#![warn(clippy::temporary_assignment)] #![allow(const_item_mutation)] use std::ops::{Deref, DerefMut}; struct TupleStruct(i32); struct Struct { field: i32, } struct MultiStruct { structure: Struct, } struct Wrapper<'a> { inner: &'a mut Struct, } impl<'a> Deref for Wrapper<'a> { type Target = Struct; fn deref(&self) -> &Struct { self.inner } } impl<'a> DerefMut for Wrapper<'a> { fn deref_mut(&mut self) -> &mut Struct { self.inner } } struct ArrayStruct { array: [i32; 1], } const A: TupleStruct = TupleStruct(1); const B: Struct = Struct { field: 1 }; const C: MultiStruct = MultiStruct { structure: Struct { field: 1 }, }; const D: ArrayStruct = ArrayStruct { array: [1] }; fn main() { let mut s = Struct { field: 0 }; let mut t = (0, 0); Struct { field: 0 }.field = 1; MultiStruct { structure: Struct { field: 0 }, } .structure .field = 1; ArrayStruct { array: [0] }.array[0] = 1; (0, 0).0 = 1; // no error s.field = 1; t.0 = 1; Wrapper { inner: &mut s }.field = 1; let mut a_mut = TupleStruct(1); a_mut.0 = 2; let mut b_mut = Struct { field: 1 }; b_mut.field = 2; let mut c_mut = MultiStruct { structure: Struct { field: 1 }, }; c_mut.structure.field = 2; let mut d_mut = ArrayStruct { array: [1] }; d_mut.array[0] = 2; }