clang-format: [JS] Fix incorrect line break leading to semicolon insertion.

clang-format only works for JavaScript code, if all the semicolons are
present anyway, so this linebreak can never be desired.

Before (with appropriate statement lengths or column limit):
  return
      [ aaa ];

After:
  return [
    aaaa
  ];

llvm-svn: 257741

clang/lib/Format/TokenAnnotator.cpp

@@ -2268,6 +2268,8 @@ bool TokenAnnotator::canBreakBefore(const AnnotatedLine &Line,
                       Keywords.kw_implements))
       return true;
   } else if (Style.Language == FormatStyle::LK_JavaScript) {
+    if (Left.is(tok::kw_return))
+      return false; // Otherwise a semicolon is inserted.
     if (Left.is(TT_JsFatArrow) && Right.is(tok::l_brace))
       return false;
     if (Left.is(TT_JsTypeColon))

clang/unittests/Format/FormatTestJS.cpp

@@ -591,6 +591,10 @@ TEST_F(FormatTestJS, AutomaticSemicolonInsertion) {
   verifyFormat("throw aaaaa;", getGoogleJSStyleWithColumns(10));
   verifyFormat("aaaaaaaaa++;", getGoogleJSStyleWithColumns(10));
   verifyFormat("aaaaaaaaa--;", getGoogleJSStyleWithColumns(10));
+  verifyFormat("return [\n"
+               "  aaa\n"
+               "];",
+               getGoogleJSStyleWithColumns(12));
 }
 
 TEST_F(FormatTestJS, ClosureStyleCasts) {