clang-format: Fix crash on invalid code.

Input "a<," made clang-format crash.

llvm-svn: 226450

2 files changed, 4 insertions, 1 deletions

diff --git a/clang/lib/Format/FormatToken.cpp b/clang/lib/Format/FormatToken.cpp
index badb3a39c82..0addbfed0ce 100644
--- a/clang/lib/Format/FormatToken.cpp
+++ b/clang/lib/Format/FormatToken.cpp
@@ -59,7 +59,8 @@ void TokenRole::precomputeFormattingInfos(const FormatToken *Token) {}
 unsigned CommaSeparatedList::formatAfterToken(LineState &State,
                                               ContinuationIndenter *Indenter,
                                               bool DryRun) {
-  if (!State.NextToken->Previous || !State.NextToken->Previous->Previous)
+  if (State.NextToken == nullptr || !State.NextToken->Previous ||
+      !State.NextToken->Previous->Previous)
     return 0;
 
   // Ensure that we start on the opening brace.
diff --git a/clang/unittests/Format/FormatTest.cpp b/clang/unittests/Format/FormatTest.cpp
index 13526158145..548273ade03 100644
--- a/clang/unittests/Format/FormatTest.cpp
+++ b/clang/unittests/Format/FormatTest.cpp
@@ -6038,6 +6038,8 @@ TEST_F(FormatTest, FormatsBracedListsInColumnLayout) {
   // No column layout should be used here.
   verifyFormat("aaaaaaaaaaaaaaa = {aaaaaaaaaaaaaaaaaaaaaaaaaaa, 0, 0,\n"
                "                   bbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbb};");
+
+  verifyNoCrash("a<,");
 }
 
 TEST_F(FormatTest, PullTrivialFunctionDefinitionsIntoSingleLine) {