recursive opaque type results in stack overflow #139402
Description
original:
struct FileSystem; impl FileSystem { fn build<'a>( &mut self, commands: impl Iterator<Item = &'a str> + 'a, ) -> Option<impl Iterator<Item = &'a str> + 'a> { let further_commands = self.build(commands); self.build(further_commands?) } } fn main() {}Version information
rustc 1.88.0-nightly (1e008dd5d 2025-04-05) binary: rustc commit-hash: 1e008dd5d83e782ad37fc9cf6824733f824cc8cd commit-date: 2025-04-05 host: x86_64-unknown-linux-gnu release: 1.88.0-nightly LLVM version: 20.1.2 Command:
/home/matthias/.rustup/toolchains/master/bin/rustc
Program output
error: rustc interrupted by SIGSEGV, printing backtrace /home/matthias/.rustup/toolchains/nightly-x86_64-unknown-linux-gnu/lib/librustc_driver-67dafa3979729d17.so(+0x391f4bf) [0x75640411f4bf] /usr/lib/libc.so.6(+0x3dcd0) [0x75640064bcd0] /home/matthias/.rustup/toolchains/nightly-x86_64-unknown-linux-gnu/lib/librustc_driver-67dafa3979729d17.so(+0x426cee4) [0x756404a6cee4] /home/matthias/.rustup/toolchains/nightly-x86_64-unknown-linux-gnu/lib/librustc_driver-67dafa3979729d17.so(+0x4260681) [0x756404a60681] /home/matthias/.rustup/toolchains/nightly-x86_64-unknown-linux-gnu/lib/librustc_driver-67dafa3979729d17.so(+0x426d087) [0x756404a6d087] /home/matthias/.rustup/toolchains/nightly-x86_64-unknown-linux-gnu/lib/librustc_driver-67dafa3979729d17.so(+0x4260681) [0x756404a60681] /home/matthias/.rustup/toolchains/nightly-x86_64-unknown-linux-gnu/lib/librustc_driver-67dafa3979729d17.so(+0x426d087) [0x756404a6d087] /home/matthias/.rustup/toolchains/nightly-x86_64-unknown-linux-gnu/lib/librustc_driver-67dafa3979729d17.so(+0x6b1f2cb) [0x75640731f2cb] /home/matthias/.rustup/toolchains/nightly-x86_64-unknown-linux-gnu/lib/librustc_driver-67dafa3979729d17.so(+0x653cb8b) [0x756406d3cb8b] ### cycle encountered after 9 frames with period 10 /home/matthias/.rustup/toolchains/nightly-x86_64-unknown-linux-gnu/lib/librustc_driver-67dafa3979729d17.so(+0x6807409) [0x756407007409] /home/matthias/.rustup/toolchains/nightly-x86_64-unknown-linux-gnu/lib/librustc_driver-67dafa3979729d17.so(+0x6807409) [0x756407007409] /home/matthias/.rustup/toolchains/nightly-x86_64-unknown-linux-gnu/lib/librustc_driver-67dafa3979729d17.so(+0x6807409) [0x756407007409] /home/matthias/.rustup/toolchains/nightly-x86_64-unknown-linux-gnu/lib/librustc_driver-67dafa3979729d17.so(+0x6807409) [0x756407007409] /home/matthias/.rustup/toolchains/nightly-x86_64-unknown-linux-gnu/lib/librustc_driver-67dafa3979729d17.so(+0x6807409) [0x756407007409] /home/matthias/.rustup/toolchains/nightly-x86_64-unknown-linux-gnu/lib/librustc_driver-67dafa3979729d17.so(+0x6807409) [0x756407007409] /home/matthias/.rustup/toolchains/nightly-x86_64-unknown-linux-gnu/lib/librustc_driver-67dafa3979729d17.so(+0x6807409) [0x756407007409] /home/matthias/.rustup/toolchains/nightly-x86_64-unknown-linux-gnu/lib/librustc_driver-67dafa3979729d17.so(+0x6807409) [0x756407007409] /home/matthias/.rustup/toolchains/nightly-x86_64-unknown-linux-gnu/lib/librustc_driver-67dafa3979729d17.so(+0x6807409) [0x756407007409] /home/matthias/.rustup/toolchains/nightly-x86_64-unknown-linux-gnu/lib/librustc_driver-67dafa3979729d17.so(+0x6807409) [0x756407007409] ### recursed 24 times /home/matthias/.rustup/toolchains/nightly-x86_64-unknown-linux-gnu/lib/librustc_driver-67dafa3979729d17.so(+0x6807409) [0x756407007409] /home/matthias/.rustup/toolchains/nightly-x86_64-unknown-linux-gnu/lib/librustc_driver-67dafa3979729d17.so(+0x6807409) [0x756407007409] /home/matthias/.rustup/toolchains/nightly-x86_64-unknown-linux-gnu/lib/librustc_driver-67dafa3979729d17.so(+0x6807409) [0x756407007409] /home/matthias/.rustup/toolchains/nightly-x86_64-unknown-linux-gnu/lib/librustc_driver-67dafa3979729d17.so(+0x6807409) [0x756407007409] /home/matthias/.rustup/toolchains/nightly-x86_64-unknown-linux-gnu/lib/librustc_driver-67dafa3979729d17.so(+0x6807409) [0x756407007409] /home/matthias/.rustup/toolchains/nightly-x86_64-unknown-linux-gnu/lib/librustc_driver-67dafa3979729d17.so(+0x6807409) [0x756407007409] /home/matthias/.rustup/toolchains/nightly-x86_64-unknown-linux-gnu/lib/librustc_driver-67dafa3979729d17.so(+0x6807409) [0x756407007409] note: rustc unexpectedly overflowed its stack! this is a bug note: maximum backtrace depth reached, frames may have been lost note: we would appreciate a report at https://github.com/rust-lang/rust help: you can increase rustc's stack size by setting RUST_MIN_STACK=16777216 note: backtrace dumped due to SIGSEGV! resuming signal [1] 2393986 segmentation fault rustc a.rs