clang-format: [JS] do not wrap before any `is`.

Summary:
`is` type annotations can occur at any nesting level. For example:

    function x() {
      return function y(): a is B { ... };
    }

Breaking before the `is` above breaks TypeScript parsing the code. This
change prevents the wrap.

Reviewers: krasimir

Subscribers: klimek, cfe-commits

Differential Revision: https://reviews.llvm.org/D47193

llvm-svn: 332968

1 files changed, 9 insertions, 1 deletions

diff --git a/clang/unittests/Format/FormatTestJS.cpp b/clang/unittests/Format/FormatTestJS.cpp
index 0a5c991b36d..1d610555778 100644
--- a/clang/unittests/Format/FormatTestJS.cpp
+++ b/clang/unittests/Format/FormatTestJS.cpp
@@ -1164,7 +1164,15 @@ TEST_F(FormatTestJS, WrapRespectsAutomaticSemicolonInsertion) {
   verifyFormat("await theReckoning;", getGoogleJSStyleWithColumns(10));
   verifyFormat("some['a']['b']", getGoogleJSStyleWithColumns(10));
   verifyFormat("x = (a['a']\n"
-               "      ['b']);", getGoogleJSStyleWithColumns(10));
+               "      ['b']);",
+               getGoogleJSStyleWithColumns(10));
+  verifyFormat("function f() {\n"
+               "  return foo.bar(\n"
+               "      (param): param is {\n"
+               "        a: SomeType\n"
+               "      }&ABC => 1)\n"
+               "}",
+               getGoogleJSStyleWithColumns(25));
 }
 
 TEST_F(FormatTestJS, AutomaticSemicolonInsertionHeuristic) {