1 files changed, 7 insertions, 3 deletions
diff --git a/thirdparty/harfbuzz/src/hb-ot-math-table.hh b/thirdparty/harfbuzz/src/hb-ot-math-table.hh
index c2e365dbd6..8d0b4317c3 100644
--- a/thirdparty/harfbuzz/src/hb-ot-math-table.hh
+++ b/thirdparty/harfbuzz/src/hb-ot-math-table.hh
@@ -511,7 +511,8 @@ struct MathGlyphInfo
     | hb_map_retains_sorting (glyph_map)
     ;
 
-    out->extendedShapeCoverage.serialize_serialize (c->serializer, it);
+    if (it) out->extendedShapeCoverage.serialize_serialize (c->serializer, it);
+    else out->extendedShapeCoverage = 0;
 
     out->mathKernInfo.serialize_subset (c, mathKernInfo, this);
     return_trace (true);
@@ -884,8 +885,11 @@ struct MathVariants
       if (!o) return_trace (false);
       o->serialize_subset (c, glyphConstruction[i], this);
     }
-
-    out->vertGlyphCoverage.serialize_serialize (c->serializer, new_vert_coverage.iter ());
+    
+    if (new_vert_coverage)
+      out->vertGlyphCoverage.serialize_serialize (c->serializer, new_vert_coverage.iter ());
+    
+    if (new_hori_coverage)
     out->horizGlyphCoverage.serialize_serialize (c->serializer, new_hori_coverage.iter ());
     return_trace (true);
   }