diff --git a/src/item_factory.cpp b/src/item_factory.cpp
index 1ffe6ab413aef..627104d799be7 100644
--- a/src/item_factory.cpp
+++ b/src/item_factory.cpp
@@ -1178,7 +1178,7 @@ void Item_factory::check_definitions() const
         }
     }
     for( const auto &elem : m_template_groups ) {
-        elem.second->check_consistency();
+        elem.second->check_consistency( elem.first );
     }
 }
 
diff --git a/src/item_group.cpp b/src/item_group.cpp
index 9fb9da64b94cd..9a8f22d35905d 100644
--- a/src/item_group.cpp
+++ b/src/item_group.cpp
@@ -114,15 +114,15 @@ Item_spawn_data::ItemList Single_item_creator::create( const time_point &birthda
     return result;
 }
 
-void Single_item_creator::check_consistency() const
+void Single_item_creator::check_consistency( const std::string &context ) const
 {
     if( type == S_ITEM ) {
         if( !item::type_is_defined( id ) ) {
-            debugmsg( "item id %s is unknown", id.c_str() );
+            debugmsg( "item id %s is unknown (in %s)", id, context );
         }
     } else if( type == S_ITEM_GROUP ) {
         if( !item_group::group_is_defined( id ) ) {
-            debugmsg( "item group id %s is unknown", id.c_str() );
+            debugmsg( "item group id %s is unknown (in %s)", id, context );
         }
     } else if( type == S_NONE ) {
         // this is okay, it will be ignored
@@ -130,7 +130,7 @@ void Single_item_creator::check_consistency() const
         debugmsg( "Unknown type of Single_item_creator: %d", static_cast<int>( type ) );
     }
     if( modifier ) {
-        modifier->check_consistency();
+        modifier->check_consistency( context );
     }
 }
 
@@ -301,13 +301,13 @@ void Item_modifier::modify( item &new_item ) const
     }
 }
 
-void Item_modifier::check_consistency() const
+void Item_modifier::check_consistency( const std::string &context ) const
 {
     if( ammo != nullptr ) {
-        ammo->check_consistency();
+        ammo->check_consistency( "ammo of " + context );
     }
     if( container != nullptr ) {
-        container->check_consistency();
+        container->check_consistency( "container of " + context );
     }
     if( with_ammo < 0 || with_ammo > 100 ) {
         debugmsg( "Item modifier's ammo chance %d is out of range", with_ammo );
@@ -432,10 +432,10 @@ item Item_group::create_single( const time_point &birthday, RecursionList &rec )
     return item( null_item_id, birthday );
 }
 
-void Item_group::check_consistency() const
+void Item_group::check_consistency( const std::string &context ) const
 {
     for( const auto &elem : items ) {
-        ( elem )->check_consistency();
+        ( elem )->check_consistency( "item in " + context );
     }
 }
 
diff --git a/src/item_group.h b/src/item_group.h
index c2be082a8706d..a727be8b5b031 100644
--- a/src/item_group.h
+++ b/src/item_group.h
@@ -127,7 +127,7 @@ class Item_spawn_data
          * Check item / spawn settings for consistency. Includes
          * checking for valid item types and valid settings.
          */
-        virtual void check_consistency() const = 0;
+        virtual void check_consistency( const std::string &context ) const = 0;
         /**
          * For item blacklisted, remove the given item from this and
          * all linked groups.
@@ -186,7 +186,7 @@ class Item_modifier
         Item_modifier( Item_modifier && ) = default;
 
         void modify( item &new_item ) const;
-        void check_consistency() const;
+        void check_consistency( const std::string &context ) const;
         bool remove_item( const Item_tag &itemid );
 
         // Currently these always have the same chance as the item group it's part of, but
@@ -233,7 +233,7 @@ class Single_item_creator : public Item_spawn_data
 
         ItemList create( const time_point &birthday, RecursionList &rec ) const override;
         item create_single( const time_point &birthday, RecursionList &rec ) const override;
-        void check_consistency() const override;
+        void check_consistency( const std::string &context ) const override;
         bool remove_item( const Item_tag &itemid ) override;
         bool has_item( const Item_tag &itemid ) const override;
         std::set<const itype *> every_item() const override;
@@ -277,7 +277,7 @@ class Item_group : public Item_spawn_data
 
         ItemList create( const time_point &birthday, RecursionList &rec ) const override;
         item create_single( const time_point &birthday, RecursionList &rec ) const override;
-        void check_consistency() const override;
+        void check_consistency( const std::string &context ) const override;
         bool remove_item( const Item_tag &itemid ) override;
         bool has_item( const Item_tag &itemid ) const override;
         std::set<const itype *> every_item() const override;
diff --git a/src/mapgen.cpp b/src/mapgen.cpp
index 52af10caad1e2..03496d9a60fef 100644
--- a/src/mapgen.cpp
+++ b/src/mapgen.cpp
@@ -1016,7 +1016,7 @@ class jmapgen_liquid_item : public jmapgen_piece
             , liquid( jsi.get_string( "liquid" ) )
             , chance( jsi, "chance", 1, 1 ) {
             if( !item::type_is_defined( itype_id( liquid ) ) ) {
-                set_mapgen_defer( jsi, "liquid", "no such item type" );
+                set_mapgen_defer( jsi, "liquid", "no such item type '" + liquid + "'" );
             }
         }
         void apply( mapgendata &dat, const jmapgen_int &x, const jmapgen_int &y ) const override {
@@ -1045,7 +1045,7 @@ class jmapgen_item_group : public jmapgen_piece
             group_id( jsi.get_string( "item" ) )
             , chance( jsi, "chance", 1, 1 ) {
             if( !item_group::group_is_defined( group_id ) ) {
-                set_mapgen_defer( jsi, "item", "no such item type" );
+                set_mapgen_defer( jsi, "item", "no such item group '" + group_id + "'" );
             }
             repeat = jmapgen_int( jsi, "repeat", 1, 1 );
         }
@@ -1075,7 +1075,7 @@ class jmapgen_loot : public jmapgen_piece
                 set_mapgen_defer( jsi, "group", "no such item group" );
             }
             if( !name.empty() && !item::type_is_defined( name ) ) {
-                set_mapgen_defer( jsi, "item", "no such item type" );
+                set_mapgen_defer( jsi, "item", "no such item type '" + name + "'" );
             }
 
             // All the probabilities are 100 because we do the roll in @ref apply.