Remove an unnecessary overload from ASTLambda.h 
As Richard pointed out to me, dyn_cast is very cheap - there is no real benefit from adding cluttery overloads to only avoid that cast.
No functionality change.

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@191646 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/Sema/SemaDecl.cpp b/lib/Sema/SemaDecl.cpp
index b15208b..4d5d559 100644
--- a/lib/Sema/SemaDecl.cpp
+++ b/lib/Sema/SemaDecl.cpp
@@ -9349,7 +9349,7 @@
   // a LambdaScopeInfo onto the function stack.  But use the information
   // that's already been calculated (ActOnLambdaExpr) when analyzing the
   // template version, to prime the current LambdaScopeInfo. 
-  if (isGenericLambdaCallOperatorSpecialization(D)) {
+  if (isGenericLambdaCallOperatorSpecialization(FD)) {
     CXXMethodDecl *CallOperator = cast<CXXMethodDecl>(D);
     CXXRecordDecl *LambdaClass = CallOperator->getParent();
     LambdaExpr    *LE = LambdaClass->getLambdaExpr();