ICE when using const generics with associated items #70273

jendrikw · 2020-03-22T13:18:32Z

Code

#![feature(const_generics)]

trait T<const A: usize> {
    type Item;
}
struct S;

impl<const A: usize> T<A> for S {
    type Item = i32;
}

fn main() {
    let _err: <S as T<0usize>>::Item;
}

Error output

   Compiling bug v0.1.0 (/tmp/bug)
warning: the feature `const_generics` is incomplete and may cause the compiler to crash
 --> src/main.rs:1:12
  |
1 | #![feature(const_generics)]
  |            ^^^^^^^^^^^^^^
  |
  = note: `#[warn(incomplete_features)]` on by default

warning: Error finalizing incremental compilation session directory `/tmp/bug/target/debug/incremental/bug-19qm6gngth5a1/s-flslgmhmjy-18wc5w7-working`: No such file or directory (os error 2)

error: internal compiler error: mir_const_qualif: MIR had errors
  --> src/main.rs:13:23
   |
13 |     let _err: <S as T<0usize>>::Item;
   |                       ^^^^^^

error: internal compiler error: PromoteTemps: MIR had errors
  --> src/main.rs:13:23
   |
13 |     let _err: <S as T<0usize>>::Item;
   |                       ^^^^^^

error: internal compiler error: broken MIR in DefId(0:12 ~ bug[538c]::main[0]::{{constant}}[0]) ("return type"): bad type [type error]
  --> src/main.rs:13:23
   |
13 |     let _err: <S as T<0usize>>::Item;
   |                       ^^^^^^

error: internal compiler error: broken MIR in DefId(0:12 ~ bug[538c]::main[0]::{{constant}}[0]) (LocalDecl { mutability: Mut, local_info: Other, internal: false, is_block_tail: None, ty: [type error], user_ty: UserTypeProjections { contents: [] }, source_info: SourceInfo { span: src/main.rs:13:23: 13:29, scope: scope[0] } }): bad type [type error]
  --> src/main.rs:13:23
   |
13 |     let _err: <S as T<0usize>>::Item;
   |                       ^^^^^^

thread 'rustc' panicked at 'no errors encountered even though `delay_span_bug` issued', src/librustc_errors/lib.rs:360:17
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/blob/master/CONTRIBUTING.md#bug-reports

note: rustc 1.44.0-nightly (f509b26a7 2020-03-18) running on x86_64-unknown-linux-gnu

note: compiler flags: -C debuginfo=2 -C incremental --crate-type bin

note: some of the compiler flags provided by cargo are hidden

error: could not compile `bug`.

To learn more, run the command again with --verbose.

Backtrace

thread 'rustc' panicked at 'no errors encountered even though `delay_span_bug` issued', src/librustc_errors/lib.rs:360:17
stack backtrace:
   0: backtrace::backtrace::libunwind::trace
             at /cargo/registry/src/github.com-1ecc6299db9ec823/backtrace-0.3.44/src/backtrace/libunwind.rs:86
   1: backtrace::backtrace::trace_unsynchronized
             at /cargo/registry/src/github.com-1ecc6299db9ec823/backtrace-0.3.44/src/backtrace/mod.rs:66
   2: std::sys_common::backtrace::_print_fmt
             at src/libstd/sys_common/backtrace.rs:78
   3: <std::sys_common::backtrace::_print::DisplayBacktrace as core::fmt::Display>::fmt
             at src/libstd/sys_common/backtrace.rs:59
   4: core::fmt::write
             at src/libcore/fmt/mod.rs:1069
   5: std::io::Write::write_fmt
             at src/libstd/io/mod.rs:1427
   6: std::sys_common::backtrace::_print
             at src/libstd/sys_common/backtrace.rs:62
   7: std::sys_common::backtrace::print
             at src/libstd/sys_common/backtrace.rs:49
   8: std::panicking::default_hook::{{closure}}
             at src/libstd/panicking.rs:198
   9: std::panicking::default_hook
             at src/libstd/panicking.rs:218
  10: rustc_driver::report_ice
  11: std::panicking::rust_panic_with_hook
             at src/libstd/panicking.rs:515
  12: std::panicking::begin_panic
  13: <rustc_errors::HandlerInner as core::ops::drop::Drop>::drop
  14: core::ptr::drop_in_place
  15: <alloc::rc::Rc<T> as core::ops::drop::Drop>::drop
  16: core::ptr::drop_in_place
  17: rustc_interface::interface::run_compiler_in_existing_thread_pool

This issue has been assigned to @lcnr via this comment.

The text was updated successfully, but these errors were encountered:

jendrikw · 2020-03-22T13:27:30Z

managed to reduce the test case a bit.

jendrikw · 2020-03-22T13:39:16Z

Also happens for this code using a function instead of an associated type:

Code

#![feature(const_generics)]

trait T<const A: usize> {
    fn f();
}
struct S;

impl T<0usize> for S {
    fn f() {}
}

fn main() {
    let _err = <S as T<0usize>>::f();
}

Error output

   Compiling bug v0.1.0 (/tmp/bug)
warning: the feature `const_generics` is incomplete and may cause the compiler to crash
 --> src/main.rs:1:12
  |
1 | #![feature(const_generics)]
  |            ^^^^^^^^^^^^^^
  |
  = note: `#[warn(incomplete_features)]` on by default

warning: Error finalizing incremental compilation session directory `/tmp/bug/target/debug/incremental/bug-19qm6gngth5a1/s-flslstafo1-1loj99m-working`: No such file or directory (os error 2)

error: internal compiler error: mir_const_qualif: MIR had errors
  --> src/main.rs:13:13
   |
13 |     <S as T<0usize>>::f();
   |             ^^^^^^

