clang-format: [JS] Fix corner case in template string parsing.

Before, these would not properly detected because of the char/string
literal found when re-lexing after the first `:

  var x = `'`;  // comment with matching quote '
  var x = `"`;  // comment with matching quote "

llvm-svn: 239693

clang/lib/Format/Format.cpp

@@ -785,7 +785,8 @@ private:
     // Backticks get lexed as tok::unknown tokens. If a template string contains
     // a comment start, it gets lexed as a tok::comment, or tok::unknown if
     // unterminated.
-    if (!EndBacktick->isOneOf(tok::comment, tok::unknown))
+    if (!EndBacktick->isOneOf(tok::comment, tok::string_literal,
+                              tok::char_constant, tok::unknown))
       return false;
     size_t CommentBacktickPos = EndBacktick->TokenText.find('`');
     // Unknown token that's not actually a backtick, or a comment that doesn't

clang/unittests/Format/FormatTestJS.cpp

@@ -809,6 +809,11 @@ TEST_F(FormatTestJS, TemplateStrings) {
             "var y;",
             format("var x =\n `/*a`;\n"
                    "var y;"));
+  // Unterminated string literals in a template string.
+  verifyFormat("var x = `'`;  // comment with matching quote '\n"
+               "var y;");
+  verifyFormat("var x = `\"`;  // comment with matching quote \"\n"
+               "var y;");
   // Backticks in a comment - not a template string.
   EXPECT_EQ("var x = 1  // `/*a`;\n"
             "    ;",