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Closure type error during const-eval (array len context) #66706

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DutchGhost opened this issue Nov 24, 2019 · 9 comments · Fixed by #70452
Closed

Closure type error during const-eval (array len context) #66706

DutchGhost opened this issue Nov 24, 2019 · 9 comments · Fixed by #70452
Labels
A-const-eval Area: Constant evaluation (MIR interpretation) A-MIR Area: Mid-level IR (MIR) - https://blog.rust-lang.org/2016/04/19/MIR.html C-bug Category: This is a bug. glacier ICE tracked in rust-lang/glacier. I-ICE Issue: The compiler panicked, giving an Internal Compilation Error (ICE) ❄️ P-high High priority T-compiler Relevant to the compiler team, which will review and decide on the PR/issue.

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@DutchGhost
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DutchGhost commented Nov 24, 2019 •
edited
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The following code ICE's on stable, beta and nightly

fn bug() {
    [0; [|f @ &ref _| {} ; 0 ].len() ];
}
Backtrace: 
error: expected identifier, found reserved identifier `_`
 --> src/lib.rs:3:20
  |
3 |     [0; [|f @ &ref _| {} ; 0 ].len() ];
  |                    ^ expected identifier, found reserved identifier

error: internal compiler error: src/librustc_mir/hair/cx/expr.rs:518: closure expr w/o closure type: [type error]
 --> src/lib.rs:3:10
  |
3 |     [0; [|f @ &ref _| {} ; 0 ].len() ];
  |          ^^^^^^^^^^^^^^^

