Kani does not support fat pointer comparison

[avanhatt]

RMC crashes on the core Rust test (src/test/ui/raw-fat-ptr.rs).

After minimizing:

trait a {}
fn main() {
  let b : &mut[ *const a] = &mut[];
  b.sort_by(| c, d | c.cmp(d))
}

thread 'rustc' panicked at 'BinaryOperation Expression does not typecheck Equal Expr { value: Symbol { identifier: "_RNvXs0_NtNtCsgWci0eQkB8o_4core3ptr9const_ptrPDNtCs8ZdcvQGSn7l_4test1aEL_NtNtB9_3cmp9PartialEq2eqBK_::1::var_3" }, typ: StructTag("tag-dyn a"), location: None } Expr { value: Symbol { identifier: "_RNvXs0_NtNtCsgWci0eQkB8o_4core3ptr9const_ptrPDNtCs8ZdcvQGSn7l_4test1aEL_NtNtB9_3cmp9PartialEq2eqBK_::1::var_4" }, typ: StructTag("tag-dyn a"), location: None }', compiler/rustc_codegen_llvm/src/gotoc/cbmc/goto_program/expr.rs:863:9
stack backtrace:
   0: rust_begin_unwind
             at ./library/std/src/panicking.rs:517:5
   1: std::panicking::begin_panic_fmt
             at ./library/std/src/panicking.rs:460:5
   2: rustc_codegen_llvm::gotoc::cbmc::goto_program::expr::Expr::binop
             at ./compiler/rustc_codegen_llvm/src/gotoc/cbmc/goto_program/expr.rs:863:9
   3: rustc_codegen_llvm::gotoc::cbmc::goto_program::expr::Expr::eq
             at ./compiler/rustc_codegen_llvm/src/gotoc/cbmc/goto_program/expr.rs:985:9
   4: rustc_codegen_llvm::gotoc::rvalue::<impl rustc_codegen_llvm::gotoc::metadata::GotocCtx>::codegen_comparison
             at ./compiler/rustc_codegen_llvm/src/gotoc/rvalue.rs:24:21
   5: rustc_codegen_llvm::gotoc::rvalue::<impl rustc_codegen_llvm::gotoc::metadata::GotocCtx>::codegen_rvalue_binary_op
             at ./compiler/rustc_codegen_llvm/src/gotoc/rvalue.rs:305:17
   6: rustc_codegen_llvm::gotoc::rvalue::<impl rustc_codegen_llvm::gotoc::metadata::GotocCtx>::codegen_rvalue
             at ./compiler/rustc_codegen_llvm/src/gotoc/rvalue.rs:373:59
   7: rustc_codegen_llvm::gotoc::statement::<impl rustc_codegen_llvm::gotoc::metadata::GotocCtx>::codegen_statement
             at ./compiler/rustc_codegen_llvm/src/gotoc/statement.rs:482:33
   8: rustc_codegen_llvm::gotoc::<impl rustc_codegen_llvm::gotoc::metadata::GotocCtx>::codegen_block
             at ./compiler/rustc_codegen_llvm/src/gotoc/mod.rs:124:32
   9: rustc_codegen_llvm::gotoc::<impl rustc_codegen_llvm::gotoc::metadata::GotocCtx>::codegen_function::{{closure}}
             at ./compiler/rustc_codegen_llvm/src/gotoc/mod.rs:295:71
  10: core::iter::traits::iterator::Iterator::for_each::call::{{closure}}
             at ./library/core/src/iter/traits/iterator.rs:730:29
  11: core::iter::adapters::map::map_fold::{{closure}}
             at ./library/core/src/iter/adapters/map.rs:84:21
  12: <core::iter::adapters::enumerate::Enumerate<I> as core::iter::traits::iterator::Iterator>::fold::enumerate::{{closure}}
             at ./library/core/src/iter/adapters/enumerate.rs:106:27
  13: core::iter::traits::iterator::Iterator::fold
             at ./library/core/src/iter/traits/iterator.rs:2170:21
  14: <core::iter::adapters::enumerate::Enumerate<I> as core::iter::traits::iterator::Iterator>::fold
             at ./library/core/src/iter/adapters/enumerate.rs:112:9
  15: <core::iter::adapters::map::Map<I,F> as core::iter::traits::iterator::Iterator>::fold
             at ./library/core/src/iter/adapters/map.rs:124:9
  16: core::iter::traits::iterator::Iterator::for_each
             at ./library/core/src/iter/traits/iterator.rs:733:9
  17: rustc_codegen_llvm::gotoc::<impl rustc_codegen_llvm::gotoc::metadata::GotocCtx>::codegen_function
             at ./compiler/rustc_codegen_llvm/src/gotoc/mod.rs:295:13
  18: <rustc_codegen_llvm::gotoc::GotocCodegenBackend as rustc_codegen_ssa::traits::backend::CodegenBackend>::codegen_crate::{{closure}}
             at ./compiler/rustc_codegen_llvm/src/gotoc/mod.rs:479:35
  19: rustc_codegen_llvm::gotoc::<impl rustc_codegen_llvm::gotoc::metadata::GotocCtx>::call_with_panic_debug_info::{{closure}}
             at ./compiler/rustc_codegen_llvm/src/gotoc/mod.rs:103:13
  20: std::thread::local::LocalKey<T>::try_with
             at ./library/std/src/thread/local.rs:399:16
  21: std::thread::local::LocalKey<T>::with
             at ./library/std/src/thread/local.rs:375:9
  22: rustc_codegen_llvm::gotoc::<impl rustc_codegen_llvm::gotoc::metadata::GotocCtx>::call_with_panic_debug_info
             at ./compiler/rustc_codegen_llvm/src/gotoc/mod.rs:101:9
