[clang-tidy] Fix assertion failure on `at` function in modernize-loop-convert.

Reviewers: alexfh

Subscribers: cfe-commits

Differential Revision: http://reviews.llvm.org/D16926

llvm-svn: 260107
diff --git a/clang-tools-extra/clang-tidy/modernize/LoopConvertUtils.cpp b/clang-tools-extra/clang-tidy/modernize/LoopConvertUtils.cpp
index c50e923..b3dfa93 100644
--- a/clang-tools-extra/clang-tidy/modernize/LoopConvertUtils.cpp
+++ b/clang-tools-extra/clang-tidy/modernize/LoopConvertUtils.cpp
@@ -391,8 +391,8 @@
     // This check is needed because getMethodDecl can return nullptr if the
     // callee is a member function pointer.
     const auto *MDecl = MemCall->getMethodDecl();
-    if (MDecl && !isa<CXXConversionDecl>(MDecl) && MDecl->getName() == "at") {
-      assert(MemCall->getNumArgs() == 1);
+    if (MDecl && !isa<CXXConversionDecl>(MDecl) && MDecl->getName() == "at" &&
+        MemCall->getNumArgs() == 1) {
       return isIndexInSubscriptExpr(MemCall->getArg(0), IndexVar);
     }
     return false;