Add test case for issue 6127

Author: ytmimi

tests/source/issue_6127.rs

@@ -0,0 +1,32 @@
+// rustfmt-version: Two
+
+trait Foo:
+    Fn(
+    ReallyLongTypeName,
+    ReallyLongTypeName,
+    ReallyLongTypeName,
+    ReallyLongTypeName,
+) -> ReallyLongTypeName
+{
+}
+
+
+trait Bar:
+    Fn(
+    ReallyLongTypeName,
+    ReallyLongTypeName,
+    ReallyLongTypeName,
+    ReallyLongTypeName,
+) -> ReallyLongTypeName + Debug + Clone
+{
+}
+
+trait FooBar:
+    Clone + Debug + Fn(
+    ReallyLongTypeName,
+    ReallyLongTypeName,
+    ReallyLongTypeName,
+    ReallyLongTypeName,
+) -> ReallyLongTypeName
+{
+}

tests/target/issue_6127.rs

@@ -0,0 +1,35 @@
+// rustfmt-version: Two
+
+trait Foo:
+    Fn(
+        ReallyLongTypeName,
+        ReallyLongTypeName,
+        ReallyLongTypeName,
+        ReallyLongTypeName,
+    ) -> ReallyLongTypeName
+{
+}
+
+trait Bar:
+    Fn(
+        ReallyLongTypeName,
+        ReallyLongTypeName,
+        ReallyLongTypeName,
+        ReallyLongTypeName,
+    ) -> ReallyLongTypeName
+    + Debug
+    + Clone
+{
+}
+
+trait FooBar:
+    Clone
+    + Debug
+    + Fn(
+        ReallyLongTypeName,
+        ReallyLongTypeName,
+        ReallyLongTypeName,
+        ReallyLongTypeName,
+    ) -> ReallyLongTypeName
+{
+}