  23: <rustc_codegen_llvm::gotoc::GotocCodegenBackend as rustc_codegen_ssa::traits::backend::CodegenBackend>::codegen_crate
             at ./compiler/rustc_codegen_llvm/src/gotoc/mod.rs:478:25
  24: rustc_interface::passes::start_codegen::{{closure}}
             at ./compiler/rustc_interface/src/passes.rs:1056:9
  25: rustc_data_structures::profiling::VerboseTimingGuard::run
             at ./compiler/rustc_data_structures/src/profiling.rs:611:9
  26: rustc_session::utils::<impl rustc_session::session::Session>::time
             at ./compiler/rustc_session/src/utils.rs:16:9
  27: rustc_interface::passes::start_codegen
             at ./compiler/rustc_interface/src/passes.rs:1055:19
  28: rustc_interface::queries::Queries::ongoing_codegen::{{closure}}::{{closure}}
             at ./compiler/rustc_interface/src/queries.rs:254:20
  29: rustc_interface::passes::QueryContext::enter::{{closure}}
             at ./compiler/rustc_interface/src/passes.rs:780:42
  30: rustc_middle::ty::context::tls::enter_context::{{closure}}
             at ./compiler/rustc_middle/src/ty/context.rs:1784:50
  31: rustc_middle::ty::context::tls::set_tlv
             at ./compiler/rustc_middle/src/ty/context.rs:1768:9
  32: rustc_middle::ty::context::tls::enter_context
             at ./compiler/rustc_middle/src/ty/context.rs:1784:9
  33: rustc_interface::passes::QueryContext::enter
             at ./compiler/rustc_interface/src/passes.rs:780:9
  34: rustc_interface::queries::Queries::ongoing_codegen::{{closure}}
             at ./compiler/rustc_interface/src/queries.rs:245:13
  35: rustc_interface::queries::Query<T>::compute
             at ./compiler/rustc_interface/src/queries.rs:38:28
  36: rustc_interface::queries::Queries::ongoing_codegen
             at ./compiler/rustc_interface/src/queries.rs:243:9
  37: rustc_driver::run_compiler::{{closure}}::{{closure}}
             at ./compiler/rustc_driver/src/lib.rs:407:13
  38: rustc_interface::queries::<impl rustc_interface::interface::Compiler>::enter
             at ./compiler/rustc_interface/src/queries.rs:394:19
  39: rustc_driver::run_compiler::{{closure}}
             at ./compiler/rustc_driver/src/lib.rs:312:22
  40: rustc_interface::interface::create_compiler_and_run::{{closure}}
             at ./compiler/rustc_interface/src/interface.rs:209:13
  41: rustc_span::with_source_map
             at ./compiler/rustc_span/src/lib.rs:911:5
  42: rustc_interface::interface::create_compiler_and_run
             at ./compiler/rustc_interface/src/interface.rs:203:5
  43: rustc_interface::interface::run_compiler::{{closure}}
             at ./compiler/rustc_interface/src/interface.rs:225:12
  44: rustc_interface::util::setup_callbacks_and_run_in_thread_pool_with_globals::{{closure}}::{{closure}}
             at ./compiler/rustc_interface/src/util.rs:157:13
  45: scoped_tls::ScopedKey<T>::set
             at /home/ubuntu/.cargo/registry/src/github.1485827954.workers.dev-1ecc6299db9ec823/scoped-tls-1.0.0/src/lib.rs:137:9
  46: rustc_span::create_session_globals_then
             at ./compiler/rustc_span/src/lib.rs:105:5
  47: rustc_interface::util::setup_callbacks_and_run_in_thread_pool_with_globals::{{closure}}
             at ./compiler/rustc_interface/src/util.rs:155:9
  48: rustc_interface::util::scoped_thread::{{closure}}
             at ./compiler/rustc_interface/src/util.rs:130:24
note: Some details are omitted, run with `RUST_BACKTRACE=full` for a verbose 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/issues/new?labels=C-bug%2C+I-ICE%2C+T-compiler&template=ice.md

note: rustc 1.56.0-dev running on x86_64-unknown-linux-gnu

note: compiler flags: -Z codegen-backend=gotoc -Z symbol-mangling-version=v0 -Z symbol_table_passes=

query stack during panic:
end of query stack

[RMC] current codegen item: codegen_function: std::ptr::const_ptr::<impl std::cmp::PartialEq for *const T>::eq

RMC unexpectedly panicked during code generation.

If you are seeing this message, please file an issue here instead of on the Rust compiler: https://github.com/model-checking/rmc/issues/new?labels=bug&template=bug_report.md
warning: 2 warnings emitted

[celinval]

Note to myself: We need to compare the data field and, potentially, the metadata. Need to double check the latter.

[celinval]

https://doc.rust-lang.org/std/ptr/fn.eq.html