servo · pcwalton · Aug 17, 2016 · Aug 18, 2016
diff --git a/components/gfx/text/glyph.rs b/components/gfx/text/glyph.rs
@@ -254,10 +254,10 @@ impl<'a> DetailedGlyphStore {
 
         let i = self.detail_lookup.binary_search(&key)
             .expect("Invalid index not found in detailed glyph lookup table!");
-
-        assert!(i + (count as usize) <= self.detail_buffer.len());
+        let main_detail_offset = self.detail_lookup[i].detail_offset;
+        assert!(main_detail_offset + (count as usize) <= self.detail_buffer.len());
         // return a slice into the buffer
-        &self.detail_buffer[i .. i + count as usize]
+        &self.detail_buffer[main_detail_offset .. main_detail_offset + count as usize]
     }
 
     fn detailed_glyph_with_index(&'a self,
@@ -274,9 +274,9 @@ impl<'a> DetailedGlyphStore {
 
         let i = self.detail_lookup.binary_search(&key)
             .expect("Invalid index not found in detailed glyph lookup table!");
-
-        assert!(i + (detail_offset as usize) < self.detail_buffer.len());
-        &self.detail_buffer[i + (detail_offset as usize)]
+        let main_detail_offset = self.detail_lookup[i].detail_offset;
+        assert!(main_detail_offset + (detail_offset as usize) < self.detail_buffer.len());
+        &self.detail_buffer[main_detail_offset + (detail_offset as usize)]
     }
 
     fn ensure_sorted(&mut self) {

diff --git a/tests/wpt/mozilla/meta/MANIFEST.json b/tests/wpt/mozilla/meta/MANIFEST.json
@@ -1328,6 +1328,18 @@
             "url": "/_mozilla/css/clip_a.html"
           }
         ],
+        "css/complex_glyphs_a.html": [
+          {
+            "path": "css/complex_glyphs_a.html",
+            "references": [
+              [
+                "/_mozilla/css/complex_glyphs_ref.html",
+                "=="
+              ]
+            ],
+            "url": "/_mozilla/css/complex_glyphs_a.html"
+          }
+        ],
         "css/content_color.html": [
           {
             "path": "css/content_color.html",

           "url": "/_mozilla/css/clip_a.html"
         }
       ],
+      "css/complex_glyphs_a.html": [
+        {
+          "path": "css/complex_glyphs_a.html",
+          "references": [
+            [
+              "/_mozilla/css/complex_glyphs_ref.html",
+              "=="
+            ]
+          ],
+          "url": "/_mozilla/css/complex_glyphs_a.html"
+        }
+      ],
       "css/content_color.html": [
         {
           "path": "css/content_color.html",
diff --git a/tests/wpt/mozilla/tests/css/complex_glyphs_a.html b/tests/wpt/mozilla/tests/css/complex_glyphs_a.html
@@ -0,0 +1,7 @@
+<!doctype html>
+<meta charset="utf-8">
+<link rel="match" href="complex_glyphs_ref.html">
+<body>
+ยินดี
+</body>
+</html>
diff --git a/tests/wpt/mozilla/tests/css/complex_glyphs_ref.html b/tests/wpt/mozilla/tests/css/complex_glyphs_ref.html
@@ -0,0 +1,6 @@
+<!doctype html>
+<meta charset="utf-8">
+<body>
+ยิน&#X200Bดี
+</body>
+<html>