error[E0382]: use of moved value: `blk` --> $DIR/once-cant-call-twice-on-heap.rs:8:5 | LL | fn foo(blk: F) { | --- move occurs because `blk` has type `F`, which does not implement the `Copy` trait LL | blk(); | ----- `blk` moved due to this call LL | blk(); | ^^^ value used here after move | note: this value implements `FnOnce`, which causes it to be moved when called --> $DIR/once-cant-call-twice-on-heap.rs:7:5 | LL | blk(); | ^^^ help: consider further restricting this bound | LL | fn foo(blk: F) { | ++++++ error: aborting due to 1 previous error For more information about this error, try `rustc --explain E0382`.