error: internal compiler error: PromoteTemps: MIR had errors
  --> src/main.rs:13:13
   |
13 |     <S as T<0usize>>::f();
   |             ^^^^^^

error: internal compiler error: broken MIR in DefId(0:12 ~ bug[538c]::main[0]::{{constant}}[0]) ("return type"): bad type [type error]
  --> src/main.rs:13:13
   |
13 |     <S as T<0usize>>::f();
   |             ^^^^^^

error: internal compiler error: broken MIR in DefId(0:12 ~ bug[538c]::main[0]::{{constant}}[0]) (LocalDecl { mutability: Mut, local_info: Other, internal: false, is_block_tail: None, ty: [type error], user_ty: UserTypeProjections { contents: [] }, source_info: SourceInfo { span: src/main.rs:13:13: 13:19, scope: scope[0] } }): bad type [type error]
  --> src/main.rs:13:13
   |
13 |     <S as T<0usize>>::f();
   |             ^^^^^^

thread 'rustc' panicked at 'no errors encountered even though `delay_span_bug` issued', src/librustc_errors/lib.rs:360:17
stack backtrace:
   0: backtrace::backtrace::libunwind::trace
             at /cargo/registry/src/github.com-1ecc6299db9ec823/backtrace-0.3.44/src/backtrace/libunwind.rs:86
   1: backtrace::backtrace::trace_unsynchronized
             at /cargo/registry/src/github.com-1ecc6299db9ec823/backtrace-0.3.44/src/backtrace/mod.rs:66
   2: std::sys_common::backtrace::_print_fmt
             at src/libstd/sys_common/backtrace.rs:78
   3: <std::sys_common::backtrace::_print::DisplayBacktrace as core::fmt::Display>::fmt
             at src/libstd/sys_common/backtrace.rs:59
   4: core::fmt::write
             at src/libcore/fmt/mod.rs:1069
   5: std::io::Write::write_fmt
             at src/libstd/io/mod.rs:1427
   6: std::sys_common::backtrace::_print
             at src/libstd/sys_common/backtrace.rs:62
   7: std::sys_common::backtrace::print
             at src/libstd/sys_common/backtrace.rs:49
   8: std::panicking::default_hook::{{closure}}
             at src/libstd/panicking.rs:198
   9: std::panicking::default_hook
             at src/libstd/panicking.rs:218
  10: rustc_driver::report_ice
  11: std::panicking::rust_panic_with_hook
             at src/libstd/panicking.rs:515
  12: std::panicking::begin_panic
  13: <rustc_errors::HandlerInner as core::ops::drop::Drop>::drop
  14: core::ptr::drop_in_place
  15: <alloc::rc::Rc<T> as core::ops::drop::Drop>::drop
  16: core::ptr::drop_in_place
  17: rustc_interface::interface::run_compiler_in_existing_thread_pool
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/blob/master/CONTRIBUTING.md#bug-reports

note: rustc 1.44.0-nightly (f509b26a7 2020-03-18) running on x86_64-unknown-linux-gnu

note: compiler flags: -C debuginfo=2 -C incremental --crate-type bin

note: some of the compiler flags provided by cargo are hidden

query stack during panic:
end of query stack
error: could not compile `bug`.

To learn more, run the command again with --verbose.

lcnr · 2020-03-22T14:26:16Z

@rustbot claim

lcnr · 2020-03-22T15:41:26Z

initial example fixed by #70223,
associated function fixed by ~~#70276~~ #70284 instead

@eddyb

…r=eddyb correctly handle const params in type_of extends rust-lang#70223, retry of rust-lang#70276 fixes rust-lang#70273 r? @eddyb cc @varkor

@eddyb

…r=eddyb correctly handle const params in type_of extends rust-lang#70223, retry of rust-lang#70276 fixes rust-lang#70273 r? @eddyb cc @varkor

jendrikw added C-bug Category: This is a bug. I-ICE Issue: The compiler panicked, giving an Internal Compilation Error (ICE) ❄️ T-compiler Relevant to the compiler team, which will review and decide on the PR/issue. labels Mar 22, 2020

jonas-schievink added A-associated-items Area: Associated items (types, constants & functions) A-const-generics Area: const generics (parameters and arguments) F-const_generics `#![feature(const_generics)]` labels Mar 22, 2020

rustbot self-assigned this Mar 22, 2020

lcnr mentioned this issue Mar 22, 2020

fix type of const params in assoc fns. #70276

Closed

lcnr mentioned this issue Mar 22, 2020

correctly handle const params in type_of #70284

Merged

Centril added the requires-nightly This issue requires a nightly compiler in some way. label Mar 23, 2020

bors closed this as completed in d309058 Mar 24, 2020

Provide feedback

Saved searches

Use saved searches to filter your results more quickly

ICE when using const generics with associated items #70273

ICE when using const generics with associated items #70273

jendrikw commented Mar 22, 2020 •

edited by rustbot

Loading

jendrikw commented Mar 22, 2020

jendrikw commented Mar 22, 2020

lcnr commented Mar 22, 2020

lcnr commented Mar 22, 2020 •

edited

Loading

ICE when using const generics with associated items #70273

ICE when using const generics with associated items #70273

Comments

jendrikw commented Mar 22, 2020 • edited by rustbot Loading

Code

Meta

Error output

jendrikw commented Mar 22, 2020

jendrikw commented Mar 22, 2020

Code

Error output

lcnr commented Mar 22, 2020

lcnr commented Mar 22, 2020 • edited Loading

jendrikw commented Mar 22, 2020 •

edited by rustbot

Loading

lcnr commented Mar 22, 2020 •

edited

Loading