thread 'rustc' panicked at 'Box<Any>', src/librustc_errors/lib.rs:851:9
stack backtrace:
   0: backtrace::backtrace::libunwind::trace
             at /cargo/registry/src/github.com-1ecc6299db9ec823/backtrace-0.3.40/src/backtrace/libunwind.rs:88
   1: backtrace::backtrace::trace_unsynchronized
             at /cargo/registry/src/github.com-1ecc6299db9ec823/backtrace-0.3.40/src/backtrace/mod.rs:66
   2: std::sys_common::backtrace::_print_fmt
             at src/libstd/sys_common/backtrace.rs:84
   3: <std::sys_common::backtrace::_print::DisplayBacktrace as core::fmt::Display>::fmt
             at src/libstd/sys_common/backtrace.rs:61
   4: core::fmt::write
             at src/libcore/fmt/mod.rs:1030
   5: std::io::Write::write_fmt
             at src/libstd/io/mod.rs:1412
   6: std::sys_common::backtrace::_print
             at src/libstd/sys_common/backtrace.rs:65
   7: std::sys_common::backtrace::print
             at src/libstd/sys_common/backtrace.rs:50
   8: std::panicking::default_hook::{{closure}}
             at src/libstd/panicking.rs:188
   9: std::panicking::default_hook
             at src/libstd/panicking.rs:205
  10: rustc_driver::report_ice
  11: std::panicking::rust_panic_with_hook
             at src/libstd/panicking.rs:468
  12: std::panicking::begin_panic
  13: rustc_errors::HandlerInner::span_bug
  14: rustc_errors::Handler::span_bug
  15: rustc::util::bug::opt_span_bug_fmt::{{closure}}
  16: rustc::ty::context::tls::with_opt::{{closure}}
  17: rustc::ty::context::tls::with_opt
  18: rustc::util::bug::opt_span_bug_fmt
  19: rustc::util::bug::span_bug_fmt
  20: rustc_mir::hair::cx::expr::make_mirror_unadjusted
  21: rustc_mir::hair::cx::expr::<impl rustc_mir::hair::Mirror for &rustc::hir::Expr>::make_mirror
  22: <rustc_mir::hair::ExprRef as rustc_mir::hair::Mirror>::make_mirror
  23: rustc_mir::build::expr::as_rvalue::<impl rustc_mir::build::Builder>::expr_as_rvalue
  24: rustc_mir::build::expr::into::<impl rustc_mir::build::Builder>::into_expr
  25: rustc_mir::build::expr::as_temp::<impl rustc_mir::build::Builder>::expr_as_temp
  26: rustc_mir::build::expr::as_place::<impl rustc_mir::build::Builder>::expr_as_place
  27: rustc_mir::build::expr::into::<impl rustc_mir::build::Builder>::into_expr
  28: rustc_mir::build::expr::as_temp::<impl rustc_mir::build::Builder>::expr_as_temp
  29: rustc_mir::build::expr::as_operand::<impl rustc_mir::build::Builder>::expr_as_operand
  30: rustc_mir::build::expr::as_rvalue::<impl rustc_mir::build::Builder>::expr_as_rvalue
  31: rustc_mir::build::expr::into::<impl rustc_mir::build::Builder>::into_expr
  32: rustc_mir::build::expr::as_temp::<impl rustc_mir::build::Builder>::expr_as_temp
  33: rustc_mir::build::expr::as_operand::<impl rustc_mir::build::Builder>::expr_as_operand
  34: rustc_mir::build::expr::as_operand::<impl rustc_mir::build::Builder>::expr_as_operand
  35: rustc_mir::build::expr::as_operand::<impl rustc_mir::build::Builder>::as_local_operand
  36: <core::iter::adapters::Map<I,F> as core::iter::traits::iterator::Iterator>::fold
  37: <alloc::vec::Vec<T> as alloc::vec::SpecExtend<T,I>>::from_iter
  38: rustc_mir::build::expr::into::<impl rustc_mir::build::Builder>::into_expr
  39: rustc_mir::build::expr::into::<impl rustc_mir::build::Builder>::into_expr
  40: rustc_mir::build::expr::into::<impl rustc_mir::build::Builder>::into_expr
  41: rustc_mir::build::construct_const
  42: rustc::ty::context::tls::with_context::{{closure}}
  43: rustc_mir::build::mir_build
  44: rustc_mir::transform::mir_built
  45: rustc::ty::query::__query_compute::mir_built
  46: rustc::ty::query::plumbing::<impl rustc::ty::context::TyCtxt>::get_query
  47: rustc_mir::transform::check_unsafety::unsafety_check_result
