diff --git a/src/hb-ot-layout-gsubgpos-private.hh b/src/hb-ot-layout-gsubgpos-private.hh
index fe4dcbcbd3cd49aef7f99ba65f2d3716f86619e4..7bf3e71ce4067b72c374acbe0f8478a435c818e1 100644
--- a/src/hb-ot-layout-gsubgpos-private.hh
+++ b/src/hb-ot-layout-gsubgpos-private.hh
@@ -1269,7 +1269,7 @@ struct ContextFormat3
     const LookupRecord *lookupRecord = &StructAtOffset<LookupRecord> (coverage, coverage[0].static_size * glyphCount);
     struct ContextCollectGlyphsLookupContext lookup_context = {
       {collect_coverage},
-      NULL
+      this
     };
 
     context_collect_glyphs_lookup (c,