compiler bug for a simple test file

[c-cube]

I got this stacktrace while running "rust test" on a file. The end of the trace contains a failure message. I have an archlinux 64bits, with rust-0.6-3 (compiled on april 6th, 2013). The code is at the bottom of the page.

RUST_LOG=rustc=1,::rt::backtrace !!                                                                                                   rust-graph [v/]
RUST_LOG=rustc=1,::rt::backtrace make
rust test src/graph.rs
src/graph.rs:24:8: 24:12 warning: unused variable: `g2`
src/graph.rs:24     let g2 : ~Graph<int,int> = g as ~Graph<int,int>;
                        ^~~~
rust: task failed at 'index out of bounds: the len is 1 but the index is 1', /build/src/rust-0.6/src/librustc/middle/ty.rs:1369
/usr/lib/librustrt.so(_ZN9rust_task13begin_failureEPKcS1_m+0x4b)[0x7f381ec5b64b]
/usr/lib/librustrt.so(+0x2a189)[0x7f381ec6c189]
/usr/lib/librustrt.so(upcall_fail+0x198)[0x7f381ec5d3a8]
/usr/lib/libcore-c3ca5d77d81b46c1-0.6.so(+0x1055db)[0x7f382078f5db]
/usr/lib/libcore-c3ca5d77d81b46c1-0.6.so(+0x4d1be)[0x7f38206d71be]
/usr/lib/libcore-c3ca5d77d81b46c1-0.6.so(_ZN8unstable4lang17fail_bounds_check16_6fb13a2fe60974b3_06E+0x22f)[0x7f38206e051f]
/usr/lib/librustc-c84825241471686d-0.6.so(_ZN6middle2ty9subst_tps15_fee8f4df464e9d3_06E+0x208)[0x7f381efc0e28]
/usr/lib/librustc-c84825241471686d-0.6.so(+0x37aa8d)[0x7f381f217a8d]
/usr/lib/librustc-c84825241471686d-0.6.so(+0x11a78f)[0x7f381efb778f]
/usr/lib/librustc-c84825241471686d-0.6.so(+0x3776fa)[0x7f381f2146fa]
/usr/lib/librustc-c84825241471686d-0.6.so(_ZN6middle2ty14fold_sty_to_ty16_838dc9297a1a6e73_06E+0x58)[0x7f381f214028]
/usr/lib/librustc-c84825241471686d-0.6.so(_ZN6middle2ty9subst_tps15_fee8f4df464e9d3_06E+0x17d)[0x7f381efc0d9d]
/usr/lib/librustc-c84825241471686d-0.6.so(+0x37aa8d)[0x7f381f217a8d]
/usr/lib/librustc-c84825241471686d-0.6.so(+0x377aa6)[0x7f381f214aa6]
/usr/lib/librustc-c84825241471686d-0.6.so(_ZN6middle2ty14fold_sty_to_ty16_838dc9297a1a6e73_06E+0x58)[0x7f381f214028]
/usr/lib/librustc-c84825241471686d-0.6.so(_ZN6middle2ty9subst_tps15_fee8f4df464e9d3_06E+0x17d)[0x7f381efc0d9d]
/usr/lib/librustc-c84825241471686d-0.6.so(+0x37aa8d)[0x7f381f217a8d]
/usr/lib/librustc-c84825241471686d-0.6.so(_ZN6middle2ty8fold_sig16_c5fce010a53c19b3_06E+0xb3)[0x7f381f215383]
/usr/lib/librustc-c84825241471686d-0.6.so(+0x37746a)[0x7f381f21446a]
/usr/lib/librustc-c84825241471686d-0.6.so(_ZN6middle2ty14fold_sty_to_ty16_838dc9297a1a6e73_06E+0x58)[0x7f381f214028]
/usr/lib/librustc-c84825241471686d-0.6.so(_ZN6middle2ty9subst_tps15_fee8f4df464e9d3_06E+0x17d)[0x7f381efc0d9d]
/usr/lib/librustc-c84825241471686d-0.6.so(+0x37aa8d)[0x7f381f217a8d]
/usr/lib/librustc-c84825241471686d-0.6.so(_ZN6middle2ty8fold_sig16_c5fce010a53c19b3_06E+0xb3)[0x7f381f215383]
/usr/lib/librustc-c84825241471686d-0.6.so(+0x3773bc)[0x7f381f2143bc]
/usr/lib/librustc-c84825241471686d-0.6.so(_ZN6middle2ty14fold_sty_to_ty16_838dc9297a1a6e73_06E+0x58)[0x7f381f214028]
/usr/lib/librustc-c84825241471686d-0.6.so(_ZN6middle2ty9subst_tps15_fee8f4df464e9d3_06E+0x17d)[0x7f381efc0d9d]
/usr/lib/librustc-c84825241471686d-0.6.so(+0x2f148b)[0x7f381f18e48b]
/usr/lib/librustc-c84825241471686d-0.6.so(+0x2f121f)[0x7f381f18e21f]
/usr/lib/librustc-c84825241471686d-0.6.so(_ZN6middle5trans4meth16make_impl_vtable16_8f771b61f2df1a53_06E+0x2fa)[0x7f381f18d22a]
/usr/lib/librustc-c84825241471686d-0.6.so(_ZN6middle5trans4meth10get_vtable17_dcd24c16d2c3ccf63_06E+0x304)[0x7f381f18cce4]
/usr/lib/librustc-c84825241471686d-0.6.so(_ZN6middle5trans4meth16trans_trait_cast16_9c795ee9255f1203_06E+0x8b8)[0x7f381f0a8008]
/usr/lib/librustc-c84825241471686d-0.6.so(+0x1fea62)[0x7f381f09ba62]
