Fix Bug 38713: clang-format mishandles a short block after "default:" in a switch statement

Summary:
See https://bugs.llvm.org/show_bug.cgi?id=38713

Patch by Owen Pan!

Reviewers: djasper, klimek, sammccall

Reviewed By: sammccall

Subscribers: cfe-commits

Differential Revision: https://reviews.llvm.org/D51294

llvm-svn: 341284
diff --git a/clang/lib/Format/UnwrappedLineFormatter.cpp b/clang/lib/Format/UnwrappedLineFormatter.cpp
index 906dae4..1b7daf6 100644
--- a/clang/lib/Format/UnwrappedLineFormatter.cpp
+++ b/clang/lib/Format/UnwrappedLineFormatter.cpp
@@ -483,6 +483,12 @@
     if (Line.First->isOneOf(tok::kw_else, tok::kw_case) ||
         (Line.First->Next && Line.First->Next->is(tok::kw_else)))
       return 0;
+    // default: in switch statement
+    if (Line.First->is(tok::kw_default)) {
+      const FormatToken *Tok = Line.First->getNextNonComment();
+      if (Tok && Tok->is(tok::colon))
+        return 0;
+    }
     if (Line.First->isOneOf(tok::kw_if, tok::kw_while, tok::kw_do, tok::kw_try,
                             tok::kw___try, tok::kw_catch, tok::kw___finally,
                             tok::kw_for, tok::r_brace, Keywords.kw___except)) {