diff --git a/src/servo-gfx/text/harfbuzz/shaper.rs b/src/servo-gfx/text/harfbuzz/shaper.rs
index b9744fa72f3..4f5a0f1313b 100644
--- a/src/servo-gfx/text/harfbuzz/shaper.rs
+++ b/src/servo-gfx/text/harfbuzz/shaper.rs
@@ -250,10 +250,10 @@ pub impl HarfbuzzShaper {
         }
 
         // some helpers
-        let glyph_span : MutableRange = range::empty_mut();
+        let mut glyph_span : MutableRange = range::empty_mut();
         // this span contains first byte of first char, to last byte of last char in range.
         // so, end() points to first byte of last+1 char, if it's less than byte_max.
-        let char_byte_span : MutableRange = range::empty_mut();
+        let mut char_byte_span : MutableRange = range::empty_mut();
         let mut y_pos = Au(0);
 
         // main loop over each glyph. each iteration usually processes 1 glyph and 1+ chars.
@@ -336,7 +336,7 @@ pub impl HarfbuzzShaper {
             // gspan:  [-]
             // cspan:  [-]
             // covsp:  [---------------]
-            let covered_byte_span = copy char_byte_span;
+            let mut covered_byte_span = copy char_byte_span;
             // extend, clipping at end of text range.
             while covered_byte_span.end() < byte_max 
                 && byteToGlyph[covered_byte_span.end()] == NO_GLYPH {
diff --git a/src/servo-gfx/text/text_run.rs b/src/servo-gfx/text/text_run.rs
index 3ef6c150d3b..eb3a8b6d32f 100644
--- a/src/servo-gfx/text/text_run.rs
+++ b/src/servo-gfx/text/text_run.rs
@@ -92,7 +92,7 @@ impl TextRun {
     fn iter_natural_lines_for_range(&self, range: Range, f: fn(Range) -> bool) {
         assert range.is_valid_for_string(self.text);
 
-        let clump = MutableRange::new(range.begin(), 0);
+        let mut clump = MutableRange::new(range.begin(), 0);
         let mut in_clump = false;
 
         // clump non-linebreaks of nonzero length
@@ -120,7 +120,7 @@ impl TextRun {
     fn iter_indivisible_pieces_for_range(&self, range: Range, f: fn(Range) -> bool) {
         assert range.is_valid_for_string(self.text);
 
-        let clump = MutableRange::new(range.begin(), 0);
+        let mut clump = MutableRange::new(range.begin(), 0);
         loop {
             // find next non-whitespace byte index, then clump all whitespace before it.
             match str::find_between(self.text, clump.begin(), range.end(), |c| !char::is_whitespace(c)) {
diff --git a/src/servo-gfx/util/range.rs b/src/servo-gfx/util/range.rs
index 3ddd57f9b62..af038547fe5 100644
--- a/src/servo-gfx/util/range.rs
+++ b/src/servo-gfx/util/range.rs
@@ -106,8 +106,8 @@ pub impl Range {
 pub pure fn empty_mut() -> MutableRange { MutableRange::new(0, 0) }
 
 pub struct MutableRange {
-    priv mut off: uint,
-    priv mut len: uint
+    priv off: uint,
+    priv len: uint
 }
 
 pub impl MutableRange {
@@ -120,48 +120,48 @@ pub impl MutableRange {
     }
 }
 
-impl MutableRange {
-    pub pure fn begin() -> uint { self.off  }
-    pub pure fn length() -> uint { self.len }
-    pub pure fn end() -> uint { self.off + self.len }
-    pub pure fn eachi(cb: fn&(uint) -> bool) {
+pub impl MutableRange {
+    pure fn begin(&const self) -> uint { self.off  }
+    pure fn length(&const self) -> uint { self.len }
+    pure fn end(&const self) -> uint { self.off + self.len }
+    pure fn eachi(&const self, cb: fn&(uint) -> bool) {
         do uint::range(self.off, self.off + self.len) |i| { cb(i) }
     }
 
-    pub pure fn contains(i: uint) -> bool {
+    pure fn contains(&const self, i: uint) -> bool {
         i >= self.begin() && i < self.end()
     }
 
