ICE: this path should not cause illegal move

[Zoxc]

Input:

struct T(u8);

fn t() -> *mut T {
    unsafe { 0u8 as *mut T }
}

fn main() {
    let a = unsafe { *t() };
}

Output:

$ rustc ../test.rs 
../test.rs:9:19: 9:23 error: internal compiler error: this path should not cause illegal move
../test.rs:9    let a = unsafe { *t() };
                                 ^~~~
note: the compiler unexpectedly panicked. this is a bug.
note: we would appreciate a bug report: http://doc.rust-lang.org/complement-bugreport.html
note: run with `RUST_BACKTRACE=1` for a backtrace
thread 'rustc' panicked at 'Box<Any>', /Users/John/Documents/dev/rust/src/libsyntax/diagnostic.rs:123

stack backtrace:
   1:        0x10f825b75 - sys::backtrace::write::h757d4037fec4513elCt
   2:        0x10f84800f - failure::on_fail::he99e1d2cd81a67a80Hz
   3:        0x10f7b3c8a - rt::unwind::begin_unwind_inner::hede15ebc165353e0Qpz
   4:        0x10d508707 - rt::unwind::begin_unwind::h5150449308391082809
   5:        0x10d50869c - diagnostic::SpanHandler::span_bug::h1cc7aa850b4525b9nQF
   6:        0x10c93bc1d - session::Session::span_bug::h9dff6f0c981e0b95mRq
   7:        0x10c547999 - borrowck::build_borrowck_dataflow_data::hbfab9f3785e58ec8QRe
   8:        0x10c5432fb - borrowck::borrowck_fn::h9d4d5a57ec1e26a2cPe
   9:        0x10c5440f2 - borrowck::borrowck_item::hd3de64f0b51b624a9Ne
  10:        0x10c54461f - borrowck::check_crate::hab49ad1d67fb67e9ZIe
  11:        0x10c09e8aa - driver::phase_3_run_analysis_passes::h3bf5eb3f470c8788gwa
  12:        0x10c082d90 - driver::compile_input::h63293298907e332cxba
  13:        0x10c14e7ba - monitor::unboxed_closure.22558
  14:        0x10c14cf15 - thunk::F.Invoke<A, R>::invoke::h15985566512806182469
  15:        0x10c14bcf0 - rt::unwind::try::try_fn::h5957420952141477940
  16:        0x10f8b1189 - rust_try_inner
  17:        0x10f8b1176 - rust_try
  18:        0x10c14c3ec - thunk::F.Invoke<A, R>::invoke::h12578415658120090831
  19:        0x10f835814 - sys::thread::thread_start::he6c5dcba45c95bf2drw
  20:     0x7fff933e22fc - _pthread_body
  21:     0x7fff933e2279 - _pthread_body

[tupshin]

FWIW, I get the same compiler bug when building my repo at the following commit:
https://github.com/tupshin/cql-ffi/tree/3e3bc9cf2143d7539996204e78b93110c90799e3
Workaround applied with the subsequent commit:
https://github.com/tupshin/cql-ffi/tree/72fd94079f336b8863b3d920f499150d8f5493f8

[tupshin]

Bump? I'm finding this increasingly hard to (elegantly, at least) to work around in my FFI code. Any idea what's going on with this?

[tupshin]

This is now a full on blocker. Pausing until this is fixed.

[kornelski]

I've ran into this as well:

pub struct Foo;
pub fn destroy(handle: *mut Foo) {
    unsafe {
        *handle;
    }
}

internal compiler error: this path should not cause illegal move
:6 *handle;

rustc 1.0.0-nightly (1d00c54 2015-01-30 19:56:34 +0000)

[jakerr]

I hit this as well when playing with an example I found on Stack Overflow

Playground half way through changing some type signatures from the SO example: http://is.gd/pBUABw

pub extern "C" fn destroy(ptr:*mut Dramatic) {
    // ...
    let obj: Box<Dramatic> = unsafe { ::std::mem::transmute(*ptr) };
    // ...
}

[lambdaxymox]

I ran this error as well. Here is an MCVE that reproduces it.

struct Foo;

fn foo(handle: &mut Foo) {
    unsafe {
        let temp: *mut Foo = &mut *handle;
        *temp;
    }
}

// This also causes the ICE.
/*
fn foo_immut(handle: & Foo) {
    unsafe {
        let temp: *const Foo = &*handle;
        *temp;
    }
}
*/
fn main() {

}

Here is the output from rustc:

$ RUST_BACKTRACE=1 rustc foo.rs
foo.rs:6:9: 6:14 error: internal compiler error: this path should not cause illegal move
foo.rs:6         *temp;
                 ^~~~~
note: the compiler unexpectedly panicked. this is a bug.
note: we would appreciate a bug report: http://doc.rust-lang.org/complement-bugreport.html
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:129

