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getConstraintOfTypeParameter:check circularity in base constraint

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Nathan Shively-Sanders
2018-01-10 15:37:27 -08:00
parent 7a1deae6aa
commit f0ef9a08d8
1 changed files with 9 additions and 6 deletions
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15
src/compiler/checker.ts
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@@ -6301,9 +6301,9 @@ namespace ts {
(type.typeParameter = getDeclaredTypeOfTypeParameter(getSymbolOfNode(type.declaration.typeParameter)));
}
function getConstraintTypeFromMappedType(type: MappedType) {
function getConstraintTypeFromMappedType(type: MappedType, typeStack?: Type[]) {
return type.constraintType ||
(type.constraintType = instantiateType(getConstraintOfTypeParameter(getTypeParameterFromMappedType(type)), type.mapper || identityMapper) || unknownType);
(type.constraintType = instantiateType(getConstraintOfTypeParameter(getTypeParameterFromMappedType(type), typeStack), type.mapper || identityMapper) || unknownType);
}
function getTemplateTypeFromMappedType(type: MappedType) {
@@ -6351,8 +6351,8 @@ namespace ts {
return getObjectFlags(type) & ObjectFlags.Mapped && !!(<MappedType>type).declaration.questionToken;
}
function isGenericMappedType(type: Type) {
return getObjectFlags(type) & ObjectFlags.Mapped && isGenericIndexType(getConstraintTypeFromMappedType(<MappedType>type));
function isGenericMappedType(type: Type, typeStack?: Type[]): type is MappedType {
return getObjectFlags(type) & ObjectFlags.Mapped && isGenericIndexType(getConstraintTypeFromMappedType(<MappedType>type, typeStack));
}
function resolveStructuredTypeMembers(type: StructuredType): ResolvedType {
@@ -6458,7 +6458,10 @@ namespace ts {
getBaseConstraintOfType(type);
}
function getConstraintOfTypeParameter(typeParameter: TypeParameter): Type {
function getConstraintOfTypeParameter(typeParameter: TypeParameter, typeStack?: Type[]): Type {
if (typeStack) {
return !contains(typeStack, typeParameter) && getConstraintFromTypeParameter(typeParameter);
}
return hasNonCircularBaseConstraint(typeParameter) ? getConstraintFromTypeParameter(typeParameter) : undefined;
}
@@ -6547,7 +6550,7 @@ namespace ts {
const baseIndexedAccess = baseObjectType && baseIndexType ? getIndexedAccessType(baseObjectType, baseIndexType) : undefined;
return baseIndexedAccess && baseIndexedAccess !== unknownType ? getBaseConstraint(baseIndexedAccess) : undefined;
}
if (isGenericMappedType(t)) {
if (isGenericMappedType(t, typeStack)) {
return emptyObjectType;
}
return t;