error[E0618]: expected function, found `S` --> $DIR/issue-80853.rs:4:5 | LL | fn repro_ref(thing: S) { | ----- `thing` has type `S` LL | thing(); | ^^^^^-- | | | call expression requires function error: aborting due to 1 previous error For more information about this error, try `rustc --explain E0618`.