Mismatched type Result instead of Option causes internal compiler error

[jmmk]

rustc 0.10-pre (22d3669 2014-02-22 15:01:58 -0800)
host: x86_64-apple-darwin

credit.rs:20:9: 20:21 error: mismatched types: expected `std::result::Result<~str,std::io::IoError>` but found `std::option::Option<<generic #68>>` (expected enum std::result::Result but found enum std::option::Option)
credit.rs:20         Some(number) => {
                     ^~~~~~~~~~~~
error: internal compiler error: unexpected failure
This message reflects a bug in the Rust compiler.
We would appreciate a bug report: http://static.rust-lang.org/doc/master/complement-bugreport.html
note: the compiler hit an unexpected failure path. this is a bug
Ok(task 'rustc' failed at 'index out of bounds: the len is 0 but the index is 0', /Library/Caches/Homebrew/rust--git/src/librustc/middle/typeck/check/method.rs:452
)

[jmmk]

If it matters - the Option was from a BufferedReader call.

[eddyb]

This is the shortest testcase I came up with:

fn main() {
    match Ok::<int, ()>(0) {
        Some(x) => {
            x.eq(&0); // ICE
        }
        None => {}
    }
}

Calling a method on the result of pattern matching a type mismatch error is what seems to trigger it.

[jmmk]

@eddyb Just tested your example on the latest rust nightly and it no longer gives the error.

[huonw]

Dupe of #11844 (now fixed): testcase https://github.com/rust-lang/rust/blob/master/src/test/compile-fail/issue-11844.rs