-    fn relation_to_range(&self, other: &MutableRange) -> RangeRelation {
+    fn relation_to_range(&const self, other: &MutableRange) -> RangeRelation {
         self.as_immutable().relation_to_range(other.as_immutable())
     }
 
-    pub pure fn as_immutable() -> Range {
+    pure fn as_immutable(&const self) -> Range {
         Range(self.begin(), self.length())
     }
 
-    pub pure fn is_valid_for_string(s: &str) -> bool {
+    pure fn is_valid_for_string(&const self, s: &str) -> bool {
         self.begin() < s.len() && self.end() <= s.len() && self.length() <= s.len()
     }
 
-    pub fn shift_by(i: int) { 
+    fn shift_by(&mut self, i: int) { 
         self.off = ((self.off as int) + i) as uint;
     }
 
-    pub fn extend_by(i: int) { 
+    fn extend_by(&mut self, i: int) { 
         self.len = ((self.len as int) + i) as uint;
     }
 
-    pub fn extend_to(i: uint) { 
+    fn extend_to(&mut self, i: uint) { 
         self.len = i - self.off;
     }
 
-    pub fn adjust_by(off_i: int, len_i: int) {
+    fn adjust_by(&mut self, off_i: int, len_i: int) {
         self.off = ((self.off as int) + off_i) as uint;
         self.len = ((self.len as int) + len_i) as uint;
     }
 
-    pub fn reset(off_i: uint, len_i: uint) {
+    fn reset(&mut self, off_i: uint, len_i: uint) {
         self.off = off_i;
         self.len = len_i;
     }
diff --git a/src/servo/layout/box.rs b/src/servo/layout/box.rs
index 36589e23a43..919b78e1150 100644
--- a/src/servo/layout/box.rs
+++ b/src/servo/layout/box.rs
@@ -189,7 +189,7 @@ impl RenderBox : RenderBoxMethods {
 
                 let mut pieces_processed_count : uint = 0;
                 let mut remaining_width : Au = max_width;
-                let left_range = MutableRange::new(data.range.begin(), 0);
+                let mut left_range = MutableRange::new(data.range.begin(), 0);
                 let mut right_range : Option<Range> = None;
                 debug!("split_to_width: splitting text box (strlen=%u, range=%?, avail_width=%?)",
                        data.run.text.len(), data.range, max_width);
diff --git a/src/servo/layout/box_builder.rs b/src/servo/layout/box_builder.rs
index 4be26b4b09e..94e3e6ea19d 100644
--- a/src/servo/layout/box_builder.rs
+++ b/src/servo/layout/box_builder.rs
@@ -151,7 +151,7 @@ impl BoxGenerator {
                         self.flow.inline().boxes.push(*spacer);
                     }
                 }
-                let node_range: MutableRange = MutableRange::new(self.range_stack.pop(), 0);
+                let mut node_range: MutableRange = MutableRange::new(self.range_stack.pop(), 0);
                 node_range.extend_to(self.flow.inline().boxes.len());
                 assert node_range.length() > 0;
 
diff --git a/src/servo/layout/inline.rs b/src/servo/layout/inline.rs
index 76b6957c1f5..e1e869fbc3d 100644
--- a/src/servo/layout/inline.rs
+++ b/src/servo/layout/inline.rs
@@ -147,36 +147,36 @@ impl ElementMapping {
 
 // stack-allocated object for scanning an inline flow into
 // TextRun-containing TextBoxes.
-struct TextRunScanner {
+priv struct TextRunScanner {
     clump: MutableRange,
-    flow: @FlowContext,
 }
 
-fn TextRunScanner(flow: @FlowContext) -> TextRunScanner {
-    TextRunScanner {
-        clump: MutableRange::empty(),
-        flow: flow,
+priv impl TextRunScanner {
+    static fn new() -> TextRunScanner {
+        TextRunScanner {
+            clump: MutableRange::empty(),
+        }
     }
 }
 
-impl TextRunScanner {
-    fn scan_for_runs(ctx: &LayoutContext) {
-        assert self.flow.inline().boxes.len() > 0;
+priv impl TextRunScanner {
+    fn scan_for_runs(&mut self, ctx: &LayoutContext, flow: @FlowContext) {
+        assert flow.inline().boxes.len() > 0;
 
