rustc guards ICE: Assertion m.len() > 0u || chk.is_some() failed

[dckc]

$ rustc -v
rustc 0.5 (57b4d10 2012-10-12 16:41:32 -0700)
host: x86_64-unknown-linux-gnu

I don't see how to attach files, so...

RUST_LOG=rustc=0,::rt::backtrace rustc mmfsm.rs --test
rust: task failed at 'Assertion m.len() > 0u || chk.is_some() failed', /home/connolly/src/rust/src/rustc/middle/trans/alt.rs:866
/usr/local/bin/../lib/librustrt.so(_ZN9rust_task13begin_failureEPKcS1_m+0x5d)[0x2b977f842fdd]
/usr/local/bin/../lib/librustrt.so(+0x3325d)[0x2b977f85b25d]
/usr/local/bin/../lib/librustrt.so(upcall_fail+0x1d0)[0x2b977f845930]
/usr/local/bin/../lib/librustc-c84825241471686d-0.5.so(_ZN6middle5trans3alt16compile_submatch16_fb9e6315b8870463_05E+0xa0b)[0x2b977effab2b]
/usr/local/bin/../lib/librustc-c84825241471686d-0.5.so(+0x2370aa)[0x2b977effa0aa]
/usr/local/bin/../lib/librustc-c84825241471686d-0.5.so(_ZN6middle5trans4base9with_cond16_fae091854fffba33_05E+0x143)[0x2b977ef34893]
/usr/local/bin/../lib/librustc-c84825241471686d-0.5.so(_ZN6middle5trans3alt13compile_guard16_5e7459203dd95c83_05E+0x9b1)[0x2b977eff9891]
/usr/local/bin/../lib/librustc-c84825241471686d-0.5.so(_ZN6middle5trans3alt16compile_submatch16_fb9e6315b8870463_05E+0x63a)[0x2b977effa75a]
/usr/local/bin/../lib/librustc-c84825241471686d-0.5.so(_ZN6middle5trans3alt16compile_submatch16_fb9e6315b8870463_05E+0x2c55)[0x2b977effcd75]
/usr/local/bin/../lib/librustc-c84825241471686d-0.5.so(_ZN6middle5trans3alt16compile_submatch16_fb9e6315b8870463_05E+0x2b50)[0x2b977effcc70]
/usr/local/bin/../lib/librustc-c84825241471686d-0.5.so(_ZN6middle5trans3alt16compile_submatch16_fb9e6315b8870463_05E+0x2c55)[0x2b977effcd75]
/usr/local/bin/../lib/librustc-c84825241471686d-0.5.so(_ZN6middle5trans3alt16compile_submatch16_fb9e6315b8870463_05E+0x2c55)[0x2b977effcd75]
/usr/local/bin/../lib/librustc-c84825241471686d-0.5.so(_ZN6middle5trans3alt16compile_submatch16_fb9e6315b8870463_05E+0x2c55)[0x2b977effcd75]
/usr/local/bin/../lib/librustc-c84825241471686d-0.5.so(_ZN6middle5trans3alt16compile_submatch16_fb9e6315b8870463_05E+0x11e6)[0x2b977effb306]
/usr/local/bin/../lib/librustc-c84825241471686d-0.5.so(_ZN6middle5trans3alt15trans_alt_inner16_ad10ecb481ad2223_05E+0x895)[0x2b977efffb15]
/usr/local/bin/../lib/librustc-c84825241471686d-0.5.so(+0x689840)[0x2b977f44c840]
/usr/local/bin/../lib/librustc-c84825241471686d-0.5.so(+0x23c278)[0x2b977efff278]
/usr/local/bin/../lib/librustc-c84825241471686d-0.5.so(_ZN6middle5trans4base10with_scope17_f715e64d24b410333_05E+0x442)[0x2b977ef34fc2]
/usr/local/bin/../lib/librustc-c84825241471686d-0.5.so(_ZN6middle5trans3alt9trans_alt17_4eb9527c11b030193_05E+0x1c5)[0x2b977ef76c45]
/usr/local/bin/../lib/librustc-c84825241471686d-0.5.so(+0x1afdda)[0x2b977ef72dda]
/usr/local/bin/../lib/librustc-c84825241471686d-0.5.so(+0x1ab21e)[0x2b977ef6e21e]
/usr/local/bin/../lib/librustc-c84825241471686d-0.5.so(_ZN6middle5trans4expr14trans_to_datum15_1cbfbbbca52c293_05E+0x434)[0x2b977ef29ba4]
/usr/local/bin/../lib/librustc-c84825241471686d-0.5.so(+0x1aed27)[0x2b977ef71d27]
/usr/local/bin/../lib/librustc-c84825241471686d-0.5.so(_ZN6middle5trans4expr10trans_into16_6c850bd8fee452e3_05E+0x738)[0x2b977ef27338]
