Decorator design:type for union types

[hcesar]

Describe the bug
When you have a union type on a decorated property the design:type is set to void 0.
TSC would set the type to Object instead.

Input code

class Xpto {
  @Decorator()
  prop!: string | number;
}

function Decorator() {
  return function (...args) {};
}

Config

{
  "module": {
    "type": "commonjs"
  },
  "jsc": {
    "target": "es2018",
    "parser": {
      "syntax": "typescript",
      "decorators": true,
      "dynamicImport": false
    },
    "transform": {
      "legacyDecorator": false,
      "decoratorMetadata": true
    }
  }
}

Current behavior

TSC:

__decorate([
    Decorator(),
   __metadata("design:type", Object)
], Xpto.prototype, "prop", void 0);

SWC:

Reflect.metadata("design:type", void 0)

Expected behavior
SWC:

Reflect.metadata("design:type", Object)

[swc-bot]

This closed issue has been automatically locked because it had no new activity for a month. If you are running into a similar issue, please create a new issue with the steps to reproduce. Thank you.