if in match arm should have multi-line formatting like an if expression

[nrc]

I.e., if a condition spans multiple lines, the lines should be aligned. E.g.,

                ItemKind::Enum(_, Generics { ref ty_params, .. })
-                    if ty_params.is_empty() &&
-                    attr::contains_name(&annitem.attrs, "derive_Copy") => {
+                    if ty_params.is_empty()
+                       && attr::contains_name(&annitem.attrs, "derive_Copy") => {

Whilst I've labelled this easy, it is probably good as a second bug, rather than a first.

[bekh6ex]

Currently I'm getting this behaviour:

 fn f() -> () {⏎
     match a {⏎
-        ItemKind::Enum(_, Generics { ref ty_params, .. }) ⏎
-          if ty_params.is_empty() && ⏎
-            ty_params.is_empty() ⏎
-        && ty_params.is_empty() ⏎
-    && attr::contains_name(&annitem.attrs, "derive_Copy") => { asd }⏎
+        ItemKind::Enum(_, Generics { ref ty_params, .. })⏎
+            if ty_params.is_empty() && ty_params.is_empty() && ty_params.is_empty() &&⏎
+               attr::contains_name(&annitem.attrs, "derive_Copy") => asd,⏎
     }⏎
 }⏎

Seems like conditions are aligned. Shouldn't issue be closed?

[nrc]

Sounds like we just need to add a test