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

2 files changed, 15 insertions, 0 deletions

diff --git a/clang-tools-extra/clang-tidy/cppcoreguidelines/ProBoundsConstantArrayIndexCheck.cpp b/clang-tools-extra/clang-tidy/cppcoreguidelines/ProBoundsConstantArrayIndexCheck.cpp
index 67e921bc3e8..a57ec49a199 100644
--- a/clang-tools-extra/clang-tidy/cppcoreguidelines/ProBoundsConstantArrayIndexCheck.cpp
+++ b/clang-tools-extra/clang-tidy/cppcoreguidelines/ProBoundsConstantArrayIndexCheck.cpp
@@ -65,6 +65,10 @@ void ProBoundsConstantArrayIndexCheck::check(
     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)) {
diff --git a/clang-tools-extra/test/clang-tidy/cppcoreguidelines-pro-bounds-constant-array-index-c++03.cpp b/clang-tools-extra/test/clang-tidy/cppcoreguidelines-pro-bounds-constant-array-index-c++03.cpp
new file mode 100644
index 00000000000..ad9fcd97daa
--- /dev/null
+++ b/clang-tools-extra/test/clang-tidy/cppcoreguidelines-pro-bounds-constant-array-index-c++03.cpp
@@ -0,0 +1,11 @@
+// RUN: clang-tidy %s -checks=-*,cppcoreguidelines-pro-bounds-constant-array-index -- -std=c++03 | count 0
+
+// Note: this test expects no diagnostics, but FileCheck cannot handle that,
+// hence the use of | count 0.
+template <int index> struct B {
+  int get() {
+    // The next line used to crash the check (in C++03 mode only).
+    return x[index];
+  }
+  int x[3];
+};