Function rustc_trait_selection::traits::is_vtable_safe_method

pub fn is_vtable_safe_method(
    tcx: TyCtxt<'_>,
    trait_def_id: DefId,
    method: AssocItem
) -> bool

We say a method is vtable safe if it can be invoked on a trait object. Note that object-safe traits can have some non-vtable-safe methods, so long as they require Self: Sized or otherwise ensure that they cannot be used when Self = Trait.