search

rust-lang / rust

Empowering everyone to build reliable and efficient software.
https://www.rust-lang.org
Other
96.91k stars 12.53k forks source link

ICE “unexpected bound ty in binder” involving type binder, `Fn`-family trait and closure #108814

Open fmease opened 1 year ago

fmease commented 1 year ago 
#![feature(non_lifetime_binders)]

fn take(_: impl for<T> FnOnce(T) -> T) {}

fn main() {
    take(|x| x)
}

Error output

warning: the feature `non_lifetime_binders` is incomplete and may not be safe to use and/or cause compiler crashes
 --> take_id.rs:1:12
  |
1 | #![feature(non_lifetime_binders)]
  |            ^^^^^^^^^^^^^^^^^^^^
  |
  = note: see issue #108185 <https://github.com/rust-lang/rust/issues/108185> for more information
  = note: `#[warn(incomplete_features)]` on by default

error: internal compiler error: /rustc/ac4379fea9e83465d814bb05005689f49bd2141e/compiler/rustc_middle/src/ty/fold.rs:297:33: unexpected bound ty in binder: BoundTy { var: 0, kind: Anon(0) }

thread 'rustc' panicked at 'Box<dyn Any>', /rustc/ac4379fea9e83465d814bb05005689f49bd2141e/compiler/rustc_errors/src/lib.rs:1644:9
Backtrace

``` stack backtrace: 0: 0x7f1e8f56653a - std::backtrace_rs::backtrace::libunwind::trace::ha7277b97837a680e at /rustc/ac4379fea9e83465d814bb05005689f49bd2141e/library/std/src/../../backtrace/src/backtrace/libunwind.rs:93:5 1: 0x7f1e8f56653a - std::backtrace_rs::backtrace::trace_unsynchronized::h2eae6446df1fb3c7 at /rustc/ac4379fea9e83465d814bb05005689f49bd2141e/library/std/src/../../backtrace/src/backtrace/mod.rs:66:5 2: 0x7f1e8f56653a - std::sys_common::backtrace::_print_fmt::hcce758637ada6e5e at /rustc/ac4379fea9e83465d814bb05005689f49bd2141e/library/std/src/sys_common/backtrace.rs:65:5 3: 0x7f1e8f56653a - ::fmt::h048020a39b1c8541 at /rustc/ac4379fea9e83465d814bb05005689f49bd2141e/library/std/src/sys_common/backtrace.rs:44:22 4: 0x7f1e8f5c9cee - core::fmt::write::h8cb0e60463f917ed at /rustc/ac4379fea9e83465d814bb05005689f49bd2141e/library/core/src/fmt/mod.rs:1232:17 5: 0x7f1e8f5593e5 - std::io::Write::write_fmt::h6a4bf43ae33fb5c2 at /rustc/ac4379fea9e83465d814bb05005689f49bd2141e/library/std/src/io/mod.rs:1684:15 6: 0x7f1e8f566305 - std::sys_common::backtrace::_print::h01686671a8f910e8 at /rustc/ac4379fea9e83465d814bb05005689f49bd2141e/library/std/src/sys_common/backtrace.rs:47:5 7: 0x7f1e8f566305 - std::sys_common::backtrace::print::hb036d568178720fa at /rustc/ac4379fea9e83465d814bb05005689f49bd2141e/library/std/src/sys_common/backtrace.rs:34:9 8: 0x7f1e8f56907f - std::panicking::default_hook::{{closure}}::hac5f47cee0e06043 at /rustc/ac4379fea9e83465d814bb05005689f49bd2141e/library/std/src/panicking.rs:271:22 9: 0x7f1e8f568dbb - std::panicking::default_hook::hc30c65fb62dafbb3 at /rustc/ac4379fea9e83465d814bb05005689f49bd2141e/library/std/src/panicking.rs:290:9 10: 0x7f1e927e25c5 - rustc_driver_impl[1bafdf3e8b0cbe0c]::DEFAULT_HOOK::{closure#0}::{closure#0} 11: 0x7f1e8f5698bd - as core::ops::function::Fn>::call::hec34b5992590fa06 at /rustc/ac4379fea9e83465d814bb05005689f49bd2141e/library/alloc/src/boxed.rs:2001:9 12: 0x7f1e8f5698bd - std::panicking::rust_panic_with_hook::h44e2196c38854f66 at /rustc/ac4379fea9e83465d814bb05005689f49bd2141e/library/std/src/panicking.rs:696:13 13: 0x7f1e92d3e671 - std[f869becc71c6b456]::panicking::begin_panic::::{closure#0} 14: 0x7f1e92d36fe6 - std[f869becc71c6b456]::sys_common::backtrace::__rust_end_short_backtrace::::{closure#0}, !