trait Hello { fn example(&self, input: &i32); // should suggest here } struct Test1(i32); impl Hello for Test1 { fn example(&self, input: &i32) { // should not suggest here *input = self.0; //~ ERROR cannot assign } } struct Test2(i32); impl Hello for Test2 { fn example(&self, input: &i32) { // should not suggest here self.0 += *input; //~ ERROR cannot assign } } fn main() { }