error[E0573]: expected type, found local variable `num`
  --> $DIR/let-binding-init-expr-as-ty.rs:2:27
   |
LL |     let foo: i32::from_be(num);
   |                           ^^^ not a type
help: maybe you meant to assign a value instead of defining this let binding's type
   |
LL |     let foo = i32::from_be(num);
   |             ^

error: parenthesized type parameters may only be used with a `Fn` trait
  --> $DIR/let-binding-init-expr-as-ty.rs:2:19
   |
LL |     let foo: i32::from_be(num);
   |                   ^^^^^^^^^^^^
   |
   = note: `#[deny(parenthesized_params_in_types_and_modules)]` on by default
   = warning: this was previously accepted by the compiler but is being phased out; it will become a hard error in a future release!
   = note: for more information, see issue #42238 <https://github.com/rust-lang/rust/issues/42238>

error[E0223]: ambiguous associated type
  --> $DIR/let-binding-init-expr-as-ty.rs:2:14
   |
LL |     let foo: i32::from_be(num);
   |              ^^^^^^^^^^^^^^^^^ help: use fully-qualified syntax: `<i32 as Trait>::from_be`

error: aborting due to 3 previous errors

Some errors have detailed explanations: E0223, E0573.
For more information about an error, try `rustc --explain E0223`.