Encountered a Stack Overflow Crash on stable compiled rust

[d3rpp]

I tried this code:

https://play.rust-lang.org/?version=stable&mode=debug&edition=2021&gist=3bc6e2fae27c0a45ec2fa59a087a291b

I expected to see this happen:
Print out a vector of dynamic trait objects

Instead, this happened:
a Stack Overflow error on the compiled output

Meta

On the Rust Playground, using Debug, Stable on the 2nd of December 2022.

Backtrace

There isn't one here

thread 'main' has overflowed its stack
fatal runtime error: stack overflow
timeout: the monitored command dumped core
/playground/tools/entrypoint.sh: line 11:     7 Aborted                 timeout --signal=KILL ${timeout} "$@"

This is the error produced by the playground

[d3rpp]

I now realise that I am causing infinite recursion in here:

impl Debug for dyn Shape {
    fn fmt(&self, f: &mut core::fmt::Formatter<'_>) -> core::fmt::Result {
        write!(f, "{:#?}", self)
    }
}

So I know it's a problem that I specifically created that is causing the Stack Overflow error.

Though given the correctness of Rust, I'll leave it up to you as to whether this should be investigated or if I'm being an idiot.

I do recognise that what I have created is a recursion with no exit condition, though part of me feels as if the compiler should have a warning about that at the very least

[jruderman]

A function unconditionally calling itself triggers the unconditional_recursion lint, with the warning "function cannot return without recursing":

fn a() { a() }

But a pair of functions co-recursing does not (#57965):

fn x() { y() }
fn y() { x() }

This case may be more complicated: it involves a trait, a macro, and a Result error case that might need to be ignored for the recursion to be considered "unconditional". So perhaps we should leave this open and revisit it after #57965 is fixed.

@rustbot label +A-diagnostics

[Noratrieb]

The compiler really shouldn't stackoverflow on normal code like this, so that is a bug.

[jruderman]

The crash is in the compiled output, not in the compiler