Replace DeclContext's vector of ScopedDecl pointers with a linked list
of ScopedDecls (using the new ScopedDecl::NextDeclInScope
pointer). Performance-wise:

  - It's a net win in memory utilization, since DeclContext is now one
    pointer smaller than it used to be (std::vectors are typically 3
    pointers; we now use 2 pointers) and 
  - Parsing Cocoa.h with -fsyntax-only (with a Release-Asserts Clang)
    is about 1.9% faster than before, most likely because we no longer
    have the memory allocations and copying associated with the
    std::vector.

I'll re-enable serialization of DeclContexts once I've sorted out the
NextDeclarator/NextDeclInScope question.



git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@62001 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/Sema/SemaDecl.cpp b/lib/Sema/SemaDecl.cpp
index ecf6de9..ee72a98 100644
--- a/lib/Sema/SemaDecl.cpp
+++ b/lib/Sema/SemaDecl.cpp
@@ -515,7 +515,7 @@
     Diag(New->getLocation(), diag::err_redefinition_different_typedef)
       << New->getUnderlyingType() << Old->getUnderlyingType();
     Diag(Old->getLocation(), diag::note_previous_definition);
-    return Old;
+    return New;
   }
   
   if (getLangOptions().Microsoft) return New;
@@ -768,7 +768,8 @@
   QualType OldCType = Context.getCanonicalType(Old->getType());
   QualType NewCType = Context.getCanonicalType(New->getType());
   if (OldCType != NewCType && !Context.typesAreCompatible(OldCType, NewCType)) {
-    Diag(New->getLocation(), diag::err_redefinition) << New->getDeclName();
+    Diag(New->getLocation(), diag::err_redefinition_different_type) 
+      << New->getDeclName();
     Diag(Old->getLocation(), diag::note_previous_definition);
     return New;
   }