Code completion: complete declarations that are required for declared protocol

conformances

rdar://16539292

This is a hack in visible decl lookup.  The general solution that would also
improve type checker errors would be to make the type checker keep these broken
conformances and syntethize missing declarations to make downstream code type
check.  For that, see:

<rdar://problem/16723339> [QoI] Type checker should not be dropping protocol
conformances explicitly spelled in the source


Swift SVN r16818

lib/IDE/CodeCompletion.cpp

@@ -927,6 +927,7 @@ public:
         return SemanticContextKind::ExpressionSpecific;
       return SemanticContextKind::CurrentNominal;
 
+    case DeclVisibilityKind::MemberOfProtocolImplementedByCurrentNominal:
     case DeclVisibilityKind::MemberOfSuper:
       return SemanticContextKind::Super;
 
@@ -1774,7 +1775,7 @@ public:
         TypeResolver(createLazyResolver(Ctx)),
         CurrDeclContext(CurrDeclContext) {}
 
-  void addMethodOverride(const FuncDecl *FD) {
+  void addMethodOverride(const FuncDecl *FD, DeclVisibilityKind Reason) {
     CodeCompletionResultBuilder Builder(
         Sink,
         CodeCompletionResult::ResultKind::Declaration,
@@ -1784,7 +1785,8 @@ public:
     llvm::SmallString<256> DeclStr;
     {
       llvm::raw_svector_ostream OS(DeclStr);
-      OS << "override ";
+      if (Reason == DeclVisibilityKind::MemberOfSuper)
+        OS << "override ";
       PrintOptions Options;
       Options.FunctionDefinitions = false;
       Options.PrintDefaultParameterPlaceholder = false;
@@ -1813,7 +1815,7 @@ public:
       if (FD->isAccessor())
         return;
 
-      addMethodOverride(FD);
+      addMethodOverride(FD, Reason);
       return;
     }
   }