cppcoreguidelines-pro-bounds-constant-array-index: crash for value dependent index in c++03 mode

Summary:
When the expression is value dependent,
isIntegerConstantExpr() crashes in C++03 mode with
 ../tools/clang/lib/AST/ExprConstant.cpp:9330: (anonymous namespace)::ICEDiag CheckICE(const clang::Expr *, const clang::ASTContext &):
  Assertion `!E->isValueDependent() && "Should not see value dependent exprs!"' failed.
In C++11 mode, that assert does not trigger.

This commit works around this in the check. We don't check
value-dependent indices and instead check their specialization.

Reviewers: alexfh, aaron.ballman

Subscribers: nemanjai, cfe-commits

Differential Revision: http://reviews.llvm.org/D22190

llvm-svn: 275461
diff --git a/clang-tools-extra/clang-tidy/cppcoreguidelines/ProBoundsConstantArrayIndexCheck.cpp b/clang-tools-extra/clang-tidy/cppcoreguidelines/ProBoundsConstantArrayIndexCheck.cpp
index 67e921b..a57ec49 100644
--- a/clang-tools-extra/clang-tidy/cppcoreguidelines/ProBoundsConstantArrayIndexCheck.cpp
+++ b/clang-tools-extra/clang-tidy/cppcoreguidelines/ProBoundsConstantArrayIndexCheck.cpp
@@ -65,6 +65,10 @@
     const MatchFinder::MatchResult &Result) {
   const auto *Matched = Result.Nodes.getNodeAs<Expr>("expr");
   const auto *IndexExpr = Result.Nodes.getNodeAs<Expr>("index");
+
+  if (IndexExpr->isValueDependent())
+    return; // We check in the specialization.
+
   llvm::APSInt Index;
   if (!IndexExpr->isIntegerConstantExpr(Index, *Result.Context, nullptr,
                                         /*isEvaluated=*/true)) {