use_self - add test case of rust-lang#4734

Author: tnielens

tests/ui/use_self.fixed

@@ -422,3 +422,16 @@ mod lint_at_impl_item_level {
         }
     }
 }
+
+mod issue4734 {
+    #[repr(C, packed)]
+    pub struct X {
+        pub x: u32,
+    }
+
+    impl From<X> for u32 {
+        fn from(c: X) -> Self {
+            unsafe { core::mem::transmute(c) }
+        }
+    }
+}

tests/ui/use_self.rs

@@ -422,3 +422,16 @@ mod lint_at_impl_item_level {
         }
     }
 }
+
+mod issue4734 {
+    #[repr(C, packed)]
+    pub struct X {
+        pub x: u32,
+    }
+
+    impl From<X> for u32 {
+        fn from(c: X) -> Self {
+            unsafe { core::mem::transmute(c) }
+        }
+    }
+}