error[E0631]: type mismatch in closure arguments
  --> $DIR/E0631.rs:7:5
   |
LL |     foo(|_: isize| {});
   |     ^^^ ---------- found signature defined here
   |     |
   |     expected due to this
   |
   = note: expected closure signature `fn(usize) -> _`
              found closure signature `fn(isize) -> _`
note: required by a bound in `foo`
  --> $DIR/E0631.rs:3:11
   |
LL | fn foo<F: Fn(usize)>(_: F) {}
   |           ^^^^^^^^^ required by this bound in `foo`

error[E0631]: type mismatch in closure arguments
  --> $DIR/E0631.rs:8:5
   |
LL |     bar(|_: isize| {});
   |     ^^^ ---------- found signature defined here
   |     |
   |     expected due to this
   |
   = note: expected closure signature `fn(usize) -> _`
              found closure signature `fn(isize) -> _`
note: required by a bound in `bar`
  --> $DIR/E0631.rs:4:11
   |
LL | fn bar<F: Fn<usize>>(_: F) {}
   |           ^^^^^^^^^ required by this bound in `bar`

error[E0631]: type mismatch in function arguments
  --> $DIR/E0631.rs:9:9
   |
LL |     fn f(_: u64) {}
   |     ------------ found signature defined here
...
LL |     foo(f);
   |     --- ^ expected due to this
   |     |
   |     required by a bound introduced by this call
   |
   = note: expected function signature `fn(usize) -> _`
              found function signature `fn(u64) -> _`
note: required by a bound in `foo`
  --> $DIR/E0631.rs:3:11
   |
LL | fn foo<F: Fn(usize)>(_: F) {}
   |           ^^^^^^^^^ required by this bound in `foo`

error[E0631]: type mismatch in function arguments
  --> $DIR/E0631.rs:10:9
   |
LL |     fn f(_: u64) {}
   |     ------------ found signature defined here
...
LL |     bar(f);
   |     --- ^ expected due to this
   |     |
   |     required by a bound introduced by this call
   |
   = note: expected function signature `fn(usize) -> _`
              found function signature `fn(u64) -> _`
note: required by a bound in `bar`
  --> $DIR/E0631.rs:4:11
   |
LL | fn bar<F: Fn<usize>>(_: F) {}
   |           ^^^^^^^^^ required by this bound in `bar`

error: aborting due to 4 previous errors

For more information about this error, try `rustc --explain E0631`.