diff --git a/src/servo/css/lexer.rs b/src/servo/css/lexer.rs
index 7c949e745c6..a4067945464 100644
--- a/src/servo/css/lexer.rs
+++ b/src/servo/css/lexer.rs
@@ -237,7 +237,7 @@ fn parser(input_port: comm::Port<ProgressMsg>, state : ParserState) -> CssLexer
     };
 }
 
-fn lex_css_from_bytes(+input_port: comm::Port<ProgressMsg>, result_chan : Chan<Token>) {
+fn lex_css_from_bytes(+input_port: comm::Port<ProgressMsg>, result_chan : &Chan<Token>) {
     let lexer = parser(input_port, CssElement);
 
     loop {
@@ -252,7 +252,7 @@ fn lex_css_from_bytes(+input_port: comm::Port<ProgressMsg>, result_chan : Chan<T
     }
 }
 
-fn spawn_css_lexer_from_string(-content : ~str) -> pipes::Port<Token> {
+fn spawn_css_lexer_from_string(+content : ~str) -> pipes::Port<Token> {
     let (result_chan, result_port) = pipes::stream();
 
     do task::spawn {
@@ -260,14 +260,14 @@ fn spawn_css_lexer_from_string(-content : ~str) -> pipes::Port<Token> {
         input_port.send(Payload(str::to_bytes(content)));
         input_port.send(Done(Ok(())));
 
-        lex_css_from_bytes(input_port, result_chan);
+        lex_css_from_bytes(input_port, &result_chan);
     }
 
     return result_port;
 }
 
 #[allow(non_implicitly_copyable_typarams)]
-pub fn spawn_css_lexer_task(-url: Url, resource_task: ResourceTask) -> pipes::Port<Token> {
+pub fn spawn_css_lexer_task(+url: Url, resource_task: ResourceTask) -> pipes::Port<Token> {
     let (result_chan, result_port) = pipes::stream();
 
     do task::spawn || {
@@ -276,7 +276,7 @@ pub fn spawn_css_lexer_task(-url: Url, resource_task: ResourceTask) -> pipes::Po
         // TODO: change copy to move once the compiler permits it
         resource_task.send(Load(copy url, input_port.chan()));
 
-        lex_css_from_bytes(input_port, result_chan);
+        lex_css_from_bytes(input_port, &result_chan);
     };
 
     return result_port;
diff --git a/src/servo/css/parser.rs b/src/servo/css/parser.rs
index 7643dca9249..f925392110e 100644
--- a/src/servo/css/parser.rs
+++ b/src/servo/css/parser.rs
@@ -21,7 +21,7 @@ type TokenReader = {stream : pipes::Port<Token>, mut lookahead : Option<Token>};
 
 trait TokenReaderMethods {
     fn get() -> Token;
-    fn unget(-tok : Token);
+    fn unget(+tok : Token);
 }
 
 impl TokenReader : TokenReaderMethods {
@@ -32,7 +32,7 @@ impl TokenReader : TokenReaderMethods {
         }
     }
 
-    fn unget(-tok : Token) {
+    fn unget(+tok : Token) {
         assert is_none(&self.lookahead);
         self.lookahead = Some(tok);
     }
diff --git a/src/servo/css/parser_util.rs b/src/servo/css/parser_util.rs
index fd6f476acb7..74d4e395d4a 100644
--- a/src/servo/css/parser_util.rs
+++ b/src/servo/css/parser_util.rs
@@ -11,27 +11,28 @@ export parse_box_sizing;
 export parse_display_type;
 
