Properly track l-paren of a CXXFucntionalCastExpr.

In addition to storing more useful information in the AST, this
fixes a semantic check in template instantiation which checks whether
the l-paren location is valid.

Fixes PR16903.

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@188495 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/Analysis/ReachableCode.cpp b/lib/Analysis/ReachableCode.cpp
index a90aebb..e15fe7d 100644
--- a/lib/Analysis/ReachableCode.cpp
+++ b/lib/Analysis/ReachableCode.cpp
@@ -227,7 +227,7 @@
     case Expr::CXXFunctionalCastExprClass: {
       const CXXFunctionalCastExpr *CE = cast <CXXFunctionalCastExpr>(S);
       R1 = CE->getSubExpr()->getSourceRange();
-      return CE->getTypeBeginLoc();
+      return CE->getLocStart();
     }
     case Stmt::CXXTryStmtClass: {
       return cast<CXXTryStmt>(S)->getHandler(0)->getCatchLoc();