ICE on nightly: "Forcing query with already existing DepNode."

[oconnor663]

Cargo/rustc version:

$ rustc +nightly --version
rustc 1.37.0-nightly (7cdaffd79 2019-06-05)
$ cargo +nightly --version
cargo 1.37.0-nightly (545f35425 2019-05-23)

Repro:

$ git clone https://github.com/oconnor663/blake2_simd
$ cd blake2_simd/blake2b
$ git rev-parse HEAD
4734a5eb5dad99b54c83bad176b3decdc081bdb1
$ cargo +nightly build
    Updating crates.io index
   Compiling arrayvec v0.4.10
   Compiling nodrop v0.1.13
   Compiling arrayref v0.3.5
   Compiling constant_time_eq v0.1.3
   Compiling blake2b_simd v0.5.1 (/tmp/blake2_simd/blake2b)
thread 'rustc' panicked at 'Forcing query with already existing DepNode.
- query-key: ParamEnvAnd { param_env: ParamEnv { caller_bounds: [], reveal: All, def_id: None }, value: (Const { ty: [u32; 8], val: ByRef(AllocId(1397).0x0, Allocation { bytes: [0, 0, 0, 0, 1, 0, 0, 0, 2, 0, 0, 0, 3, 0, 0, 0, 4, 0, 0, 0, 5, 0, 0, 0, 6, 0, 0, 0, 7, 0, 0, 0], relocations: Relocations(SortedMap { data: [] }), undef_mask: UndefMask { blocks: [4294967295], len: Size { raw: 32 } }, align: Align { pow2: 2 }, mutability: Immutable, extra: () }) }, field[0]) }
- dep-node: const_field(eb99858e4874f291-9a55d263e1a1abdf)', src/librustc/ty/query/plumbing.rs:548:9
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 1.37.0-nightly (7cdaffd79 2019-06-05) running on x86_64-unknown-linux-gnu
note: compiler flags: -C debuginfo=2 -C incremental --crate-type lib
note: some of the compiler flags provided by cargo are hidden
error: Could not compile `blake2b_simd`.
To learn more, run the command again with --verbose.

[sfackler]

I just ran into this as well.

[mati865]

It's the same as #61530
See #61530 (comment) for details

[gnzlbg]

Similar error on many stdsimd targets, e.g., aarch64: https://travis-ci.com/rust-lang-nursery/stdsimd/jobs/206228395#L941

thread 'rustc' panicked at 'Forcing query with already existing DepNode.
- query-key: ParamEnvAnd { param_env: ParamEnv { caller_bounds: [], reveal: All, def_id: None }, value: (Const { ty: [u32; 16], val: ByRef(AllocId(3181).0x0, Allocation { bytes: [0, 0, 0, 0, 1, 0, 0, 0, 2, 0, 0, 0, 3, 0, 0, 0, 4, 0, 0, 0, 5, 0, 0, 0, 6, 0, 0, 0, 7, 0, 0, 0, 8, 0, 0, 0, 9, 0, 0, 0, 10, 0, 0, 0, 11, 0, 0, 0, 12, 0, 0, 0, 13, 0, 0, 0, 14, 0, 0, 0, 15, 0, 0, 0], relocations: Relocations(SortedMap { data: [] }), undef_mask: UndefMask { blocks: [18446744073709551615, 0], len: Size { raw: 64 } }, align: Align { pow2: 2 }, mutability: Immutable, extra: () }) }, field[0]) }
- dep-node: const_field(449c8050006f9d1b-207c1d76bc38c220)', src/librustc/ty/query/plumbing.rs:548:9

[pnkfelix]

(It doesn't seem like this is an exact duplicate of #61530, at least not as titled, since #61530 describes a bug that is exposed by using #![feature(stdsimd)], but the crate here on #61594 claims to target stable rust.)

[pnkfelix]

ugh and @eddyb's notes on #61530 indicate that bug is somehow dependent on incremental compilation. fun...

[pnkfelix]

triage: P-high, leaving nominated to discuss relationship with #61530, assigning to self for initial investigation.

[mati865]

@pnkfelix #61530 title is wrong. The issue comes down to using LLVM intrinsics, blake2b_simd works on stable because it's using core::arch which leads to stdsimd.
In #61530 it's done directly but underlying issue remains the same.

[oconnor663]

Re: incremental compilation, the ICE does seem to go away when I build with --release. Didn't notice that before.