  48: rustc::ty::query::__query_compute::unsafety_check_result
  49: rustc::ty::query::plumbing::<impl rustc::ty::context::TyCtxt>::get_query
  50: rustc_mir::transform::mir_const
  51: rustc::ty::query::__query_compute::mir_const
  52: rustc::ty::query::plumbing::<impl rustc::ty::context::TyCtxt>::get_query
  53: rustc_mir::transform::mir_const_qualif
  54: rustc::ty::query::__query_compute::mir_const_qualif
  55: rustc::ty::query::plumbing::<impl rustc::ty::context::TyCtxt>::get_query
  56: rustc_mir::transform::mir_validated
  57: rustc::ty::query::__query_compute::mir_validated
  58: rustc::ty::query::plumbing::<impl rustc::ty::context::TyCtxt>::get_query
  59: rustc_mir::borrow_check::mir_borrowck
  60: rustc::ty::query::__query_compute::mir_borrowck
  61: rustc::ty::query::plumbing::<impl rustc::ty::context::TyCtxt>::get_query
  62: rustc::ty::query::plumbing::<impl rustc::ty::context::TyCtxt>::ensure_query
  63: rustc_mir::transform::optimized_mir
  64: rustc::ty::query::__query_compute::optimized_mir
  65: rustc::ty::query::plumbing::<impl rustc::ty::context::TyCtxt>::get_query
  66: rustc_mir::interpret::eval_context::InterpCx<M>::load_mir
  67: rustc_mir::const_eval::const_eval_raw_provider
  68: rustc::ty::query::__query_compute::const_eval_raw
  69: rustc::ty::query::plumbing::<impl rustc::ty::context::TyCtxt>::get_query
  70: rustc_mir::const_eval::const_eval_provider
  71: rustc::ty::query::__query_compute::const_eval
  72: rustc::ty::query::<impl rustc::ty::query::config::QueryAccessors for rustc::ty::query::queries::const_eval>::compute
  73: rustc::dep_graph::graph::DepGraph::with_task_impl
  74: rustc::ty::query::plumbing::<impl rustc::ty::context::TyCtxt>::get_query
  75: rustc_typeck::check::expr::<impl rustc_typeck::check::FnCtxt>::check_expr_kind
  76: rustc_typeck::check::expr::<impl rustc_typeck::check::FnCtxt>::check_expr_with_expectation_and_needs
  77: rustc_typeck::check::FnCtxt::check_stmt
  78: rustc_typeck::check::FnCtxt::check_block_with_expected
  79: rustc_typeck::check::expr::<impl rustc_typeck::check::FnCtxt>::check_expr_kind
  80: rustc_typeck::check::expr::<impl rustc_typeck::check::FnCtxt>::check_expr_with_expectation_and_needs
  81: rustc_typeck::check::expr::<impl rustc_typeck::check::FnCtxt>::check_return_expr
  82: rustc_typeck::check::check_fn
  83: rustc::ty::context::tls::with_context::{{closure}}
  84: rustc_typeck::check::typeck_tables_of
  85: rustc::ty::query::__query_compute::typeck_tables_of
  86: rustc::ty::query::<impl rustc::ty::query::config::QueryAccessors for rustc::ty::query::queries::typeck_tables_of>::compute
  87: rustc::dep_graph::graph::DepGraph::with_task_impl
  88: rustc::ty::query::plumbing::<impl rustc::ty::context::TyCtxt>::get_query
  89: rustc::ty::<impl rustc::ty::context::TyCtxt>::par_body_owners
  90: rustc_typeck::check::typeck_item_bodies
  91: rustc::ty::query::__query_compute::typeck_item_bodies
  92: rustc::dep_graph::graph::DepGraph::with_task_impl
  93: rustc::ty::query::plumbing::<impl rustc::ty::context::TyCtxt>::get_query
  94: rustc::util::common::time
  95: rustc_typeck::check_crate
  96: rustc_interface::passes::analysis
  97: rustc::ty::query::__query_compute::analysis
  98: rustc::dep_graph::graph::DepGraph::with_task_impl
  99: rustc::ty::query::plumbing::<impl rustc::ty::context::TyCtxt>::get_query
 100: rustc_interface::passes::BoxedGlobalCtxt::access::{{closure}}
 101: rustc_interface::passes::create_global_ctxt::{{closure}}
 102: rustc_interface::passes::BoxedGlobalCtxt::enter
 103: rustc_interface::interface::run_compiler_in_existing_thread_pool
 104: std::thread::local::LocalKey<T>::with
 105: scoped_tls::ScopedKey<T>::set
note: Some details are omitted, run with `RUST_BACKTRACE=full` for a verbose backtrace.

