ICE with `clippy::undocumented_unsafe_blocks`

[calebzulawski]

Code

I couldn't figure out how to reduce this (simple examples pass), but this occurs when running clippy on Portable SIMD (https://github.com/rust-lang/portable-simd, check out the feature/safety branch) after enabling this lint. I'm pretty sure it has something to do with macros.

Meta

Rust version (rustc -Vv):

cargo 1.58.0-nightly (94ca096af 2021-10-29)
release: 1.58.0
commit-hash: 94ca096afbf25f670e76e07dca754fcfe27134be
commit-date: 2021-10-29
host: x86_64-unknown-linux-gnu
libgit2: 1.3.0 (sys:0.13.23 vendored)
libcurl: 7.79.1-DEV (sys:0.4.49+curl-7.79.1 vendored ssl:OpenSSL/1.1.1l)
os: Ubuntu 20.04 (focal) [64-bit]

Clippy version from master: clippy 0.1.58 (84a4ab7f3 2021-11-04)

Error output

thread 'rustc' panicked at 'assertion failed: self.start_pos.to_u32() + total_extra_bytes <= bpos.to_u32()', compiler/rustc_span/src/lib.rs:1682:9
note: run with `RUST_BACKTRACE=1` environment variable to display a backtrace

error: internal compiler error: unexpected panic

note: the compiler unexpectedly panicked. this is a bug.

note: we would appreciate a bug report: https://github.com/rust-lang/rust-clippy/issues/new

note: Clippy version: clippy 0.1.58 (84a4ab7f3 2021-11-04)

query stack during panic:
#0 [analysis] running analysis passes on this crate
end of query stack
error: could not compile `core_simd`

