Skip to content

ICE: cycle detected when computing function signature of #125512

Closed
@matthiaskrgr

Description

@matthiaskrgr
Member

auto-reduced (treereduce-rust):

#![feature(object_safe_for_dispatch)]
trait B {
    fn f(a: A) -> A;
}
trait A {
    fn concrete(b: B) -> B;
}
fn main() {}

original:

#![feature(object_safe_for_dispatch)]
trait B { fn f(a: A) -> A; }
trait A { fn concrete(b: B) -> B; }
fn main() {}

Version information

rustc 1.80.0-nightly (9e297bf54 2024-05-24)
binary: rustc
commit-hash: 9e297bf54d31eb3b30067208ff9af4416945a2ed
commit-date: 2024-05-24
host: x86_64-unknown-linux-gnu
release: 1.80.0-nightly
LLVM version: 18.1.6

Command:
/home/matthias/.rustup/toolchains/master/bin/rustc -Zunstable-options --edition=2024

Program output

warning: trait `B` is never used
 --> /tmp/icemaker_global_tempdir.Y2ZB7VqiZYxB/rustc_testrunner_tmpdir_reporting.n6c2niMcV32C/mvce.rs:2:7
  |
2 | trait B {
  |       ^
  |
  = note: `#[warn(dead_code)]` on by default

warning: trait `A` is never used
 --> /tmp/icemaker_global_tempdir.Y2ZB7VqiZYxB/rustc_testrunner_tmpdir_reporting.n6c2niMcV32C/mvce.rs:5:7
  |
5 | trait A {
  |       ^

warning: 2 warnings emitted

note: no errors encountered even though delayed bugs were created

note: those delayed bugs will now be shown as internal compiler errors

error: internal compiler error[E0391]: cycle detected when computing function signature of `B::f`
 --> /tmp/icemaker_global_tempdir.Y2ZB7VqiZYxB/rustc_testrunner_tmpdir_reporting.n6c2niMcV32C/mvce.rs:3:5
  |
3 |     fn f(a: A) -> A;
  |     ^^^^^^^^^^^^^^^^
  |
note: ...which requires checking if trait `A` is object safe...
 --> /tmp/icemaker_global_tempdir.Y2ZB7VqiZYxB/rustc_testrunner_tmpdir_reporting.n6c2niMcV32C/mvce.rs:5:1
  |
5 | trait A {
  | ^^^^^^^
note: ...which requires determining object safety of trait `A`...
 --> /tmp/icemaker_global_tempdir.Y2ZB7VqiZYxB/rustc_testrunner_tmpdir_reporting.n6c2niMcV32C/mvce.rs:5:1
  |
5 | trait A {
  | ^^^^^^^
note: ...which requires computing function signature of `A::concrete`...
 --> /tmp/icemaker_global_tempdir.Y2ZB7VqiZYxB/rustc_testrunner_tmpdir_reporting.n6c2niMcV32C/mvce.rs:6:5
  |
6 |     fn concrete(b: B) -> B;
  |     ^^^^^^^^^^^^^^^^^^^^^^^
note: ...which requires checking if trait `B` is object safe...
 --> /tmp/icemaker_global_tempdir.Y2ZB7VqiZYxB/rustc_testrunner_tmpdir_reporting.n6c2niMcV32C/mvce.rs:2:1
  |
2 | trait B {
  | ^^^^^^^
note: ...which requires determining object safety of trait `B`...
 --> /tmp/icemaker_global_tempdir.Y2ZB7VqiZYxB/rustc_testrunner_tmpdir_reporting.n6c2niMcV32C/mvce.rs:2:1
  |
2 | trait B {
  | ^^^^^^^
  = note: ...which again requires computing function signature of `B::f`, completing the cycle
note: cycle used when checking that `B` is well-formed
 --> /tmp/icemaker_global_tempdir.Y2ZB7VqiZYxB/rustc_testrunner_tmpdir_reporting.n6c2niMcV32C/mvce.rs:2:1
  |
2 | trait B {
  | ^^^^^^^
  = note: see https://rustc-dev-guide.rust-lang.org/overview.html#queries and https://rustc-dev-guide.rust-lang.org/query.html for more information
note: delayed at compiler/rustc_query_system/src/query/job.rs:597:16 - disabled backtrace
 --> /tmp/icemaker_global_tempdir.Y2ZB7VqiZYxB/rustc_testrunner_tmpdir_reporting.n6c2niMcV32C/mvce.rs:3:5
  |
3 |     fn f(a: A) -> A;
  |     ^^^^^^^^^^^^^^^^

error: internal compiler error[E0782]: trait objects must include the `dyn` keyword
 --> /tmp/icemaker_global_tempdir.Y2ZB7VqiZYxB/rustc_testrunner_tmpdir_reporting.n6c2niMcV32C/mvce.rs:6:20
  |
6 |     fn concrete(b: B) -> B;
  |                    ^
  |
  = note: `B` it is not object safe, so it can't be `dyn`
note: delayed at compiler/rustc_hir_analysis/src/hir_ty_lowering/lint.rs:63:17 - disabled backtrace
 --> /tmp/icemaker_global_tempdir.Y2ZB7VqiZYxB/rustc_testrunner_tmpdir_reporting.n6c2niMcV32C/mvce.rs:6:20
  |
6 |     fn concrete(b: B) -> B;
  |                    ^
help: use a new generic type parameter, constrained by `B`
  |
6 |     fn concrete<T: B>(b: T) -> B;
  |                ++++++    ~
help: you can also use an opaque type, but users won't be able to specify the type parameter when calling the `fn`, having to rely exclusively on type inference
  |
6 |     fn concrete(b: impl B) -> B;
  |                    ++++