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 1.41.0-nightly (0c987c5c0 2019-11-23) running on x86_64-unknown-linux-gnu

note: compiler flags: -C codegen-units=1 -C debuginfo=2 --crate-type lib

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

query stack during panic:
#0 [mir_built] processing `bug::{{constant}}#0`
#1 [unsafety_check_result] processing `bug::{{constant}}#0`
#2 [mir_const] processing `bug::{{constant}}#0`
#3 [mir_const_qualif] const checking `bug::{{constant}}#0`
#4 [mir_validated] processing `bug::{{constant}}#0`
#5 [mir_borrowck] processing `bug::{{constant}}#0`
#6 [optimized_mir] processing `bug::{{constant}}#0`
#7 [const_eval_raw] const-evaluating `bug::{{constant}}#0`
#8 [const_eval] const-evaluating + checking `bug::{{constant}}#0`
#9 [typeck_tables_of] processing `bug`
#10 [typeck_item_bodies] type-checking all item bodies
#11 [analysis] running analysis passes on this crate
end of query stack
error: aborting due to 2 previous errors
@jonas-schievink jonas-schievink added A-coroutines Area: Coroutines 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. A-MIR Area: Mid-level IR (MIR) - https://blog.rust-lang.org/2016/04/19/MIR.html labels Nov 24, 2019
@DutchGhost
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@jonas-schievink , I experimented a little further. Generators are not needed anymore, so that label can be removed :)

