const enum not inlined

[magicdawn]

Describe the bug

src/demo.ts

const enum Prop {
  Display = 1,
  Isolation,
  Position,
}
console.log(Prop.Display)

tsdown@^0.9.8

tsdown.config.ts

import { defineConfig } from 'tsdown'

export default defineConfig({
  entry: ['./src/demo.ts'],
  outDir: 'dist',
  format: 'esm',
  target: 'node16',
  clean: true,
  dts: true,
  minify: true,
  noExternal: ['es-toolkit'],
})

Reproduction

see the GIF

System Info

System:
    OS: macOS 15.4.1
    CPU: (10) arm64 Apple M2 Pro
    Memory: 99.69 MB / 16.00 GB
    Shell: 5.9 - /bin/zsh
  Binaries:
    Node: 22.14.0 - ~/.local/state/fnm_multishells/86831_1745648882839/bin/node
    Yarn: 1.22.22 - ~/Library/pnpm/yarn
    npm: 10.9.2 - ~/.local/state/fnm_multishells/86831_1745648882839/bin/npm
    pnpm: 10.8.0 - ~/Library/pnpm/pnpm
    bun: 1.2.10 - /opt/homebrew/bin/bun
  Browsers:
    Brave Browser: 133.1.75.180
    Chrome: 135.0.7049.115
    Edge: 135.0.3179.98
    Safari: 18.4

Used Package Manager

pnpm

Validations

• Follow our Code of Conduct
• Read the Contributing Guide.
• Check that there isn't already an issue that reports the same bug to avoid creating a duplicate.
• Check that this is a concrete bug. For Q&A, please open a GitHub Discussion instead.
• The provided reproduction is a minimal reproducible of the bug.

[sxzz]

Upstream: rolldown/rolldown#4342 oxc-project/oxc#6073