{"ast_node_type":"other","tokens":[{"end":88,"kind":"keyword","start":0,"text":"//"}]}
        // We allow impls on pattern types exactly when we allow impls on the base type.
        let mut self_ty = self.tcx.peel_off_free_alias_tys(self_ty);
        // FIXME(pattern_types): Figure out the exact coherence rules we want here.