trap invalid opcode

[ihrwein]

When I try to use the following grammar I get this error in dmesg and the build scipt stops with signal 4:

traps: build-script-bu[7480] trap invalid opcode ip:7f1febafb8f0 sp:7fff55edf848 error:0 in libstd-198068b3.so[7f1feb9ff000+1c1000]

Grammar (It's just an example I can reproduce this with other grammars as well)

grammar;

pub Message: Vec<String> =
  <Token*>;

Token: Token = {
  Ipv4,
  Prec1
};

Prec1 = {
  Float,
  Prec2
};

Prec2 = {
  r".*" => { <>.to_string() }
};

Ipv4: Token = {
  "." <o0:Octet> "." <o1:Octet> "." <o2:Octet> "." <o3:Octet> => {
    format!("{}.{}.{}.{}", o0, o1, o2, o3)
  }
};

Octet =
  r"(25[0-5]|2[0-4][0-9]|[01]?[1-9][0-9]?)\.";

Float: Token = {
  r"[-+]?[0-9]*\.?[0-9]+" => { <>.to_string() }
};

[nikomatsakis]

Woah. Let me check it out.

[nikomatsakis]

Ah, I think this is a duplicate of #32. The problem has to do with this:

Prec2 = {
  r".*" => { <>.to_string() }
};

I need to figure out what is going on here, but this is surely not going to work for you in any case. The problem is that LALRPOP operates on a two-stage tokenize-and-then-parse model, and here you have specified a token of "._". This will surely conflict with all the other tokens (e.g., r"[-+]?[0-9]_.?[0-9]+"). In other words, the way that LR(1) parsers work, the generated code must first (unambiguously) decide which regular expression the text belongs to, without consider where we are in the grammar. (It might be interesting, though, to add a PEG mode, which would accept things like this, or perhaps some other similar hybrid.)