Replace TypeLoc llvm::cast support to be well-defined.

The TypeLoc hierarchy used the llvm::cast machinery to perform undefined
behavior by casting pointers/references to TypeLoc objects to derived types
and then using the derived copy constructors (or even returning pointers to
derived types that actually point to the original TypeLoc object).

Some context is in this thread:
http://lists.cs.uiuc.edu/pipermail/llvmdev/2012-December/056804.html
Though it's spread over a few months which can be hard to read in the mail
archive.

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@175462 91177308-0d34-0410-b5e6-96231b3b80d8

1 files changed, 2 insertions, 2 deletions

diff --git a/lib/AST/TemplateBase.cpp b/lib/AST/TemplateBase.cpp
index 6519340c87..f1b5e4b0b8 100644
--- a/lib/AST/TemplateBase.cpp
+++ b/lib/AST/TemplateBase.cpp
@@ -466,8 +466,8 @@ TemplateArgumentLoc::getPackExpansionPattern(SourceLocation &Ellipsis,
       ExpansionTSInfo = Context.getTrivialTypeSourceInfo(
                                                      getArgument().getAsType(),
                                                          Ellipsis);
-    PackExpansionTypeLoc Expansion
-      = cast<PackExpansionTypeLoc>(ExpansionTSInfo->getTypeLoc());
+    PackExpansionTypeLoc Expansion =
+        ExpansionTSInfo->getTypeLoc().castAs<PackExpansionTypeLoc>();
     Ellipsis = Expansion.getEllipsisLoc();
     
     TypeLoc Pattern = Expansion.getPatternLoc();