Template literal ending with label-like pattern (e.g., `a:`) breaks syntax highlighting

[ThanhNguyxn]

Summary

Template literal content ending with a pattern that looks like a JavaScript label (e.g., `a:`) breaks syntax highlighting for subsequent code.

This bug was reported in vscode#282423 and affects both JavaScript and TypeScript grammars.

Reproduction

var a = (
  {
    b: function () { return `:` } // ✅ Normal
  }
);

var b = (
  {
    b: function () { return `:a` } // ✅ Normal
  }
);

var c = (
  {
    b: function () { return `::` } // ✅ Normal
  }
);

var d = (
  {
    b: function () { return ` :` } // ✅ Normal
  }
);

var e = (
  {
    b: function () { return `a:` } // ❌ BUG - breaks highlighting
  }
);

console.log("syntax highlighter has error"); // This line is incorrectly highlighted

Expected Behavior

All template literals should highlight correctly, and subsequent code should not be affected.

Actual Behavior

When the template literal ends with a colon preceded by an identifier (matching the label pattern identifier:), subsequent code loses correct tokenization.

Analysis

The pattern a: inside the template literal appears to match the label rule:

{
  "match": "([_$[:alpha:]][_$[:alnum:]]*)\\s*(:)",
  "captures": {
    "1": { "name": "entity.name.label.js" },
    "2": { "name": "punctuation.separator.label.js" }
  }
}

The patterns that work don't match this regex:

• `:` - No identifier before colon
• `:a` - Colon comes first
• `::` - No identifier before first colon
• ` :` - Space breaks the pattern

Environment

• VS Code: 1.106.3
• OS: Windows/macOS
• Occurs with all extensions disabled

[RedCMD]

Issue caused by variable assignment var a = (
unrelated to any template strings
notice that function and return are not highlighted correctly in all lines

see that adding any non-whitespace character after the opening bracket fixes it
var a = ( // coment