/usr/local/bin/../lib/librustc-c84825241471686d-0.5.so(_ZN6middle5trans4base10trans_stmt17_902f2bbc1f1bf65e3_05E+0x3c8)[0x2b977ef269f8]
/usr/local/bin/../lib/librustc-c84825241471686d-0.5.so(_ZN6middle5trans11controlflow11trans_block16_26b9d945b6471483_05E+0x17d)[0x2b977ef250cd]
/usr/local/bin/../lib/librustc-c84825241471686d-0.5.so(_ZN6middle5trans4base10with_scope17_f715e64d24b410333_05E+0x442)[0x2b977ef34fc2]
/usr/local/bin/../lib/librustc-c84825241471686d-0.5.so(+0x1b03ee)[0x2b977ef733ee]
/usr/local/bin/../lib/librustc-c84825241471686d-0.5.so(_ZN6middle5trans4expr10trans_into16_6c850bd8fee452e3_05E+0x69e)[0x2b977ef2729e]
/usr/local/bin/../lib/librustc-c84825241471686d-0.5.so(_ZN6middle5trans11controlflow11trans_block16_26b9d945b6471483_05E+0x1d1)[0x2b977ef25121]
/usr/local/bin/../lib/librustc-c84825241471686d-0.5.so(_ZN6middle5trans4base13trans_closure15_5fd055394070353_05E+0x76b)[0x2b977efbe08b]
/usr/local/bin/../lib/librustc-c84825241471686d-0.5.so(+0x2438c3)[0x2b977f0068c3]
/usr/local/bin/../lib/librustc-c84825241471686d-0.5.so(_ZN6middle5trans7closure13trans_expr_fn15_a663c1c9738d993_05E+0x7f7)[0x2b977ef6bbd7]
/usr/local/bin/../lib/librustc-c84825241471686d-0.5.so(+0x1b013c)[0x2b977ef7313c]
/usr/local/bin/../lib/librustc-c84825241471686d-0.5.so(_ZN6middle5trans4expr10trans_into16_6c850bd8fee452e3_05E+0x69e)[0x2b977ef2729e]
/usr/local/bin/../lib/librustc-c84825241471686d-0.5.so(+0x1b024c)[0x2b977ef7324c]
/usr/local/bin/../lib/librustc-c84825241471686d-0.5.so(+0x1ab21e)[0x2b977ef6e21e]
/usr/local/bin/../lib/librustc-c84825241471686d-0.5.so(_ZN6middle5trans4expr14trans_to_datum15_1cbfbbbca52c293_05E+0x434)[0x2b977ef29ba4]
/usr/local/bin/../lib/librustc-c84825241471686d-0.5.so(_ZN6middle5trans6callee14trans_arg_expr17_1658b0a3d6341f653_05E+0x700)[0x2b977ef69620]
/usr/local/bin/../lib/librustc-c84825241471686d-0.5.so(+0x1a5e7c)[0x2b977ef68e7c]
/usr/local/bin/../lib/librustc-c84825241471686d-0.5.so(_ZN6middle5trans6callee10trans_args16_c46359aa314c3803_05E+0x391)[0x2b977ef68521]
/usr/local/bin/../lib/librustc-c84825241471686d-0.5.so(+0x1a4af9)[0x2b977ef67af9]
/usr/local/bin/../lib/librustc-c84825241471686d-0.5.so(_ZN6middle5trans4base10with_scope17_f715e64d24b410333_05E+0x442)[0x2b977ef34fc2]
/usr/local/bin/../lib/librustc-c84825241471686d-0.5.so(_ZN6middle5trans6callee16trans_call_inner17_bce4bdcb48562e5c3_05E+0x114)[0x2b977ef5c914]
/usr/local/bin/../lib/librustc-c84825241471686d-0.5.so(_ZN6middle5trans6callee10trans_call17_adf4ba1882312adc3_05E+0x281)[0x2b977ef5c7a1]
/usr/local/bin/../lib/librustc-c84825241471686d-0.5.so(+0x1afb3f)[0x2b977ef72b3f]
/usr/local/bin/../lib/librustc-c84825241471686d-0.5.so(+0x689840)[0x2b977f44c840]
/usr/local/bin/../lib/librustc-c84825241471686d-0.5.so(_ZN6middle5trans4expr10trans_into16_6c850bd8fee452e3_05E+0x69e)[0x2b977ef2729e]
/usr/local/bin/../lib/librustc-c84825241471686d-0.5.so(_ZN6middle5trans4base10trans_stmt17_902f2bbc1f1bf65e3_05E+0x3c8)[0x2b977ef269f8]
/usr/local/bin/../lib/librustc-c84825241471686d-0.5.so(_ZN6middle5trans11controlflow11trans_block16_26b9d945b6471483_05E+0x17d)[0x2b977ef250cd]
/usr/local/bin/../lib/librustc-c84825241471686d-0.5.so(_ZN6middle5trans4base13trans_closure15_5fd055394070353_05E+0x76b)[0x2b977efbe08b]
