commit e8292b10a61adc03a8c0a3be47d3e39e0aa29b64
author Richard Smith <richard-llvm@metafoo.co.uk> Tue Feb 10 03:28:10 2015 +0000
committer Richard Smith <richard-llvm@metafoo.co.uk> Tue Feb 10 03:28:10 2015 +0000
tree 223e8c3ae1aaa04b6f8c33b8d3940a1406a5533a
parent c11b101fb64c621e6bc1a36904bc775ce6202beb

[modules] When determining whether a name from a module replaces a name we
already have, check whether the name from the module is actually newer than the
existing declaration. If it isn't, we might (say) replace a visible declaration
with an injected friend, and thus make it invisible (or lose a default argument
or an array bound).

llvm-svn: 228661

clang/include/clang/AST/Decl.h

diff --git a/clang/include/clang/AST/Decl.h b/clang/include/clang/AST/Decl.h
index 84ed286..ee2f760 100644
--- a/clang/include/clang/AST/Decl.h
+++ b/clang/include/clang/AST/Decl.h
@@ -179,14 +179,17 @@
                                     const PrintingPolicy &Policy,
                                     bool Qualified) const;
 
-  /// declarationReplaces - Determine whether this declaration, if
+  /// \brief Determine whether this declaration, if
   /// known to be well-formed within its context, will replace the
   /// declaration OldD if introduced into scope. A declaration will
   /// replace another declaration if, for example, it is a
   /// redeclaration of the same variable or function, but not if it is
   /// a declaration of a different kind (function vs. class) or an
   /// overloaded function.
-  bool declarationReplaces(NamedDecl *OldD) const;
+  ///
+  /// \param IsKnownNewer \c true if this declaration is known to be newer
+  /// than \p OldD (for instance, if this declaration is newly-created).
+  bool declarationReplaces(NamedDecl *OldD, bool IsKnownNewer = true) const;
 
   /// \brief Determine whether this declaration has linkage.
   bool hasLinkage() const;

clang/include/clang/AST/DeclContextInternals.h

diff --git a/clang/include/clang/AST/DeclContextInternals.h b/clang/include/clang/AST/DeclContextInternals.h
index 9068c00..e0830d0 100644
--- a/clang/include/clang/AST/DeclContextInternals.h
+++ b/clang/include/clang/AST/DeclContextInternals.h
@@ -163,10 +163,10 @@
 
   /// HandleRedeclaration - If this is a redeclaration of an existing decl,
   /// replace the old one with D and return true.  Otherwise return false.
-  bool HandleRedeclaration(NamedDecl *D) {
+  bool HandleRedeclaration(NamedDecl *D, bool IsKnownNewer) {
     // Most decls only have one entry in their list, special case it.
     if (NamedDecl *OldD = getAsDecl()) {
-      if (!D->declarationReplaces(OldD))
+      if (!D->declarationReplaces(OldD, IsKnownNewer))
         return false;
       setOnlyValue(D);
       return true;
@@ -177,7 +177,7 @@
     for (DeclsTy::iterator OD = Vec.begin(), ODEnd = Vec.end();
          OD != ODEnd; ++OD) {
       NamedDecl *OldD = *OD;
-      if (D->declarationReplaces(OldD)) {
+      if (D->declarationReplaces(OldD, IsKnownNewer)) {
         *OD = D;
         return true;
       }