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

2 files changed, 4 insertions, 1 deletions

diff --git a/clang/lib/Frontend/ASTUnit.cpp b/clang/lib/Frontend/ASTUnit.cpp
index c1f6bc5bb0e..9251fc0daa0 100644
--- a/clang/lib/Frontend/ASTUnit.cpp
+++ b/clang/lib/Frontend/ASTUnit.cpp
@@ -2410,10 +2410,10 @@ void ASTUnit::CodeComplete(StringRef File, unsigned Line, unsigned Column,
     
   // Set up diagnostics, capturing any diagnostics produced.
   Clang->setDiagnostics(&Diag);
-  ProcessWarningOptions(Diag, CCInvocation->getDiagnosticOpts());
   CaptureDroppedDiagnostics Capture(true, 
                                     Clang->getDiagnostics(), 
                                     StoredDiagnostics);
+  ProcessWarningOptions(Diag, CCInvocation->getDiagnosticOpts());
   
   // Create the target instance.
   Clang->setTarget(TargetInfo::CreateTargetInfo(Clang->getDiagnostics(),
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 00000000000..82ed06359d7
--- /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();