+#[derive(Clone, Copy, Debug, PartialEq, Eq, RustcEncodable, RustcDecodable, HashStable)]
+pub enum PointerCast {
+ /// Go from a fn-item type to a fn-pointer type.
+ ReifyFnPointer,
+
+ /// Go from a safe fn pointer to an unsafe fn pointer.
+ UnsafeFnPointer,
+
+ /// Go from a non-capturing closure to an fn pointer or an unsafe fn pointer.
+ /// It cannot convert a closure that requires unsafe.
+ ClosureFnPointer(hir::Unsafety),
+
+ /// Go from a mut raw pointer to a const raw pointer.
+ MutToConstPointer,
+
+ /// Unsize a pointer/reference value, e.g., `&[T; n]` to
+ /// `&[T]`. Note that the source could be a thin or fat pointer.
+ /// This will do things like convert thin pointers to fat
+ /// pointers, or convert structs containing thin pointers to
+ /// structs containing fat pointers, or convert between fat
+ /// pointers. We don't store the details of how the transform is
+ /// done (in fact, we don't know that, because it might depend on
+ /// the precise type parameters). We just store the target
+ /// type. Codegen backends and miri figure out what has to be done
+ /// based on the precise source/target type at hand.
+ Unsize,
+}
+