> 15: 0x7f1e92daba26 - std[f869becc71c6b456]::panicking::begin_panic:: 16: 0x7f1e92d8a1a6 - std[f869becc71c6b456]::panic::panic_any:: 17: 0x7f1e92d85ba6 - ::bug::<&alloc[56a1e614eb299497]::string::String> 18: 0x7f1e92d85870 - ::bug::<&alloc[56a1e614eb299497]::string::String> 19: 0x7f1e92d7cb7b - rustc_middle[6b96750649b9b523]::util::bug::opt_span_bug_fmt::::{closure#0} 20: 0x7f1e92d7b4ca - rustc_middle[6b96750649b9b523]::ty::context::tls::with_opt::::{closure#0}, !>::{closure#0} 21: 0x7f1e92d7b496 - rustc_middle[6b96750649b9b523]::ty::context::tls::with_context_opt::::{closure#0}, !>::{closure#0}, !> 22: 0x7f1e92d7cac6 - rustc_middle[6b96750649b9b523]::util::bug::opt_span_bug_fmt:: 23: 0x7f1e90eeec13 - rustc_middle[6b96750649b9b523]::util::bug::bug_fmt 24: 0x7f1e92a4230c - ::replace_late_bound_regions_uncached::::replace_late_bound_regions::erase_late_bound_regions::{closure#0}>::{closure#0}>::{closure#0} 25: 0x7f1e90e228fd - <&rustc_middle[6b96750649b9b523]::ty::list::List as rustc_type_ir[52d4fefb1527696e]::fold::TypeFoldable>::try_fold_with::> 26: 0x7f1e90c1236b - ::closure_sigs 27: 0x7f1e90c10183 - ::check_expr_closure 28: 0x7f1e90b9f3fc - ::check_expr_with_expectation_and_args 29: 0x7f1e90e86ebd - ::check_argument_types 30: 0x7f1e90b6d7bb - ::check_call 31: 0x7f1e90b9b6ad - ::check_expr_with_expectation_and_args 32: 0x7f1e90bcacbe - ::check_block_with_expected 33: 0x7f1e90b9bbdf - ::check_expr_with_expectation_and_args 34: 0x7f1e9166f7d4 - ::check_return_expr 35: 0x7f1e91667bc7 - rustc_hir_typeck[b98449f9e1a7a434]::check::check_fn 36: 0x7f1e91651c37 - rustc_hir_typeck[b98449f9e1a7a434]::typeck 37: 0x7f1e90a2052c - rustc_query_system[5157c2c547c7c596]::query::plumbing::try_execute_query:: 38: 0x7f1e91faf34f - rustc_data_structures[afc619c2eff4eef5]::sync::par_for_each_in::<&[rustc_span[481fe46353bf1cdc]::def_id::LocalDefId], ::par_body_owners::{closure#0}> 39: 0x7f1e91faf10f - rustc_hir_typeck[b98449f9e1a7a434]::typeck_item_bodies 40: 0x7f1e91e2c55d - rustc_query_system[5157c2c547c7c596]::query::plumbing::try_execute_query:: 41: 0x7f1e91e2c24b - ::typeck_item_bodies 42: 0x7f1e90b68493 - ::time::<(), rustc_hir_analysis[717970e329447c82]::check_crate::{closure#7}> 43: 0x7f1e90b64f4d - rustc_hir_analysis[717970e329447c82]::check_crate 44: 0x7f1e90b5b072 - rustc_interface[841154c2f5280d71]::passes::analysis 45: 0x7f1e92033d9d - rustc_query_system[5157c2c547c7c596]::query::plumbing::try_execute_query:: 46: 0x7f1e92033a9f - ::analysis 47: 0x7f1e91e63616 - ::enter::> 48: 0x7f1e91a47f48 - rustc_span[481fe46353bf1cdc]::with_source_map::, rustc_interface[841154c2f5280d71]::interface::run_compiler, rustc_driver_impl[1bafdf3e8b0cbe0c]::run_compiler::{closure#1}>::{closure#0}::{closure#0}> 49: 0x7f1e91a3f4dc - std[f869becc71c6b456]::sys_common::backtrace::__rust_begin_short_backtrace::, rustc_driver_impl[1bafdf3e8b0cbe0c]::run_compiler::{closure#1}>::{closure#0}, core[c7837a1117e32cc5]::result::Result<(), rustc_span[481fe46353bf1cdc]::ErrorGuaranteed>>::{closure#0}::{closure#0}, core[c7837a1117e32cc5]::result::Result<(), rustc_span[481fe46353bf1cdc]::ErrorGuaranteed>> 