auto merge of #5182 : zslayton/servo/master, r=jdm

Opening this PR to invite feedback. 

Of the many `match` statement candidates for conversion to `if let`, several included `if` guards. Since `if let` doesn't support this syntax, I used nested if statements. If this is undesirable, say the word and I can revert those cases to `match`.

1 files changed, 9 insertions, 13 deletions

diff --git a/components/script/dom/htmloptionelement.rs b/components/script/dom/htmloptionelement.rs
index def3d358e8d..d50c832eda4 100644
--- a/components/script/dom/htmloptionelement.rs
+++ b/components/script/dom/htmloptionelement.rs
@@ -129,9 +129,8 @@ impl<'a> VirtualMethods for JSRef<'a, HTMLOptionElement> {
     }
 
     fn after_set_attr(&self, attr: JSRef<Attr>) {
-        match self.super_type() {
-            Some(ref s) => s.after_set_attr(attr),
-            _ => ()
+        if let Some(ref s) = self.super_type() {
+            s.after_set_attr(attr);
         }
 
         match attr.local_name() {
@@ -139,15 +138,14 @@ impl<'a> VirtualMethods for JSRef<'a, HTMLOptionElement> {
                 let node: JSRef<Node> = NodeCast::from_ref(*self);
                 node.set_disabled_state(true);
                 node.set_enabled_state(false);
-            }
+            },
             _ => ()
         }
     }
 
     fn before_remove_attr(&self, attr: JSRef<Attr>) {
-        match self.super_type() {
-            Some(ref s) => s.before_remove_attr(attr),
-            _ => ()
+        if let Some(ref s) = self.super_type() {
+            s.before_remove_attr(attr);
         }
 
         match attr.local_name() {
@@ -162,9 +160,8 @@ impl<'a> VirtualMethods for JSRef<'a, HTMLOptionElement> {
     }
 
     fn bind_to_tree(&self, tree_in_doc: bool) {
-        match self.super_type() {
-            Some(ref s) => s.bind_to_tree(tree_in_doc),
-            _ => (),
+        if let Some(ref s) = self.super_type() {
+            s.bind_to_tree(tree_in_doc);
         }
 
         let node: JSRef<Node> = NodeCast::from_ref(*self);
@@ -172,9 +169,8 @@ impl<'a> VirtualMethods for JSRef<'a, HTMLOptionElement> {
     }
 
     fn unbind_from_tree(&self, tree_in_doc: bool) {
-        match self.super_type() {
-            Some(ref s) => s.unbind_from_tree(tree_in_doc),
-            _ => (),
+        if let Some(ref s) = self.super_type() {
+            s.unbind_from_tree(tree_in_doc);
         }
 
         let node: JSRef<Node> = NodeCast::from_ref(*self);