error[E0308]: mismatched types
  --> $DIR/issue-53348.rs:20:13
   |
LL |         a = *i.to_string();
   |             ^^^^^^^^^^^^^^ expected struct `std::string::String`, found str
   |
   = note: expected type `std::string::String`
              found type `str`

error: aborting due to previous error

For more information about this error, try `rustc --explain E0308`.