error[E0495]: cannot infer an appropriate lifetime due to conflicting requirements
  --> $DIR/issue-75777.rs:11:14
   |
LL |     Box::new(move |_| fut)
   |              ^^^^^^^^^^^^
   |
note: first, the lifetime cannot outlive the lifetime `'a` as defined here...
  --> $DIR/issue-75777.rs:9:11
   |
LL | fn inject<'a, Env: 'a, A: 'a + Send>(v: A) -> Box<dyn FnOnce(&'a Env) -> BoxFuture<'a, A>> {
   |           ^^
note: ...so that the types are compatible
  --> $DIR/issue-75777.rs:11:14
   |
LL |     Box::new(move |_| fut)
   |              ^^^^^^^^^^^^
   = note: expected `(Pin<Box<dyn Future<Output = A> + Send>>,)`
              found `(Pin<Box<(dyn Future<Output = A> + Send + 'a)>>,)`
   = note: but, the lifetime must be valid for the static lifetime...
note: ...so that the types are compatible
  --> $DIR/issue-75777.rs:11:5
   |
LL |     Box::new(move |_| fut)
   |     ^^^^^^^^^^^^^^^^^^^^^^
   = note: expected `Box<(dyn FnOnce(&'a Env) -> Pin<Box<(dyn Future<Output = A> + Send + 'a)>> + 'static)>`
              found `Box<dyn FnOnce(&'a Env) -> Pin<Box<(dyn Future<Output = A> + Send + 'a)>>>`

error: aborting due to previous error

For more information about this error, try `rustc --explain E0495`.