Teach NestedNameSpecifier to keep track of namespace aliases the same

way it keeps track of namespaces. Previously, we would map from the
namespace alias to its underlying namespace when building a
nested-name-specifier, losing source information in the process.

llvm-svn: 126358

1 files changed, 31 insertions, 0 deletions

diff --git a/clang/lib/Sema/TreeTransform.h b/clang/lib/Sema/TreeTransform.h
index 7a0754fc883..1b2822ead7b 100644
--- a/clang/lib/Sema/TreeTransform.h
+++ b/clang/lib/Sema/TreeTransform.h
@@ -877,6 +877,16 @@ public:
                                                   NamespaceDecl *NS);
 
   /// \brief Build a new nested-name-specifier given the prefix and the
+  /// namespace alias named in the next step in the nested-name-specifier.
+  ///
+  /// By default, performs semantic analysis when building the new
+  /// nested-name-specifier. Subclasses may override this routine to provide
+  /// different behavior.
+  NestedNameSpecifier *RebuildNestedNameSpecifier(NestedNameSpecifier *Prefix,
+                                                  SourceRange Range,
+                                                  NamespaceAliasDecl *Alias);
+
+  /// \brief Build a new nested-name-specifier given the prefix and the
   /// type named in the next step in the nested-name-specifier.
   ///
   /// By default, performs semantic analysis when building the new
@@ -2450,6 +2460,19 @@ TreeTransform<Derived>::TransformNestedNameSpecifier(NestedNameSpecifier *NNS,
     return getDerived().RebuildNestedNameSpecifier(Prefix, Range, NS);
   }
 
+  case NestedNameSpecifier::NamespaceAlias: {
+    NamespaceAliasDecl *Alias
+      = cast_or_null<NamespaceAliasDecl>(
+                                    getDerived().TransformDecl(Range.getBegin(),
+                                                    NNS->getAsNamespaceAlias()));
+    if (!getDerived().AlwaysRebuild() &&
+        Prefix == NNS->getPrefix() &&
+        Alias == NNS->getAsNamespaceAlias())
+      return NNS;
+
+    return getDerived().RebuildNestedNameSpecifier(Prefix, Range, Alias);
+  }
+
   case NestedNameSpecifier::Global:
     // There is no meaningful transformation that one could perform on the
     // global scope.
@@ -7571,6 +7594,14 @@ template<typename Derived>
 NestedNameSpecifier *
 TreeTransform<Derived>::RebuildNestedNameSpecifier(NestedNameSpecifier *Prefix,
                                                    SourceRange Range,
+                                                   NamespaceAliasDecl *Alias) {
+  return NestedNameSpecifier::Create(SemaRef.Context, Prefix, Alias);
+}
+
+template<typename Derived>
+NestedNameSpecifier *
+TreeTransform<Derived>::RebuildNestedNameSpecifier(NestedNameSpecifier *Prefix,
+                                                   SourceRange Range,
                                                    bool TemplateKW,
                                                    QualType T) {
   if (T->isDependentType() || T->isRecordType() ||