/usr/local/bin/../lib/librustc-c84825241471686d-0.5.so(_ZN6middle5trans4base8trans_fn17_7b6cbffb898dd1b73_05E+0x145)[0x2b977eeb77b5]
/usr/local/bin/../lib/librustc-c84825241471686d-0.5.so(_ZN6middle5trans4base10trans_item16_45a6cab39b2a9983_05E+0x92a)[0x2b977eeb3f2a]
/usr/local/bin/../lib/librustc-c84825241471686d-0.5.so(_ZN6middle5trans4base9trans_mod17_917c80e8ce495a1d3_05E+0x8f)[0x2b977efc536f]
/usr/local/bin/../lib/librustc-c84825241471686d-0.5.so(_ZN6middle5trans4base11trans_crate17_51569cb9b4ec671c3_05E+0x149a)[0x2b977efdeb5a]
/usr/local/bin/../lib/librustc-c84825241471686d-0.5.so(_ZN6driver6driver12compile_upto17_f866b092d9b7dfd43_05E+0x2560)[0x2b977f422ac0]
/usr/local/bin/../lib/librustc-c84825241471686d-0.5.so(+0x689840)[0x2b977f44c840]
/usr/local/bin/../lib/librustc-c84825241471686d-0.5.so(_ZN6driver6driver13compile_input17_c85efee3d65e343b3_05E+0xbd)[0x2b977f424ead]
rustc[0x408eb7]
rustc[0x412214]
rustc[0x40e693]
rustc[0x40d34c]
/usr/local/bin/../lib/libcore-c3ca5d77d81b46c1-0.5.so(+0x7580f)[0x2b977e19b80f]
/usr/local/bin/../lib/libcore-c3ca5d77d81b46c1-0.5.so(+0xb50e0)[0x2b977e1db0e0]
/usr/local/bin/../lib/librustrt.so(_Z18task_start_wrapperP10spawn_args+0x24)[0x2b977f843784]
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=0,::rt::backtrace to get further details and report the results to github.com/mozilla/rust/issues
rust: task failed at 'explicit failure', /home/connolly/src/rust/src/rustc/driver/rustc.rs:275
/usr/local/bin/../lib/librustrt.so(_ZN9rust_task13begin_failureEPKcS1_m+0x5d)[0x2b977f842fdd]
/usr/local/bin/../lib/librustrt.so(+0x3325d)[0x2b977f85b25d]
/usr/local/bin/../lib/librustrt.so(upcall_fail+0x1d0)[0x2b977f845930]
rustc(_rust_main+0x838)[0x411a28]
rustc[0x412214]
/usr/local/bin/../lib/librustrt.so(_Z18task_start_wrapperP10spawn_args+0x24)[0x2b977f843784]
rust: domain main @0xf19200 root task failed
rust: task failed at 'killed', /home/connolly/src/rust/src/libcore/task.rs:663
/usr/local/bin/../lib/librustrt.so(_ZN9rust_task13begin_failureEPKcS1_m+0x5d)[0x2b977f842fdd]
/usr/local/bin/../lib/librustrt.so(+0x3325d)[0x2b977f85b25d]
/usr/local/bin/../lib/librustrt.so(upcall_fail+0x1d0)[0x2b977f845930]
/usr/local/bin/../lib/libcore-c3ca5d77d81b46c1-0.5.so(_ZN4task5yield16_9531951b4f79f8b3_05E+0xbd)[0x2b977e184ddd]
/usr/local/bin/../lib/libcore-c3ca5d77d81b46c1-0.5.so(+0x90246)[0x2b977e1b6246]
/usr/local/bin/../lib/libcore-c3ca5d77d81b46c1-0.5.so(_ZN7private11weaken_task16_cf742a1b771015c3_05E+0xd2)[0x2b977e1b6082]
/usr/local/bin/../lib/libcore-c3ca5d77d81b46c1-0.5.so(+0x8ff7b)[0x2b977e1b5f7b]
/usr/local/bin/../lib/libcore-c3ca5d77d81b46c1-0.5.so(+0xb50e0)[0x2b977e1db0e0]
/usr/local/bin/../lib/libcore-c3ca5d77d81b46c1-0.5.so(+0x8f2d0)[0x2b977e1b52d0]
/usr/local/bin/../lib/libcore-c3ca5d77d81b46c1-0.5.so(+0x8ec6e)[0x2b977e1b4c6e]
/usr/local/bin/../lib/libcore-c3ca5d77d81b46c1-0.5.so(+0x8e2d6)[0x2b977e1b42d6]
/usr/local/bin/../lib/libcore-c3ca5d77d81b46c1-0.5.so(+0x7580f)[0x2b977e19b80f]
/usr/local/bin/../lib/libcore-c3ca5d77d81b46c1-0.5.so(+0xb50e0)[0x2b977e1db0e0]
/usr/local/bin/../lib/librustrt.so(_Z18task_start_wrapperP10spawn_args+0x24)[0x2b977f843784]

