diff --git a/src/hb-aat-layout-feat-table.hh b/src/hb-aat-layout-feat-table.hh
index 8de7873e4..14f91bf9a 100644
--- a/src/hb-aat-layout-feat-table.hh
+++ b/src/hb-aat-layout-feat-table.hh
@@ -129,6 +129,9 @@ struct FeatureName
 
   hb_ot_name_id_t get_feature_name_id () const { return nameIndex; }
 
+  /* A FeatureName with no settings is meaningless */
+  bool has_data () const { return nSettings > 0; }
+
   bool sanitize (hb_sanitize_context_t *c, const void *base) const
   {
     TRACE_SANITIZE (this);
@@ -172,6 +175,9 @@ struct feat
     return featureNameCount;
   }
 
+  bool exposes_feature (hb_aat_layout_feature_type_t feature_type) const
+  { return get_feature (feature_type).has_data (); }
+
   const FeatureName& get_feature (hb_aat_layout_feature_type_t feature_type) const
   { return namesZ.bsearch (featureNameCount, feature_type); }
 
diff --git a/src/hb-aat-map.cc b/src/hb-aat-map.cc
index bc879359a..fc1dcbd2d 100644
--- a/src/hb-aat-map.cc
+++ b/src/hb-aat-map.cc
@@ -33,13 +33,19 @@
 #include "hb-aat-map.hh"
 
 #include "hb-aat-layout.hh"
+#include "hb-aat-layout-feat-table.hh"
 
 
 void hb_aat_map_builder_t::add_feature (hb_tag_t tag,
 					unsigned int value)
 {
+  hb_blob_t *feat_blob = face->table.feat.get_blob ();
+  const AAT::feat& feat = *feat_blob->as<AAT::feat> ();
+  if (!feat.has_data ()) return;
+
   if (tag == HB_TAG ('a','a','l','t'))
   {
+    if (!feat.exposes_feature (HB_AAT_LAYOUT_FEATURE_TYPE_CHARACTER_ALTERNATIVES)) return;
     feature_info_t *info = features.push();
     info->type = HB_AAT_LAYOUT_FEATURE_TYPE_CHARACTER_ALTERNATIVES;
     info->setting = (hb_aat_layout_feature_selector_t) value;
@@ -48,6 +54,7 @@ void hb_aat_map_builder_t::add_feature (hb_tag_t tag,
 
   const hb_aat_feature_mapping_t *mapping = hb_aat_layout_find_feature_mapping (tag);
   if (!mapping) return;
+  if (!feat.exposes_feature (mapping->aatFeatureType)) return;
 
   feature_info_t *info = features.push();
   info->type = mapping->aatFeatureType;