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panic with "Layout mismatch when copying!" #58742

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mattheww opened this issue Feb 25, 2019 · 5 comments
Closed

panic with "Layout mismatch when copying!" #58742

mattheww opened this issue Feb 25, 2019 · 5 comments
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@oli-obk
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A-const-eval Area: Constant evaluation (MIR interpretation) I-ICE Issue: The compiler panicked, giving an Internal Compilation Error (ICE) ❄️ P-high High priority regression-from-stable-to-beta Performance or correctness regression from stable to beta. regression-from-stable-to-nightly Performance or correctness regression from stable to nightly. T-compiler Relevant to the compiler team, which will review and decide on the PR/issue.

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@mattheww
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Running yesterday's nightly rustdoc on the following file panics for me:

const fn one(arr: &[u8; 1]) -> u8 {
    arr[0]
}

const fn two(byte: u8) -> [u8; 1] {[
    byte
]}

const fn three(data: u8) -> u8 {
    one(&two(data))
}

const FOO: u8 = three(0x0);

It says thread 'rustc' panicked at 'Layout mismatch when copying!.

The version is rustdoc 1.34.0-nightly (097c04cf4 2019-02-24).

There isn't a problem compiling the file.

Output including backtrace:

% RUST_BACKTRACE=1 rustdoc +nightly --color=never src/lib.rs
thread 'rustc' panicked at 'Layout mismatch when copying!
src: OpTy {
    op: Indirect(
        MemPlace {
            ptr: Ptr(
                Pointer {
                    alloc_id: AllocId(
                        4
                    ),
                    offset: Size {
                        raw: 0
                    },
                    tag: ()
                }
            ),
            align: Align {
                pow2: 0
            },
            meta: None
        }
    ),
    layout: TyLayout {
        ty: [u8; 1],
        details: LayoutDetails {
            variants: Single {
                index: 0
            },
            fields: Array {
                stride: Size {
                    raw: 1
                },
                count: 1
            },
            abi: Aggregate {
                sized: true
            },
            align: AbiAndPrefAlign {
                abi: Align {
                    pow2: 0
                },
                pref: Align {
                    pow2: 0
                }
            },
            size: Size {
                raw: 1
            }
        }
    }
}
dest: PlaceTy {
    place: Local {
        frame: 0,
        local: _2
    },
    layout: TyLayout {
        ty: u8,
        details: LayoutDetails {
            variants: Single {
                index: 0
            },
            fields: Union(
                0
            ),
            abi: Scalar(
                Scalar {
                    value: Int(
                        I8,
                        false
                    ),
                    valid_range: 0..=255
                }
            ),
            align: AbiAndPrefAlign {
                abi: Align {
                    pow2: 0
                },
                pref: Align {
                    pow2: 0
                }
            },
            size: Size {
                raw: 1
            }
        }
    }
}', src/librustc_mir/interpret/place.rs:826:9
note: Some details are omitted, run with `RUST_BACKTRACE=full` for a verbose backtrace.
stack backtrace:
   0: std::sys::unix::backtrace::tracing::imp::unwind_backtrace
             at src/libstd/sys/unix/backtrace/tracing/gcc_s.rs:39
   1: std::sys_common::backtrace::_print
             at src/libstd/sys_common/backtrace.rs:70
   2: std::panicking::default_hook::{{closure}}
             at src/libstd/sys_common/backtrace.rs:58
             at src/libstd/panicking.rs:200
   3: std::panicking::default_hook
             at src/libstd/panicking.rs:215
   4: std::panicking::rust_panic_with_hook
             at src/libstd/panicking.rs:478
   5: std::panicking::continue_panic_fmt
             at src/libstd/panicking.rs:385
   6: std::panicking::begin_panic_fmt
             at src/libstd/panicking.rs:340
   7: rustc_mir::interpret::place::<impl rustc_mir::interpret::eval_context::EvalContext<'a, 'mir, 'tcx, M>>::copy_op_no_validate
   8: rustc_mir::interpret::step::<impl rustc_mir::interpret::eval_context::EvalContext<'a, 'mir, 'tcx, M>>::run
   9: rustc_mir::const_eval::eval_body_using_ecx
  10: rustc_mir::const_eval::const_eval_raw_provider
  11: rustc::ty::query::__query_compute::const_eval_raw
  12: rustc::ty::query::<impl rustc::ty::query::config::QueryAccessors<'tcx> for rustc::ty::query::queries::const_eval_raw<'tcx>>::compute
  13: rustc::dep_graph::graph::DepGraph::with_task_impl
  14: rustc::ty::query::plumbing::<impl rustc::ty::context::TyCtxt<'a, 'gcx, 'tcx>>::get_query