Backtrace

thread 'rustc' panicked at 'assertion failed: self.start_pos.to_u32() + total_extra_bytes <= bpos.to_u32()', compiler/rustc_span/src/lib.rs:1682:9
stack backtrace:
 0: rust_begin_unwind
           at /rustc/baba6687df3e83fdb15cc6ec239b4a1c75a30505/library/std/src/panicking.rs:498:5
 1: core::panicking::panic_fmt
           at /rustc/baba6687df3e83fdb15cc6ec239b4a1c75a30505/library/core/src/panicking.rs:106:14
 2: core::panicking::panic
           at /rustc/baba6687df3e83fdb15cc6ec239b4a1c75a30505/library/core/src/panicking.rs:47:5
 3: <rustc_span::SourceFile>::lookup_file_pos_with_col_display
 4: clippy_lints::undocumented_unsafe_blocks::UndocumentedUnsafeBlocks::block_has_safety_comment
           at /home/caleb/rust-clippy/clippy_lints/src/undocumented_unsafe_blocks.rs:173:48
 5: <clippy_lints::undocumented_unsafe_blocks::UndocumentedUnsafeBlocks as rustc_lint::passes::LateLintPass>::check_block
           at /home/caleb/rust-clippy/clippy_lints/src/undocumented_unsafe_blocks.rs:70:16
 6: <rustc_lint::late::LateLintPassObjects as rustc_lint::passes::LateLintPass>::check_block
 7: <rustc_lint::late::LateContextAndPass<rustc_lint::late::LateLintPassObjects> as rustc_hir::intravisit::Visitor>::visit_block
 8: <rustc_lint::late::LateContextAndPass<rustc_lint::late::LateLintPassObjects> as rustc_hir::intravisit::Visitor>::visit_expr
 9: <rustc_lint::late::LateContextAndPass<rustc_lint::late::LateLintPassObjects> as rustc_hir::intravisit::Visitor>::visit_block
10: <rustc_lint::late::LateContextAndPass<rustc_lint::late::LateLintPassObjects> as rustc_hir::intravisit::Visitor>::visit_expr
11: <rustc_lint::late::LateContextAndPass<rustc_lint::late::LateLintPassObjects> as rustc_hir::intravisit::Visitor>::visit_nested_body
12: <rustc_lint::late::LateContextAndPass<rustc_lint::late::LateLintPassObjects> as rustc_hir::intravisit::Visitor>::visit_fn
13: rustc_hir::intravisit::walk_impl_item::<rustc_lint::late::LateContextAndPass<rustc_lint::late::LateLintPassObjects>>
14: <rustc_lint::late::LateContextAndPass<rustc_lint::late::LateLintPassObjects> as rustc_hir::intravisit::Visitor>::visit_nested_impl_item
15: rustc_hir::intravisit::walk_impl_item_ref::<rustc_lint::late::LateContextAndPass<rustc_lint::late::LateLintPassObjects>>
16: rustc_hir::intravisit::walk_item::<rustc_lint::late::LateContextAndPass<rustc_lint::late::LateLintPassObjects>>
17: <rustc_lint::late::LateContextAndPass<rustc_lint::late::LateLintPassObjects> as rustc_hir::intravisit::Visitor>::visit_nested_item
18: rustc_hir::intravisit::walk_mod::<rustc_lint::late::LateContextAndPass<rustc_lint::late::LateLintPassObjects>>
19: <rustc_lint::late::LateContextAndPass<rustc_lint::late::LateLintPassObjects> as rustc_hir::intravisit::Visitor>::visit_mod
20: <rustc_lint::late::LateContextAndPass<rustc_lint::late::LateLintPassObjects> as rustc_hir::intravisit::Visitor>::visit_nested_item
21: rustc_hir::intravisit::walk_mod::<rustc_lint::late::LateContextAndPass<rustc_lint::late::LateLintPassObjects>>
22: <rustc_lint::late::LateContextAndPass<rustc_lint::late::LateLintPassObjects> as rustc_hir::intravisit::Visitor>::visit_mod
23: <rustc_lint::late::LateContextAndPass<rustc_lint::late::LateLintPassObjects> as rustc_hir::intravisit::Visitor>::visit_nested_item
24: rustc_hir::intravisit::walk_mod::<rustc_lint::late::LateContextAndPass<rustc_lint::late::LateLintPassObjects>>
25: <rustc_lint::late::LateContextAndPass<rustc_lint::late::LateLintPassObjects> as rustc_hir::intravisit::Visitor>::visit_mod
26: <rustc_middle::hir::map::Map>::walk_toplevel_module::<rustc_lint::late::LateContextAndPass<rustc_lint::late::LateLintPassObjects>>
27: rustc_lint::late::late_lint_pass_crate::<rustc_lint::late::LateLintPassObjects>
28: <rustc_session::session::Session>::time::<(), rustc_lint::late::check_crate<rustc_lint::BuiltinCombinedLateLintPass, rustc_interface::passes::analysis::{closure#5}::{closure#0}::{closure#3}::{closure#0}::{closure#0}>::{closure#0}::{closure#0}>
29: <rustc_session::session::Session>::time::<(), rustc_interface::passes::analysis::{closure#5}::{closure#0}::{closure#3}::{closure#0}>
30: <core::panic::unwind_safe::AssertUnwindSafe<rustc_interface::passes::analysis::{closure#5}::{closure#0}> as core::ops::function::FnOnce<()>>::call_once
31: <rustc_session::session::Session>::time::<(), rustc_interface::passes::analysis::{closure#5}>
32: rustc_interface::passes::analysis
33: <rustc_query_system::dep_graph::graph::DepGraph<rustc_middle::dep_graph::dep_node::DepKind>>::with_task::<rustc_middle::ty::context::TyCtxt, (), core::result::Result<(), rustc_errors::ErrorReported>>
34: rustc_data_structures::stack::ensure_sufficient_stack::<(core::result::Result<(), rustc_errors::ErrorReported>, rustc_query_system::dep_graph::graph::DepNodeIndex), rustc_query_system::query::plumbing::execute_job<rustc_query_impl::plumbing::QueryCtxt, (), core::result::Result<(), rustc_errors::ErrorReported>>::{closure#3}>
35: rustc_query_system::query::plumbing::try_execute_query::<rustc_query_impl::plumbing::QueryCtxt, rustc_query_system::query::caches::DefaultCache<(), core::result::Result<(), rustc_errors::ErrorReported>>>
36: rustc_query_system::query::plumbing::get_query::<rustc_query_impl::queries::analysis, rustc_query_impl::plumbing::QueryCtxt>
37: <rustc_interface::passes::QueryContext>::enter::<rustc_driver::run_compiler::{closure#1}::{closure#2}::{closure#3}, core::result::Result<(), rustc_errors::ErrorReported>>
38: <rustc_interface::interface::Compiler>::enter::<rustc_driver::run_compiler::{closure#1}::{closure#2}, core::result::Result<core::option::Option<rustc_interface::queries::Linker>, rustc_errors::ErrorReported>>
39: rustc_span::with_source_map::<core::result::Result<(), rustc_errors::ErrorReported>, rustc_interface::interface::create_compiler_and_run<core::result::Result<(), rustc_errors::ErrorReported>, rustc_driver::run_compiler::{closure#1}>::{closure#0}>
40: <scoped_tls::ScopedKey<rustc_span::SessionGlobals>>::set::<rustc_interface::util::setup_callbacks_and_run_in_thread_pool_with_globals<rustc_interface::interface::run_compiler<core::result::Result<(), rustc_errors::ErrorReported>, rustc_driver::run_compiler::{closure#1}>::{closure#0}, core::result::Result<(), rustc_errors::ErrorReported>>::{closure#0}::{closure#0}, core::result::Result<(), rustc_errors::ErrorReported>>
note: Some details are omitted, run with `RUST_BACKTRACE=full` for a verbose backtrace.

error: internal compiler error: unexpected panic

note: the compiler unexpectedly panicked. this is a bug.

note: we would appreciate a bug report: https://github.com/rust-lang/rust-clippy/issues/new

note: Clippy version: clippy 0.1.58 (84a4ab7f3 2021-11-04)

query stack during panic:
#0 [analysis] running analysis passes on this crate
end of query stack
error: could not compile `core_simd` due to 232 previous errors

[dylni]

MCVE for the same issue (add comment to #7868):

main.rs

#![warn(clippy::undocumented_unsafe_blocks)]

mod zero;

fn main() {}

zero.rs:

fn zero() {
    // SAFETY:
    unsafe { 0 };
}

[Serial-ATA]

@rustbot claim

[kpreid]

I went to try out clippy::undocumented_unsafe_blocks which is newly stable in 1.58.0, and hit this ICE, whose fix didn't make it into 1.58.0 stable (going by the branch info GitHub shows).

I'm mentioning this in case anyone else met the problem and is looking for information, and in a small hope of prompting a backport so it can be used (though from this it sounds like only fixes for regressions are backported?)

[daprilik]

Yep, just hit this one as well after updating to 1.58.0 stable 😞