src/test/ui/borrowck/issue-83309-ice-immut-in-for-loop.rs

   1 // rust-lang/rust#83309: The compiler tries to suggest potential
   2 // methods that return `&mut` items. However, when it doesn't
   3 // find such methods, it still tries to add suggestions
   4 // which then fails an assertion later because there was
   5 // no suggestions to make.
   6
   7
   8 fn main() {
   9     for v in Query.iter_mut() {
  10         //~^ NOTE this iterator yields `&` references
  11         *v -= 1;
  12         //~^ ERROR cannot assign to `*v`, which is behind a `&` reference
  13         //~| NOTE `v` is a `&` reference, so the data it refers to cannot be written
  14     }
  15 }
  16
  17 pub struct Query;
  18 pub struct QueryIter<'a>(&'a i32);
  19
  20 impl Query {
  21     pub fn iter_mut<'a>(&'a mut self) -> QueryIter<'a> {
  22         todo!();
  23     }
  24 }
  25
  26 impl<'a> Iterator for QueryIter<'a> {
  27     type Item = &'a i32;
  28
  29     fn next(&mut self) -> Option<Self::Item> {
  30         todo!();
  31     }
  32 }