ICE with associated type on trait

[mdup]

Given the following code,

use std::ops::Add;

trait T: Add<Output=Self> {
}

impl T<Output=T> {
}

fn main() {
}

the compiler crashes:

$ RUST_BACKTRACE=1 rustc main.rs
main.rs:6:15: 6:16 error: the value of the associated type `Output` (from the trait `core::ops::Add`) must be specified [E0191]
main.rs:6 impl T<Output=T> {
                        ^
error: internal compiler error: unexpected panic
note: the compiler unexpectedly panicked. this is a bug.
note: we would appreciate a bug report: https://github.com/rust-lang/rust/blob/master/CONTRIBUTING.md#bug-reports
note: run with `RUST_BACKTRACE=1` for a backtrace
thread 'rustc' panicked at 'assertion failed: !ty::type_needs_infer(ty)', /Users/rustbuild/src/rust-buildbot/slave/nightly-dist-rustc-mac/build/src/librustc_typeck/lib.rs:148

stack backtrace:
   1:        0x103d6cb3f - sys::backtrace::write::he7c1ee6a91037116KVr
   2:        0x103d75242 - panicking::on_panic::h95811d48f94bff2aNVv
   3:        0x103d31985 - rt::unwind::begin_unwind_inner::h83dd7700bec4d3dcwDv
   4:        0x100b0b8af - rt::unwind::begin_unwind::h5521202385013033086
   5:        0x100c3058e - collect::convert_item::he430b0ba35372b84KGx
   6:        0x100c7ba06 - check_crate::closure.38384
   7:        0x100c7997a - check_crate::h38598962c6951e9d2EC
   8:        0x1004d4f72 - driver::phase_3_run_analysis_passes::h4345ea303ca2819ctGa
   9:        0x1004b6b18 - driver::compile_input::h83758d277994a32eQba
  10:        0x10057bb43 - run_compiler::h2639405527e4221cF4b
  11:        0x1005792aa - boxed::F.FnBox<A>::call_box::h1823104088724806648
  12:        0x1005787f7 - rt::unwind::try::try_fn::h7700810389900064321
  13:        0x103df7618 - rust_try_inner
  14:        0x103df7605 - rust_try
  15:        0x100578ace - boxed::F.FnBox<A>::call_box::h1089084376626579945
  16:        0x103d73c3d - sys::thread::Thread::new::thread_start::he43a1bd6638c19advYu
  17:     0x7fff930b9898 - _pthread_body
  18:     0x7fff930b9729 - _pthread_start

$ rustc --version
rustc 1.1.0-nightly (21f278a68 2015-04-23) (built 2015-04-24)

As a sidenote, I've played with it and was not able to find the correct syntax. The goal is to have a trait requires all implementers be able to add to themselves.

[mdup]

I believe I might have finally got the syntax right; the error message disappears. However, the ICE remains.

use std::ops::Add;

trait T: Add {
}

impl<X: T> T<Output=X> {
}

fn main() {
}

[joliv]

Not sure if this is relevant, but I got the same error in a similar situation running cargo build on this code:

extern crate num;

use num::Num;

fn foo (x: Num<Output=::std::num::ParseIntError>) {}

Backtrace follows.

unexpected panic
note: the compiler unexpectedly panicked. this is a bug.
note: we would appreciate a bug report: https://github.com/rust-lang/rust/blob/master/CONTRIBUTING.md#bug-reports
thread 'rustc' panicked at 'assertion failed: !ty::type_needs_infer(ty)', /home/rustbuild/src/rust-buildbot/slave/nightly-dist-rustc-linux/build/src/librustc_typeck/lib.rs:147

stack backtrace:
   1: 0xb732a077 - sys::backtrace::write::h6952996a21c47c07ads
   2: 0xb7333434 - panicking::on_panic::hd35d988ee3a5c2f1ZXw
   3: 0xb72ef773 - rt::unwind::begin_unwind_inner::he8bdefc833f13e3eJDw
   4: 0xb6cfbdc2 - rt::unwind::begin_unwind::h16236413390050183289
   5: 0xb6e1f99f - collect::convert_item::h9d94d3548d25d26ffSx
   6: 0xb6e1c7ef - collect::collect_item_types::h4bbb002ff41bd8d7cZw
   7: 0xb6e70912 - check_crate::h049a1ef5eff22056w8C
   8: 0xb7679d02 - driver::phase_3_run_analysis_passes::h41e2f1d518a20260GGa
   9: 0xb76584f6 - driver::compile_input::hb258e9d05d852669Qba
  10: 0xb77278fd - run_compiler::hb667b3f9ee661164n6b
  11: 0xb7724c6e - boxed::F.FnBox<A>::call_box::h4284501152216545036
  12: 0xb7724441 - rt::unwind::try::try_fn::h3762789488623463148
  13: 0xb73beb8a - rust_try_inner
  14: 0xb73beb63 - rust_try
  15: 0xb731cd7c - rt::unwind::try::inner_try::h778b76ec9ae57243Czw
  16: 0xb7724668 - boxed::F.FnBox<A>::call_box::h8463684128851076905
  17: 0xb7332054 - sys::thread::Thread::new::thread_start::h5f3e9b55c97be469OJv
  18: 0xb31c81c2 - start_thread
  19: 0xb717ee8d - __clone
  20:        0x0 - <unknown>

$ rustc --version
rustc 1.2.0-nightly (8f9f2fe97 2015-06-07)

[nham]

None of the examples above ICE for me. Using rustc 1.8.0 (db2939409 2016-04-11), the first results in:

iss_24810_1.rs:6:15: 6:16 error: the trait `T` cannot be made into an object [E0038]
iss_24810_1.rs:6 impl T<Output=T> {
                               ^
iss_24810_1.rs:6:15: 6:16 help: run `rustc --explain E0038` to see a detailed explanation
iss_24810_1.rs:6:15: 6:16 note: the trait cannot use `Self` as a type parameter in the supertrait listing
iss_24810_1.rs:6:6: 6:17 error: the trait `T` cannot be made into an object [E0038]
iss_24810_1.rs:6 impl T<Output=T> {
                      ^~~~~~~~~~~
iss_24810_1.rs:6:6: 6:17 help: run `rustc --explain E0038` to see a detailed explanation
iss_24810_1.rs:6:6: 6:17 note: the trait cannot use `Self` as a type parameter in the supertrait listing
error: aborting due to 2 previous errors

The second gives a similar error:

iss_24810_2.rs:6:12: 6:23 error: the trait `T` cannot be made into an object [E0038]
iss_24810_2.rs:6 impl<X: T> T<Output=X> {
                            ^~~~~~~~~~~
iss_24810_2.rs:6:12: 6:23 help: run `rustc --explain E0038` to see a detailed explanation
iss_24810_2.rs:6:12: 6:23 note: the trait cannot use `Self` as a type parameter in the supertrait listing
iss_24810_2.rs:6:6: 6:7 error: the type parameter `X` is not constrained by the impl trait, self type, or predicates [E0207]
iss_24810_2.rs:6 impl<X: T> T<Output=X> {
                      ^
iss_24810_2.rs:6:6: 6:7 help: run `rustc --explain E0207` to see a detailed explanation
error: aborting due to 2 previous errors

The third example also results in E0038.

Can this issue be closed?

[Mark-Simulacrum]

Closing, as per the note in the previous comment.