diff --git a/components/layout_2020/flow/construct.rs b/components/layout_2020/flow/construct.rs
index a7056f23ca9..f3afabf15fc 100644
--- a/components/layout_2020/flow/construct.rs
+++ b/components/layout_2020/flow/construct.rs
@@ -210,7 +210,6 @@ where
                         self.handle_block_level_element(style.clone(), inside, contents, box_slot)
                     }
                 },
-                DisplayOutside::None => panic!(":("),
             },
         }
     }
@@ -352,7 +351,6 @@ where
                     inline_box.last_fragment = true;
                     Arc::new(InlineLevelBox::InlineBox(inline_box))
                 },
-                DisplayInside::None | DisplayInside::Contents => panic!(":("),
             },
         };
         self.current_inline_level_boxes().push(box_.clone());
diff --git a/components/layout_2020/flow/inline.rs b/components/layout_2020/flow/inline.rs
index 59b822976ca..133654f32b7 100644
--- a/components/layout_2020/flow/inline.rs
+++ b/components/layout_2020/flow/inline.rs
@@ -122,7 +122,6 @@ impl InlineFormattingContext {
                                     inline: match outside {
                                         DisplayOutside::Inline => ifc.inline_position,
                                         DisplayOutside::Block => Length::zero(),
-                                        DisplayOutside::None => unreachable!(":("),
                                     },
                                     block: ifc.line_boxes.next_line_block_position,
                                 },
diff --git a/components/layout_2020/lib.rs b/components/layout_2020/lib.rs
index 5c046feecd7..052cb4b0540 100644
--- a/components/layout_2020/lib.rs
+++ b/components/layout_2020/lib.rs
@@ -38,11 +38,10 @@ use crate::flow::{BlockFormattingContext, FlowChildren};
 use crate::geom::flow_relative::Vec2;
 use crate::positioned::AbsolutelyPositionedFragment;
 use crate::replaced::ReplacedContent;
-use crate::style_ext::{ComputedValuesExt, Direction, Position, WritingMode};
+use crate::style_ext::{ComputedValuesExt, Direction, DisplayInside, Position, WritingMode};
 use servo_arc::Arc;
 use std::convert::TryInto;
 use style::context::SharedStyleContext;
-use style::values::specified::box_::DisplayInside;
 
 /// https://drafts.csswg.org/css-display/#independent-formatting-context
 #[derive(Debug)]
@@ -74,7 +73,6 @@ impl IndependentFormattingContext {
                         non_replaced,
                     ))
                 },
-                DisplayInside::None | DisplayInside::Contents => panic!(":("),
             },
             Err(replaced) => IndependentFormattingContext::Replaced(replaced),
         }
diff --git a/components/layout_2020/style_ext.rs b/components/layout_2020/style_ext.rs
index bb0b0411dec..e6d4537f47c 100644
--- a/components/layout_2020/style_ext.rs
+++ b/components/layout_2020/style_ext.rs
@@ -4,14 +4,12 @@
 
 use crate::geom::{flow_relative, physical};
 use style::properties::ComputedValues;
-use style::values::computed::{
-    Display as PackedDisplay, Length, LengthPercentage, LengthPercentageOrAuto, Size,
-};
+use style::values::computed::{Length, LengthPercentage, LengthPercentageOrAuto, Size};
+use style::values::specified::box_ as stylo;
 
 pub use style::computed_values::direction::T as Direction;
 pub use style::computed_values::position::T as Position;
 pub use style::computed_values::writing_mode::T as WritingMode;
-pub use style::values::specified::box_::{DisplayInside, DisplayOutside};
 
 #[derive(Clone, Copy, Eq, PartialEq)]
 pub(crate) enum Display {
@@ -31,6 +29,18 @@ pub(crate) enum DisplayGeneratingBox {
     // https://drafts.csswg.org/css-display-3/#layout-specific-display
 }
 
+#[derive(Clone, Copy, Eq, PartialEq)]
+pub(crate) enum DisplayOutside {
+    Block,
+    Inline,
+}
+
+#[derive(Clone, Copy, Eq, PartialEq)]
+pub(crate) enum DisplayInside {
+    Flow,
+    FlowRoot,
+}
+
 pub(crate) trait ComputedValuesExt {
     fn writing_mode(&self) -> (WritingMode, Direction);
     fn box_offsets(&self) -> flow_relative::Sides<LengthPercentageOrAuto>;
@@ -105,18 +115,27 @@ impl ComputedValuesExt for ComputedValues {
     }
 }
 
-impl From<PackedDisplay> for Display {
-    fn from(packed_display: PackedDisplay) -> Self {
-        if packed_display == PackedDisplay::None {
-            return Self::None;
-        }
-        if packed_display == PackedDisplay::Contents {
-            return Self::Contents;
-        }
-        Self::GeneratingBox(DisplayGeneratingBox::OutsideInside {
-            outside: packed_display.outside(),
-            inside: packed_display.inside(),
-            // list_item: packed_display.is_list_item(),
+impl From<stylo::Display> for Display {
+    fn from(packed: stylo::Display) -> Self {
+        let inside = match packed.inside() {
+            stylo::DisplayInside::Flow => DisplayInside::Flow,
+            stylo::DisplayInside::FlowRoot => DisplayInside::FlowRoot,
+
+            // These should not be values of DisplayInside, but oh well
+            stylo::DisplayInside::None => return Display::None,
+            stylo::DisplayInside::Contents => return Display::Contents,
+        };
+        let outside = match packed.outside() {
+            stylo::DisplayOutside::Block => DisplayOutside::Block,
+            stylo::DisplayOutside::Inline => DisplayOutside::Inline,
+
+            // This should not be a value of DisplayInside, but oh well
+            stylo::DisplayOutside::None => return Display::None,
+        };
+        Display::GeneratingBox(DisplayGeneratingBox::OutsideInside {
+            outside,
+            inside,
+            // list_item: packed.is_list_item(),
         })
     }
 }