Provide a naming class for UnresolvedLookupExprs, even when occuring on

template names. We were completely missing naming classes for many unqualified
lookups, but this didn't trigger code paths that need it. This removes part of
an optimization that re-uses the template name lookup done by the parser to
determine if explicit template arguments actually form a template-id.
Unfortunately the technique for avoiding the duplicate lookup lost needed data
such as the class context in which the lookup succeeded.

llvm-svn: 104117

2 files changed, 10 insertions, 12 deletions

diff --git a/clang/lib/Sema/SemaExpr.cpp b/clang/lib/Sema/SemaExpr.cpp
index 5e1f21b4c3b..94aa6b09fe6 100644
--- a/clang/lib/Sema/SemaExpr.cpp
+++ b/clang/lib/Sema/SemaExpr.cpp
@@ -1077,17 +1077,12 @@ Sema::OwningExprResult Sema::ActOnIdExpression(Scope *S,
   // Perform the required lookup.
   LookupResult R(*this, Name, NameLoc, LookupOrdinaryName);
   if (TemplateArgs) {
-    // Just re-use the lookup done by isTemplateName.
-    DecomposeTemplateName(R, Id);
-
-    // Re-derive the naming class.
-    if (SS.isSet()) {
-      NestedNameSpecifier *Qualifier
-        = static_cast<NestedNameSpecifier *>(SS.getScopeRep());
-      if (const Type *Ty = Qualifier->getAsType())
-        if (CXXRecordDecl *NamingClass = Ty->getAsCXXRecordDecl())
-          R.setNamingClass(NamingClass);
-    }
+    // Lookup the template name again to correctly establish the context in
+    // which it was found. This is really unfortunate as we already did the
+    // lookup to determine that it was a template name in the first place. If
+    // this becomes a performance hit, we can work harder to preserve those
+    // results until we get here but it's likely not worth it.
+    LookupTemplateName(R, S, SS, QualType(), /*EnteringContext=*/false);
   } else {
     bool IvarLookupFollowUp = (!SS.isSet() && II && getCurMethodDecl());
     LookupParsedName(R, S, &SS, !IvarLookupFollowUp);
diff --git a/clang/lib/Sema/SemaLookup.cpp b/clang/lib/Sema/SemaLookup.cpp
index 774a82b7c74..b25ecb1e06e 100644
--- a/clang/lib/Sema/SemaLookup.cpp
+++ b/clang/lib/Sema/SemaLookup.cpp
@@ -665,6 +665,8 @@ bool Sema::CppLookupName(LookupResult &R, Scope *S) {
   //
   DeclContext *OutsideOfTemplateParamDC = 0;
   for (; S && !isNamespaceOrTranslationUnitScope(S); S = S->getParent()) {
+    DeclContext *Ctx = static_cast<DeclContext*>(S->getEntity());
+
     // Check whether the IdResolver has anything in this scope.
     bool Found = false;
     for (; I != IEnd && S->isDeclScope(DeclPtrTy::make(*I)); ++I) {
@@ -675,10 +677,11 @@ bool Sema::CppLookupName(LookupResult &R, Scope *S) {
     }
     if (Found) {
       R.resolveKind();
+      if (S->isClassScope())
+        R.setNamingClass(dyn_cast<CXXRecordDecl>(Ctx));
       return true;
     }
 
-    DeclContext *Ctx = static_cast<DeclContext*>(S->getEntity());
     if (!Ctx && S->isTemplateParamScope() && OutsideOfTemplateParamDC &&
         S->getParent() && !S->getParent()->isTemplateParamScope()) {
       // We've just searched the last template parameter scope and