diff --git a/Semantic_Analizer_Tests/src/Basic_tests/OopNegativeSemanticTest.ttcn b/Semantic_Analizer_Tests/src/Basic_tests/OopNegativeSemanticTest.ttcn
index 1d0bb8fe6111ac83a521388db6669ddbcebc6db1..3aee4bc6e5f9c9c6a114e61a9b0e4cdc7edd0dc2 100755
--- a/Semantic_Analizer_Tests/src/Basic_tests/OopNegativeSemanticTest.ttcn
+++ b/Semantic_Analizer_Tests/src/Basic_tests/OopNegativeSemanticTest.ttcn
@@ -62,6 +62,16 @@ type class OuterClass {
 		class InnerClass {
 			private template MyUnion t_union;
 			public var integer badInteger := "xyz";
+			
+			public class EvenDeeper {
+				public const charstring chr := "abc";
+				
+				public class Core {			  
+    				public function f_inside(in integer pl_int) return charstring {
+    					return this.chr;
+	  				}
+				}
+			}
 		}
 	}
 }
@@ -163,6 +173,9 @@ testcase tc_basicSyntax() runs on CT {
 	
 	var integer vl_integer := vl_outer of OuterClass;			// type mismatch
 	var boolean vl_boolean := vl_outer of BaseFunctionClass;	// semanticall correct
+	
+	// nested class member reference
+	var octetstring vl_octet := vl_outer.NestedClass.InnerClass.EvenDeeper.Core.f_inside(1)
 }
 
 }
\ No newline at end of file
diff --git a/Semantic_Analizer_Tests/src/Basic_tests/OopPositiveBasicSyntax.ttcn b/Semantic_Analizer_Tests/src/Basic_tests/OopPositiveBasicSyntax.ttcn
index dc2f7367dce94d1ce7cfdc599ba8d556ba2e4e3b..9a922691c5f51b2e1d5e91490271b435bc8451cc 100644
--- a/Semantic_Analizer_Tests/src/Basic_tests/OopPositiveBasicSyntax.ttcn
+++ b/Semantic_Analizer_Tests/src/Basic_tests/OopPositiveBasicSyntax.ttcn
@@ -113,6 +113,14 @@ type class OuterClass {
 		
 		class DeeplyNested {
 			const integer m_const := 0;
+			class EvenDeeper {
+				const charstring m_str := "abc";
+				public class Core {
+					function f_inside(in integer pl_int) return float {
+						return 0.1;
+					}
+				}
+			}
 		}
 	}
 }
@@ -230,6 +238,9 @@ testcase tc_basicSyntax() runs on CT {
 	if (vl_outerClass of OuterClass) {
 		vl_outerClass.m_string := "xyz";
 	}
+	
+// nested class member reference
+	var float vl_float := vl_outerClass.NestedClass.DeeplyNested.EvenDeeper.Core.f_inside(1);
 }
 
 control {
diff --git a/org.eclipse.titan.designer/src/org/eclipse/titan/designer/AST/TTCN3/statements/Unknown_Instance_Statement.java b/org.eclipse.titan.designer/src/org/eclipse/titan/designer/AST/TTCN3/statements/Unknown_Instance_Statement.java
index 3a986acf1a2fc4fd718791d57c4f2460aca5a4f3..a17e6b9c8a2869f97f7b32d95aae88974977d06f 100644
--- a/org.eclipse.titan.designer/src/org/eclipse/titan/designer/AST/TTCN3/statements/Unknown_Instance_Statement.java
+++ b/org.eclipse.titan.designer/src/org/eclipse/titan/designer/AST/TTCN3/statements/Unknown_Instance_Statement.java
@@ -153,6 +153,7 @@ public final class Unknown_Instance_Statement extends Statement {
 			realStatement.check(timestamp);
 			break;
 		case A_VAR:
+		case A_PAR_VAL:
 			Assignment refdAssignment = reference.getRefdAssignment(timestamp, false);
 			IType assignmentType = refdAssignment.getType(timestamp);
 			IType refdType = assignmentType.getTypeRefdLast(timestamp);
diff --git a/org.eclipse.titan.designer/src/org/eclipse/titan/designer/AST/TTCN3/types/Class_Type.java b/org.eclipse.titan.designer/src/org/eclipse/titan/designer/AST/TTCN3/types/Class_Type.java
index 732503652e1977223708897f77a3c9ead98b329c..d82b1e7006f1f5f10f93e4b18c8a6add6a745a68 100755
--- a/org.eclipse.titan.designer/src/org/eclipse/titan/designer/AST/TTCN3/types/Class_Type.java
+++ b/org.eclipse.titan.designer/src/org/eclipse/titan/designer/AST/TTCN3/types/Class_Type.java
@@ -55,6 +55,7 @@ public final class Class_Type extends Type implements ITypeWithComponents {
 	private static final String TRAITCANNOTBEFINAL = "A trait class cannot be final";
 	private static final String ABSTRACTCANNOTBETRAIT = "A class cannot be both abstract and trait";
 	private static final String TRAITWITHFINALLY = "A trait class should not define a finally block";
+	private static final String UNKNOWNFIELD = "Unknown field reference";
 	
 	private final ClassTypeBody classBody;
 	
