1 files changed, 45 insertions, 0 deletions
diff --git a/tests/cxx/scope_crash.cc b/tests/cxx/scope_crash.cc
new file mode 100644
index 0000000..1659e08
--- /dev/null
+++ b/tests/cxx/scope_crash.cc
@@ -0,0 +1,45 @@
+//===--- scope_crash.cc - test input file for iwyu ------------------------===//
+//
+//                     The LLVM Compiler Infrastructure
+//
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+
+// This is a weak testcase, but it's the smallest example we've found to
+// reproduce an IWYU crash where Sema::TUScope was unexpectedly null.
+//
+// For some reason libstdc++9's std::map with a value with explicit default
+// constructor triggers some path in Sema's constructor lookup that needs a
+// non-null TUScope.
+//
+// Clang or libstdc++ might change so that this can no longer trigger the
+// original bug, or so that the bug manifests some other way. But testers can't
+// be choosers.
+
+#include <string>
+#include <map>
+
+struct A {};
+
+bool operator<(const A& lhs, const A& rhs) {
+  return false;
+}
+
+struct B {
+  // Used to crash with libstdc++ 9, worked without 'explicit'
+  explicit B() = default;
+  std::string data;
+};
+
+void foo(const A& a) {
+  std::map<A, B> m;
+  m.erase(a);
+}
+
+/**** IWYU_SUMMARY
+
+(tests/cxx/scope_crash.cc has correct #includes/fwd-decls)
+
+***** IWYU_SUMMARY */