{"ast_node_type":"other","tokens":[{"end":59,"kind":"keyword","start":0,"text":"(PtrToPtr,"}]}
                    (PtrToPtr, PtrToPtr) => Some(PtrToPtr),
                    // `*mut [i32] -> *const [i32] -> *const i32` can skip the middle in MIR.
                    // PtrToPtr-then-Transmute is fine so long as the pointer cast is identity: