ICE: translating unsupported cast: *mut [u32] (cast_other) -> *mut c_void (cast_pointer)

[strega-nil]

error: internal compiler error: translating unsupported cast: *mut [u32] (cast_other) -> *mut libc::types::common::c95::c_void (cast_pointer)
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: run with `RUST_BACKTRACE=1` for a backtrace
thread 'rustc' panicked at 'Box<Any>', /home/rustbuild/src/rust-buildbot/slave/nightly-dist-rustc-linux/build/src/libsyntax/diagnostic.rs:189

stack backtrace:
   1:     0x7f58387ff2f2 - sys::backtrace::write::hd861c9cad5664affQBA
   2:     0x7f5838825342 - panicking::on_panic::h2d36a117ae395cb9jHJ
   3:     0x7f583876ba89 - rt::unwind::begin_unwind_inner::h020c424433824dc2mnJ
   4:     0x7f5835d790ed - rt::unwind::begin_unwind::h10233696008248825440
   5:     0x7f5835d79925 - diagnostic::Handler::bug::h5b4a3d5d737e3662KdE
   6:     0x7f5836782d2b - session::Session::bug::hc4ea5c682d373bb1tYp
   7:     0x7f5837ef9cde - trans::expr::trans_imm_cast::hcd3ecb042c0927e9bTj
   8:     0x7f5837ee637c - trans::expr::trans_unadjusted::h98b3a24d34abc9f436h
   9:     0x7f5837ea80e0 - trans::expr::trans::h66ceb310b9edf1f9bwh
  10:     0x7f5837ed986b - trans::callee::trans_args::hf2cfa069a4970bdbG3g
  11:     0x7f5837edee74 - trans::callee::trans_call_inner::h17056753389190948462
  12:     0x7f5837ee8077 - trans::expr::trans_rvalue_dps_unadjusted::hbd2cd1fd54de27cayCi
  13:     0x7f5837ea6bd6 - trans::expr::trans_into::hf1ef6b0748ac8f9eTph
  14:     0x7f5837ea5f5e - trans::controlflow::trans_stmt_semi::h91aecc9fc3a8807dI6d
  15:     0x7f5837ea762d - trans::controlflow::trans_block::h47e6e8902755cf9cv7d
  16:     0x7f5837ee768a - trans::expr::trans_rvalue_dps_unadjusted::hbd2cd1fd54de27cayCi
  17:     0x7f5837ea6bd6 - trans::expr::trans_into::hf1ef6b0748ac8f9eTph
  18:     0x7f5837ea7987 - trans::controlflow::trans_block::h47e6e8902755cf9cv7d
  19:     0x7f5837f62ed0 - trans::base::trans_closure::h70b835bf44b08f62ent
  20:     0x7f5837e96f4b - trans::base::trans_fn::h88672d255f7695867xt
  21:     0x7f5837e9809d - trans::monomorphize::monomorphic_fn::h5456f629cfa11f62Oud
  22:     0x7f5837eb86e7 - trans::glue::trans_struct_drop::hca0bf2ab407ff704XKe
  23:     0x7f5837eb60c8 - trans::glue::trans_struct_drop_flag::hd2fdfa898dbd0abe5Ie
  24:     0x7f5837eaf229 - trans::glue::get_drop_glue::h995ee19a14e101b31De
  25:     0x7f5837eae72d - trans::glue::drop_ty::h5b7f57924de7b3bdvAe
  26:     0x7f5837fd1819 - trans::cleanup::DropValue<'tcx>.Cleanup<'tcx>::trans::h050e22dd6399d306nXK
  27:     0x7f5837ebfe1e - trans::cleanup::FunctionContext<'blk, 'tcx>.CleanupMethods<'blk, 'tcx>::pop_and_trans_custom_cleanup_scope::h4f8733d43bdc3f3cR0J
  28:     0x7f5837f7daa5 - trans::_match::trans_match_inner::hafede36b631dfe103Kw
  29:     0x7f5837ee7659 - trans::expr::trans_rvalue_dps_unadjusted::hbd2cd1fd54de27cayCi
  30:     0x7f5837ea6bd6 - trans::expr::trans_into::hf1ef6b0748ac8f9eTph
  31:     0x7f5837f92b2e - trans::_match::mk_binding_alloca::h6781106208550372573
  32:     0x7f5837ea60ad - trans::base::init_local::h6b5a17c439dc15bfGBs
  33:     0x7f5837ea7662 - trans::controlflow::trans_block::h47e6e8902755cf9cv7d
  34:     0x7f5837f62ed0 - trans::base::trans_closure::h70b835bf44b08f62ent
  35:     0x7f5837e96f4b - trans::base::trans_fn::h88672d255f7695867xt
  36:     0x7f5837e93819 - trans::base::trans_item::h1cf2dcffa3cf86bfZVt
  37:     0x7f5837f6967c - trans::base::trans_crate::h88960ef764a955bcaSu
  38:     0x7f5838e23f92 - driver::phase_4_translate_to_llvm::h5d3ca9bd44c7f33agOa
  39:     0x7f5838dff8ea - driver::compile_input::h124aae68147ae8b8Nba
  40:     0x7f5838ec415d - run_compiler::hffd5283ae5d6d3abG6b
  41:     0x7f5838ec1ecc - thunk::F.Invoke<A, R>::invoke::h16438916220137010031
  42:     0x7f5838ec0b20 - rt::unwind::try::try_fn::h17325604874211535233
  43:     0x7f5838891118 - rust_try_inner
  44:     0x7f5838891105 - rust_try
  45:     0x7f5838ec12ab - thunk::F.Invoke<A, R>::invoke::h5807416775295653773
  46:     0x7f5838812b45 - sys::thread::thread_start::h2188587ec04914c6t8E
  47:     0x7f583285d181 - start_thread
  48:     0x7f58383e447c - __clone
  49:                0x0 - <unknown>

Could not compile `handmade_libsdl`.

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

This is done when compiling this repository. Use cargo build on either the entire handmade_hero crate, or handmade_libsdl. Warning: Ugly, no_std code ahead!

Cleaned up repo: newrepo

It does need to be across crate lines, and needs to be returned in a result, afaict.

rustc 1.0.0-nightly (91bdf23f5 2015-03-09) (built 2015-03-09)

[strega-nil]

The issue is that I should not be able to write *self.data as *mut c_void because self.data is a [T].

Same with #23240.

[strega-nil]

Actually, to that end, why is *mut [T] bigger than a *mut anything? Why is a *mut a fat pointer at all?

[jdm]

Very similar to #22554, #21397, #19424.

[strega-nil]

@jdm Yes it is, pretty much the same. A *const [x] should not be differently sized from a *const y, at least IMHO, so why is it?

[huonw]

*const X is a &X with fewer guarantees; one can convert between them freely (if you ensure the guarantees are maintained for *const X -> &X). In particular, this means *const [T] is a fat pointer to match &[T].

[strega-nil]

That is weird...

[strega-nil]

NVM, I now understand why it is a fat pointer. However, this should be an easy fix, right? Why is a *mut [T] seen as the same size as a *mut T in rustc?

Well, now it isn't, so #23240 is fixed, but it still panics at translating unsupported cast.