clang-format: [JS] Properly set scopes inside template strings.

Before:
  var f = `aaaaaaaaaaaaa:${aaaaaaa
              .aaaaa} aaaaaaaa
           aaaaaaaaaaaaa:${aaaaaaa.aaaaa} aaaaaaaa`;

After:
  var f = `aaaaaaaaaaaaa:${aaaaaaa.aaaaa} aaaaaaaa
           aaaaaaaaaaaaa:${aaaaaaa.aaaaa} aaaaaaaa`;

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@293622 91177308-0d34-0410-b5e6-96231b3b80d8

Author: djasper-gh

lib/Format/FormatToken.h

@@ -337,11 +337,15 @@ struct FormatToken {
 
   /// \brief Returns whether \p Tok is ([{ or a template opening <.
   bool opensScope() const {
+    if (is(TT_TemplateString) && TokenText.endswith("${"))
+      return true;
     return isOneOf(tok::l_paren, tok::l_brace, tok::l_square,
                    TT_TemplateOpener);
   }
   /// \brief Returns whether \p Tok is )]} or a template closing >.
   bool closesScope() const {
+    if (is(TT_TemplateString) && TokenText.startswith("}"))
+      return true;
     return isOneOf(tok::r_paren, tok::r_brace, tok::r_square,
                    TT_TemplateCloser);
   }

lib/Format/TokenAnnotator.cpp

@@ -1454,7 +1454,9 @@ class ExpressionParser {
 
       // Consume scopes: (), [], <> and {}
       if (Current->opensScope()) {
-        while (Current && !Current->closesScope()) {
+        // In fragment of a JavaScript template string can look like '}..${' and
+        // thus close a scope and open a new one at the same time.
+        while (Current && (!Current->closesScope() || Current->opensScope())) {
           next();
           parse();
         }

unittests/Format/FormatTestJS.cpp

@@ -1392,6 +1392,13 @@ TEST_F(FormatTestJS, TemplateStrings) {
   // The token stream can contain two string_literals in sequence, but that
   // doesn't mean that they are implicitly concatenated in JavaScript.
   verifyFormat("var f = `aaaa ${a ? 'a' : 'b'}`;");
+
+  // Ensure that scopes are appropriately set around evaluated expressions in
+  // template strings.
+  verifyFormat("var f = `aaaaaaaaaaaaa:${aaaaaaa.aaaaa} aaaaaaaa\n"
+               "         aaaaaaaaaaaaa:${aaaaaaa.aaaaa} aaaaaaaa`;",
+               "var f = `aaaaaaaaaaaaa:${aaaaaaa.  aaaaa} aaaaaaaa\n"
+               "         aaaaaaaaaaaaa:${  aaaaaaa. aaaaa} aaaaaaaa`;");
 }
 
 TEST_F(FormatTestJS, TemplateStringASI) {