Allow dumping the fragment tree in layout_2020

This is done when the dump-flow-tree debug option is passed.

1 files changed, 14 insertions, 1 deletions

diff --git a/components/layout_2020/geom.rs b/components/layout_2020/geom.rs
index 86e6faf45a7..166ba7a0494 100644
--- a/components/layout_2020/geom.rs
+++ b/components/layout_2020/geom.rs
@@ -45,7 +45,7 @@ pub(crate) mod flow_relative {
         pub block: T,
     }
 
-    #[derive(Clone, Debug)]
+    #[derive(Clone)]
     pub(crate) struct Rect<T> {
         pub start_corner: Vec2<T>,
         pub size: Vec2<T>,
@@ -200,6 +200,19 @@ impl flow_relative::Rect<Length> {
     }
 }
 
+impl fmt::Debug for flow_relative::Rect<Length> {
+    fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
+        write!(
+            f,
+            "Rect(i{}×b{} @ (i{},b{}))",
+            self.size.inline.px(),
+            self.size.block.px(),
+            self.start_corner.inline.px(),
+            self.start_corner.block.px(),
+        )
+    }
+}
+
 impl<T: Clone> flow_relative::Vec2<T> {
     pub fn size_to_physical(&self, mode: WritingMode) -> physical::Vec2<T> {
         // https://drafts.csswg.org/css-writing-modes/#logical-to-physical