diff --git a/include/clang/Basic/DiagnosticKinds.def b/include/clang/Basic/DiagnosticKinds.def
index 243d561..1de1b6b 100644
--- a/include/clang/Basic/DiagnosticKinds.def
+++ b/include/clang/Basic/DiagnosticKinds.def
@@ -631,6 +631,8 @@
 
 DIAG(err_unexpected_typedef, ERROR,
      "unexpected type name '%0': expected expression")
+DIAG(err_unexpected_typedef_ident, ERROR,
+     "unexpected type name '%0': expected identifier")
 DIAG(err_undeclared_var_use, ERROR,
      "use of undeclared identifier '%0'")
 DIAG(warn_deprecated, WARNING,
diff --git a/lib/Parse/ParseDecl.cpp b/lib/Parse/ParseDecl.cpp
index 9445a48..cae0cbb 100644
--- a/lib/Parse/ParseDecl.cpp
+++ b/lib/Parse/ParseDecl.cpp
@@ -1415,8 +1415,12 @@
       SkipUntil(tok::r_paren);
       return;
     }
-    
+
     IdentifierInfo *ParmII = Tok.getIdentifierInfo();
+
+    // Reject 'typedef int y; int test(x, y)', but continue parsing.
+    if (Actions.isTypeName(*ParmII, CurScope))
+      Diag(Tok, diag::err_unexpected_typedef_ident, ParmII->getName());
     
     // Verify that the argument identifier has not already been mentioned.
     if (!ParamsSoFar.insert(ParmII)) {
diff --git a/test/Parser/declarators.c b/test/Parser/declarators.c
index 15ae7c6..410ac36 100644
--- a/test/Parser/declarators.c
+++ b/test/Parser/declarators.c
@@ -25,4 +25,8 @@
   int Array[*(int*)P+A];
 }
 
+typedef int atype;
+int test3(x, 
+          atype         /* expected-error {{unexpected type name 'atype': expected identifier}} */
+         ) int x, atype; {}
 
diff --git a/test/Sema/arg-duplicate.c b/test/Sema/arg-duplicate.c
index b57fd95..81cb8fd 100644
--- a/test/Sema/arg-duplicate.c
+++ b/test/Sema/arg-duplicate.c
@@ -1,6 +1,5 @@
 // RUN: clang -fsyntax-only -verify %s
 
-typedef int x; 
 int f3(y, x, 
        x)          // expected-error {{redefinition of parameter}}
   int y, x,