error[E0308]: mismatched types
  --> $DIR/issue-5216.rs:3:21
   |
LL | pub static C: S = S(f);
   |                   - ^ expected `Box<dyn FnMut() + Sync>`, found fn item
   |                   |
   |                   arguments to this struct are incorrect
   |
   = note: expected struct `Box<(dyn FnMut() + Sync + 'static)>`
             found fn item `fn() {f}`
note: tuple struct defined here
  --> $DIR/issue-5216.rs:2:8
   |
LL | struct S(Box<dyn FnMut() + Sync>);
   |        ^

error[E0308]: mismatched types
  --> $DIR/issue-5216.rs:8:19
   |
LL | pub static D: T = g;
   |                   ^ expected `Box<dyn FnMut() + Sync>`, found fn item
   |
   = note: expected struct `Box<(dyn FnMut() + Sync + 'static)>`
             found fn item `fn() {g}`

error: aborting due to 2 previous errors

For more information about this error, try `rustc --explain E0308`.