syntax_data: {"ast_node_type":"other","tokens":[{"end":67,"kind":"keyword","start":0,"text":"//"}]}
source_snippet:         // `Deref(Mut)::deref(_mut)` and `Index(Mut)::index(_mut)`.
context_before:         // same region and mutability as the receiver. This holds for
context_after:         let ty::Ref(region, _, mutbl) = *self.thir[args[0]].ty.kind() else {