 
-fn parse_length(str : ~str) -> Option<Length> {
+fn parse_length(str : &str) -> Option<Length> {
     // TODO: use these once we stop lexing below
     const PTS_PER_INCH: float = 72.0;
     const CM_PER_INCH: float = 2.54;
     const PX_PER_PT: float = 1.0 / 0.75;
 
     match str {
-      s if s.ends_with(~"in") => from_str(str.substr(0, str.len() - 2)).map(|f| Px(1.0/0.75 * 72.0 * *f)),
-      s if s.ends_with(~"cm") => from_str(str.substr(0, str.len() - 2)).map(|f| Px(*f / 2.54 * 72.0 * 1.0/0.75)),
-      s if s.ends_with(~"mm") => from_str(str.substr(0, str.len() - 2)).map(|f| Px(*f * 0.1 / 2.54 * 72.0 * 1.0/0.75)),
-      s if s.ends_with(~"pt") => from_str(str.substr(0, str.len() - 2)).map(|f| Px(1.0/0.75 * *f)),
-      s if s.ends_with(~"pc") => from_str(str.substr(0, str.len() - 2)).map(|f| Px(1.0/0.75 * 12.0 * *f)),
-      s if s.ends_with(~"px") => from_str(str.substr(0, str.len() - 2)).map(|f| Px(*f)),
-      s if s.ends_with(~"em") => from_str(str.substr(0, str.len() - 2)).map(|f| Em(*f)),
-      s if s.ends_with(~"ex") => from_str(str.substr(0, str.len() - 2)).map(|f| Em(0.5 * *f)),
+      s if s.ends_with("in") => from_str(str.substr(0, str.len() - 2)).map(|f| Px(1.0/0.75 * 72.0 * *f)),
+      s if s.ends_with("cm") => from_str(str.substr(0, str.len() - 2)).map(|f| Px(*f / 2.54 * 72.0 * 1.0/0.75)),
+      s if s.ends_with("mm") => from_str(str.substr(0, str.len() - 2)).map(|f| Px(*f * 0.1 / 2.54 * 72.0 * 1.0/0.75)),
+      s if s.ends_with("pt") => from_str(str.substr(0, str.len() - 2)).map(|f| Px(1.0/0.75 * *f)),
+      s if s.ends_with("pc") => from_str(str.substr(0, str.len() - 2)).map(|f| Px(1.0/0.75 * 12.0 * *f)),
+      s if s.ends_with("px") => from_str(str.substr(0, str.len() - 2)).map(|f| Px(*f)),
+      s if s.ends_with("em") => from_str(str.substr(0, str.len() - 2)).map(|f| Em(*f)),
+      s if s.ends_with("ex") => from_str(str.substr(0, str.len() - 2)).map(|f| Em(0.5 * *f)),
       _ => None,
     }
 }
 
-fn parse_absolute_size(str : ~str) -> ParseResult<AbsoluteSize> {
-    match str {
+fn parse_absolute_size(str : &str) -> ParseResult<AbsoluteSize> {
+    // FIXME: Bad copy. Can't match &str
+    match str.to_str() {
       ~"xx-small" => Value(XXSmall),
       ~"x-small" => Value(XSmall),
       ~"small" => Value(Small),
@@ -43,30 +44,33 @@ fn parse_absolute_size(str : ~str) -> ParseResult<AbsoluteSize> {
     }
 }
 
-fn parse_relative_size(str: ~str) -> ParseResult<RelativeSize> {
-    match str {
+fn parse_relative_size(str: &str) -> ParseResult<RelativeSize> {
+    // FIXME: Bad copy. Can't match &str
+    match str.to_str() {
       ~"smaller" => Value(Smaller),
       ~"larger" => Value(Larger),
       _ => Fail
     }
 }
 
-fn parse_font_size(_str: ~str) -> ParseResult<CSSFontSize> {
+fn parse_font_size(_str: &str) -> ParseResult<CSSFontSize> {
     // TODO: complete me
     Value(LengthSize(Px(14.0)))
 }
 
 // For width / height, and anything else with the same attribute values
-fn parse_box_sizing(str : ~str) -> ParseResult<BoxSizing> {
-    match str {
+fn parse_box_sizing(str : &str) -> ParseResult<BoxSizing> {
+    // FIXME: Bad copy. Can't match &str
+    match str.to_str() {
       ~"auto" => Value(BoxAuto),
       ~"inherit" => CSSInherit,
       _ => Fail,
     }
 }
 
