{"ast_node_type":"other","tokens":[{"end":91,"kind":"keyword","start":0,"text":"#[rustc_const_unstable(feature"}]}
            #[rustc_const_unstable(feature = "const_fn_trait_ref_impls", issue = "101803")]
            #[stable(feature = "rust1", since = "1.0.0")]
            impl<A: Tuple, F: ?Sized> const FnMut<A> for &F