This error occurs when there was a recursive trait requirement that overflowed before it could be evaluated. Often this means that there is unbounded recursion in resolving some type bounds. For example, in the following code: ```compile_fail,E0275 trait Foo {} struct Bar(T); impl Foo for T where Bar: Foo {} ``` To determine if a `T` is `Foo`, we need to check if `Bar` is `Foo`. However, to do this check, we need to determine that `Bar>` is `Foo`. To determine this, we check if `Bar>>` is `Foo`, and so on. This is clearly a recursive requirement that can't be resolved directly. Consider changing your trait bounds so that they're less self-referential.