typeCouldHaveNoTopLevelSingletonTypes(type: Type) {
return forEachType(type, typeCouldHaveNoTopLevelSingletonTypesWorker);
}
function typeCouldHaveNoTopLevelSingletonTypesWorker(type: Type): boolean {
return (type.flags & TypeFlags.Intersection)
? !!forEach((type as IntersectionType).types, typeCouldHaveNoTopLevelSingletonTypesWorker)
: isUnitType(type) || !!(type.flags & TypeFlags.Instantiable);
}
function tryElaborateErrorsForPrimitivesAndObjects(source: Type, target: Type) {
const sourceType = symbolValueDeclarationIsContextSensitive(source.symbol) ? typeToString(source, source.symbol.valueDeclaration) : typeToString(source);
const targetType = symbolValueDeclarationIsContextSensitive(target.symbol) ? typeToString(target, target.symbol.valueDeclaration) : typeToString(target);
@@ -17375,6 +17365,21 @@ namespace ts {
}
}
function typeCouldHaveTopLevelSingletonTypes(type: Type): boolean {
if (type.flags & TypeFlags.UnionOrIntersection) {
return !!forEach((type as IntersectionType).types, typeCouldHaveTopLevelSingletonTypes);
}
if (type.flags & TypeFlags.Instantiable) {
const constraint = getConstraintOfType(type);
if (constraint) {
return typeCouldHaveTopLevelSingletonTypes(constraint);
}
}
return isUnitType(type);
}
function getBestMatchingType(source: Type, target: UnionOrIntersectionType, isRelatedTo = compareTypesAssignable) {
return findMatchingDiscriminantType(source, target, isRelatedTo, /*skipPartial*/ true) ||
findMatchingTypeReferenceOrTypeAliasReference(source, target) ||