add tests for 2506

Author: kngwyu

tests/source/issue-2506.rs

@@ -0,0 +1,16 @@
+#![feature(dyn_trait)]
+fn main() {
+    // checks rustfmt doesn't remove dyn
+    trait MyTrait {
+        fn method(&self) -> u64;
+    }
+    fn f1(a: Box<dyn MyTrait>) {}
+
+    // checks if line wrap works correctly
+    trait Very_______________________Long__________________Name____________________Trait {
+        fn method(&self) -> u64;
+    }
+
+    fn f2(a: Box<dyn Very_______________________Long__________________Name____________________Trait+ 'static,>) {}
+
+}

tests/target/issue-2506.rs

@@ -0,0 +1,22 @@
+#![feature(dyn_trait)]
+fn main() {
+    // checks rustfmt doesn't remove dyn
+    trait MyTrait {
+        fn method(&self) -> u64;
+    }
+    fn f1(a: Box<dyn MyTrait>) {}
+
+    // checks if line wrap works correctly
+    trait Very_______________________Long__________________Name____________________Trait
+         {
+        fn method(&self) -> u64;
+    }
+
+    fn f2(
+        a: Box<
+            dyn Very_______________________Long__________________Name____________________Trait
+                + 'static,
+        >,
+    ) {
+    }
+}