  15: <rustc_mir::interpret::eval_context::EvalContext<'a, 'mir, 'tcx, M>>::const_eval_raw
  16: rustc_mir::interpret::place::<impl rustc_mir::interpret::eval_context::EvalContext<'a, 'mir, 'tcx, M>>::eval_place_to_mplace
  17: rustc_mir::interpret::place::<impl rustc_mir::interpret::eval_context::EvalContext<'a, 'mir, 'tcx, M>>::eval_place
  18: rustc_mir::interpret::step::<impl rustc_mir::interpret::eval_context::EvalContext<'a, 'mir, 'tcx, M>>::run
  19: rustc_mir::const_eval::eval_body_using_ecx
  20: rustc_mir::const_eval::const_eval_raw_provider
  21: rustc::ty::query::__query_compute::const_eval_raw
  22: rustc::ty::query::<impl rustc::ty::query::config::QueryAccessors<'tcx> for rustc::ty::query::queries::const_eval_raw<'tcx>>::compute
  23: rustc::dep_graph::graph::DepGraph::with_task_impl
  24: rustc::ty::query::plumbing::<impl rustc::ty::context::TyCtxt<'a, 'gcx, 'tcx>>::get_query
  25: rustc_mir::const_eval::const_eval_provider
  26: rustc::ty::query::__query_compute::const_eval
  27: rustc::ty::query::<impl rustc::ty::query::config::QueryAccessors<'tcx> for rustc::ty::query::queries::const_eval<'tcx>>::compute
  28: rustc::dep_graph::graph::DepGraph::with_task_impl
  29: rustc::ty::query::plumbing::<impl rustc::ty::context::TyCtxt<'a, 'gcx, 'tcx>>::get_query
  30: rustc_lint::builtin::check_const
  31: <rustc_lint::register_builtins::BuiltinCombinedLateLintPass as rustc::lint::LateLintPass<'a, 'tcx>>::check_item
  32: <rustc::lint::context::LateContext<'a, 'tcx> as rustc::hir::intravisit::Visitor<'tcx>>::visit_item
  33: <rustc::lint::context::LateContext<'a, 'tcx> as rustc::hir::intravisit::Visitor<'tcx>>::visit_mod
  34: rustc::hir::intravisit::walk_crate
  35: rustc::lint::context::check_crate
  36: rustc_driver::driver::phase_3_run_analysis_passes::{{closure}}::{{closure}}
             at /rustc/097c04cf433048585dd9e3f63b30e03cc3509e4b/src/librustc_driver/driver.rs:1333
             at /rustc/097c04cf433048585dd9e3f63b30e03cc3509e4b/src/librustc/util/common.rs:150
             at /rustc/097c04cf433048585dd9e3f63b30e03cc3509e4b/src/librustc/util/common.rs:144
             at /rustc/097c04cf433048585dd9e3f63b30e03cc3509e4b/src/librustc_driver/driver.rs:1333
  37: rustc::util::common::time
             at /rustc/097c04cf433048585dd9e3f63b30e03cc3509e4b/src/librustc/util/common.rs:150
             at /rustc/097c04cf433048585dd9e3f63b30e03cc3509e4b/src/librustc/util/common.rs:144
  38: <std::thread::local::LocalKey<T>>::with
             at /rustc/097c04cf433048585dd9e3f63b30e03cc3509e4b/src/librustc_driver/driver.rs:1321
             at /rustc/097c04cf433048585dd9e3f63b30e03cc3509e4b/src/librustc/ty/context.rs:2000
             at /rustc/097c04cf433048585dd9e3f63b30e03cc3509e4b/src/librustc/ty/context.rs:1966
             at /rustc/097c04cf433048585dd9e3f63b30e03cc3509e4b/src/librustc/ty/context.rs:1899
             at /rustc/097c04cf433048585dd9e3f63b30e03cc3509e4b/src/librustc/ty/context.rs:1965
             at /rustc/097c04cf433048585dd9e3f63b30e03cc3509e4b/src/librustc/ty/context.rs:1999
             at /rustc/097c04cf433048585dd9e3f63b30e03cc3509e4b/src/librustc/ty/context.rs:1954
             at /rustc/097c04cf433048585dd9e3f63b30e03cc3509e4b/src/libstd/thread/local.rs:300
             at /rustc/097c04cf433048585dd9e3f63b30e03cc3509e4b/src/libstd/thread/local.rs:246
             at /rustc/097c04cf433048585dd9e3f63b30e03cc3509e4b/src/librustc/ty/context.rs:1946
             at /rustc/097c04cf433048585dd9e3f63b30e03cc3509e4b/src/libstd/thread/local.rs:300
             at /rustc/097c04cf433048585dd9e3f63b30e03cc3509e4b/src/libstd/thread/local.rs:246
  39: rustc::ty::context::TyCtxt::create_and_enter
             at /rustc/097c04cf433048585dd9e3f63b30e03cc3509e4b/src/librustc/ty/context.rs:1938
             at /rustc/097c04cf433048585dd9e3f63b30e03cc3509e4b/src/librustc/ty/context.rs:1977
             at /rustc/097c04cf433048585dd9e3f63b30e03cc3509e4b/src/librustc/ty/context.rs:1290
  40: rustc_driver::driver::phase_3_run_analysis_passes
             at /rustc/097c04cf433048585dd9e3f63b30e03cc3509e4b/src/librustc_driver/driver.rs:1213
  41: <scoped_tls::ScopedKey<T>>::set
             at src/librustdoc/core.rs:494
             at /rustc/097c04cf433048585dd9e3f63b30e03cc3509e4b/src/librustc_driver/driver.rs:65
             at /cargo/registry/src/github.com-1ecc6299db9ec823/scoped-tls-0.1.2/src/lib.rs:155
  42: <scoped_tls::ScopedKey<T>>::set
             at /rustc/097c04cf433048585dd9e3f63b30e03cc3509e4b/src/librustc_driver/driver.rs:64
             at src/librustdoc/core.rs:400
             at src/librustdoc/lib.rs:434
             at /cargo/registry/src/github.com-1ecc6299db9ec823/scoped-tls-0.1.2/src/lib.rs:155
             at /rustc/097c04cf433048585dd9e3f63b30e03cc3509e4b/src/libsyntax/lib.rs:100
             at /cargo/registry/src/github.com-1ecc6299db9ec823/scoped-tls-0.1.2/src/lib.rs:155
  43: syntax::with_globals
             at /rustc/097c04cf433048585dd9e3f63b30e03cc3509e4b/src/libsyntax/lib.rs:99

