error[E0277]: the trait bound `fn() -> impl T {foo}: T` is not satisfied
  --> $DIR/fn-ctor-passed-as-arg-where-it-should-have-been-called.rs:17:9
   |
LL | fn foo() -> impl T<O=()> { S }
   |    --- consider calling this function
LL | 
LL | fn bar(f: impl T<O=()>) {}
   |                ------- required by this bound in `bar`
...
LL |     bar(foo);
   |         ^^^ the trait `T` is not implemented for `fn() -> impl T {foo}`
   |
help: use parentheses to call the function
   |
LL |     bar(foo());
   |            ^^

error[E0277]: the trait bound `[closure@$DIR/fn-ctor-passed-as-arg-where-it-should-have-been-called.rs:18:19: 18:23]: T` is not satisfied
  --> $DIR/fn-ctor-passed-as-arg-where-it-should-have-been-called.rs:19:9
   |
LL | fn bar(f: impl T<O=()>) {}
   |                ------- required by this bound in `bar`
...
LL |     let closure = || S;
   |                   -- consider calling this closure
LL |     bar(closure);
   |         ^^^^^^^ the trait `T` is not implemented for `[closure@$DIR/fn-ctor-passed-as-arg-where-it-should-have-been-called.rs:18:19: 18:23]`
   |
help: use parentheses to call the closure
   |
LL |     bar(closure());
   |                ^^

error: aborting due to 2 previous errors

For more information about this error, try `rustc --explain E0277`.