[AST] Remove more interface-type redundancy from ProtocolConformance.

Author: DougGregor

include/swift/AST/ASTContext.h

@@ -662,7 +662,6 @@ class ASTContext {
   /// Produce a new normal conformance for a property behavior.
   NormalProtocolConformance *
   getBehaviorConformance(Type conformingType,
-                         Type conformingInterfaceType,
                          ProtocolDecl *protocol,
                          SourceLoc loc,
                          AbstractStorageDecl *storage,

include/swift/AST/ProtocolConformance.h

@@ -355,7 +355,6 @@ class NormalProtocolConformance : public ProtocolConformance,
   }
 
   NormalProtocolConformance(Type conformingType,
-                            Type conformingInterfaceType,
                             ProtocolDecl *protocol,
                             SourceLoc loc, AbstractStorageDecl *behaviorStorage,
                             ProtocolConformanceState state)

lib/AST/ASTContext.cpp

@@ -1476,16 +1476,14 @@ void ValueDecl::setLocalDiscriminator(unsigned index) {
 
 NormalProtocolConformance *
 ASTContext::getBehaviorConformance(Type conformingType,
-                                   Type conformingInterfaceType,
                                    ProtocolDecl *protocol,
                                    SourceLoc loc,
                                    AbstractStorageDecl *storage,
                                    ProtocolConformanceState state) {
   auto conformance = new (*this, AllocationArena::Permanent)
-    NormalProtocolConformance(conformingType, conformingInterfaceType,
-                              protocol, loc, storage, state);
+    NormalProtocolConformance(conformingType, protocol, loc, storage, state);
 
-  if (auto nominal = conformingInterfaceType->getAnyNominal()) {
+  if (auto nominal = conformingType->getRValueInstanceType()->getAnyNominal()) {
     // Note: this is an egregious hack. The conformances need to be associated
     // with the actual storage declarations.
     SmallVector<ProtocolConformance *, 2> conformances;

lib/Sema/CodeSynthesis.cpp

@@ -1805,19 +1805,16 @@ void swift::maybeAddAccessorsToVariable(VarDecl *var, TypeChecker &TC) {
       // The conformance will be on the containing 'self' type, or '()' if the
       // property is in a non-type context.
       Type behaviorSelf;
-      Type behaviorInterfaceSelf;
       if (dc->isTypeContext()) {
-        behaviorInterfaceSelf = dc->getSelfInterfaceType();
-        behaviorSelf = dc->mapTypeIntoContext(behaviorInterfaceSelf);
+        behaviorSelf = dc->getSelfTypeInContext();
         assert(behaviorSelf && "type context doesn't have self type?!");
         if (var->isStatic())
           behaviorSelf = MetatypeType::get(behaviorSelf);
       } else {
-        behaviorSelf = behaviorInterfaceSelf = TC.Context.TheEmptyTupleType;
+        behaviorSelf = TC.Context.TheEmptyTupleType;
       }
 
       conformance = TC.Context.getBehaviorConformance(behaviorSelf,
-                                            behaviorInterfaceSelf,
                                             behaviorProto,
                                             behavior->getLoc(), var,
                                             ProtocolConformanceState::Checking);