Only 'static is permitted within type bounds (causes ICE: Cannot relate bound region)

Once we can declare lifetime parameters, there is no reason not to permit them in type bounds. Also, I am not entirely sure if the way we are handling them is correct/sound. I've tagged places where such bounds appear with FIXMEs so that I can look into them later.

Example:

trait Iterable<'a> {
    fn my_iter(&'a self);
}

fn foo<'a, C: Iterable<'a>>(c: C) {
    c.my_iter();
}

fn main() { }

5121.rs:6:5: 6:6 error: internal compiler error: Cannot relate bound region: ReLateBound(12, BrNamed(syntax::ast::DefId{crate: 0u32, node: 21u32}, a)) <= ReInfer(1)
This message reflects a bug in the Rust compiler. 
We would appreciate a bug report: https://github.com/mozilla/rust/wiki/HOWTO-submit-a-Rust-bug-report
5121.rs:6     c.my_iter();
              ^
task 'rustc' failed at 'explicit failure', /home/huon/rust/src/libsyntax/diagnostic.rs:41
task '<main>' failed at 'explicit failure', /home/huon/rust/src/librustc/lib.rs:440

pnkfelix: I am adding a checklist to the bottom of this bug, where the unchecked issues represent problems that still remain unfixed (and the entire list of issues were closed as duplicates of this ticket).

see also #5715

@nikomatsakis

@nikomatsakis this going to land in time for 0.7? I really hope so, it's really obnoxious.

(Also, 'self is allowed too, I think)

Bumping from 0.7

I ran into this when trying to devise a too-clever interface for select2 that would let me avoid code duplication, but it would not let me use non-static borrowed pointers. https://gist.github.com/bblum/6042762

This will be the final part of #4846. Turns out that this is not so simple as I originally thought (but also not horribly scary or complex). I'll put up a blog post soon (and link it here) describing my proposal.

See http://smallcultfollowing.com/babysteps/blog/2013/10/29/intermingled-parameter-lists/ for a detailed write-up of the changes I propose to fix this.

Make trait lifetime parameters early bound in static fn type. This is…

auto merge of #12807 : pnkfelix/rust/fsk-issue5121-fns-with-early-lif…

Taken from #12851

trait MyTrait<'a> {
    fn yo(&'a self);
}

struct MyStruct<'a> {
    inner: &'a  MyTrait<'a>,
}

impl<'a> MyStruct<'a> {

    fn foo_inner(&mut self) {
        self.inner.yo()
    }
}

well, I guess it is a good thing I didn't have bors automatically close this ticket with PR #12807.

Will investigate these ICE's. (i had noted others above, may be related.)

Fix rust-lang#5121: Early/Late Bound related ICEs.

I have a patch that fixes most of the ICE's above, though not all of them.

I will try to put it up for review either tonight or tomorrow.

After reviewing the bugs that have been marked as duplicates of this bug, I've collected all of the cases that were not fixed by the original Early/Late patch and put them into their own modules. (Sometimes I tried to reduce them into smaller test cases, but usually when I did that I made a variant module with the reduced case while also keeping the original.)

The result of this collection process is posted in a file at the following gist:
https://gist.github.com/pnkfelix/9788730

(It wasn't originally a single file, but that is the easiest way to distribute the collection. It is easy enough to go back and forth between separate files and a single file for the modules, thanks to the beauty of Rust's module system.)

PR #13157 fixes most of the ICE's exposed by https://gist.github.com/pnkfelix/9788730

The main exceptions are the ICE's that are exposed by passing --cfg defer_for_5121_fix2 and --cfg defer_for_5121_fix3.

The other important things that are not fixed by PR #13157 (a fix to issue #13140) are the non-ICE unsoundness issues that are represented by the print out from the gisted code when you run it, namely the output:

Warning, non-3 value from m3: 140658622872720
bar.get(0) = 9
bar = [9, 9, 9, 9, 9], should be [1, 2, 3, 4, 5]

corresponding to #11971 and #12856.

auto merge of #13157 : pnkfelix/rust/fsk-iss13140, r=nikomatsakis

So, as mentioned above, there still remain issues #11971 and #12856 that remain unfixed. (They are already open, since they were not marked as dupes, just related.)

Also, we probably need to make some other changes, such as allowing one to put a lifetime bound on a trait (which means that all impls need to have that bound on themSelfs (sic)).

But, most of the work has been done here, and I claim that new bugs related to this one should not be closed as dupes of this one (but rather should be classified as unique on their own or classified as dupes of some other, more specific bug). So I am going to close this bug.

Auto merge of rust-lang#5121 - lzutao:comptest, r=flip1995

Auto merge of rust-lang#5145 - lzutao:rmeta, r=flip1995

Merge pull request rust-lang#5121 from calebcartwright/subtree-sync-2…

Merge pull request rust-lang#5121 from rust-lang/rustup-2026-06-21

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Only `'static` is permitted within type bounds (causes ICE: Cannot relate bound region) #5121

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Only 'static is permitted within type bounds (causes ICE: Cannot relate bound region) #5121

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nikomatsakis commented on Apr 5, 2013

emberian commented on Jun 25, 2013

emberian commented on Jun 25, 2013

brson commented on Jul 3, 2013

bblum commented on Jul 19, 2013

nikomatsakis commented on Oct 29, 2013

nikomatsakis commented on Oct 29, 2013

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pnkfelix commented on Mar 31, 2014

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Only `'static` is permitted within type bounds (causes ICE: Cannot relate bound region) #5121