use_self - add test case of rust-lang#3859

Author: tnielens

tests/ui/use_self.fixed

@@ -341,12 +341,26 @@ mod issue2843 {
     trait Foo {
         type Bar;
     }
-    
+
     impl Foo for usize {
         type Bar = u8;
     }
-    
+
     impl<T: Foo> Foo for Option<T> {
         type Bar = Option<T::Bar>;
     }
-}
+}
+
+mod issue3859 {
+    pub struct Foo;
+    pub struct Bar([usize; 3]);
+
+    impl Foo {
+        pub const BAR: usize = 3;
+
+        pub fn foo() {
+            const _X: usize = Foo::BAR;
+            // const _Y: usize = Self::BAR;
+        }
+    }
+}

tests/ui/use_self.rs

@@ -341,12 +341,26 @@ mod issue2843 {
     trait Foo {
         type Bar;
     }
-    
+
     impl Foo for usize {
         type Bar = u8;
     }
-    
+
     impl<T: Foo> Foo for Option<T> {
         type Bar = Option<T::Bar>;
     }
-}
+}
+
+mod issue3859 {
+    pub struct Foo;
+    pub struct Bar([usize; 3]);
+
+    impl Foo {
+        pub const BAR: usize = 3;
+
+        pub fn foo() {
+            const _X: usize = Foo::BAR;
+            // const _Y: usize = Self::BAR;
+        }
+    }
+}