JS output contains imports only used in types when `emitDecoratorMetadata: true`

Bug Report

🔎 Search Terms

• emitDecoratorMetadata require
• emitDecoratorMetadata import

🕗 Version & Regression Information

• This is the behavior in every version I tried, and I reviewed the FAQ for entries about 3.3.3, 4.1.3

⏯ Playground Link

Playground link with relevant code

💻 Code

import * as vscode from 'vscode';

function LogMethod(
  target: any,
  propertyKey: string | symbol,
  descriptor: PropertyDescriptor
) {
  console.log(target);
  console.log(propertyKey);
  console.log(descriptor);
}

class Demo {
  @LogMethod
  public foo(bar: vscode.Memento) {
    // do nothing
  }
}

const demo = new Demo();

🙁 Actual behavior

The output contains const vscode = __importStar(require("vscode")); when emitDecoratorMetadata: true but not when emitDecoratorMetadata: false

🙂 Expected behavior

As the type of bar as nothing to do with the compiled JS, the import of vscode should not exist regardless of the value of emitDecoratorMetadata

从链接的 TypeScript Playground 示例开始，比较启用和禁用 emitDecoratorMetadata 时生成的 JavaScript。报告没有列出 repository 文件或测试，因此需要阅读相关实现来定位编译器路径。当两个输出中都不存在 type-only 的 vscode 导入时，即表示完成。