diff --git a/bin/cloudnet/tosca/type_system.py b/bin/cloudnet/tosca/type_system.py
index 76805a6..d4526ea 100644
--- a/bin/cloudnet/tosca/type_system.py
+++ b/bin/cloudnet/tosca/type_system.py
@@ -24,7 +24,7 @@
 from cloudnet.tosca.diagnostics import diagnostic
 from cloudnet.tosca.processors import CEND, CRED, Checker
 from cloudnet.tosca.utils import merge_dict, normalize_dict
-from cloudnet.tosca.yaml_line_numbering import StrCoord, DictCoord
+from cloudnet.tosca.yaml_line_numbering import Coord as YamlCoord
 
 profiles_directory = "file:" + os.path.dirname(__file__) + "/profiles"
 
@@ -3630,7 +3630,8 @@ def check_required_fields(
                         + " required "
                         + kind
                         + " unassigned",
-                        definition,
+                        definition if isinstance(definition, YamlCoord)
+                            else self.reserved_function_keywords.get("SELF"),
                     )
                 else:
                     self.info(
diff --git a/tests/issues/issue_40.yaml b/tests/issues/issue_40.yaml
new file mode 100644
index 0000000..b096294
--- /dev/null
+++ b/tests/issues/issue_40.yaml
@@ -0,0 +1,20 @@
+# https://github.com/Orange-OpenSource/Cloudnet-TOSCA-toolbox/issues/40
+tosca_definitions_version: tosca_simple_yaml_1_3
+
+capability_types:
+  CT:
+    properties:
+      p1:
+        type: integer
+
+node_types:
+  NT:
+    capabilities:
+      c1:
+        type: CT
+
+topology_template:
+  node_templates:
+    n1:
+      type: NT
+      # ERROR: p1 required property unassigned
diff --git a/tests/run.sh b/tests/run.sh
index 8e407d9..9a68d96 100755
--- a/tests/run.sh
+++ b/tests/run.sh
@@ -3,7 +3,7 @@
 #
 # Software Name : Cloudnet TOSCA toolbox
 # Version: 1.0
-# SPDX-FileCopyrightText: Copyright (c) 2020-21 Orange
+# SPDX-FileCopyrightText: Copyright (c) 2020-22 Orange
 # SPDX-License-Identifier: Apache-2.0
 #
 # This software is distributed under the Apache License 2.0
@@ -67,6 +67,7 @@ check_regression topology_template_substitution_mapping.yaml
 
 # Cloudnet TOSCA Toolbox issues
 check_regression issues/issue_39.yaml
+check_regression issues/issue_40.yaml
 check_regression issues/issue_41.yaml
 check_regression issues/issue_42.yaml
 check_regression issues/issue_43.yaml