error[E0618]: expected function, found `&str`
  --> $DIR/issue-22468.rs:3:13
   |
LL |     let foo = "bar";
   |         --- `&str` defined here
LL |     let x = foo("baz");
   |             ^^^-------
   |             |
   |             call expression requires function

error: aborting due to previous error

For more information about this error, try `rustc --explain E0618`.