error[E0308]: mismatched types --> $DIR/issue-102206.rs:6:27 | LL | std::mem::size_of_val(foo()); | --------------------- ^^^^^ expected `&_`, found future | | | arguments to this function are incorrect | note: function defined here --> $SRC_DIR/core/src/mem/mod.rs:LL:COL help: consider borrowing here | LL | std::mem::size_of_val(&foo()); | + error: aborting due to previous error For more information about this error, try `rustc --explain E0308`.