AST: TypeBase::isConstraintType() answers true for ParameterizedProtocolType also

Author: slavapestov

include/swift/AST/Types.h

@@ -6365,7 +6365,8 @@ inline bool TypeBase::isConstraintType() const {
 
 inline bool CanType::isConstraintTypeImpl(CanType type) {
   return (isa<ProtocolType>(type) ||
-          isa<ProtocolCompositionType>(type));
+          isa<ProtocolCompositionType>(type) ||
+          isa<ParameterizedProtocolType>(type));
 }
 
 inline bool TypeBase::isExistentialType() {

lib/AST/GenericSignatureBuilder.cpp

@@ -4500,9 +4500,7 @@ ConstraintResult GenericSignatureBuilder::addTypeRequirement(
   }
 
   // Check whether we have a reasonable constraint type at all.
-  if (!constraintType->is<ProtocolType>() &&
-      !constraintType->is<ProtocolCompositionType>() &&
-      !constraintType->is<ParameterizedProtocolType>() &&
+  if (!constraintType->isConstraintType() &&
       !constraintType->getClassOrBoundGenericClass()) {
     if (source.getLoc().isValid() && !constraintType->hasError()) {
       Impl->HadAnyError = true;

lib/AST/RequirementMachine/RequirementLowering.cpp

@@ -212,9 +212,7 @@ static void realizeTypeRequirement(Type subjectType, Type constraintType,
                                    SmallVectorImpl<StructuralRequirement> &result) {
   SmallVector<Requirement, 2> reqs;
 
-  if (constraintType->is<ProtocolType>() ||
-      constraintType->is<ProtocolCompositionType>() ||
-      constraintType->is<ParameterizedProtocolType>()) {
+  if (constraintType->isConstraintType()) {
     // Handle conformance requirements.
     desugarConformanceRequirement(subjectType, constraintType, reqs);
   } else if (constraintType->getClassOrBoundGenericClass()) {

lib/Sema/TypeCheckGeneric.cpp

@@ -227,10 +227,8 @@ OpaqueResultTypeRequest::evaluate(Evaluator &evaluator,
         return nullptr;
 
       // Error out if the constraint type isn't a class or existential type.
-      if (!constraintType->getClassOrBoundGenericClass() &&
-          !constraintType->is<ProtocolType>() &&
-          !constraintType->is<ProtocolCompositionType>() &&
-          !constraintType->is<ParameterizedProtocolType>()) {
+      if (!constraintType->isConstraintType() &&
+          !constraintType->getClassOrBoundGenericClass()) {
         ctx.Diags.diagnose(currentRepr->getLoc(),
                            diag::opaque_type_invalid_constraint);
         return nullptr;

lib/Sema/TypeCheckType.cpp

@@ -3856,7 +3856,10 @@ TypeResolver::resolveCompositionType(CompositionTypeRepr *repr,
       continue;
     }
 
-    if (ty->isConstraintType()) {
+    // FIXME: Support compositions involving parameterized protocol types,
+    // like Collection<String> & Sendable, etc.
+    if (ty->isConstraintType() &&
+        !ty->is<ParameterizedProtocolType>()) {
       auto layout = ty->getExistentialLayout();
       if (auto superclass = layout.explicitSuperclass)
         if (checkSuperclass(tyR->getStartLoc(), superclass))