diff --git a/components/gfx/text/glyph.rs b/components/gfx/text/glyph.rs
index 727e693726a..98dc39bc0e4 100644
--- a/components/gfx/text/glyph.rs
+++ b/components/gfx/text/glyph.rs
@@ -434,7 +434,7 @@ pub struct GlyphStore {
 
     /// A cache of the number of word separators in the entire glyph store.
     /// See <https://drafts.csswg.org/css-text/#word-separator>.
-    total_word_separators: i32,
+    total_word_separators: usize,
 
     /// Used to check if fast path should be used in glyph iteration.
     has_detailed_glyphs: bool,
@@ -476,7 +476,7 @@ impl<'a> GlyphStore {
     }
 
     #[inline]
-    pub fn total_word_separators(&self) -> i32 {
+    pub fn total_word_separators(&self) -> usize {
         self.total_word_separators
     }
 
@@ -622,7 +622,7 @@ impl<'a> GlyphStore {
     #[inline]
     pub fn advance_for_byte_range(&self, range: &Range<ByteIndex>, extra_word_spacing: Au) -> Au {
         if range.begin() == ByteIndex(0) && range.end() == self.len() {
-            self.total_advance + extra_word_spacing * self.total_word_separators
+            self.total_advance + extra_word_spacing * (self.total_word_separators as i32)
         } else if !self.has_detailed_glyphs {
             self.advance_for_byte_range_simple_glyphs(range, extra_word_spacing)
         } else {
diff --git a/components/layout_2020/flow/inline.rs b/components/layout_2020/flow/inline.rs
index 6b9e8669468..6a2b7cf879e 100644
--- a/components/layout_2020/flow/inline.rs
+++ b/components/layout_2020/flow/inline.rs
@@ -179,13 +179,14 @@ impl LineUnderConstruction {
         // >    as well as any trailing U+1680   OGHAM SPACE MARK whose white-space
         // >    property is normal, nowrap, or pre-line.
         let mut whitespace_trimmed = Length::zero();
-        let mut spaces_trimmed = 0;
+        let mut word_seperators_trimmed = 0;
         for item in self.line_items.iter_mut().rev() {
-            if !item.trim_whitespace_at_end(&mut whitespace_trimmed, &mut spaces_trimmed) {
+            if !item.trim_whitespace_at_end(&mut whitespace_trimmed, &mut word_seperators_trimmed) {
                 break;
             }
         }
-        self.justification_opportunities -= spaces_trimmed;
+
+        self.justification_opportunities -= word_seperators_trimmed;
         whitespace_trimmed
     }
 }
@@ -399,14 +400,15 @@ impl UnbreakableSegmentUnderConstruction {
     /// This prevents whitespace from being added to the beginning of a line.
     fn trim_leading_whitespace(&mut self) {
         let mut whitespace_trimmed = Length::zero();
-        let mut spaces_trimmed = 0;
+        let mut word_seperators_trimmed = 0;
         for item in self.line_items.iter_mut() {
-            if !item.trim_whitespace_at_start(&mut whitespace_trimmed, &mut spaces_trimmed) {
+            if !item.trim_whitespace_at_start(&mut whitespace_trimmed, &mut word_seperators_trimmed)
+            {
                 break;
             }
         }
         self.inline_size -= whitespace_trimmed;
-        self.justification_opportunities -= spaces_trimmed;
+        self.justification_opportunities -= word_seperators_trimmed;
     }
 
     /// Prepare this segment for placement on a new and empty line. This happens when the
diff --git a/components/layout_2020/flow/line.rs b/components/layout_2020/flow/line.rs
index 42df588538e..0c0a4c026de 100644
--- a/components/layout_2020/flow/line.rs
+++ b/components/layout_2020/flow/line.rs
@@ -120,11 +120,11 @@ impl LineItem {
     pub(super) fn trim_whitespace_at_end(
         &mut self,
         whitespace_trimmed: &mut Length,
-        spaces_trimmed: &mut usize,
+        word_seperators_trimmed: &mut usize,
     ) -> bool {
         match self {
             LineItem::TextRun(ref mut item) => {
-                item.trim_whitespace_at_end(whitespace_trimmed, spaces_trimmed)
+                item.trim_whitespace_at_end(whitespace_trimmed, word_seperators_trimmed)
             },
             LineItem::StartInlineBox(_) => true,
             LineItem::EndInlineBox => true,
@@ -137,11 +137,11 @@ impl LineItem {
     pub(super) fn trim_whitespace_at_start(
         &mut self,
         whitespace_trimmed: &mut Length,
-        spaces_trimmed: &mut usize,
+        word_separators_trimmed: &mut usize,
     ) -> bool {
         match self {
             LineItem::TextRun(ref mut item) => {
-                item.trim_whitespace_at_start(whitespace_trimmed, spaces_trimmed)
+                item.trim_whitespace_at_start(whitespace_trimmed, word_separators_trimmed)
             },
             LineItem::StartInlineBox(_) => true,
             LineItem::EndInlineBox => true,
@@ -165,7 +165,7 @@ impl TextRunLineItem {
     fn trim_whitespace_at_end(
         &mut self,
         whitespace_trimmed: &mut Length,
-        spaces_trimmed: &mut usize,
+        word_seperators_trimmed: &mut usize,
     ) -> bool {
         if self
             .parent_style
@@ -184,11 +184,13 @@ impl TextRunLineItem {
             .map(|offset_from_end| self.text.len() - offset_from_end);
 
         let first_whitespace_index = index_of_last_non_whitespace.unwrap_or(0);
-        *spaces_trimmed += self.text.len() - first_whitespace_index;
         *whitespace_trimmed += self
             .text
             .drain(first_whitespace_index..)
-            .map(|glyph| Length::from(glyph.total_advance()))
+            .map(|glyph| {
+                *word_seperators_trimmed += glyph.total_word_separators();
+                Length::from(glyph.total_advance())
+            })
             .sum();
 
         // Only keep going if we only encountered whitespace.
@@ -198,7 +200,7 @@ impl TextRunLineItem {
     fn trim_whitespace_at_start(
         &mut self,
         whitespace_trimmed: &mut Length,
-        spaces_trimmed: &mut usize,
+        word_separators_trimmed: &mut usize,
     ) -> bool {
         if self
             .parent_style
@@ -215,11 +217,13 @@ impl TextRunLineItem {
             .position(|glyph| !glyph.is_whitespace())
             .unwrap_or(self.text.len());
 
-        *spaces_trimmed += index_of_first_non_whitespace;
         *whitespace_trimmed += self
             .text
             .drain(0..index_of_first_non_whitespace)
-            .map(|glyph| Length::from(glyph.total_advance()))
+            .map(|glyph| {
+                *word_separators_trimmed += glyph.total_word_separators();
+                Length::from(glyph.total_advance())
+            })
             .sum();
 
         // Only keep going if we only encountered whitespace.