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 1.34.0-nightly (097c04cf4 2019-02-24) running on i686-unknown-linux-gnu
@matthewjasper matthewjasper added I-ICE Issue: The compiler panicked, giving an Internal Compilation Error (ICE) ❄️ A-const-eval Area: Constant evaluation (MIR interpretation) labels Feb 25, 2019
@matthewjasper
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This applies when compiling as well.

Possibly due to #58511 cc @oli-obk @RalfJung

@matthewjasper matthewjasper changed the title rustdoc panics with "Layout mismatch when copying!" panic with "Layout mismatch when copying!" Feb 25, 2019
@Centril Centril added regression-from-stable-to-nightly Performance or correctness regression from stable to nightly. T-compiler Relevant to the compiler team, which will review and decide on the PR/issue. regression-from-stable-to-beta Performance or correctness regression from stable to beta. labels Feb 26, 2019
@Centril
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Centril commented Feb 26, 2019

This doesn't yet apply to beta but will soon.

@RalfJung
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So copy_op complains that a [u8; 1] gets copied to a u8. But where does the layout mismatch come from? Almost looks like we fail to adjust the layout when indexing the slice?

@pnkfelix
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triage: P-high. Speculatively assigning to @oli-obk

@pnkfelix pnkfelix added the P-high High priority label Feb 28, 2019
mattheww added a commit to mattheww/rmicrobit that referenced this issue Mar 10, 2019
@mattheww
Revert "font_entry(): pass small array by value"
7d9842f 
This reverts commit 6c1bdf3.

At present this change breaks nightly builds and nightly rustdoc:
rust-lang/rust#58742
@oli-obk
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oli-obk commented Mar 11, 2019

Fixed by #58784

@oli-obk oli-obk closed this as completed Mar 11, 2019
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A-const-eval Area: Constant evaluation (MIR interpretation) I-ICE Issue: The compiler panicked, giving an Internal Compilation Error (ICE) ❄️ P-high High priority regression-from-stable-to-beta Performance or correctness regression from stable to beta. regression-from-stable-to-nightly Performance or correctness regression from stable to nightly. T-compiler Relevant to the compiler team, which will review and decide on the PR/issue.
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@pnkfelix @RalfJung @oli-obk @mattheww @Centril @matthewjasper