50: 0x7f1e91a3ef0a - <::spawn_unchecked_, rustc_driver_impl[1bafdf3e8b0cbe0c]::run_compiler::{closure#1}>::{closure#0}, core[c7837a1117e32cc5]::result::Result<(), rustc_span[481fe46353bf1cdc]::ErrorGuaranteed>>::{closure#0}::{closure#0}, core[c7837a1117e32cc5]::result::Result<(), rustc_span[481fe46353bf1cdc]::ErrorGuaranteed>>::{closure#1} as core[c7837a1117e32cc5]::ops::function::FnOnce<()>>::call_once::{shim:vtable#0} 51: 0x7f1e8f5737b3 - as core::ops::function::FnOnce>::call_once::hc371c06232f0c824 at /rustc/ac4379fea9e83465d814bb05005689f49bd2141e/library/alloc/src/boxed.rs:1987:9 52: 0x7f1e8f5737b3 - as core::ops::function::FnOnce>::call_once::h7dc3758286df85d1 at /rustc/ac4379fea9e83465d814bb05005689f49bd2141e/library/alloc/src/boxed.rs:1987:9 53: 0x7f1e8f5737b3 - std::sys::unix::thread::Thread::new::thread_start::h64782255c7c71ccd at /rustc/ac4379fea9e83465d814bb05005689f49bd2141e/library/std/src/sys/unix/thread.rs:108:17 54: 0x7f1e8f3068fd - 55: 0x7f1e8f388a60 - 56: 0x0 - 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: rustc 1.70.0-nightly (ac4379fea 2023-03-06) running on x86_64-unknown-linux-gnu query stack during panic: #0 [typeck] type-checking `main` #1 [typeck_item_bodies] type-checking all item bodies #2 [analysis] running analysis passes on this crate end of query stack error: aborting due to previous error; 1 warning emitted ```

Meta

Latest master (ac4379fea9e83465d814bb05005689f49bd2141e).

rustc -Vv:

rustc 1.70.0-nightly (ac4379fea 2023-03-06)
binary: rustc
commit-hash: ac4379fea9e83465d814bb05005689f49bd2141e
commit-date: 2023-03-06
host: x86_64-unknown-linux-gnu
release: 1.70.0-nightly
LLVM version: 15.0.7

@rustbot label F-non_lifetime_binders

fmease commented 1 year ago

Doesn't actually need ITIAP, a normal bound works just as well:

#![feature(non_lifetime_binders)]

fn take<F>(_: F) where F: for<T> FnOnce(T) -> T {}

fn main() {
    take(|x| x)
}
fmease commented 1 year ago

|x| x should probably be rejected since we don't support type-generic closures (yet).

It's probably fine that the following is well-typed under non_lifetime_binders since it's impossible to call take at this time anyway.

fn take(id: impl for<T> Fn(T) -> T) {
    id(0);
    id("");
}
compiler-errors commented 1 year ago

@fmease no need to, I've got a more minimal repro of that issue here:

#![feature(non_lifetime_binders)]

trait Foo: for<T> Bar<T> {}

trait Bar<T> {
    fn method() -> T;
}

fn x<T: Foo>() {
    let _: i32 = T::method();
}

fn main() {}

I'll need to fix this in a couple of steps.

matthiaskrgr commented 1 year ago

another one, possibly

#![crate_type="lib"]

pub trait Foo<T> {
    type A;
    fn get::A
}

struct YetAnotherStruct<'a, I: for<isize> Foo<&'x &isize>> {
    field: I::A,
}
compiler-errors commented 1 year ago

That ^ is a separate bug, also doesn't ICE with the code provided. I did minimize it tho:

#![feature(non_lifetime_binders)]

pub trait Foo<T> {
    type A;
}

struct YetAnotherStruct<'a, I: for<T> Foo<T>> {
    field: I::A,
}

fn main() {}