ICE with #![feature(trivial_bounds)]: SizeOf nullary MIR operator called for unsized type #6663
Open
Description
I tried this code:
#![feature(trivial_bounds)]
#![warn(const_err)]
use core::mem::size_of;
struct Helper<T: ?Sized>(T);
trait Unsized<T: ?Sized> {
const SIZE: usize = usize::MAX;
}
impl<T: ?Sized> Unsized<T> for Helper<T> {}
impl<T> Helper<T> {
const SIZE: usize = size_of::<T>();
}
struct TrickClippy(str);
impl TrickClippy {
fn trick_clippy() -> bool
where
Self: Sized,
{
Helper::<Self>::SIZE == Helper::<str>::SIZE
}
}rustc compiled the code successfully with only dead_code warnings, while Clippy gave me an additional const_err warning and an ICE (SizeOf nullary MIR operator called for unsized type TrickClippy):
warning: any use of this value will cause an error
--> /rustup/home/toolchains/nightly-2021-01-28-x86_64-unknown-linux-gnu/lib/rustlib/src/rust/library/core/src/mem/mod.rs:310:5
|
310 | intrinsics::size_of::<T>()
| ^^^^^^^^^^^^^^^^^^^^^^^^^^
| |
| size_of called on unsized type `TrickClippy`
| inside `std::mem::size_of::<TrickClippy>` at /rustup/home/toolchains/nightly-2021-01-28-x86_64-unknown-linux-gnu/lib/rustlib/src/rust/library/core/src/mem/mod.rs:310:5
| inside `Helper::<TrickClippy>::SIZE` at <anon>:15:25
|
::: <anon>:15:5
|
15 | const SIZE: usize = size_of::<T>();
| -----------------------------------
|
note: the lint level is defined here
--> <anon>:2:9
|
2 | #![warn(const_err)]
| ^^^^^^^^^
warning: 4 warnings emitted
error: internal compiler error: SizeOf nullary MIR operator called for unsized type TrickClippy
--> /rustup/home/toolchains/nightly-2021-01-28-x86_64-unknown-linux-gnu/lib/rustlib/src/rust/library/core/src/mem/mod.rs:310:5
|
310 | intrinsics::size_of::<T>()
| ^^^^^^^^^^^^^^^^^^^^^^^^^^
|
= note: delayed at compiler/rustc_mir/src/interpret/step.rs:269:35
thread 'rustc' panicked at 'no errors encountered even though `delay_span_bug` issued', compiler/rustc_errors/src/lib.rs:974:13
Backtrace with -Z treat-err-as-bug
thread 'rustc' panicked at 'aborting due to `-Z treat-err-as-bug=1`', compiler/rustc_errors/src/lib.rs:1028:27
stack backtrace:
0: std::panicking::begin_panic
1: rustc_errors::HandlerInner::emit_diagnostic
2: rustc_errors::HandlerInner::emit_diag_at_span
3: rustc_errors::HandlerInner::span_bug
4: rustc_errors::Handler::delay_span_bug
5: rustc_mir::interpret::step::<impl rustc_mir::interpret::eval_context::InterpCx<M>>::eval_rvalue_into_place
6: rustc_mir::interpret::step::<impl rustc_mir::interpret::eval_context::InterpCx<M>>::run
7: rustc_mir::const_eval::eval_queries::eval_to_allocation_raw_provider
8: rustc_query_impl::<impl rustc_query_system::query::config::QueryAccessors<rustc_query_impl::plumbing::QueryCtxt> for rustc_query_impl::queries::eval_to_allocation_raw>::compute
9: rustc_query_system::dep_graph::graph::DepGraph<K>::with_task_impl
10: rustc_data_structures::stack::ensure_sufficient_stack
11: rustc_query_system::query::plumbing::force_query_with_job
12: rustc_query_system::query::plumbing::get_query_impl
13: <rustc_query_impl::Queries as rustc_middle::ty::query::QueryEngine>::eval_to_allocation_raw
14: rustc_mir::const_eval::eval_queries::eval_to_const_value_raw_provider
