AST: Merge GenericSignature::get{Non,}DependentUpperBounds()

Author: slavapestov

include/swift/AST/GenericSignature.h

@@ -362,8 +362,6 @@ class alignas(1 << TypeAlignInBits) GenericSignatureImpl final
   /// Determine whether the given dependent type is required to be a class.
   bool requiresClass(Type type) const;
 
-  Type getUpperBound(Type type, bool wantDependentUpperBound = false) const;
-
   /// Determine the superclass bound on the given dependent type.
   Type getSuperclassBound(Type type) const;
 
@@ -457,19 +455,12 @@ class alignas(1 << TypeAlignInBits) GenericSignatureImpl final
   /// generic parameter types by their sugared form.
   Type getSugaredType(Type type) const;
 
-  /// Given a type parameter, compute the most specific supertype (upper bound)
-  /// that is not dependent on other type parameters.
-  ///
-  /// \note If the upper bound is a protocol or protocol composition,
-  /// will return an instance of \c ExistentialType.
-  Type getNonDependentUpperBounds(Type type) const;
-
-  /// Given a type parameter, compute the most specific supertype (upper bound)
-  /// that is possibly dependent on other type parameters.
+  /// Given a type parameter, compute the most specific supertype (upper bound),
+  /// possibly dependent on other type parameters.
   ///
   /// \note If the upper bound is a protocol or protocol composition,
   /// will return an instance of \c ExistentialType.
-  Type getDependentUpperBounds(Type type) const;
+  Type getUpperBound(Type type) const;
 
   static void Profile(llvm::FoldingSetNodeID &ID,
                       ArrayRef<GenericTypeParamType *> genericParams,

lib/AST/GenericSignature.cpp

@@ -635,26 +635,23 @@ unsigned GenericSignatureImpl::getGenericParamOrdinal(
   return GenericParamKey(param).findIndexIn(getGenericParams());
 }
 
-Type GenericSignatureImpl::getNonDependentUpperBounds(Type type) const {
-  return getUpperBound(type);
-}
-
-Type GenericSignatureImpl::getDependentUpperBounds(Type type) const {
-  return getUpperBound(type, /*wantDependentBound=*/true);
-}
-
-Type GenericSignatureImpl::getUpperBound(Type type,
-                                         bool wantDependentBound) const {
+Type GenericSignatureImpl::getUpperBound(Type type) const {
   assert(type->isTypeParameter());
 
-  bool hasExplicitAnyObject = requiresClass(type);
-
   llvm::SmallVector<Type, 2> types;
+  unsigned rootDepth = type->getRootGenericParam()->getDepth();
+
+  bool hasExplicitAnyObject = requiresClass(type);
 
   if (Type superclass = getSuperclassBound(type)) {
     do {
       superclass = getReducedType(superclass);
-      if (wantDependentBound || !superclass->hasTypeParameter()) {
+
+      if (!superclass.findIf([&](Type t) {
+            if (auto *paramTy = t->getAs<GenericTypeParamType>())
+              return (paramTy->getDepth() == rootDepth);
+            return false;
+          })) {
         break;
       }
     } while ((superclass = superclass->getSuperclass()));
@@ -684,31 +681,13 @@ Type GenericSignatureImpl::getUpperBound(Type type,
 
         // If the reduced type is at a lower depth than the root generic
         // parameter of T, then it's constrained.
-        bool hasOuterGenericParam = false;
-        bool hasInnerGenericParam = false;
-        reducedType.visit([&](Type t) {
-          if (auto *paramTy = t->getAs<GenericTypeParamType>()) {
-            unsigned rootDepth = type->getRootGenericParam()->getDepth();
-            if (paramTy->getDepth() == rootDepth)
-              hasInnerGenericParam = true;
-            else {
-              assert(paramTy->getDepth() < rootDepth);
-              hasOuterGenericParam = true;
-            }
-          }
-        });
-
-        if (hasInnerGenericParam && hasOuterGenericParam) {
-          llvm::errs() << "Weird same-type requirements?\n";
-          llvm::errs() << "Interface type: " << type << "\n";
-          llvm::errs() << "Member type: " << memberType << "\n";
-          llvm::errs() << "Reduced member type: " << reducedType << "\n";
-          llvm::errs() << GenericSignature(this) << "\n";
-          abort();
-        }
-
-        if (!hasInnerGenericParam && (wantDependentBound || !hasOuterGenericParam))
+        if (!reducedType.findIf([&](Type t) {
+            if (auto *paramTy = t->getAs<GenericTypeParamType>())
+              return (paramTy->getDepth() == rootDepth);
+            return false;
+          })) {
           argTypes.push_back(reducedType);
+        }
       }
 
       // If we have constrained all primary associated types, create a
@@ -721,7 +700,8 @@ Type GenericSignatureImpl::getUpperBound(Type type,
       //
       // In that case just add the base type in the default branch below.
       if (argTypes.size() == primaryAssocTypes.size()) {
-        types.push_back(ParameterizedProtocolType::get(getASTContext(), baseType, argTypes));
+        types.push_back(ParameterizedProtocolType::get(
+            getASTContext(), baseType, argTypes));
         continue;
       }
     }

lib/AST/Type.cpp

@@ -673,8 +673,7 @@ Type TypeBase::typeEraseOpenedArchetypesWithRoot(
       if (root->isEqual(archetype)) {
         erasedTy = root->getExistentialType();
       } else {
-        erasedTy =
-            sig->getNonDependentUpperBounds(archetype->getInterfaceType());
+        erasedTy = sig->getUpperBound(archetype->getInterfaceType());
       }
 
       if (metatypeDepth) {
@@ -3687,7 +3686,7 @@ Type ArchetypeType::getExistentialType() const {
   auto interfaceType = getInterfaceType();
   auto genericSig = genericEnv->getGenericSignature();
 
-  auto upperBound = genericSig->getDependentUpperBounds(interfaceType);
+  auto upperBound = genericSig->getUpperBound(interfaceType);
 
   return genericEnv->mapTypeIntoContext(upperBound);
 }

lib/Sema/ConstraintSystem.cpp

@@ -2232,7 +2232,7 @@ static Type typeEraseExistentialSelfReferences(Type refTy, Type baseTy,
           if (t->is<GenericTypeParamType>()) {
             erasedTy = baseTy;
           } else {
-            erasedTy = existentialSig->getNonDependentUpperBounds(t);
+            erasedTy = existentialSig->getUpperBound(t);
           }
 
           if (metatypeDepth) {