Use dyn_cast instead of cast to allow our assumptions to be safely wrong.


git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@71843 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/Analysis/GRExprEngineInternalChecks.cpp b/lib/Analysis/GRExprEngineInternalChecks.cpp
index a298629..9aea124 100644
--- a/lib/Analysis/GRExprEngineInternalChecks.cpp
+++ b/lib/Analysis/GRExprEngineInternalChecks.cpp
@@ -631,22 +631,30 @@
 
 static const Stmt *GetReceiverExpr(const ExplodedNode<GRState> *N) {
   const Stmt *S = N->getLocationAs<PostStmt>()->getStmt();
-  return cast<ObjCMessageExpr>(S)->getReceiver();
+  if (const ObjCMessageExpr *ME = dyn_cast<ObjCMessageExpr>(S))
+    return ME->getReceiver();
+  return NULL;
 }
   
 static const Stmt *GetDenomExpr(const ExplodedNode<GRState> *N) {
   const Stmt *S = N->getLocationAs<PostStmt>()->getStmt();
-  return cast<BinaryOperator>(S)->getRHS();
+  if (const BinaryOperator *BE = dyn_cast<BinaryOperator>(S))
+    return BE->getRHS();
+  return NULL;
 }
   
 static const Stmt *GetCalleeExpr(const ExplodedNode<GRState> *N) {
   const Stmt *S = N->getLocationAs<PostStmt>()->getStmt();
-  return cast<CallExpr>(S)->getCallee();
+  if (const CallExpr *CE = dyn_cast<CallExpr>(S))
+    return CE->getCallee();
+  return NULL;
 }
   
 static const Stmt *GetRetValExpr(const ExplodedNode<GRState> *N) {
   const Stmt *S = N->getLocationAs<PostStmt>()->getStmt();
-  return cast<ReturnStmt>(S)->getRetValue();
+  if (const ReturnStmt *RS = dyn_cast<ReturnStmt>(S))
+    return RS->getRetValue();
+  return NULL;
 }
 
 namespace {