Running simple TypeScript crashes Deno

[garethj2]

Version: Deno 2.1.5

I upgraded to Deno 2.1.5 and found the Deno process immediately crashes when running my TypeScript. I've boiled down the code to a reproducible test case here.

Here's the resultant error...

./run.sh: line 2: 61461 Trace/BPT trap: 5       deno run ./core/src/main.ts

System

• Macbook Pro M2
• 16 GB of RAM
• macOS Sequoia

Considering the code is so very minor, I find this extremely worrying that it completely crashes the process outright.

[0f-0b]

This might be the same bug as #25192.

[nathanwhit]

Confirmed this is a bug in SWC, likely the same as #27399

Running with a debug build yields:

thread 'tokio-runtime-worker' panicked at /home/.cargo/registry/src/index.crates.io-6f17d22bba15001f/swc_ecma_visit-0.104.8/src/lib.rs:552:9:
internal error: entered unreachable code: This visitor does not support TypeScript. This method fails for optimization purposes. Encountered in unreachable visitor: visit_mut_ts_type
note: run with `RUST_BACKTRACE=1` environment variable to display a backtrace

[rracariu]

Managed to reduce this and looks that the cause is this line:

constructor(test: unknown) {
    this.#test = test as string; // <- this cast is what causes the crash :(
}

Removing the cast or using the string type directly will allow this to function correctly.