stack backtrace:
   1:     0x7f2c8bc66870 - sys::backtrace::write::h26b40214a7757117H8t
   2:     0x7f2c8bc89be0 - failure::on_fail::h7a79bf921b6662fbzkB
   3:     0x7f2c8bbf61f0 - rt::unwind::begin_unwind_inner::hfe1c0e12f5e834cfAZA
   4:     0x7f2c89011ac0 - rt::unwind::begin_unwind::h18088714452159156163
   5:     0x7f2c89011a50 - diagnostic::SpanHandler::span_bug::hb14d16d0c0973c4aeFE
   6:     0x7f2c89b0c7b0 - session::Session::span_bug::h25b7c4dc09b94f23P3o
   7:     0x7f2c8add3640 - borrowck::build_borrowck_dataflow_data::h15eb45fb12515356kPe
   8:     0x7f2c8add00e0 - borrowck::borrowck_fn::hb69937ff45b88f0dHMe
   9:     0x7f2c8add10d0 - borrowck::borrowck_item::hf7ef73cfdfac21f5FLe
  10:     0x7f2c8add1770 - borrowck::check_crate::h7ef96074ee6de484xGe
  11:     0x7f2c8c1f1f50 - driver::phase_3_run_analysis_passes::h3a3da09b2eae9713NFa
  12:     0x7f2c8c1d9330 - driver::compile_input::h802d2a6759ac022fBba
  13:     0x7f2c8c29f230 - run_compiler::h4517938d3296cfc5l9b
  14:     0x7f2c8c29d8c0 - thunk::F.Invoke<A, R>::invoke::h5452441173088021345
  15:     0x7f2c8c29c7f0 - rt::unwind::try::try_fn::h8490101008730471441
  16:     0x7f2c8bcf4f60 - rust_try_inner
  17:     0x7f2c8bcf4f50 - rust_try
  18:     0x7f2c8c29caa0 - thunk::F.Invoke<A, R>::invoke::h13338196279056651375
  19:     0x7f2c8bc763b0 - sys::thread::thread_start::h395b8c6815673c5cN3w
  20:     0x7f2c85e9afe0 - start_thread
  21:     0x7f2c8b878859 - __clone
  22:                0x0 - <unknown>

Here is the rustc version:

$ rustc --verbose --version
rustc 1.0.0-nightly (1d00c545e 2015-01-30 19:56:34 +0000)
binary: rustc
commit-hash: 1d00c545ede609b9d43fdf9f252c15da5a66dac7
commit-date: 2015-01-30 19:56:34 +0000
host: x86_64-unknown-linux-gnu
release: 1.0.0-nightly

[Hansyperman]

Still in the latest nightly today:

/*
Output is:

hans@yperman:~/proggies/th$ RUST_BACKTRACE=1 rustc --verbose src/main_crash.rs
src/main_crash.rs:48:12: 48:32 error: internal compiler error: this path should not cause illegal move
src/main_crash.rs:48 x=(*(someMap.unwrap()));
^~~~~~~~~~~~~~~~~~~~
note: the compiler unexpectedly panicked. this is a bug.
note: we would appreciate a bug report: http://doc.rust-lang.org/complement-bugreport.html
note: run with RUST_BACKTRACE=1 for a backtrace
thread 'rustc' panicked at 'Box', /home/rustbuild/src/rust-buildbot/slave/nightly-dist-rustc-linux/build/src/libsyntax/diagnostic.rs:129

stack backtrace:
1: 0x7fce722a2e80 - sys::backtrace::write::h84a1347ec8a3d425Aru
2: 0x7fce722c64a0 - failure::on_fail::h1cb2299eb5e255ae9GB
3: 0x7fce722312d0 - rt::unwind::begin_unwind_inner::ha34a1c7f0630f466IlB
4: 0x7fce6f663bf0 - rt::unwind::begin_unwind::h12804436560652988965
5: 0x7fce6f663b80 - diagnostic::SpanHandler::span_bug::h7782d96edbc369daAME
6: 0x7fce7016d860 - session::Session::span_bug::hdac738587fe4342308p
7: 0x7fce71442720 - borrowck::build_borrowck_dataflow_data::h9045861811b22014EVe
8: 0x7fce7143f1c0 - borrowck::borrowck_fn::h36353c72fe383ef91Se
9: 0x7fce714401b0 - borrowck::borrowck_item::hb95afd845c4698caZRe
10: 0x7fce71440850 - borrowck::check_crate::hfcab8da4b1fb581bRMe
11: 0x7fce72833710 - driver::phase_3_run_analysis_passes::h198ed79d6101094dtGa
12: 0x7fce7281a2b0 - driver::compile_input::h08caf95be513bd6bBba
13: 0x7fce728e4dd0 - run_compiler::hf1a36c26381910e09ac
14: 0x7fce728e3460 - thunk::F.Invoke<A, R>::invoke::h6996223324138754953
15: 0x7fce728e2390 - rt::unwind::try::try_fn::h16059966258548481805
16: 0x7fce72331910 - rust_try_inner
17: 0x7fce72331900 - rust_try
18: 0x7fce728e2640 - thunk::F.Invoke<A, R>::invoke::h12998514134271589737
19: 0x7fce722b2ca0 - sys::thread::thread_start::h756cedb2df1b4200Pnx
20: 0x7fce6c4e8a80 - start_thread
21: 0x0 -

hans@yperman:/proggies/th$ uname -a
Linux yperman 3.16.0-0.bpo.4-amd64 #1 SMP Debian 3.16.7-ckt2-1bpo70+1 (2014-12-08) x86_64 GNU/Linux
hans@yperman:~/proggies/th$ rustc --version
rustc 1.0.0-nightly (eaf4c5c 2015-02-02 15:04:54 +0000)

*_/
static mut someMap: std::option::Option<_mut std::collections::HashMap<String,i64>>=None;

fn new(name:&str)-> i64{
let x;
unsafe{
x=(*(someMap.unwrap()));
}
return 0;
}

pub fn main() {
}

[thepowersgang]

Note - While the ICE is a bug, the above code is already invalid. All versions attempt to move out of a raw pointer (which is invalid, in the same way as moving out of a &-ptr is). The correct way of "moving" out of a raw pointer is to use ::std::ptr::read

[pnkfelix]

(i am fixing this to produce proper compiler error now. its a one line fix.)