Rewrite of our handling of name lookup in C++ member access expressions, e.g.,

  x->Base::f

We no longer try to "enter" the context of the type that "x" points
to. Instead, we drag that object type through the parser and pass it
into the Sema routines that need to know how to perform lookup within
member access expressions.

We now implement most of the crazy name lookup rules in C++
[basic.lookup.classref] for non-templated code, including performing
lookup both in the context of the type referred to by the member
access and in the scope of the member access itself and then detecting
ambiguities when the two lookups collide (p1 and p4; p3 and p7 are
still TODO). This change also corrects our handling of name lookup
within template arguments of template-ids inside the
nested-name-specifier (p6; we used to look into the scope of the
object expression for them) and fixes PR4703.

I have disabled some tests that involve member access expressions
where the object expression has dependent type, because we don't yet
have the ability to describe dependent nested-name-specifiers starting
with an identifier.



git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@80843 91177308-0d34-0410-b5e6-96231b3b80d8

1 files changed, 18 insertions, 23 deletions

diff --git a/lib/Sema/SemaLookup.cpp b/lib/Sema/SemaLookup.cpp
index 4a699de6c8..38abd1641d 100644
--- a/lib/Sema/SemaLookup.cpp
+++ b/lib/Sema/SemaLookup.cpp
@@ -1004,8 +1004,9 @@ Sema::LookupQualifiedName(DeclContext *LookupCtx, DeclarationName Name,
                           LookupNameKind NameKind, bool RedeclarationOnly) {
   assert(LookupCtx && "Sema::LookupQualifiedName requires a lookup context");
   
-  if (!Name) return LookupResult::CreateLookupResult(Context, 0);
-
+  if (!Name) 
+    return LookupResult::CreateLookupResult(Context, 0);
+  
   // If we're performing qualified name lookup (e.g., lookup into a
   // struct), find fields as part of ordinary name lookup.
   unsigned IDNS
@@ -1013,16 +1014,25 @@ Sema::LookupQualifiedName(DeclContext *LookupCtx, DeclarationName Name,
                                                 getLangOptions().CPlusPlus);
   if (NameKind == LookupOrdinaryName)
     IDNS |= Decl::IDNS_Member;
-
+  
+  // Make sure that the declaration context is complete.
+  assert((!isa<TagDecl>(LookupCtx) ||
+          LookupCtx->isDependentContext() ||
+          cast<TagDecl>(LookupCtx)->isDefinition() ||
+          Context.getTypeDeclType(cast<TagDecl>(LookupCtx))->getAs<TagType>()
+            ->isBeingDefined()) &&
+         "Declaration context must already be complete!");
+    
   // Perform qualified name lookup into the LookupCtx.
   DeclContext::lookup_iterator I, E;
   for (llvm::tie(I, E) = LookupCtx->lookup(Name); I != E; ++I)
     if (isAcceptableLookupResult(*I, NameKind, IDNS))
       return LookupResult::CreateLookupResult(Context, I, E);
 
-  // If this isn't a C++ class or we aren't allowed to look into base
-  // classes, we're done.
-  if (RedeclarationOnly || !isa<CXXRecordDecl>(LookupCtx))
+  // If this isn't a C++ class, we aren't allowed to look into base
+  // classes, we're done, or the lookup context is dependent, we're done.
+  if (RedeclarationOnly || !isa<CXXRecordDecl>(LookupCtx) || 
+      LookupCtx->isDependentContext())
     return LookupResult::CreateLookupResult(Context, 0);
 
   // Perform lookup into our base classes.
@@ -1152,24 +1162,9 @@ Sema::LookupParsedName(Scope *S, const CXXScopeSpec *SS,
     if (DeclContext *DC = computeDeclContext(*SS, EnteringContext)) {
       // We have resolved the scope specifier to a particular declaration 
       // contex, and will perform name lookup in that context.
-      
-      if (DC->isDependentContext()) {
-        // If this is a dependent context, then we are looking for a member of
-        // the current instantiation. This is a narrow search that looks into
-        // just the described declaration context (C++0x [temp.dep.type]).
-        unsigned IDNS = getIdentifierNamespacesFromLookupNameKind(NameKind, 
-                                                                  true);
-        DeclContext::lookup_iterator I, E;
-        for (llvm::tie(I, E) = DC->lookup(Name); I != E; ++I)
-          if (isAcceptableLookupResult(*I, NameKind, IDNS))
-            return LookupResult::CreateLookupResult(Context, I, E);
-      }
-      
-      // Qualified name lookup into the named declaration context.
-      // The declaration context must be complete.
-      if (RequireCompleteDeclContext(*SS))
+      if (!DC->isDependentContext() && RequireCompleteDeclContext(*SS))
         return LookupResult::CreateLookupResult(Context, 0);
-            
+                                    
       return LookupQualifiedName(DC, Name, NameKind, RedeclarationOnly);
     }