-        do self.flow.inline().boxes.swap |in_boxes| {
+        do flow.inline().boxes.swap |in_boxes| {
             debug!("TextRunScanner: scanning %u boxes for text runs...", in_boxes.len());
             let out_boxes = DVec();
 
             for uint::range(0, in_boxes.len()) |box_i| {
                 debug!("TextRunScanner: considering box: %?", in_boxes[box_i].debug_str());
                 if box_i > 0 && !can_coalesce_text_nodes(in_boxes, box_i-1, box_i) {
-                    self.flush_clump_to_list(ctx, in_boxes, &out_boxes);
+                    self.flush_clump_to_list(ctx, flow, in_boxes, &out_boxes);
                 }
                 self.clump.extend_by(1);
             }
             // handle remaining clumps
             if self.clump.length() > 0 {
-                self.flush_clump_to_list(ctx, in_boxes, &out_boxes);
+                self.flush_clump_to_list(ctx, flow, in_boxes, &out_boxes);
             }
 
             debug!("TextRunScanner: swapping out boxes.");
@@ -212,7 +212,9 @@ impl TextRunScanner {
     // N.B. in_boxes is passed by reference, since we cannot
     // recursively borrow or swap the flow's dvec of boxes. When all
     // boxes are appended, the caller swaps the flow's box list.
-    fn flush_clump_to_list(ctx: &LayoutContext, 
+    fn flush_clump_to_list(&mut self,
+                           ctx: &LayoutContext, 
+                           flow: @FlowContext,
                            in_boxes: &[@RenderBox],
                            out_boxes: &DVec<@RenderBox>) {
         assert self.clump.length() > 0;
@@ -285,7 +287,8 @@ impl TextRunScanner {
                 let fontgroup = ctx.font_ctx.get_resolved_font_for_style(&font_style);
                 let run = @TextRun::new(fontgroup.fonts[0], move run_str);
                 debug!("TextRunScanner: pushing box(es) in range: %?", self.clump);
-                for self.clump.eachi |i| {
+                let clump = self.clump;
+                for clump.eachi |i| {
                     let range = new_ranges[i - self.clump.begin()];
                     if range.length() == 0 { 
                         error!("Elided an UnscannedTextbox because it was zero-length after compression; %s",
@@ -311,7 +314,7 @@ impl TextRunScanner {
         debug!("------------------");
 
         debug!("--- Elem ranges: ---");
-        for self.flow.inline().elems.eachi_mut |i: uint, nr: &NodeRange| {
+        for flow.inline().elems.eachi_mut |i: uint, nr: &NodeRange| {
             debug!("%u: %? --> %s", i, nr.range, nr.node.debug_str()); ()
         }
         debug!("--------------------");
@@ -324,7 +327,7 @@ struct LineboxScanner {
     flow: @FlowContext,
     new_boxes: DVec<@RenderBox>,
     work_list: DList<@RenderBox>,
-    pending_line: {range: MutableRange, mut width: Au},
+    pending_line: {mut range: MutableRange, mut width: Au},
     line_spans: DVec<Range>,
 }
 
@@ -335,7 +338,7 @@ fn LineboxScanner(inline: @FlowContext) -> LineboxScanner {
         flow: inline,
         new_boxes: DVec(),
         work_list: DList(),
-        pending_line: {range: MutableRange::empty(), mut width: Au(0)},
+        pending_line: {mut range: MutableRange::empty(), mut width: Au(0)},
         line_spans: DVec()
     }
 }
@@ -594,8 +597,8 @@ impl FlowContext : InlineLayout {
     fn bubble_widths_inline(@self, ctx: &LayoutContext) {
         assert self.starts_inline_flow();
 
-        let scanner = TextRunScanner(self);
-        scanner.scan_for_runs(ctx);
+        let mut scanner = TextRunScanner::new();
+        scanner.scan_for_runs(ctx, self);
 
         let mut min_width = Au(0);
         let mut pref_width = Au(0);
@@ -630,7 +633,7 @@ impl FlowContext : InlineLayout {
             };
         } // for boxes.each |box|
 
-        let scanner = LineboxScanner(self);
+        let mut scanner = LineboxScanner(self);
         scanner.scan_for_lines(ctx);
    
         /* There are no child contexts, so stop here. */