and the code:

/**
start = space start
      | statement start
      | comment start
      | EOF

statement = '${' space+ | '$}' tspace | keyword_statement
keyword_statement = label? keyword expr proof? '$.' tspace
label = label_char+ space+
keyword = ($a | $p | ...) space+
expr = symbol*
symbol = symbol_char+ space+

comment = '$(' space (not_$) space)* '$)' tspace
ispace = (space+ comment?)*  # inter-token space

tspace = space+ | EOF

proof = '$=' space+ label+ '$'  # TODO: compressed proof
 */
use core::vec::{any};

extern mod std;
use std::rope;

fn each_statement(text: rope::Rope) -> bool {
    enum IsSpace { Space, Printable }
    enum IsLabel { Label, NotLabel }

    enum State {
        Start,
        StLabel,
        StKeyword,
        StExpr,
        TSpace,

        BadChar,  // TODO: line, col?
        BadSyntax, // line, col?
    }

    let mut state = Start;
    let mut ch1 = '\u0000'; // LL(2)

    do rope::loop_chars(text) |ch| {
        let is_space = " \t\r\n\x0A".contains_char(ch);
        let is_label = any(&[('A', 'Z'), ('a', 'z'), ('0', '9')],
                           |r| match r { &(lo, hi) => ch >= lo && ch <= hi })
            || "'-_.".contains_char(ch);

        state = match (state, ch1, ch,
               if (is_space) { Space } else { Printable },
               if (is_label) { Label } else { NotLabel }) {
          (_, _, _, Printable, _) if ch > '\u007F' || ch < ' ' => BadChar,

          (Start, _, _, Space, _) => Start,
          (Start, _, _, _, Label) => StLabel,
          (Start, _, _, _, _) => BadSyntax,  // not implemented

          (StLabel, _, _, _, Label) => StLabel,
          (StLabel, _, _, Space, _) => StKeyword,
          (StLabel, _, _, _, _) => BadSyntax,

          (StKeyword, _, _, Space, _) => StKeyword,
          (StKeyword, '$', 'a', _, _) => StExpr,
          (StKeyword, _, _, _, _) => BadSyntax,

          (StExpr, '$', '.', _, _) => TSpace,
          (StExpr, '$', _, _, _) => BadSyntax,
          (StExpr, _, _, Printable, _) => StExpr,
          (StExpr, _, _, Space, _) => StExpr,

          (TSpace, _, _, Space, _) => TSpace,
          (TSpace, _, _, Printable, _) => BadSyntax,

          (BadChar, _, _, _, _)
          | (BadSyntax, _, _, _, _) => fail fmt!("unexpected state: %?", state)
        };

        ch1 = ch;
        debug!("hi: %c", ch);
        match state {
            BadChar | BadSyntax => false,
            _ => true
        }
    };

    match state {
      TSpace => true,
      _ => false
    }
}

#[cfg(test)]
mod test {
    #[test]
    fn each_statement1() {
        let doc = rope::of_str(@~"axiom.1 $a |- x = x $.");
        each_statement(doc);
    }
}

[dckc]

Reducing the complexity of the tuple is no help:

use core::vec::{any};

extern mod std;
use std::rope;

fn each_statement(text: rope::Rope) -> bool {
    enum IsSpace { Space, Printable }

    enum State {
        Start,
        StLabel,
        StKeyword,
        StExpr,
        TSpace,

