Handle decltype keyword in Parser::isDeclarationSpecifier.
Fixes PR10154. Found by parsing MFC 2010 code with clang.

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@133380 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/Parse/ParseDecl.cpp b/lib/Parse/ParseDecl.cpp
index 2d3fcf8..9af7345 100644
--- a/lib/Parse/ParseDecl.cpp
+++ b/lib/Parse/ParseDecl.cpp
@@ -3018,6 +3018,10 @@
   case tok::kw___attribute:
     return true;
 
+    // C++0x decltype.
+  case tok::kw_decltype:
+    return true;
+
     // GNU ObjC bizarre protocol extension: <proto1,proto2> with implicit 'id'.
   case tok::less:
     return getLang().ObjC1;
diff --git a/test/SemaCXX/decltype.cpp b/test/SemaCXX/decltype.cpp
index d4ef7e3..f61a92b 100644
--- a/test/SemaCXX/decltype.cpp
+++ b/test/SemaCXX/decltype.cpp
@@ -16,3 +16,8 @@
   float &fr = f2(AC().a);
 }
 
+namespace pr10154 {
+  class A{
+      A(decltype(nullptr) param);
+  };
+}
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