@jonas-schievink jonas-schievink added I-nominated and removed A-coroutines Area: Coroutines labels Nov 24, 2019
@DutchGhost
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DutchGhost commented Nov 24, 2019 •
edited
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Another version of this is:

fn bug() {
    [0; [|&_: _ &_| {}; 0 ].len()]
}

A quick look in Godbolt gives that this ICE's since 1.24

@hellow554
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hellow554 commented Nov 25, 2019 •
edited
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You can omit that last 0 here (yeah.. saved 5 more bytes 🎉) ^^

fn bug() {
    [0; [|_: _ &_| ()].len()]
}

@pnkfelix pnkfelix changed the title Closure type error Closure type error during const-eval (array len context) Nov 28, 2019
@pnkfelix pnkfelix added A-const-eval Area: Constant evaluation (MIR interpretation) P-high High priority and removed I-nominated labels Nov 28, 2019
@DutchGhost
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DutchGhost commented Nov 29, 2019 •
edited
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Posting here, since the code looks verry similar. However, the message from the ICE is different, but I guess they have the same cause? Feel free to move it to its own place if needed :)

fn bug() {
    [0; match [|f @ &ref _| () ] {} ]
}
Backtrace: 

error: expected identifier, found reserved identifier `_`
 --> src/lib.rs:2:26
  |
2 |     [0; match [|f @ &ref _| () ] {} ]
  |                          ^ expected identifier, found reserved identifier

error[E0658]: `match` is not allowed in a `const`
 --> src/lib.rs:2:9
  |
2 |     [0; match [|f @ &ref _| () ] {} ]
  |         ^^^^^^^^^^^^^^^^^^^^^^^^^^^
  |
  = note: for more information, see https://github.com/rust-lang/rust/issues/49146
  = help: add `#![feature(const_if_match)]` to the crate attributes to enable

error: internal compiler error: src/librustc/ty/sty.rs:1815: `sequence_element_type` called on non-sequence value: [type error]