-fn parse_display_type(str : ~str) -> ParseResult<CSSDisplay> {
-    match str {
+fn parse_display_type(str : &str) -> ParseResult<CSSDisplay> {
+    // FIXME: Bad copy. Can't match &str
+    match str.to_str() {
       ~"inline" => Value(DisplayInline),
       ~"block" => Value(DisplayBlock),
       ~"none" => Value(DisplayNone),
diff --git a/src/servo/css/resolve/apply.rs b/src/servo/css/resolve/apply.rs
index 722915fba44..e3cc05c84e7 100644
--- a/src/servo/css/resolve/apply.rs
+++ b/src/servo/css/resolve/apply.rs
@@ -41,7 +41,7 @@ struct StyleApplicator {
 }
 
 // TODO: normalize this into a normal preorder tree traversal function
-fn apply_style(layout_ctx: &LayoutContext, node: Node, reflow: fn~()) {
+fn apply_style(layout_ctx: &LayoutContext, node: Node, +reflow: fn~()) {
     let applicator = StyleApplicator {
         node: node,
         reflow: reflow
@@ -55,7 +55,7 @@ fn apply_style(layout_ctx: &LayoutContext, node: Node, reflow: fn~()) {
 /** A wrapper around a set of functions that can be applied as a
  * top-down traversal of layout boxes.
  */
-fn inheritance_wrapper(layout_ctx: &LayoutContext, node : Node, reflow: fn~()) {
+fn inheritance_wrapper(layout_ctx: &LayoutContext, node : Node, +reflow: fn~()) {
     let applicator = StyleApplicator {
         node: node,
         reflow: reflow
diff --git a/src/servo/css/resolve/matching.rs b/src/servo/css/resolve/matching.rs
index d1d058cf0c2..94822b25ca3 100644
--- a/src/servo/css/resolve/matching.rs
+++ b/src/servo/css/resolve/matching.rs
@@ -11,8 +11,8 @@ use styles::{SpecifiedStyle};
 /** 
    Check if a CSS attribute matches the attribute of an HTML element.
 */
-fn attrs_match(attr: Attr, elmt: ElementData) -> bool {
-    match attr {
+fn attrs_match(attr: &Attr, elmt: &ElementData) -> bool {
+    match *attr {
       Exists(name) => {
         match elmt.get_attr(name) {
           Some(_) => true,
@@ -55,8 +55,8 @@ fn attrs_match(attr: Attr, elmt: ElementData) -> bool {
 }
 
 trait PrivMatchingMethods {
-    fn matches_element(sel: ~Selector) -> bool;
-    fn matches_selector(sel : ~Selector) -> bool;
+    fn matches_element(sel: &Selector) -> bool;
+    fn matches_selector(sel: &Selector) -> bool;
 }
 
 impl Node : PrivMatchingMethods { 
@@ -66,7 +66,7 @@ impl Node : PrivMatchingMethods {
     element with no relational information, describes the given HTML
     element.
     */
-    fn matches_element(sel: ~Selector) -> bool {
+    fn matches_element(sel: &Selector) -> bool {
         match *sel {
           Child(_, _) | Descendant(_, _) | Sibling(_, _) => { return false; }
           Element(tag, attrs) => {
@@ -78,7 +78,7 @@ impl Node : PrivMatchingMethods {
                 
                 let mut i = 0u;
                 while i < attrs.len() {
-                    if !attrs_match(attrs[i], elmt) { return false; }
+                    if !attrs_match(&attrs[i], &elmt) { return false; }
                     i += 1u;
                 }
 
