"Incremental" progress on using expressions, by which I mean totally ripping

into pretty much everything about overload resolution in order to wean
BuildDeclarationNameExpr off LookupResult::getAsSingleDecl().  Replace  
UnresolvedFunctionNameExpr with UnresolvedLookupExpr, which generalizes the
idea of a non-member lookup that we haven't totally resolved yet, whether by
overloading, argument-dependent lookup, or (eventually) the presence of   
a function template in the lookup results.  

Incidentally fixes a problem with argument-dependent lookup where we were 
still performing ADL even when the lookup results contained something from
a block scope.  

Incidentally improves a diagnostic when using an ObjC ivar from a class method.
This just fell out from rewriting BuildDeclarationNameExpr's interaction with
lookup, and I'm too apathetic to break it out.

The only remaining uses of OverloadedFunctionDecl that I know of are in
TemplateName and MemberExpr.

llvm-svn: 89544

clang/lib/Sema/SemaCodeComplete.cpp

@@ -1467,7 +1467,7 @@ void Sema::CodeCompleteCall(Scope *S, ExprTy *FnIn,
       Expr::hasAnyTypeDependentArguments(Args, NumArgs))
     return;
   
-  NamedDecl *Function;
+  llvm::SmallVector<NamedDecl*,8> Fns;
   DeclarationName UnqualifiedName;
   NestedNameSpecifier *Qualifier;
   SourceRange QualifierRange;
@@ -1476,8 +1476,7 @@ void Sema::CodeCompleteCall(Scope *S, ExprTy *FnIn,
   const TemplateArgumentLoc *ExplicitTemplateArgs;
   unsigned NumExplicitTemplateArgs;
   
-  DeconstructCallFunction(Fn,
-                          Function, UnqualifiedName, Qualifier, QualifierRange,
+  DeconstructCallFunction(Fn, Fns, UnqualifiedName, Qualifier, QualifierRange,
                           ArgumentDependentLookup, HasExplicitTemplateArgs,
                           ExplicitTemplateArgs, NumExplicitTemplateArgs);
 
@@ -1488,7 +1487,7 @@ void Sema::CodeCompleteCall(Scope *S, ExprTy *FnIn,
   
   // Build an overload candidate set based on the functions we find.
   OverloadCandidateSet CandidateSet;
-  AddOverloadedCallCandidates(Function, UnqualifiedName, 
+  AddOverloadedCallCandidates(Fns, UnqualifiedName, 
                               ArgumentDependentLookup, HasExplicitTemplateArgs,
                               ExplicitTemplateArgs, NumExplicitTemplateArgs,
                               Args, NumArgs,