miri fails to apply recursion limit, hits stack overflow instead

[matthiaskrgr]

tests/ui/issues/issue-37311-type-length-limit/issue-37311.rs

// build-fail
// normalize-stderr-test: ".nll/" -> "/"
// ignore-compare-mode-next-solver (hangs)

trait Mirror {
    type Image;
}

impl<T> Mirror for T { type Image = T; }

trait Foo {
    fn recurse(&self);
}

impl<T> Foo for T {
    #[allow(unconditional_recursion)]
    fn recurse(&self) {
        (self, self).recurse(); //~ ERROR reached the recursion limit
    }
}

fn main() {
    ().recurse();
}

cargo check or build:

error: reached the recursion limit while instantiating `<(&(&(..., ...), ...), ...) as Foo>::recurse`
  --> src/main.rs:18:9
   |
18 |         (self, self).recurse(); //~ ERROR reached the recursion limit
   |         ^^^^^^^^^^^^^^^^^^^^^^
   |
note: `<T as Foo>::recurse` defined here
  --> src/main.rs:17:5
   |
17 |     fn recurse(&self) {
   |     ^^^^^^^^^^^^^^^^^
   = note: the full type name has been written to '/tmp/im/mri/target/release/deps/mri-6a905e68387b7bf1.long-type.txt'

error: could not compile `mri` (bin "mri") due to previous error

Yet cargo miri run accepts this code and will stack overflow eventually 🤔

thread 'rustc' has overflowed its stack
fatal runtime error: stack overflow
[1]    378748 IOT instruction  cargo --color=always miri run

[saethlin]

The recursion looks like this:

#13981 0x00007f6eb527eb02 in <rustc_infer[91c6539b30333cb7]::infer::generalize::Generalizer<rustc_infer[91c6539b30333cb7]::infer::generalize::CombineDelegate> as rustc_middle[419c519ecacfa367]::ty::relate::TypeRelation>::tys ()
   from /home/ben/.rustup/toolchains/miri/lib/rustlib/x86_64-unknown-linux-gnu/lib/librustc_driver-796e47691512e4e9.so
#13982 0x00007f6eb5274dc6 in rustc_middle[419c519ecacfa367]::ty::relate::structurally_relate_tys::<rustc_infer[91c6539b30333cb7]::infer::generalize::Generalizer<rustc_infer[91c6539b30333cb7]::infer::generalize::CombineDelegate>> ()
   from /home/ben/.rustup/toolchains/miri/lib/rustlib/x86_64-unknown-linux-gnu/lib/librustc_driver-796e47691512e4e9.so
#13983 0x00007f6eb527eb02 in <rustc_infer[91c6539b30333cb7]::infer::generalize::Generalizer<rustc_infer[91c6539b30333cb7]::infer::generalize::CombineDelegate> as rustc_middle[419c519ecacfa367]::ty::relate::TypeRelation>::tys ()
   from /home/ben/.rustup/toolchains/miri/lib/rustlib/x86_64-unknown-linux-gnu/lib/librustc_driver-796e47691512e4e9.so

And this is of course hit during interpreting:

#13998 0x00007f6eb5f3cdc1 in <rustc_middle[419c519ecacfa367]::ty::instance::Instance>::resolve ()
   from /home/ben/.rustup/toolchains/miri/lib/rustlib/x86_64-unknown-linux-gnu/lib/librustc_driver-796e47691512e4e9.so
#13999 0x000055555c294acb in rustc_const_eval::interpret::eval_context::InterpCx<miri::machine::MiriMachine>::resolve<miri::machine::MiriMachine> (self=<optimized out>, def=..., substs=0x0)
    at /rustc/33c3d101280c8eb3cd8af421bfb56a8afcc3881d/compiler/rustc_const_eval/src/interpret/eval_context.rs:541
#14000 0x000055555c2be1c3 in rustc_const_eval::interpret::eval_context::InterpCx<miri::machine::MiriMachine>::eval_terminator<miri::machine::MiriMachine> (self=0x7f6eaabe7840, terminator=0x7f6ea40515a0)
    at /rustc/33c3d101280c8eb3cd8af421bfb56a8afcc3881d/compiler/rustc_const_eval/src/interpret/terminator.rs:87
#14001 rustc_const_eval::interpret::eval_context::InterpCx<miri::machine::MiriMachine>::terminator<miri::machine::MiriMachine>
    (self=0x7f6eaabe7840, terminator=0x7f6ea40515a0)
    at /rustc/33c3d101280c8eb3cd8af421bfb56a8afcc3881d/compiler/rustc_const_eval/src/interpret/step.rs:339

(the code between the two chunks of the backtrace is query runtime stuff)