@@ -96,7 +96,7 @@ impl Node : PrivMatchingMethods {
     /**
     Checks if a generic CSS selector matches a given HTML element
     */
-    fn matches_selector(sel : ~Selector) -> bool {
+    fn matches_selector(sel : &Selector) -> bool {
         match *sel {
           Element(*) => { return self.matches_element(sel); }
           Child(sel1, sel2) => {
@@ -188,7 +188,7 @@ impl Node : PrivStyleMethods {
 }
 
 trait MatchingMethods {
-    fn match_css_style(styles : Stylesheet);
+    fn match_css_style(styles : &Stylesheet);
 }
 
 impl Node : MatchingMethods {
@@ -196,7 +196,7 @@ impl Node : MatchingMethods {
     Compare an html element to a list of css rules and update its
     style according to the rules matching it.
     */
-    fn match_css_style(styles : Stylesheet) {
+    fn match_css_style(styles : &Stylesheet) {
         // Loop over each rule, see if our node matches what is
         // described in the rule. If it matches, update its style. As
         // we don't currently have priorities of style information,
@@ -225,7 +225,7 @@ mod test {
     use dvec::DVec;
 
     #[allow(non_implicitly_copyable_typarams)]
-    fn new_node_from_attr(scope: NodeScope, -name: ~str, -val: ~str) -> Node {
+    fn new_node_from_attr(scope: NodeScope, +name: ~str, +val: ~str) -> Node {
         let elmt = ElementData(~"div", ~HTMLDivElement);
         let attr = ~Attr(name, val);
         elmt.attrs.push(attr);
diff --git a/src/servo/css/styles.rs b/src/servo/css/styles.rs
index efae44c1b37..4df3d88003b 100644
--- a/src/servo/css/styles.rs
+++ b/src/servo/css/styles.rs
@@ -72,7 +72,7 @@ impl NodeKind : DefaultStyleMethods {
  * style is computed so that it can be used to short-circuit selector matching to avoid computing
  * style for children of display:none objects.
  */
-fn empty_style_for_node_kind(kind: NodeKind) -> SpecifiedStyle {
+fn empty_style_for_node_kind(kind: &NodeKind) -> SpecifiedStyle {
     let display_type = kind.default_display_type();
 
     {mut background_color : Initial,
@@ -89,7 +89,7 @@ trait StyleMethods {
 
     fn style() -> SpecifiedStyle;
     fn initialize_style_for_subtree(ctx: &LayoutContext, refs: &DVec<@LayoutData>);
-    fn recompute_style_for_subtree(ctx: &LayoutContext, styles : ARC<Stylesheet>);
+    fn recompute_style_for_subtree(ctx: &LayoutContext, styles : &ARC<Stylesheet>);
 }
 
 impl Node : StyleMethods {
@@ -101,7 +101,7 @@ impl Node : StyleMethods {
             false => {
                 let node_kind = self.read(|n| copy *n.kind);
                 let data = @LayoutData({
-                    mut style : ~empty_style_for_node_kind(node_kind),
+                    mut style : ~empty_style_for_node_kind(&node_kind),
                     mut flow  : None
                 });
                 self.set_aux(data); Some(data)
@@ -142,17 +142,15 @@ impl Node : StyleMethods {
      * the node (the reader-auxiliary box in the RCU model) with the
      * computed style.
      */
-    fn recompute_style_for_subtree(ctx: &LayoutContext, styles : ARC<Stylesheet>) {
+    fn recompute_style_for_subtree(ctx: &LayoutContext, styles : &ARC<Stylesheet>) {
         let mut i = 0u;
         
         // Compute the styles of each of our children in parallel
         for NodeTree.each_child(&self) |kid| {
             i = i + 1u;
-            let new_styles = clone(&styles);
-            
-            kid.recompute_style_for_subtree(ctx, new_styles); 
+            kid.recompute_style_for_subtree(ctx, styles); 
         }
 
-        self.match_css_style(*get(&styles));
+        self.match_css_style(get(styles));
     }
 }
diff --git a/src/servo/css/values.rs b/src/servo/css/values.rs
index 89044910348..c73eca1c9c6 100644
--- a/src/servo/css/values.rs
+++ b/src/servo/css/values.rs
@@ -24,11 +24,11 @@ enum CSSValue<T : Copy> {
 }
 
 impl<T : Copy> ParseResult<T> {
-    pure fn extract<U>(f: fn(CSSValue<T>) -> U) -> Option<U> { extract(self, f) }
+    pure fn extract<U>(f: fn(+v: CSSValue<T>) -> U) -> Option<U> { extract(&self, f) }
 }
 
