+ /// **What it does:** Checks for calls of `mem::discriminant()` on a non-enum type.
+ ///
+ /// **Why is this bad?** The value of `mem::discriminant()` on non-enum types
+ /// is unspecified.
+ ///
+ /// **Known problems:** None.
+ ///
+ /// **Example:**
+ /// ```rust
+ /// use std::mem;
+ ///
+ /// mem::discriminant(&"hello");
+ /// mem::discriminant(&&Some(2));
+ /// ```