Error on empty code block

[mlund]

Update: The error can be reproduced by simply an empty code block, {}.

This code

use ufmt_stdio::*;
d_println!("this is shown only in Debug mode")

causes a compilation error (or crash?) if in Release mode. I also tried variants where code inside the println macro is disabled by a const variable or a feature flag, and I get the same error. It seems to be a problem when the macro is empty.

The errors look like this:

error: could not compile `eleven`; 2 warnings emitted

Caused by:
  process didn't exit successfully: `rustc --crate-name eleven --edition=2021 src/main.rs --error-format=json --json=diagnostic-rendered-ansi,artifacts,future-incompat --crate-type bin --emit=dep-info,link -C opt-level=s -C lto -C debuginfo=2 -C metadata=e63cb991ca2c34bc -C extra-filename=-e63cb991ca2c34bc --out-dir /workspaces/eleven/target/mos-mega65-none/release/deps --target mos-mega65-none -L dependency=/workspaces/eleven/target/mos-mega65-none/release/deps -L dependency=/workspaces/eleven/target/release/deps --extern 'noprelude:alloc=/workspaces/eleven/target/mos-mega65-none/release/deps/liballoc-d34ff214b6311af9.rlib' --extern 'noprelude:compiler_builtins=/workspaces/eleven/target/mos-mega65-none/release/deps/libcompiler_builtins-0e401619b0b3b909.rlib' --extern 'noprelude:core=/workspaces/eleven/target/mos-mega65-none/release/deps/libcore-e05457835ecac2ad.rlib' --extern eleven=/workspaces/eleven/target/mos-mega65-none/release/deps/libeleven-7528eecb988352d1.rlib --extern mos_alloc=/workspaces/eleven/target/mos-mega65-none/release/deps/libmos_alloc-490e59d66c4016cc.rlib --extern mos_hardware=/workspaces/eleven/target/mos-mega65-none/release/deps/libmos_hardware-5f164b1d74cf65da.rlib --extern rand=/workspaces/eleven/target/mos-mega65-none/release/deps/librand-33b4498fcc9f23f0.rlib --extern ufmt_stdio=/workspaces/eleven/target/mos-mega65-none/release/deps/libufmt_stdio-18e7fdf3e5dfc5ae.rlib -Z unstable-options -L native=/workspaces/eleven/target/mos-mega65-none/release/build/mos-hardware-f2f66bdf1ef951b3/out -L native=/workspaces/eleven/target/mos-mega65-none/release/build/mos-hardware-f2f66bdf1ef951b3/out` (signal: 11, SIGSEGV: invalid memory reference)

Meta

I'm using the mrkits/rust-mos:latest docker image.

rustc --version --verbose:

rustc 1.66.0-dev
binary: rustc
commit-hash: unknown
commit-date: unknown
host: aarch64-unknown-linux-gnu
release: 1.66.0-dev
LLVM version: 16.0.0