thread 'rustc' panicked at 'Box<Any>', src/librustc_errors/lib.rs:892:9
stack backtrace:
   0: backtrace::backtrace::libunwind::trace
             at /cargo/registry/src/github.com-1ecc6299db9ec823/backtrace-0.3.40/src/backtrace/libunwind.rs:88
   1: backtrace::backtrace::trace_unsynchronized
             at /cargo/registry/src/github.com-1ecc6299db9ec823/backtrace-0.3.40/src/backtrace/mod.rs:66
   2: std::sys_common::backtrace::_print_fmt
             at src/libstd/sys_common/backtrace.rs:84
   3: <std::sys_common::backtrace::_print::DisplayBacktrace as core::fmt::Display>::fmt
             at src/libstd/sys_common/backtrace.rs:61
   4: core::fmt::write
             at src/libcore/fmt/mod.rs:1024
   5: std::io::Write::write_fmt
             at src/libstd/io/mod.rs:1412
   6: std::sys_common::backtrace::_print
             at src/libstd/sys_common/backtrace.rs:65
   7: std::sys_common::backtrace::print
             at src/libstd/sys_common/backtrace.rs:50
   8: std::panicking::default_hook::{{closure}}
             at src/libstd/panicking.rs:190
   9: std::panicking::default_hook
             at src/libstd/panicking.rs:207
  10: rustc_driver::report_ice
  11: std::panicking::rust_panic_with_hook
             at src/libstd/panicking.rs:470
  12: std::panicking::begin_panic
  13: rustc_errors::HandlerInner::bug
  14: rustc_errors::Handler::bug
  15: rustc::util::bug::opt_span_bug_fmt::{{closure}}
  16: rustc::ty::context::tls::with_opt::{{closure}}
  17: rustc::ty::context::tls::with_opt
  18: rustc::util::bug::opt_span_bug_fmt
  19: rustc::util::bug::bug_fmt
  20: rustc::ty::sty::<impl rustc::ty::TyS>::sequence_element_type
  21: rustc_mir::build::expr::as_rvalue::<impl rustc_mir::build::Builder>::expr_as_rvalue
  22: rustc_mir::build::expr::into::<impl rustc_mir::build::Builder>::into_expr
  23: rustc_mir::build::expr::as_temp::<impl rustc_mir::build::Builder>::expr_as_temp
  24: rustc_mir::build::expr::as_place::<impl rustc_mir::build::Builder>::expr_as_place
  25: rustc_mir::build::expr::as_place::<impl rustc_mir::build::Builder>::expr_as_place
  26: rustc_mir::build::expr::as_place::<impl rustc_mir::build::Builder>::as_place
  27: rustc_mir::build::expr::into::<impl rustc_mir::build::Builder>::into_expr
  28: rustc_mir::build::expr::as_temp::<impl rustc_mir::build::Builder>::expr_as_temp
  29: rustc_mir::build::expr::as_operand::<impl rustc_mir::build::Builder>::expr_as_operand
  30: rustc_mir::build::expr::as_rvalue::<impl rustc_mir::build::Builder>::expr_as_rvalue
  31: rustc_mir::build::expr::into::<impl rustc_mir::build::Builder>::into_expr
  32: rustc_mir::build::expr::into::<impl rustc_mir::build::Builder>::into_expr
  33: rustc_mir::build::expr::into::<impl rustc_mir::build::Builder>::into_expr
  34: rustc_mir::build::construct_const
  35: rustc::ty::context::tls::with_context::{{closure}}
  36: rustc_mir::build::mir_build
  37: rustc_mir::transform::mir_built
  38: rustc::ty::query::__query_compute::mir_built
  39: rustc::ty::query::plumbing::<impl rustc::ty::context::TyCtxt>::get_query
  40: rustc_mir::transform::check_unsafety::unsafety_check_result
  41: rustc::ty::query::__query_compute::unsafety_check_result
  42: rustc::ty::query::plumbing::<impl rustc::ty::context::TyCtxt>::get_query
  43: rustc_mir::transform::mir_const
  44: rustc::ty::query::__query_compute::mir_const
  45: rustc::ty::query::plumbing::<impl rustc::ty::context::TyCtxt>::get_query
  46: rustc_mir::transform::mir_const_qualif
  47: rustc::ty::query::__query_compute::mir_const_qualif
  48: rustc::ty::query::plumbing::<impl rustc::ty::context::TyCtxt>::get_query
  49: rustc_mir::transform::mir_validated
  50: rustc::ty::query::__query_compute::mir_validated
  51: rustc::ty::query::plumbing::<impl rustc::ty::context::TyCtxt>::get_query
  52: rustc_mir::borrow_check::mir_borrowck
  53: rustc::ty::query::__query_compute::mir_borrowck
  54: rustc::ty::query::plumbing::<impl rustc::ty::context::TyCtxt>::get_query
  55: rustc::ty::query::plumbing::<impl rustc::ty::context::TyCtxt>::ensure_query
  56: rustc_mir::transform::optimized_mir
  57: rustc::ty::query::__query_compute::optimized_mir
  58: rustc::ty::query::plumbing::<impl rustc::ty::context::TyCtxt>::get_query
  59: rustc_mir::interpret::eval_context::InterpCx<M>::load_mir
  60: rustc_mir::const_eval::const_eval_raw_provider
  61: rustc::ty::query::__query_compute::const_eval_raw
  62: rustc::ty::query::plumbing::<impl rustc::ty::context::TyCtxt>::get_query
  63: rustc_mir::const_eval::const_eval_provider
  64: rustc::ty::query::__query_compute::const_eval
  65: rustc::ty::query::<impl rustc::ty::query::config::QueryAccessors for rustc::ty::query::queries::const_eval>::compute
  66: rustc::dep_graph::graph::DepGraph::with_task_impl
  67: rustc::ty::query::plumbing::<impl rustc::ty::context::TyCtxt>::get_query
  68: rustc_typeck::check::expr::<impl rustc_typeck::check::FnCtxt>::check_expr_kind
  69: rustc_typeck::check::expr::<impl rustc_typeck::check::FnCtxt>::check_expr_with_expectation_and_needs
  70: rustc_typeck::check::FnCtxt::check_block_with_expected
  71: rustc_typeck::check::expr::<impl rustc_typeck::check::FnCtxt>::check_expr_kind
  72: rustc_typeck::check::expr::<impl rustc_typeck::check::FnCtxt>::check_expr_with_expectation_and_needs
  73: rustc_typeck::check::expr::<impl rustc_typeck::check::FnCtxt>::check_return_expr
  74: rustc_typeck::check::check_fn
  75: rustc::ty::context::tls::with_context::{{closure}}
  76: rustc_typeck::check::typeck_tables_of
  77: rustc::ty::query::__query_compute::typeck_tables_of
  78: rustc::ty::query::<impl rustc::ty::query::config::QueryAccessors for rustc::ty::query::queries::typeck_tables_of>::compute
  79: rustc::dep_graph::graph::DepGraph::with_task_impl
  80: rustc::ty::query::plumbing::<impl rustc::ty::context::TyCtxt>::get_query
  81: rustc::ty::<impl rustc::ty::context::TyCtxt>::par_body_owners
  82: rustc_typeck::check::typeck_item_bodies
  83: rustc::ty::query::__query_compute::typeck_item_bodies
  84: rustc::dep_graph::graph::DepGraph::with_task_impl
  85: rustc::ty::query::plumbing::<impl rustc::ty::context::TyCtxt>::get_query
  86: rustc_typeck::check_crate
  87: rustc_interface::passes::analysis
  88: rustc::ty::query::__query_compute::analysis
  89: rustc::dep_graph::graph::DepGraph::with_task_impl
  90: rustc::ty::query::plumbing::<impl rustc::ty::context::TyCtxt>::get_query
  91: rustc_interface::passes::BoxedGlobalCtxt::access::{{closure}}
  92: rustc_interface::passes::create_global_ctxt::{{closure}}
  93: rustc_interface::passes::BoxedGlobalCtxt::enter
  94: rustc_interface::interface::run_compiler_in_existing_thread_pool
  95: std::thread::local::LocalKey<T>::with
  96: scoped_tls::ScopedKey<T>::set
  97: syntax::with_globals
note: Some details are omitted, run with `RUST_BACKTRACE=full` for a verbose backtrace.

