Unhelpful "overflow evaluating the requirement" error for infinitely recursive generators #46415
Description
Obviously this shouldn't actually work, due to the state type being infinitely sized (at least not without become/TCO for generators), but it should generate an error similar to recursive types.
Program:
#![feature(generators, conservative_impl_trait, generator_trait)] use std::ops::{Generator, GeneratorState}; fn foo() -> impl Generator<Yield = (), Return = ()> { || { let mut gen = foo(); let mut r = gen.resume(); while let GeneratorState::Yielded(v) = r { yield v; r = gen.resume(); } } } fn main() { foo(); }Output:
Compiling playground v0.0.1 (file:///playground) thread 'rustc' has overflowed its stack fatal runtime error: stack overflow error: Could not compile `playground`. To learn more, run the command again with --verbose. Expected (something like):
Compiling playground v0.0.1 (file:///playground) error[E0072]: recursive type `Foo` has infinite size --> src/main.rs:1:1 | 1 | struct Foo(Foo); | ^^^^^^^^^^^----^ | | | | | recursive without indirection | recursive type has infinite size | = help: insert indirection (e.g., a `Box`, `Rc`, or `&`) at some point to make `Foo` representable error: aborting due to previous error error: Could not compile `playground`. To learn more, run the command again with --verbose.