-pure fn extract<T : Copy, U>(res: ParseResult<T>, f: fn(CSSValue<T>) -> U) -> Option<U> {
-    match res {
+pure fn extract<T : Copy, U>(res: &ParseResult<T>, f: fn(+v: CSSValue<T>) -> U) -> Option<U> {
+    match *res {
         Fail => None,
         CSSInitial => Some(f(Initial)),
         CSSInherit => Some(f(Inherit)),
diff --git a/src/servo/layout/box_builder.rs b/src/servo/layout/box_builder.rs
index 01983435570..4e21459ff48 100644
--- a/src/servo/layout/box_builder.rs
+++ b/src/servo/layout/box_builder.rs
@@ -50,7 +50,7 @@ impl LayoutTreeBuilder {
 
         // TODO: remove this once UA styles work
         // TODO: handle interactions with 'float', 'position' (CSS 2.1, Section 9.7)
-        let simulated_display = match self.simulate_UA_display_rules(cur_node, style) {
+        let simulated_display = match self.simulate_UA_display_rules(cur_node, &style) {
             DisplayNone => return, // tree ends here if 'display: none'
             v => v
         };
@@ -151,7 +151,7 @@ impl LayoutTreeBuilder {
         fail ~"TODO: handle case where an inline is split by a block"
     }
 
-    priv fn simulate_UA_display_rules(node: Node, style: SpecifiedStyle) -> CSSDisplay {
+    priv fn simulate_UA_display_rules(node: Node, style: &SpecifiedStyle) -> CSSDisplay {
         let resolved = match style.display_type {
             Inherit | Initial => DisplayInline, // TODO: remove once resolve works
             Specified(v) => v
diff --git a/src/servo/layout/flow.rs b/src/servo/layout/flow.rs
index ccb675dfc36..75efaf2ea98 100644
--- a/src/servo/layout/flow.rs
+++ b/src/servo/layout/flow.rs
@@ -170,7 +170,7 @@ impl FlowContext {
 
 // Actual methods that do not require much flow-specific logic
 impl FlowContext {
-    pure fn foldl_boxes_for_node<B: Copy>(node: Node, seed: B, blk: pure fn&(B,@RenderBox) -> B) -> B {
+    pure fn foldl_boxes_for_node<B: Copy>(node: Node, +seed: B, blk: pure fn&(+a: B,@RenderBox) -> B) -> B {
         match self {
             RootFlow(*) => match self.root().box {
                 Some(box) if box.d().node == node => { blk(seed, box) },
@@ -181,6 +181,7 @@ impl FlowContext {
                 _ => seed
             },
             InlineFlow(*) => do self.inline().boxes.foldl(seed) |acc, box| {
+                // FIXME: Bad copies. foldl's accumulator should be by-value
                 if box.d().node == node { blk(*acc, *box) }
                 else { *acc }
             },
diff --git a/src/servo/layout/layout_task.rs b/src/servo/layout/layout_task.rs
index d9ba3b6e7a9..79af4717e06 100644
--- a/src/servo/layout/layout_task.rs
+++ b/src/servo/layout/layout_task.rs
@@ -144,7 +144,7 @@ impl Layout {
                 do util::time::time(~"layout") {
                     // TODO: this is dumb. we don't need 3 separate traversals.
                     node.initialize_style_for_subtree(&layout_ctx, &self.layout_refs);
-                    node.recompute_style_for_subtree(&layout_ctx, styles);
+                    node.recompute_style_for_subtree(&layout_ctx, &styles);
                     /* resolve styles (convert relative values) down the node tree */
                     apply_style(&layout_ctx, node, layout_ctx.reflow_cb);