15: rustc_query_impl::<impl rustc_query_system::query::config::QueryAccessors<rustc_query_impl::plumbing::QueryCtxt> for rustc_query_impl::queries::eval_to_const_value_raw>::compute
16: rustc_query_system::dep_graph::graph::DepGraph<K>::with_task_impl
17: rustc_data_structures::stack::ensure_sufficient_stack
18: rustc_query_system::query::plumbing::force_query_with_job
19: rustc_query_system::query::plumbing::get_query_impl
20: <rustc_query_impl::Queries as rustc_middle::ty::query::QueryEngine>::eval_to_const_value_raw
21: rustc_middle::mir::interpret::queries::<impl rustc_middle::ty::context::TyCtxt>::const_eval_global_id
22: rustc_middle::mir::interpret::queries::<impl rustc_middle::ty::context::TyCtxt>::const_eval_resolve
23: clippy_utils::consts::ConstEvalLateContext::expr
24: clippy_utils::hir_utils::HirEqInterExpr::eq_expr
25: clippy_utils::hir_utils::eq_expr_value
26: <clippy_lints::eq_op::EqOp as rustc_lint::passes::LateLintPass>::check_expr
27: <rustc_lint::late::LateLintPassObjects as rustc_lint::passes::LateLintPass>::check_expr
28: <rustc_lint::late::LateContextAndPass<T> as rustc_hir::intravisit::Visitor>::visit_expr
29: <rustc_lint::late::LateContextAndPass<T> as rustc_hir::intravisit::Visitor>::visit_block
30: <rustc_lint::late::LateContextAndPass<T> as rustc_hir::intravisit::Visitor>::visit_expr
31: <rustc_lint::late::LateContextAndPass<T> as rustc_hir::intravisit::Visitor>::visit_nested_body
32: <rustc_lint::late::LateContextAndPass<T> as rustc_hir::intravisit::Visitor>::visit_fn
33: rustc_hir::intravisit::walk_impl_item
34: rustc_hir::intravisit::Visitor::visit_nested_impl_item
35: rustc_hir::intravisit::walk_impl_item_ref
36: rustc_hir::intravisit::walk_item
37: rustc_hir::intravisit::Visitor::visit_nested_item
38: rustc_hir::intravisit::walk_mod
39: <rustc_lint::late::LateContextAndPass<T> as rustc_hir::intravisit::Visitor>::visit_mod
40: rustc_hir::intravisit::walk_crate
41: rustc_lint::late::late_lint_pass_crate
42: rustc_session::utils::<impl rustc_session::session::Session>::time
43: std::panic::catch_unwind
44: rustc_session::utils::<impl rustc_session::session::Session>::time
45: rustc_interface::passes::analysis
46: rustc_query_system::dep_graph::graph::DepGraph<K>::with_task_impl
47: rustc_data_structures::stack::ensure_sufficient_stack
48: rustc_query_system::query::plumbing::force_query_with_job
49: rustc_query_system::query::plumbing::get_query_impl
50: <rustc_query_impl::Queries as rustc_middle::ty::query::QueryEngine>::analysis
51: rustc_interface::passes::QueryContext::enter
52: rustc_interface::queries::<impl rustc_interface::interface::Compiler>::enter
53: rustc_span::with_source_map
54: rustc_interface::interface::create_compiler_and_run
55: rustc_span::with_session_globals
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 0.1.52 (3a5d45f 2021-03-09)
query stack during panic:
#0 [eval_to_allocation_raw] const-evaluating + checking `<impl at clippy-trivial-bounds-ice.rs:15:1: 17:2>::SIZE`
#1 [eval_to_const_value_raw] simplifying constant for the type system `<impl at clippy-trivial-bounds-ice.rs:15:1: 17:2>::SIZE`
#2 [analysis] running analysis passes on this crate
end of query stack
I believe the const_err warning was incorrect. rustc did not report it and core::intrinsics::size_of() has a Sized bound.