More progress towards getting same-type constraints working correctly.

Swift SVN r16023

include/swift/AST/ProtocolConformance.h

@@ -40,7 +40,7 @@ enum class AllocationArena;
   
 /// \brief Type substitution mapping from substitutable types to their
 /// replacements.
-typedef llvm::DenseMap<SubstitutableType *, Type> TypeSubstitutionMap;
+typedef llvm::DenseMap<TypeBase *, Type> TypeSubstitutionMap;
 
 /// Map from non-type requirements to the corresponding conformance witnesses.
 typedef llvm::DenseMap<ValueDecl *, ConcreteDeclRef> WitnessMap;

include/swift/AST/Type.h

@@ -43,7 +43,7 @@ class TypeWalker;
 
 /// \brief Type substitution mapping from substitutable types to their
 /// replacements.
-typedef llvm::DenseMap<SubstitutableType *, Type> TypeSubstitutionMap;
+typedef llvm::DenseMap<TypeBase *, Type> TypeSubstitutionMap;
 
 /// Type - This is a simple value object that contains a pointer to a type
 /// class.  This is potentially sugared.  We use this throughout the codebase

lib/AST/Type.cpp

@@ -1640,10 +1640,6 @@ GenericParamList::getSubstitutionMap(ArrayRef<swift::Substitution> Subs) const {
     auto sub = Subs.front();
     Subs = Subs.slice(1);
     
-    // Only substitute primary archetypes.
-    if (!arch->isPrimary())
-      continue;
-    
     map.insert({arch, sub.Replacement});
   }
   
@@ -1757,13 +1753,22 @@ GenericSignature::getSubstitutionMap(ArrayRef<Substitution> args) const {
     return subs;
   }
   
+  // Seed the type map with pre-existing substitutions.
+  for (auto sub : args) {
+    subs[sub.Archetype] = sub.Replacement;
+  }
+  
   for (auto depTy : getAllDependentTypes()) {
     auto replacement = args.front().Replacement;
     args = args.slice(1);
-    // FIXME: DependentMemberTypes aren't SubstitutableTypes.
-    if (auto subTy = depTy->getAs<SubstitutableType>())
+    
+    if (auto subTy = depTy->getAs<SubstitutableType>()) {
       subs[subTy] = replacement;
     }
+    else if (auto dTy = depTy->getAs<DependentMemberType>()) {
+      subs[dTy] = replacement;
+    }
+  }
   
   assert(args.empty() && "did not use all substitutions?!");
   return subs;
@@ -1896,8 +1901,15 @@ Type Type::subst(Module *module, TypeSubstitutionMap &substitutions,
         .subst(module, substitutions, ignoreMissing, resolver);
       
       // Resolve the member relative to the substituted base.
-      if (Type r = depMemTy->substBaseType(module, newBase, resolver))
+      if (Type r = depMemTy->substBaseType(module, newBase, resolver)) {
+        
+        // Substitute archtypes for generic type parameters to prevent
+        // dependent types from leaking.
+        if (auto GTPT = r->getAs<GenericTypeParamType>()) {
+          return GTPT->getDecl()->getArchetype();
+        }
         return r;
+      }
       return failed(type);
     }
     

lib/Sema/CSSimplify.cpp

@@ -566,8 +566,8 @@ ConstraintSystem::matchTypes(Type type1, Type type2, TypeMatchKind kind,
             // Add a new constraint between these types. We consider the current
             // type-matching problem to the "solved" by this addition, because
             // this new constraint will be solved at a later point.
-            // Obviously, this must not happen at the top level, or the algorithm
-            // would not terminate.
+            // Obviously, this must not happen at the top level, or the
+            // algorithm would not terminate.
             addConstraint(getConstraintKind(kind), rep1, rep2,
                           getConstraintLocator(locator));
             return SolutionKind::Solved;

lib/Sema/ConstraintSystem.cpp

@@ -1189,10 +1189,17 @@ void ConstraintSystem::resolveOverload(ConstraintLocator *locator,
   // in the case of a conformance check against an associated type rooted off of
   // "Self"), we'll need to open the type up so as not to short-circuit the
   // binding constraint against the already bound overload type.
-  if ((choice.getKind() == OverloadChoiceKind::TypeDecl) &&
-      refType->getAs<DependentMemberType>()) {
+  if (refType->isDependentType()) {
+    openedFullType = openType(openedFullType,
+                              choice.getDecl()->
+                                        getPotentialGenericDeclContext());
     refType = openType(refType,
                          choice.getDecl()->getPotentialGenericDeclContext());
+    
+    if (auto FT = openedFullType->getAs<FunctionType>()) {
+      auto returnType = FT->getResult();
+      addConstraint(ConstraintKind::Bind, returnType, refType);
+    }
   }
 
   // Add the type binding constraint.

lib/Sema/TypeCheckGeneric.cpp

@@ -824,10 +824,12 @@ bool TypeChecker::checkSubstitutions(TypeSubstitutionMap &Substitutions,
   // Find all of the primary archetypes and enter them into the archetype
   // stack.
   for (const auto &sub : Substitutions) {
-    auto archetype = sub.first->getArchetype();
+    if (auto subTy = sub.first->getAs<SubstitutableType>()) {
+      auto archetype = subTy->getArchetype();
       if (archetype->isPrimary() && knownArchetypes.insert(archetype))
         archetypeStack.push_back(archetype);
     }
+  }
 
   // Check that each of the replacements for the archetypes conform
   // to the required protocols.

lib/Sema/TypeCheckPattern.cpp

@@ -352,7 +352,7 @@ public:
   //   then required to have keywords for every argument that name properties
   //   of the type.
   Pattern *visitCallExpr(CallExpr *ce) {
-    DependentGenericTypeResolver resolver;
+    PartialGenericTypeToArchetypeResolver resolver(TC);
     
     SmallVector<ComponentIdentTypeRepr *, 2> components;
     if (!ExprToIdentTypeRepr(components, TC.Context).visit(ce->getFn()))