/usr/lib/librustc-c84825241471686d-0.6.so(_ZN6middle5trans4expr10trans_into16_54d763e594233573_06E+0xe97)[0x7f381effc727]
/usr/lib/librustc-c84825241471686d-0.6.so(_ZN6middle5trans4base10init_local15_3c07168daf987d3_06E+0x65f)[0x7f381f0ff3ef]
/usr/lib/librustc-c84825241471686d-0.6.so(+0x8b8c14)[0x7f381f755c14]
/usr/lib/librustc-c84825241471686d-0.6.so(+0x2646db)[0x7f381f1016db]
/usr/lib/librustc-c84825241471686d-0.6.so(_ZN6middle5trans4base10trans_stmt17_2c2aa18584fe5be63_06E+0x5ae)[0x7f381effb45e]
/usr/lib/librustc-c84825241471686d-0.6.so(+0x15d49c)[0x7f381effa49c]
/usr/lib/librustc-c84825241471686d-0.6.so(_ZN6middle5trans11controlflow11trans_block16_a4e9a67bdd72ccb3_06E+0x19e)[0x7f381eff8c0e]
/usr/lib/librustc-c84825241471686d-0.6.so(_ZN6middle5trans4base13trans_closure17_85d646a672f846683_06E+0x50e)[0x7f381f10a7ae]
/usr/lib/librustc-c84825241471686d-0.6.so(_ZN6middle5trans4base8trans_fn17_fe1e7f81b93e452d3_06E+0x3b9)[0x7f381efb2489]
/usr/lib/librustc-c84825241471686d-0.6.so(_ZN6middle5trans4base10trans_item16_ed7df62f5f126563_06E+0xd52)[0x7f381efaa0e2]
/usr/lib/librustc-c84825241471686d-0.6.so(_ZN6middle5trans4base9trans_mod17_33f95ffa6ea6f19d3_06E+0xa3)[0x7f381f111323]
/usr/lib/librustc-c84825241471686d-0.6.so(_ZN6middle5trans4base11trans_crate15_aa5d2b86af98143_06E+0x13c4)[0x7f381f130fd4]
/usr/lib/librustc-c84825241471686d-0.6.so(+0x87a380)[0x7f381f717380]
/usr/lib/librustc-c84825241471686d-0.6.so(_ZN6driver6driver12compile_rest17_b2b258b84b35f3533_06E+0x331e)[0x7f381f71438e]
/usr/lib/librustc-c84825241471686d-0.6.so(+0x8b8c14)[0x7f381f755c14]
/usr/lib/librustc-c84825241471686d-0.6.so(_ZN6driver6driver12compile_upto17_12335154b455986e3_06E+0x108)[0x7f381f717598]
/usr/lib/librustc-c84825241471686d-0.6.so(+0x8b8c14)[0x7f381f755c14]
/usr/lib/librustc-c84825241471686d-0.6.so(_ZN6driver6driver13compile_input15_bb29edf7a232863_06E+0xca)[0x7f381f7179da]
/usr/lib/librustc-c84825241471686d-0.6.so(_ZN12run_compiler17_64d52739a36d169c3_06E+0x20aa)[0x7f381f7470aa]
/usr/lib/librustc-c84825241471686d-0.6.so(+0x8b66e1)[0x7f381f7536e1]
/usr/lib/librustc-c84825241471686d-0.6.so(+0x8b2f0c)[0x7f381f74ff0c]
/usr/lib/librustc-c84825241471686d-0.6.so(+0x8b8c14)[0x7f381f755c14]
/usr/lib/libcore-c3ca5d77d81b46c1-0.6.so(+0xce08e)[0x7f382075808e]
/usr/lib/libcore-c3ca5d77d81b46c1-0.6.so(+0x14dcb4)[0x7f38207d7cb4]
/usr/lib/librustrt.so(_Z18task_start_wrapperP10spawn_args+0x24)[0x7f381ec5be64]
error: internal compiler error: unexpected failure
note: the compiler hit an unexpected failure path. this is a bug
note: try running with RUST_LOG=rustc=1,::rt::backtrace to get further details and report the results to github.com/mozilla/rust/issues
rust: task failed at 'explicit failure', /build/src/rust-0.6/src/librustc/rustc.rc:357
/usr/lib/librustrt.so(_ZN9rust_task13begin_failureEPKcS1_m+0x4b)[0x7f381ec5b64b]
/usr/lib/librustrt.so(+0x2a189)[0x7f381ec6c189]
/usr/lib/librustrt.so(upcall_fail+0x198)[0x7f381ec5d3a8]
/usr/lib/libcore-c3ca5d77d81b46c1-0.6.so(+0x1055db)[0x7f382078f5db]
/usr/lib/libcore-c3ca5d77d81b46c1-0.6.so(+0x105582)[0x7f382078f582]
/usr/lib/libcore-c3ca5d77d81b46c1-0.6.so(_ZN3sys12begin_unwind17_61fe198059b9e3fc3_06E+0x71)[0x7f38206d7651]
/usr/lib/libcore-c3ca5d77d81b46c1-0.6.so(+0x14dcb4)[0x7f38207d7cb4]
/usr/lib/librustc-c84825241471686d-0.6.so(_ZN7monitor17_78935df9ff9e1afa3_06E+0x1577)[0x7f381f7496d7]
/usr/lib/librustc-c84825241471686d-0.6.so(+0x8b8c14)[0x7f381f755c14]
/usr/lib/librustc-c84825241471686d-0.6.so(_ZN4main15_c4de63b748e03d3_06E+0x7e)[0x7f381f75582e]
/usr/lib/librustrt.so(_Z18task_start_wrapperP10spawn_args+0x24)[0x7f381ec5be64]
rust: domain main @0x23b03c0 root task failed

