TypeScript - incorrect highlighting when a new line is added

Does this issue occur when all extensions are disabled?: Yes

• VS Code Version: 1.63.2
• OS Version: Windows_NT x64 6.3.9600

Steps to Reproduce:

1. Paste the code below to the VS Code

type testType = {
  on<Key extends string>
  (eventName: `${Key}Changed`): void;
}

let a = 1;

The result is, that the "let" keyword is highlighted incorrectly. Same happens with any other keyword (const, function, etc.):

After removing the new line between the second and the third line, everything works correctly. The content of the third line doesn't matter; there could be only parentheses as well.

使用提供的 TypeScript 代码片段，在 VS Code 1.63.2 或等效环境中重现该报告，首先确认空行导致的高亮变化。然后跟踪此存储库中的 TypeScript TextMate 语法文件，找到处理泛型类型和后续声明的规则。当 let、const 和 function 等关键字在有空行和没有空行的情况下都能正确高亮时，即表示完成。