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 1.41.0-nightly (bbb664a99 2019-11-28) running on x86_64-unknown-linux-gnu

note: compiler flags: -C codegen-units=1 -C debuginfo=2 --crate-type lib

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

query stack during panic:
#0 [mir_built] processing `bug::{{constant}}#0`
#1 [unsafety_check_result] processing `bug::{{constant}}#0`
#2 [mir_const] processing `bug::{{constant}}#0`
#3 [mir_const_qualif] const checking `bug::{{constant}}#0`
#4 [mir_validated] processing `bug::{{constant}}#0`
#5 [mir_borrowck] processing `bug::{{constant}}#0`
#6 [optimized_mir] processing `bug::{{constant}}#0`
#7 [const_eval_raw] const-evaluating `bug::{{constant}}#0`
#8 [const_eval] const-evaluating + checking `bug::{{constant}}#0`
#9 [typeck_tables_of] processing `bug`
#10 [typeck_item_bodies] type-checking all item bodies
#11 [analysis] running analysis passes on this crate
end of query stack
error: aborting due to 3 previous errors

For more information about this error, try `rustc --explain E0658`.
error: could not compile `playground`.

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

@rust-lang-glacier-bot rust-lang-glacier-bot added the glacier ICE tracked in rust-lang/glacier. label Dec 18, 2019
@Centril
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Centril commented Mar 10, 2020 •
edited
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We shouldn't be reaching MIR building in the first place due to the [type error], but for some reason, when it happens in an AnonConst, we don't bail on type errors. cc @oli-obk @varkor

@github-actions github-actions bot mentioned this issue Mar 25, 2020
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@Alexendoo
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Alexendoo commented Mar 25, 2020 •
edited
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Things changed slightly from 342c5f3:

No longer ICEs:

fn bug() {
    [0; [|f @ &ref _| {} ; 0 ].len() ];
}
fn bug() {
    [0; [|_: _ &_| ()].len()]
}

Still ICEs:

fn bug() {
    [0; [|&_: _ &_| {}; 0 ].len()]
}
fn bug() {
    [0; match [|f @ &ref _| () ] {} ]
}

@Centril
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Centril commented Mar 25, 2020

@Alexendoo Would you be game to add the two cases no longer ICEing as tests in a PR?

@Alexendoo
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Yeah no problem, I'll get on that tomorrow

@Alexendoo Alexendoo mentioned this issue Mar 26, 2020
Merged
Alexendoo added a commit to Alexendoo/rust that referenced this issue Mar 26, 2020
@Alexendoo
Add regression test for rust-lang#66706
40a0fdc
Dylan-DPC-zz pushed a commit to Dylan-DPC-zz/rust that referenced this issue Mar 27, 2020
@Dylan-DPC
Rollup merge of rust-lang#70435 - Alexendoo:test-66706, r=Centril
fa15774 
Add regression test for rust-lang#66706

Adds the two cases that no longer ICE (rust-lang#66706 (comment))
@Dylan-DPC-zz Dylan-DPC-zz mentioned this issue Mar 27, 2020
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bors added a commit to rust-lang-ci/rust that referenced this issue Mar 27, 2020
@bors
Auto merge of rust-lang#70451 - Dylan-DPC:rollup-2g9oyht, r=Dylan-DPC
7b73d14 
Rollup of 5 pull requests

Successful merges:

 - rust-lang#69644 (Remove framework in `dataflow/mod.rs` in favor of "generic" one)
 - rust-lang#69936 (Fix cycle error when emitting suggestion for mismatched `fn` type)
 - rust-lang#70048 (Allow obtaining &mut OsStr)
 - rust-lang#70344 (Decouple `rustc_hir::print` into `rustc_hir_pretty`)
 - rust-lang#70435 (Add regression test for rust-lang#66706)

Failed merges:

r? @ghost
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eddyb commented Mar 27, 2020

I think the reason these doesn't ICE anymore is a bug, the ICE itself wasn't fixed.
I'm saying that because I've just triggered it with the first commit of #70452, which should cover most of the WF hole around constants right now.

I'm guessing what's happening is #69981 introduced a bug, hiding the ICEs, as some of these cases no longer fail during type-checking, but with my changes, they do again.

I've just looked at the debug log and this is fascinating: I believe what's happening is, because there are inference variables, this gets hit, but the TypeckTables are not marked as tainted:

rust/src/librustc_typeck/check/writeback.rs

Lines 639 to 646 in 6c19a10

match self.infcx.fully_resolve(&t) {
Ok(t) => self.infcx.tcx.erase_regions(&t),
Err(_) => {
debug!("Resolver::fold_ty: input type `{:?}` not fully resolvable", t);
self.report_error(t);
self.tcx().types.err
}
}

So we end up with ty::Error types with no indication that there were errors.
I'll try to see how targeted of a fix I can make.

@eddyb eddyb mentioned this issue Mar 27, 2020
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@bors bors closed this as completed in d12f030 Apr 15, 2020
This was referenced Apr 16, 2020
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A-const-eval Area: Constant evaluation (MIR interpretation) A-MIR Area: Mid-level IR (MIR) - https://blog.rust-lang.org/2016/04/19/MIR.html C-bug Category: This is a bug. glacier ICE tracked in rust-lang/glacier. I-ICE Issue: The compiler panicked, giving an Internal Compilation Error (ICE) ❄️ P-high High priority T-compiler Relevant to the compiler team, which will review and decide on the PR/issue.
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typeck: always expose repeat count AnonConsts' parent in generics_of. eddyb/rust
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@eddyb @pnkfelix @Centril @hellow554 @jonas-schievink @Alexendoo @DutchGhost @rust-lang-glacier-bot