error[E0641]: cannot cast to a pointer of an unknown kind
  --> $DIR/issue-45730.rs:3:28
   |
LL |     let x: *const _ = 0 as _;
   |                            ^ needs more type information
   |
   = note: the type information given here is insufficient to check whether the pointer cast is valid

error[E0641]: cannot cast to a pointer of an unknown kind
  --> $DIR/issue-45730.rs:5:28
   |
LL |     let x: *const _ = 0 as *const _;
   |                            ^^^^^^^^ needs more type information
   |
   = note: the type information given here is insufficient to check whether the pointer cast is valid

error[E0641]: cannot cast to a pointer of an unknown kind
  --> $DIR/issue-45730.rs:8:44
   |
LL |     let x = 0 as *const i32 as *const _ as *mut _;
   |                                            ^^^^^^ needs more type information
   |
   = note: the type information given here is insufficient to check whether the pointer cast is valid

error: aborting due to 3 previous errors

For more information about this error, try `rustc --explain E0641`.