diff --git a/include/clang/AST/Decl.h b/include/clang/AST/Decl.h
index 8d6cdcb..57b967e 100644
--- a/include/clang/AST/Decl.h
+++ b/include/clang/AST/Decl.h
@@ -484,8 +484,9 @@
   ObjCDeclQualifier getObjCDeclQualifier() const {
     return ObjCDeclQualifier(objcDeclQualifier);
   }
-  void setObjCDeclQualifier(ObjCDeclQualifier QTVal) 
-  { objcDeclQualifier = QTVal; }
+  void setObjCDeclQualifier(ObjCDeclQualifier QTVal) {
+    objcDeclQualifier = QTVal;
+  }
     
   const Expr *getDefaultArg() const { return DefaultArg; }
   Expr *getDefaultArg() { return DefaultArg; }
diff --git a/include/clang/Basic/DiagnosticKinds.def b/include/clang/Basic/DiagnosticKinds.def
index b379ab2..42ce6c7 100644
--- a/include/clang/Basic/DiagnosticKinds.def
+++ b/include/clang/Basic/DiagnosticKinds.def
@@ -720,6 +720,8 @@
      "expected parameter declarator")
 DIAG(err_bad_variable_name, ERROR,
      "'%0' cannot be the name of a variable or data member")
+DIAG(err_parameter_name_omitted, ERROR,
+     "parameter name omitted")
 
 DIAG(err_declarator_need_ident, ERROR,
      "declarator requires an identifier")
diff --git a/lib/Sema/SemaDecl.cpp b/lib/Sema/SemaDecl.cpp
index 424ce7f..6ef9ecd 100644
--- a/lib/Sema/SemaDecl.cpp
+++ b/lib/Sema/SemaDecl.cpp
@@ -720,6 +720,11 @@
       Param->setInvalidDecl();
       HasInvalidParm = true;
     }
+    
+    // C99 6.9.1p5: If the declarator includes a parameter type list, the
+    // declaration of each parameter shall include an identifier.
+    if (Param->getIdentifier() == 0 && !getLangOptions().CPlusPlus)
+      Diag(Param->getLocation(), diag::err_parameter_name_omitted);
   }
 
   return HasInvalidParm;
diff --git a/test/CodeGen/rdr-6140807-alias-references-forward.c b/test/CodeGen/rdr-6140807-alias-references-forward.c
index eff69ac..5fe15d1 100644
--- a/test/CodeGen/rdr-6140807-alias-references-forward.c
+++ b/test/CodeGen/rdr-6140807-alias-references-forward.c
@@ -10,5 +10,5 @@
   return f(1.);
 }
 
-int x(int) {
+int x(int a) {
 }
diff --git a/test/Parser/recovery.c b/test/Parser/recovery.c
index f77b570..78addb9 100644
--- a/test/Parser/recovery.c
+++ b/test/Parser/recovery.c
@@ -20,7 +20,7 @@
 
 
 // rdar://6094870
-int test(int) {
+int test(int a) {
   struct { int i; } x;
   
   if (x.hello)   // expected-error {{no member named 'hello'}}
diff --git a/test/Sema/c89.c b/test/Sema/c89.c
index 70949f0..b1780e9 100644
--- a/test/Sema/c89.c
+++ b/test/Sema/c89.c
@@ -44,7 +44,8 @@
 void test8(int, x);  /* expected-warning {{declaration specifier missing, defaulting to 'int'}} */
 
 typedef int sometype;
-int a(sometype, y) {return 0;}  /* expected-warning {{declaration specifier missing, defaulting to 'int'}} */
+int a(sometype, y) {return 0;}  /* expected-warning {{declaration specifier missing, defaulting to 'int'}} \
+                                   expected-error {{parameter name omitted}}*/
 
 
 
diff --git a/test/Sema/function.c b/test/Sema/function.c
index 7c67bba..f2aa8d9 100644
--- a/test/Sema/function.c
+++ b/test/Sema/function.c
@@ -29,3 +29,6 @@
 void t10(){}
 void t11(){t10(1);}
 
+// PR3208
+void t12(int) {}  // expected-error{{parameter name omitted}}
+
diff --git a/test/Sema/redefinition.c b/test/Sema/redefinition.c
index 9ad77f6..5e79070 100644
--- a/test/Sema/redefinition.c
+++ b/test/Sema/redefinition.c
@@ -1,5 +1,5 @@
 // RUN: clang %s -fsyntax-only -verify
-int f(int) { } // expected-note {{previous definition is here}}
+int f(int a) { } // expected-note {{previous definition is here}}
 int f(int);
-int f(int) { } // expected-error {{redefinition of 'f'}}
+int f(int a) { } // expected-error {{redefinition of 'f'}}