{"ast_node_type":"other","tokens":[{"end":95,"kind":"keyword","start":0,"text":"//!"}]}
//! matches some other type X -- *without* affecting `X`. That means that if the type `X` is in
//! in the trait matching algorithm, which needs to be able to cache whether an `impl` self type
//! fact an unbound type variable, we want the match to be regarded as ambiguous, because depending