"internal error in instantiate" when using a generic impl method

[jsternberg]

This problem is illustrated with the following code:

use std;
import std::io::*;

iface ninja_str {
fn to_str() -> str;
}

impl of ninja_str for str {
fn to_str() -> str { self }
}

impl of ninja_str for [str] {
fn to_str() -> str {
alt vec::len(self) {
0u { "" }
x {
vec::foldl(self[0], vec::slice(self, 1u, x)) {|iter, y|
iter + ", " + y
}
}
}
}
}

// this works fine
fn print<T: ninja_str>(str: T) {
println(str.to_str());
}

impl ninja_file for writer {
// this causes 'error: internal error in instantiate'
fn build<T: ninja_str>(str: T) {
self.write(str::bytes(str.to_str()));
}
}

fn main() {
print("hello, world");
}

[jsternberg]

Here's the pastebin for more readable code:
http://pastebin.com/abiZ8fNC

[marijnh]

(Use triple-backticks before and after code blocks to have github format it properly.)

The problem is that typeck::dict::resolve_expr should also handle the cases of method_param and method_iface for expr_field. It's probably an easy fix. I'll look into it tomorrow.