Verify overlap check doesn't occur with default format

- add test for verification

DAFFODIL-1842

daffodil-test/src/test/resources/org/apache/daffodil/section07/property_syntax/PropertySyntax.tdml

@@ -359,4 +359,46 @@
     </tdml:infoset>
   </tdml:parserTestCase>
 
+  <tdml:parserTestCase name="overlappingProperties1" root="outer" roundTrip="onePass"
+      model="/org/apache/daffodil/section07/property_syntax/property_syntax_overlap2.dfdl.xsd"
+      ignoreUnexpectedWarnings="false">
+    <tdml:document>hello</tdml:document>
+    <tdml:infoset>
+      <tdml:dfdlInfoset>
+        <outer>
+          <e1>hello</e1>
+        </outer>
+      </tdml:dfdlInfoset>
+    </tdml:infoset>
+  </tdml:parserTestCase>
+
+  <tdml:defineSchema name="PropertySyntaxOverlap">
+
+    <xs:include schemaLocation="/org/apache/daffodil/xsd/DFDLGeneralFormat.dfdl.xsd"/>
+    <dfdl:format ref="ex:GeneralFormat" lengthKind="delimited"
+        lengthUnits="bytes" encoding="UTF-8" separator="" initiator=""
+        terminator="" occursCountKind="parsed" ignoreCase="no"
+        textNumberRep="standard" representation="text" initiatedContent="no" />
+
+    <xs:element name="e1" type="xs:string" dfdl:lengthUnits="bits"/>
+
+    <xs:element name="outer">
+      <xs:complexType>
+        <xs:sequence>
+          <xs:element ref="ex:e1" dfdl:lengthUnits="bytes"/>
+        </xs:sequence>
+      </xs:complexType>
+    </xs:element>
+
+  </tdml:defineSchema>
+
+  <tdml:parserTestCase name="overlappingProperties2" root="outer" roundTrip="onePass"
+      model="PropertySyntaxOverlap"
+      ignoreUnexpectedWarnings="false">
+    <tdml:document>hello</tdml:document>
+    <tdml:errors>
+      <tdml:error>Overlap is not allowed</tdml:error>
+    </tdml:errors>
+  </tdml:parserTestCase>
+
 </tdml:testSuite>

daffodil-test/src/test/resources/org/apache/daffodil/section07/property_syntax/property_syntax_overlap1.dfdl.xsd

@@ -0,0 +1,35 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<!--
+  Licensed to the Apache Software Foundation (ASF) under one or more
+  contributor license agreements.  See the NOTICE file distributed with
+  this work for additional information regarding copyright ownership.
+  The ASF licenses this file to You under the Apache License, Version 2.0
+  (the "License"); you may not use this file except in compliance with
+  the License.  You may obtain a copy of the License at
+
+      http://www.apache.org/licenses/LICENSE-2.0
+
+  Unless required by applicable law or agreed to in writing, software
+  distributed under the License is distributed on an "AS IS" BASIS,
+  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+  See the License for the specific language governing permissions and
+  limitations under the License.
+-->
+
+<xs:schema xmlns:xs="http://www.w3.org/2001/XMLSchema" xmlns:dfdl="http://www.ogf.org/dfdl/dfdl-1.0/"
+targetNamespace="urn:overlap1" xmlns:o1="urn:overlap1">
+
+  <xs:include schemaLocation="/org/apache/daffodil/xsd/DFDLGeneralFormat.dfdl.xsd"/>
+
+  <xs:annotation>
+    <xs:appinfo source="http://www.ogf.org/dfdl/">
+      <dfdl:format ref="o1:GeneralFormat" lengthKind="delimited"
+          lengthUnits="bytes" encoding="UTF-8" separator="" initiator=""
+          terminator="" occursCountKind="parsed" ignoreCase="no"
+          textNumberRep="standard" representation="text" initiatedContent="no" />
+    </xs:appinfo>
+  </xs:annotation>
+
+  <xs:element name="e1" type="xs:string"/>
+
+</xs:schema>

daffodil-test/src/test/resources/org/apache/daffodil/section07/property_syntax/property_syntax_overlap2.dfdl.xsd

@@ -0,0 +1,42 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<!--
+  Licensed to the Apache Software Foundation (ASF) under one or more
+  contributor license agreements.  See the NOTICE file distributed with
+  this work for additional information regarding copyright ownership.
+  The ASF licenses this file to You under the Apache License, Version 2.0
+  (the "License"); you may not use this file except in compliance with
+  the License.  You may obtain a copy of the License at
+
+      http://www.apache.org/licenses/LICENSE-2.0
+
+  Unless required by applicable law or agreed to in writing, software
+  distributed under the License is distributed on an "AS IS" BASIS,
+  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+  See the License for the specific language governing permissions and
+  limitations under the License.
+-->
+
+<xs:schema xmlns:xs="http://www.w3.org/2001/XMLSchema" xmlns:dfdl="http://www.ogf.org/dfdl/dfdl-1.0/"
+targetNamespace="urn:overlap2" xmlns:o1="urn:overlap1" xmlns:o2="urn:overlap2">
+
+  <xs:include schemaLocation="/org/apache/daffodil/xsd/DFDLGeneralFormat.dfdl.xsd"/>
+  <xs:import namespace="urn:overlap1" schemaLocation="/org/apache/daffodil/section07/property_syntax/property_syntax_overlap1.dfdl.xsd"/>
+
+  <xs:annotation>
+    <xs:appinfo source="http://www.ogf.org/dfdl/">
+      <dfdl:format ref="o2:GeneralFormat" lengthKind="delimited"
+          lengthUnits="bits" encoding="UTF-8" separator="" initiator=""
+          terminator="" occursCountKind="parsed" ignoreCase="no"
+          textNumberRep="standard" representation="text" initiatedContent="no" />
+    </xs:appinfo>
+  </xs:annotation>
+
+  <xs:element name="outer">
+    <xs:complexType>
+      <xs:sequence>
+        <xs:element ref="o1:e1" dfdl:lengthUnits="characters" dfdl:length="5" dfdl:lengthKind="explicit"/>
+      </xs:sequence>
+    </xs:complexType>
+  </xs:element>
+
+</xs:schema>

daffodil-test/src/test/scala/org/apache/daffodil/section07/property_syntax/TestPropertySyntax.scala

@@ -66,6 +66,13 @@ class TestPropertySyntax {
   @Test def test_ignoredPropertiesWarning(): Unit = {
     runner1.runOneTest("ignoredPropertiesWarning")
   }
+  // DFDL-1842
+  @Test def test_overlappingProperties1(): Unit = {
+    runner1.runOneTest("overlappingProperties1")
+  }
+  @Test def test_overlappingProperties2(): Unit = {
+    runner1.runOneTest("overlappingProperties2")
+  }
 
   @Test def test_badElementFormProperty(): Unit = {
     runner1.runOneTest("badElementFormProperty")