Change:
This occurs on 1.34.1 and 1.34.0, is a regression from 1.33.0, and does.. not occur on nightly? Reproduction: compiled with Yields: I found this in building crates like and but pared it down to this
I think this is fixed in which might explain why it doesn't occur on nightly
triage: Probably fixed by . Normally an ICE would lead me to tag this as P-high, but the fact that this is only exposed by leads me to prioritize this as P-medium.
assigning to self to confirm that is the reason this is fixed, and (if need be) add a regression test.
Here's a slightly smaller case of what appears to potentially be the same thing which shows up if you select the "show MIR" option in In particular the following error is observed:
I think this issue is fixed in all channels. I tried stable and nightly both locally and on , and couldn't get any ICEs. Should we add a test? Otherwise we can just close I think.
Adding a test with seems like a good idea.

Discussion:
<ins> // build-fail // ignore-emscripten no asm! support // Regression test for #69092 #![feature(asm)] fn main() { unsafe { asm!(".ascii "Xen0""); } //~^ ERROR: <inline asm>:1:9: error: expected string in '.ascii' directive } </ins>

<ins> error: <inline asm>:1:9: error: expected string in '.ascii' directive .ascii "Xen ^ --> $DIR/issue-69092.rs:8:14 | LL |     unsafe { asm!(".ascii "Xen0""); } |              ^^^^^^^^^^^^^^^^^^^^^^^^^ error: aborting due to previous error </ins>

<ins> // Regression test for #62504 #![feature(const_generics)] #![allow(incomplete_features)] trait HasSize { const SIZE: usize; } impl<const X: usize> HasSize for ArrayHolder<{ X }> { const SIZE: usize = X; } struct ArrayHolder<const X: usize>([u32; X]); impl<const X: usize> ArrayHolder<{ X }> { pub const fn new() -> Self { ArrayHolder([0; Self::SIZE]) //~^ ERROR: array lengths can't depend on generic parameters } } fn main() { let mut array = ArrayHolder::new(); } </ins>

<ins> error: array lengths can't depend on generic parameters --> $DIR/issue-62504.rs:18:25 | LL |         ArrayHolder([0; Self::SIZE]) |                         ^^^^^^^^^^ error: aborting due to previous error </ins>

<ins> // Regression test for #67739 #![allow(incomplete_features)] #![feature(const_generics)] use std::mem; pub trait Trait { type Associated: Sized; fn associated_size(&self) -> usize { [0u8; mem::size_of::<Self::Associated>()]; //~^ ERROR: array lengths can't depend on generic parameters 0 } } fn main() {} </ins>

<ins> error: array lengths can't depend on generic parameters --> $DIR/issue-67739.rs:12:15 | LL |         [0u8; mem::size_of::<Self::Associated>()]; |               ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ error: aborting due to previous error </ins>

<ins> // Regression test for #58490 macro_rules! a { ( @1 $i:item ) => { a! { @2 $i } }; ( @2 $i:item ) => { $i }; } mod b { a! { @1 #[macro_export] macro_rules! b { () => () } } #[macro_export] macro_rules! b { () => () } //~^ ERROR: the name `b` is defined multiple times } mod c { #[allow(unused_imports)] use crate::b; } fn main() {} </ins>

<ins> error[E0428]: the name `b` is defined multiple times --> $DIR/issue-58490.rs:18:5 | LL |         macro_rules! b { () => () } |         -------------- previous definition of the macro `b` here ... LL |     macro_rules! b { () => () } |     ^^^^^^^^^^^^^^ `b` redefined here | = note: `b` must be defined only once in the macro namespace of this module error: aborting due to previous error For more information about this error, try `rustc --explain E0428`. </ins>

<ins> // check-pass // compile-flags: --emit=mir,link // Regression test for #60390, this ICE requires `--emit=mir` flag. fn main() { enum Inner { Member(u32) }; Inner::Member(0); } </ins>