        BadChar,  // TODO: line, col?
        BadSyntax, // line, col?
    }

    let mut state = Start;
    let mut ch1 = '\u0000'; // LL(2)

    do rope::loop_chars(text) |ch| {
        let cclass = if(" \t\r\n\x0A".contains_char(ch))
                        { Space } else { Printable };
        let is_label = any(&[('A', 'Z'), ('a', 'z'), ('0', '9')],
                           |r| match r { &(lo, hi) => ch >= lo && ch <= hi })
            || "'-_.".contains_char(ch);

        state = match (state, cclass) {
          (_, Printable) if ch > '\u007F' || ch < ' ' => BadChar,

          (Start, Space) => Start,
          (Start, _) if is_label => StLabel,
          (Start, _) => BadSyntax,  // not implemented

          (StLabel, _) if is_label => StLabel,
          (StLabel, Space) => StKeyword,
          (StLabel, _) => BadSyntax,

          (StKeyword, Space) => StKeyword,
          (StKeyword, _) if ch1 == '$' && ch == 'a' => StExpr,
          (StKeyword, _) => BadSyntax,

          (StExpr, _) if ch1 == '$' && ch == '.' => TSpace,
          (StExpr, _) if ch1 == '$' => BadSyntax,
          (StExpr, _) => StExpr,

          (TSpace, Space) => TSpace,
          (TSpace, Printable) => BadSyntax,  // not implemented

          (BadChar, _)
          | (BadSyntax, _) => fail fmt!("unexpected state: %?", state)
        };

        ch1 = ch;
        debug!("hi: %c", ch);
        match state {
            BadChar | BadSyntax => false,
            _ => true
        }
    };

    match state {
      TSpace => true,
      _ => false
    }
}

#[cfg(test)]
mod test {
    #[test]
    fn each_statement1() {
        let doc = rope::of_str(@~"axiom.1 $a |- x = x $.");
        each_statement(doc);
    }
}

[dckc]

eliminating guards makes the problem go away

use core::vec::{any};

extern mod std;
use std::rope;

fn each_statement(text: rope::Rope) -> bool {
    enum CharClass { Space, Printable, BadChar }

    enum State {
        Start,
        StLabel,
        StKeyword,
        StExpr,
        TSpace,

        BadSyntax, // line, col?
    }

    let mut state = Start;
    let mut ch1 = '\u0000'; // LL(2)

    do rope::loop_chars(text) |ch| {
        let cclass =
            if(" \t\r\n\x0A".contains_char(ch)) { Space }
            else if (ch > '\u007F' || ch < ' ') { BadChar }
            else { Printable };

        let is_label = any(&[('A', 'Z'), ('a', 'z'), ('0', '9')],
                           |r| match r { &(lo, hi) => ch >= lo && ch <= hi })
            || "'-_.".contains_char(ch);

        state = match (state, cclass, is_label, ch1, ch) {
          (_, BadChar, _, _, _) => BadSyntax,

          (Start, Space, _, _, _) => Start,
          (Start, Printable, true, _, _) => StLabel,
          (Start, _, _, _, _) => BadSyntax,  // not implemented

          (StLabel, Printable, true, _, _) => StLabel,
          (StLabel, Space, _, _, _) => StKeyword,
          (StLabel, _, _, _, _) => BadSyntax,

          (StKeyword, Space, _, _, _) => StKeyword,
          (StKeyword, Printable, _, '$', 'a') => StExpr,
          (StKeyword, _, _, _, _) => BadSyntax,

          (StExpr, _, _, '$', '.') => TSpace,
          (StExpr, _, _, '$', _)  => BadSyntax,
          (StExpr, _, _, _, _) => StExpr,

          (TSpace, Space, _, _, _) => TSpace,
          (TSpace, Printable, _, _, _) => BadSyntax,  // not implemented

          (BadSyntax, _, _, _, _) => fail fmt!("unexpected state: %?", state)
        };

        ch1 = ch;
        debug!("hi: %c", ch);
        match state {
            BadSyntax => false,
            _ => true
        }
    };

    match state {
      TSpace => true,
      _ => false
    }
}

#[cfg(test)]
mod test {
    #[test]
    fn each_statement1() {
        let doc = rope::of_str(@~"axiom.1 $a |- x = x $.");
        each_statement(doc);
    }
}

[catamorphism]

Could be related to #2869

[catamorphism]

Minimized version:

fn main() {
    enum State { BadChar, BadSyntax }

    match BadChar {
        _ if true => BadChar,
        BadChar | BadSyntax => fail
    };
}

I'm still not sure if this is a dup of #2869 or not. The combination of a disjunctive pattern and a guard in a different pattern seems to be essential.

[catamorphism]

This is indeed a dup of #2869.