Code
struct C;
struct S<T>(Option<T>);
trait Tr {
type Out;
}
impl<T> Clone for S<C>
where
S<T>: Tr<Out = T>,
{
fn clone(&self) -> Self {
*self
}
}
fn main() {}A mutant of tests/ui/associated-types/issue-25700-1.rs
Meta
rustc --version --verbose:
rustc 1.93.0-nightly (c90bcb957 2025-11-06)
binary: rustc
commit-hash: c90bcb9571b7aab0d8beaa2ce8a998ffaf079d38
commit-date: 2025-11-06
host: x86_64-apple-darwin
release: 1.93.0-nightly
LLVM version: 21.1.3
Error output
Command: rustc
error[E0207]: the type parameter `T` is not constrained by the impl trait, self type, or predicates
--> 08.rs:9:6
|
9 | impl<T> Clone for S<C>
| ^ unconstrained type parameter
thread 'rustc' (6161155) panicked at compiler/rustc_borrowck/src/diagnostics/conflict_errors.rs:1353:27:
internal error: entered unreachable code
Backtrace
thread 'rustc' (6161155) panicked at compiler/rustc_borrowck/src/diagnostics/conflict_errors.rs:1353:27:
internal error: entered unreachable code
stack backtrace:
0: __rustc::rust_begin_unwind
1: core::panicking::panic_fmt
2: core::panicking::panic
3: <rustc_borrowck::MirBorrowckCtxt>::suggest_cloning
4: <rustc_borrowck::MirBorrowckCtxt>::report
5: <rustc_borrowck::MirBorrowckCtxt>::report_move_errors
6: rustc_borrowck::borrowck_check_region_constraints
7: <rustc_borrowck::root_cx::BorrowCheckRootCtxt>::do_mir_borrowck
8: rustc_borrowck::mir_borrowck
[... omitted 1 frame ...]
9: <rustc_middle::ty::context::TyCtxt>::par_hir_body_owners::<rustc_interface::passes::run_required_analyses::{closure#1}::{closure#0}>::{closure#0}
10: rustc_interface::passes::analysis
[... omitted 1 frame ...]
11: rustc_interface::passes::create_and_enter_global_ctxt::<core::option::Option<rustc_interface::queries::Linker>, rustc_driver_impl::run_compiler::{closure#0}::{closure#2}>
12: rustc_interface::interface::run_compiler::<(), rustc_driver_impl::run_compiler::{closure#0}>::{closure#1}
note: Some details are omitted, run with `RUST_BACKTRACE=full` for a verbose backtrace.
error: the compiler unexpectedly panicked. this is a bug.
note: we would appreciate a bug report: https://github.com/rust-lang/rust/issues/new?labels=C-bug%2C+I-ICE%2C+T-compiler&template=ice.md
note: please make sure that you have updated to the latest nightly
note: please attach the file at `/Users/jb/Library/CloudStorage/Dropbox/Desk/2503_rustc_ice/20251106 ice 보고용/rustc-ice-2025-11-07T05_57_22-5613.txt` to your bug report
query stack during panic:
#0 [mir_borrowck] borrow-checking `<impl at 08.rs:9:1: 11:23>::clone`
#1 [analysis] running analysis passes on crate `08`
end of query stack
error: aborting due to 1 previous error
For more information about this error, try `rustc --explain E0207`.
Notes
Code
A mutant of
tests/ui/associated-types/issue-25700-1.rsMeta
rustc --version --verbose:Error output
Command:
rustcBacktrace
Notes
ICE location:
compiler/rustc_borrowck/src/diagnostics/conflict_errors.rs Line-1353rust/compiler/rustc_borrowck/src/diagnostics/conflict_errors.rs
Lines 1346 to 1358 in c90bcb9
Duplication Check