Fix crash in libclang if code completion is used with unknown flags.
Use CaptureDroppedDiagnostics to make sure that there is a diagnostic
client installed when warning flags are parsed.
llvm-svn: 186582
diff --git a/clang/test/Index/c-index-unsupported-warning-test.c b/clang/test/Index/c-index-unsupported-warning-test.c
new file mode 100644
index 0000000..82ed063
--- /dev/null
+++ b/clang/test/Index/c-index-unsupported-warning-test.c
@@ -0,0 +1,3 @@
+// RUN: c-index-test -code-completion-at=%s:1:1 -Wunknown-foo-bar-warning -Werror %s
+
+void f();