Support parentheses in patterns

Author: topecongiro

src/expr.rs

@@ -1536,7 +1536,9 @@ fn is_short_pattern_inner(pat: &ast::Pat) -> bool {
         ast::PatKind::TupleStruct(ref path, ref subpats, _) => {
             path.segments.len() <= 1 && subpats.len() <= 1
         }
-        ast::PatKind::Box(ref p) | ast::PatKind::Ref(ref p, _) => is_short_pattern_inner(&*p),
+        ast::PatKind::Box(ref p) | ast::PatKind::Ref(ref p, _) | ast::PatKind::Paren(ref p) => {
+            is_short_pattern_inner(&*p)
+        }
     }
 }
 

src/patterns.rs

@@ -129,6 +129,8 @@ impl Rewrite for Pat {
                 rewrite_struct_pat(path, fields, ellipsis, self.span, context, shape)
             }
             PatKind::Mac(ref mac) => rewrite_macro(mac, None, context, shape, MacroPosition::Pat),
+            PatKind::Paren(ref pat) => pat.rewrite(context, shape.offset_left(1)?.sub_width(1)?)
+                .map(|inner_pat| format!("({})", inner_pat)),
         }
     }
 }