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

Inizia dall’esempio collegato di TypeScript Playground e confronta il JavaScript generato con emitDecoratorMetadata abilitato e disabilitato. Il report non indica file o test del repository, quindi per individuare il percorso del compilatore sarà necessario leggere l’implementazione pertinente. Il lavoro è completato quando l’importazione type-only di vscode è assente in entrambi gli output.