segfault `Rust::TyTy::VariantDef::as_string`

Nobody has claimed this yet.

auto-reduced (treereduce-rust):

//@compile-flags: -frust-incomplete-and-experimental-compiler-do-not-use -frust-crate-attr=no_core
struct Apple;

enum Delicious {
    ApplePie = Apple::PIE,
}

original:

struct Apple;

enum Delicious {
    ApplePie = Apple::PIE,
}

fn main() {}

Version information:

696cb485cfa9969c952d6765889d82ed548ca15c

Command:
/home/matthias/vcs/github/gccrs/gccrs-build/gcc/crab1 -frust-incomplete-and-experimental-compiler-do-not-use -frust-crate-attr=no_core -frust-crate-attr=feature(no_core)

Program output

/tmp/icemaker_global_tempdir.RY1PwrhEurnc/rustc_testrunner_tmpdir_reporting.9ZrSqs6EnYBu/mvce.rs:4:23: error: failed to resolve path segment using an impl Probe
    4 |     ApplePie = Apple::PIE,
      |                       ^~~
crab1: internal compiler error: Segmentation fault
0x32c0107 internal_error(char const*, ...)
	../../gcc/diagnostic-global-context.cc:787
0x1a7e17f crash_signal
	../../gcc/toplev.cc:325
0x1038837 Rust::TyTy::VariantDef::as_string[abi:cxx11]() const
	../../gcc/rust/typecheck/rust-tyty.cc:1685
0x1039140 Rust::TyTy::ADTType::as_string[abi:cxx11]() const
	../../gcc/rust/typecheck/rust-tyty.cc:1821
0x106a5b2 Rust::TyTy::VarianceAnalysis::GenericTyVisitorCtx::process_type(Rust::TyTy::ADTType&)
	../../gcc/rust/typecheck/rust-tyty-variance-analysis.cc:234
0x106aba7 Rust::TyTy::VarianceAnalysis::GenericTyPerCrateCtx::process_type(Rust::TyTy::ADTType&)
	../../gcc/rust/typecheck/rust-tyty-variance-analysis.cc:131
0x106aba7 Rust::TyTy::VarianceAnalysis::CrateCtx::add_type_constraints(Rust::TyTy::ADTType&)
	../../gcc/rust/typecheck/rust-tyty-variance-analysis.cc:26
0x10a3d6f Rust::Resolver::TypeCheckItem::visit(Rust::HIR::Enum&)
	../../gcc/rust/typecheck/rust-hir-type-check-item.cc:446
0x109749c Rust::Resolver::TypeCheckItem::Resolve(Rust::HIR::Item&)
	../../gcc/rust/typecheck/rust-hir-type-check-item.cc:60
0x1027e1b Rust::Resolver::TypeResolution::Resolve(Rust::HIR::Crate&)
	../../gcc/rust/typecheck/rust-hir-type-check.cc:72
0xec74c9 Rust::Session::compile_crate(char const*)
	../../gcc/rust/rust-session-manager.cc:804
/home/matthias/vcs/github/gccrs/gccrs-build/gcc/crab1 /tmp/icemaker_global_tempdir.RY1PwrhEurnc/rustc_testrunner_tmpdir_reporting.9ZrSqs6EnYBu/mvce.rs -o/tmp/icemaker_global_tempdir.RY1PwrhEurnc/rustc_testrunner_tmpdir_reporting.9ZrSqs6EnYBu/binaryname -frust-incomplete-and-experimental-compiler-do-not-use -frust-crate-attr=no_core -frust-crate-attr=feature(no_core)
Please submit a full bug report, with preprocessed source (by using -freport-bug).
Please include the complete backtrace with any bug report.
See <https://gcc.gnu.org/bugs/> for instructions.

Start by reproducing the crash with the reduced Rust program and the listed compiler flags. Read Rust::TyTy::VariantDef::as_string in gcc/rust/typecheck/rust-tyty.cc, then follow its callers in rust-tyty-variance-analysis.cc and rust-hir-type-check-item.cc. Done means the reproducer reports the resolution error without a segmentation fault and has regression coverage.

Written by the indexing model from the issue text.

Description

Contributor guide

First steps

Research direction

Assessment