error: internal compiler error[E0782]: trait objects must include the `dyn` keyword
 --> /tmp/icemaker_global_tempdir.Y2ZB7VqiZYxB/rustc_testrunner_tmpdir_reporting.n6c2niMcV32C/mvce.rs:6:26
  |
6 |     fn concrete(b: B) -> B;
  |                          ^
  |
note: delayed at compiler/rustc_hir_analysis/src/hir_ty_lowering/lint.rs:63:17 - disabled backtrace
 --> /tmp/icemaker_global_tempdir.Y2ZB7VqiZYxB/rustc_testrunner_tmpdir_reporting.n6c2niMcV32C/mvce.rs:6:26
  |
6 |     fn concrete(b: B) -> B;
  |                          ^
help: `B` is not object safe, use `impl B` to return an opaque type, as long as you return a single underlying type
  |
6 |     fn concrete(b: B) -> impl B;
  |                          ++++

error: internal compiler error[E0782]: trait objects must include the `dyn` keyword
 --> /tmp/icemaker_global_tempdir.Y2ZB7VqiZYxB/rustc_testrunner_tmpdir_reporting.n6c2niMcV32C/mvce.rs:3:13
  |
3 |     fn f(a: A) -> A;
  |             ^
  |
  = note: `A` it is not object safe, so it can't be `dyn`
note: delayed at compiler/rustc_hir_analysis/src/hir_ty_lowering/lint.rs:63:17 - disabled backtrace
 --> /tmp/icemaker_global_tempdir.Y2ZB7VqiZYxB/rustc_testrunner_tmpdir_reporting.n6c2niMcV32C/mvce.rs:3:13
  |
3 |     fn f(a: A) -> A;
  |             ^
help: use a new generic type parameter, constrained by `A`
  |
3 |     fn f<T: A>(a: T) -> A;
  |         ++++++    ~
help: you can also use an opaque type, but users won't be able to specify the type parameter when calling the `fn`, having to rely exclusively on type inference
  |
3 |     fn f(a: impl A) -> A;
  |             ++++

error: internal compiler error[E0782]: trait objects must include the `dyn` keyword
 --> /tmp/icemaker_global_tempdir.Y2ZB7VqiZYxB/rustc_testrunner_tmpdir_reporting.n6c2niMcV32C/mvce.rs:3:19
  |
3 |     fn f(a: A) -> A;
  |                   ^
  |
note: delayed at compiler/rustc_hir_analysis/src/hir_ty_lowering/lint.rs:63:17 - disabled backtrace
 --> /tmp/icemaker_global_tempdir.Y2ZB7VqiZYxB/rustc_testrunner_tmpdir_reporting.n6c2niMcV32C/mvce.rs:3:19
  |
3 |     fn f(a: A) -> A;
  |                   ^
help: `A` is not object safe, use `impl A` to return an opaque type, as long as you return a single underlying type
  |
3 |     fn f(a: A) -> impl A;
  |                   ++++

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: rustc 1.80.0-nightly (9e297bf54 2024-05-24) running on x86_64-unknown-linux-gnu

note: compiler flags: -Z unstable-options -Z dump-mir-dir=dir

query stack during panic:
end of query stack

@rustbot label +F-object_safe_for_dispatch

Activity

added
I-ICEIssue: The compiler panicked, giving an Internal Compilation Error (ICE) ❄️
T-compilerRelevant to the compiler team, which will review and decide on the PR/issue.
C-bugCategory: This is a bug.
on May 24, 2024
added
needs-triageThis issue may need triage. Remove it if it has been sufficiently triaged.
F-dyn_compatible_for_dispatch`#![feature(dyn_compatible_for_dispatch)]`; formerly `object_safe_for_dispatch`
on May 24, 2024
added
A-HIRArea: The high-level intermediate representation (HIR)
S-has-mcveStatus: A Minimal Complete and Verifiable Example has been found for this issue
and removed
needs-triageThis issue may need triage. Remove it if it has been sufficiently triaged.
on Jun 4, 2024
added
S-bug-has-testStatus: This bug is tracked inside the repo by a `known-bug` test.
on Jun 8, 2024
added 3 commits that reference this issue on Oct 12, 2024

Rollup merge of rust-lang#131239 - VulnBandit:trait-vulnerability, r=…

cb64e28

Rollup merge of rust-lang#131239 - VulnBandit:trait-vulnerability, r=…

5ce78bf

Rollup merge of rust-lang#131239 - VulnBandit:trait-vulnerability, r=…

663da00
added a commit that references this issue on Oct 13, 2024
Sign up for free to join this conversation on GitHub. Already have an account? Sign in to comment

Metadata

Metadata

Assignees

No one assigned

    Labels

    A-HIRArea: The high-level intermediate representation (HIR)C-bugCategory: This is a bug.F-dyn_compatible_for_dispatch`#![feature(dyn_compatible_for_dispatch)]`; formerly `object_safe_for_dispatch`I-ICEIssue: The compiler panicked, giving an Internal Compilation Error (ICE) ❄️S-bug-has-testStatus: This bug is tracked inside the repo by a `known-bug` test.S-has-mcveStatus: A Minimal Complete and Verifiable Example has been found for this issueT-compilerRelevant to the compiler team, which will review and decide on the PR/issue.

    Type

    No type

    Projects

    No projects

    Milestone

    No milestone

    Relationships

    None yet

      Development

      Participants

      @matthiaskrgr@jieyouxu@rustbot

      Issue actions

        ICE: `cycle detected when computing function signature of` · Issue #125512 · rust-lang/rust