Build hangs forever (SWC infinite loop) when a locally-derived JSX component is combined with a member-expression styled-jsx interpolation

Link to the code that reproduces this issue

https://github.com/hivapazira/next-swc-styled-jsx-hang-repro

To Reproduce

1. Create a Pages Router app containing this single page:

// pages/index.tsx
const Probe = (props: { theme: { color: string; icon: any } }) => {
  const t = props.theme;
  const Icon = t.icon;
  return (
    <div className="probe">
      <Icon />
      <style jsx>{`
        .probe {
          color: ${t.color};
        }
      `}</style>
    </div>
  );
};

export default function Home() {
  return <Probe theme={{ color: '#f00', icon: 'div' }} />;
}

2. Run next build (or next dev and request the page).
3. The build prints Creating an optimized production build ... and never finishes — a next-swc thread spins at full CPU indefinitely (left for 15+ minutes; no output, no error, low/stable RSS).

Current vs. Expected behavior

• Current: compilation never completes and never errors. next build (Turbopack), next build --webpack, and next dev all hang the same way, so it appears to be in the shared SWC styled-jsx transform, not a bundler. A macOS sample of the spinning process shows the loop inside next-swc.darwin-arm64.node.
• Expected: the page compiles (it does on Next 13.4.4), or at minimum the compiler fails with an error.

Provide environment information

Operating System:
  Platform: darwin
  Arch: arm64
  Version: Darwin Kernel Version 25.6.0: Fri Jul 31 19:18:29 PDT 2026; root:xnu-12377.161.14~5/RELEASE_ARM64_T8122
  Available memory (MB): 16384
  Available CPU cores: 8
Binaries:
  Node: 24.19.0
  npm: 11.17.0
  Yarn: 1.22.22
  pnpm: N/A
Relevant Packages:
  next: 16.4.0-canary.0 // Latest available version is detected (16.4.0-canary.0).
  eslint-config-next: N/A
  react: 18.3.1
  react-dom: 18.3.1
  typescript: 5.9.3
Next.js Config:
  output: N/A

Which area(s) are affected? (Select all that apply)

SWC

Which stage(s) are affected? (Select all that apply)

next build (local), next dev (local)

Additional context

No response

Clone the linked next-swc-styled-jsx-hang-repro and run next build, then compare with next dev and next build --webpack. Trace the shared SWC styled-jsx transform implicated by the issue and use pages/index.tsx as the minimal input. Done means the page compiles, or the compiler exits with an error instead of hanging indefinitely.