code:

extern mod core;                                                                                    

use core::hashmap::linear::LinearMap;                                                               
use core::hashmap::linear::linear_map_with_capacity;                                                

// #[crate_type = "lib"];                                                                           

trait Graph<Node, Edge> {                                                                           
    fn children(&self, Node, &fn(&(Edge, Node)) ⟶  bool);   // iterate on outgoing edges            
}                                                                                                    

impl<E> Graph<int,E> for LinearMap<int, ~[(E,int)]> {                                               
    fn children(&self, n:int, f : &fn(&(E,int)) ⟶  bool) {                                          
        match self.find(&n) {                                                                           
            None ⟹  (),                                                                              
            Some(list) ⟹  list.each(f)                                                               
        };                                                                                              
    }                                                                                               
}                                                                                                    

#[test]                                                                                             
fn test_1() {                                                                                       
    let g : ~LinearMap<int, ~[(int,int)]> = ~linear_map_with_capacity(15);                          
    let g2 : ~Graph<int,int> = g as ~Graph<int,int>;                                                
}                           

[Thiez]

It seems you are using an old version of rust (based on your use of LinearMap, which has since been renamed to HashMap). Does this crash also happen on incoming?

[c-cube]

Looks like my computer is not powerful enough to build rust from git+https://github.com/mozilla/rust.git ...

[Tristramg]

I tested with master (bfccfdc)

And I get the same problem https://gist.github.com/Tristramg/5494814

[catamorphism]

Simpler test case:

use std::hashmap::HashMap;

trait Graph<Node, Edge> {
    fn f(&self, Edge);

}

impl<E> Graph<int, E> for HashMap<int, int> {
    fn f(&self, _e: E) {
        fail!();
    }
}

fn main() {
    let g : ~HashMap<int, int> = ~HashMap::new();
    let _g2 : ~Graph<int,int> = g as ~Graph<int,int>;
}

Reproduced with 8d0feb5 . Nominating for milestone 5, production-ready.

[graydon]

accepted for production-ready milestone

[sanxiyn]

I don't get ICE anymore.

[alexcrichton]

Hurrah! flagging as needstest, but this probably just needs the test case un-xfail'd

[alexcrichton]

The test was actually already checked in and was un-xfail'd in 364beaa