[analyzer] Fix an assertion fail in VirtualCallChecker

Differential Revision: https://reviews.llvm.org/D37978

llvm-svn: 313866
diff --git a/clang/lib/StaticAnalyzer/Checkers/VirtualCallChecker.cpp b/clang/lib/StaticAnalyzer/Checkers/VirtualCallChecker.cpp
index ea1976e..c5010f5 100644
--- a/clang/lib/StaticAnalyzer/Checkers/VirtualCallChecker.cpp
+++ b/clang/lib/StaticAnalyzer/Checkers/VirtualCallChecker.cpp
@@ -146,7 +146,7 @@
     if (CME->getQualifier())
       CallIsNonVirtual = true;
 
-    if (const Expr *Base = CME->getBase()->IgnoreImpCasts()) {
+    if (const Expr *Base = CME->getBase()) {
       // The most derived class is marked final.
       if (Base->getBestDynamicClassType()->hasAttr<FinalAttr>())
         CallIsNonVirtual = true;