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Type parameter with 'unknown' constraint not assignable to '{}'

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This commit is contained in:
Anders Hejlsberg
2018-12-10 08:59:12 -08:00
parent 34d9d4bc8c
commit a8964cbc60
1 changed files with 16 additions and 18 deletions
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34
src/compiler/checker.ts
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@@ -12168,10 +12168,6 @@ namespace ts {
return result;
}
function getConstraintForRelation(type: Type) {
return relation === definitelyAssignableRelation ? undefined : getConstraintOfType(type);
}
function structuredTypeRelatedTo(source: Type, target: Type, reportErrors: boolean, isIntersectionConstituent: boolean): Ternary {
const flags = source.flags & target.flags;
if (relation === identityRelation && !(flags & TypeFlags.Object)) {
@@ -12304,24 +12300,26 @@ namespace ts {
return result;
}
}
const constraint = getConstraintForRelation(<TypeParameter>source);
if (!constraint || (source.flags & TypeFlags.TypeParameter && constraint.flags & TypeFlags.AnyOrUnknown)) {
// A type variable with no constraint is not related to the non-primitive object type.
if (result = isRelatedTo(emptyObjectType, extractTypesOfKind(target, ~TypeFlags.NonPrimitive))) {
if (relation !== definitelyAssignableRelation) {
const constraint = getConstraintOfType(<TypeParameter>source);
if (!constraint || (source.flags & TypeFlags.TypeParameter && constraint.flags & TypeFlags.Any)) {
// A type variable with no constraint is not related to the non-primitive object type.
if (result = isRelatedTo(emptyObjectType, extractTypesOfKind(target, ~TypeFlags.NonPrimitive))) {
errorInfo = saveErrorInfo;
return result;
}
}
// hi-speed no-this-instantiation check (less accurate, but avoids costly `this`-instantiation when the constraint will suffice), see #28231 for report on why this is needed
else if (result = isRelatedTo(constraint, target, /*reportErrors*/ false, /*headMessage*/ undefined, isIntersectionConstituent)) {
errorInfo = saveErrorInfo;
return result;
}
// slower, fuller, this-instantiated check (necessary when comparing raw `this` types from base classes), see `subclassWithPolymorphicThisIsAssignable.ts` test for example
else if (result = isRelatedTo(getTypeWithThisArgument(constraint, source), target, reportErrors, /*headMessage*/ undefined, isIntersectionConstituent)) {
errorInfo = saveErrorInfo;
return result;
}
}
// hi-speed no-this-instantiation check (less accurate, but avoids costly `this`-instantiation when the constraint will suffice), see #28231 for report on why this is needed
else if (result = isRelatedTo(constraint, target, /*reportErrors*/ false, /*headMessage*/ undefined, isIntersectionConstituent)) {
errorInfo = saveErrorInfo;
return result;
}
// slower, fuller, this-instantiated check (necessary when comparing raw `this` types from base classes), see `subclassWithPolymorphicThisIsAssignable.ts` test for example
else if (result = isRelatedTo(getTypeWithThisArgument(constraint, source), target, reportErrors, /*headMessage*/ undefined, isIntersectionConstituent)) {
errorInfo = saveErrorInfo;
return result;
}
}
else if (source.flags & TypeFlags.Index) {
if (result = isRelatedTo(keyofConstraintType, target, reportErrors)) {