@@ -141,10 +142,12 @@ public final class Class_Type extends Type implements ITypeWithComponents {
 		}
 		
 		Assignment assignment = classBody.getAssByIdentifier(timestamp, subreference.getId());
-		if (assignment == null)
+		if (assignment == null) {
+			subreference.getLocation().reportSemanticError(UNKNOWNFIELD);
 			return null;
+		}
 				
-		if (subreferences.size() < 3) {
+		if (subreferences.size() == actualSubReference + 1) {
 			return assignment.getType(timestamp);
 		}
 		
diff --git a/org.eclipse.titan.designer/src/org/eclipse/titan/designer/parsers/ttcn3parser/Ttcn3Parser.g4 b/org.eclipse.titan.designer/src/org/eclipse/titan/designer/parsers/ttcn3parser/Ttcn3Parser.g4
index ff1971d7e989cc2aa30657b61227d8f0fb4e5e8d..e67fdfaca9a6a936025a79c5486b0586fd931eda 100644
--- a/org.eclipse.titan.designer/src/org/eclipse/titan/designer/parsers/ttcn3parser/Ttcn3Parser.g4
+++ b/org.eclipse.titan.designer/src/org/eclipse/titan/designer/parsers/ttcn3parser/Ttcn3Parser.g4
@@ -7900,9 +7900,22 @@ pr_Primary returns[Value value]
 pr_ExtendedFieldReference returns[List<ISubReference> subReferences]
 @init {
 	$subReferences = new ArrayList<ISubReference>();
+	ParsedActualParameters parameters = null;
 }:
 (	a = pr_Dot
-	(	structFieldId = pr_Identifier
+	(	funcid = pr_Identifier 
+		LPAREN 
+		( par = pr_FunctionActualParList { 
+			parameters = $par.parsedParameters; 
+			parameters.setLocation( getLocation( $par.start, $par.stop ) ); 
+		} )? 
+		RPAREN
+			{
+				ParameterisedSubReference funcReference = new ParameterisedSubReference($funcid.identifier, parameters);
+				funcReference.setLocation( getLocation( $funcid.start, $par.stop ) );
+				$subReferences.add(funcReference);
+			}
+	|	structFieldId = pr_Identifier
 			{	FieldSubReference tempReference = new FieldSubReference($structFieldId.identifier);
 				tempReference.setLocation(getLocation( $structFieldId.start, $structFieldId.stop));
 				$subReferences.add(tempReference);
@@ -9189,7 +9202,7 @@ pr_ClassFunctionDef returns[Def_Function def_func]
 	( sb=pr_StatementBlock { statementBlock = $sb.statementblock; })? 
 )
 {
-	if($id.identifier != null && statementBlock != null) {
+	if($id.identifier != null) {
 		if(parameters == null) { parameters = new FormalParameterList(new ArrayList<FormalParameter>()); }
 		parameters.setLocation(getLocation( $start1.start, $end.stop));
 		$def_func = new Def_Function($id.identifier, parameters, runsonHelper.runsonReference, runsonHelper.mtcReference, runsonHelper.systemReference, portReference, returnType, returnsTemplate, templateRestriction, statementBlock);
diff --git a/org.eclipse.titan.regressiontests/src/org/eclipse/titan/regressiontests/designer/statictests/Basic_tests/OOP_Semantic_tests.java b/org.eclipse.titan.regressiontests/src/org/eclipse/titan/regressiontests/designer/statictests/Basic_tests/OOP_Semantic_tests.java
index 20c2a98b0f50fbd22e859a048f4963298b46b452..56be6306be4b0c8094ecee5da9c7182b7c912b98 100755
--- a/org.eclipse.titan.regressiontests/src/org/eclipse/titan/regressiontests/designer/statictests/Basic_tests/OOP_Semantic_tests.java
+++ b/org.eclipse.titan.regressiontests/src/org/eclipse/titan/regressiontests/designer/statictests/Basic_tests/OOP_Semantic_tests.java
@@ -45,7 +45,7 @@ public class OOP_Semantic_tests {
 
 	private ArrayList<MarkerToCheck> oopNegative_ttcn_initializer() {
 		//oopNegativeSemanticTest.ttcn
-		ArrayList<MarkerToCheck> markersToCheck = new ArrayList<MarkerToCheck>(16);
+		ArrayList<MarkerToCheck> markersToCheck = new ArrayList<MarkerToCheck>(18);
 		int lineNum = 28;
 		markersToCheck.add(new MarkerToCheck("class type expected",  lineNum, IMarker.SEVERITY_ERROR));
 		lineNum += 15;
@@ -54,7 +54,7 @@ public class OOP_Semantic_tests {
 		markersToCheck.add(new MarkerToCheck("Local Definiton `vl_b' collides with definition inherited from class type `@classesNegativeSemantic.SubClass'",  lineNum, IMarker.SEVERITY_ERROR));
 		lineNum += 17;
 		markersToCheck.add(new MarkerToCheck("integer value was expected",  lineNum, IMarker.SEVERITY_ERROR));
-		lineNum += 11;
+		lineNum += 21;
 		markersToCheck.add(new MarkerToCheck("integer value was expected",  lineNum, IMarker.SEVERITY_ERROR));
 		lineNum += 4;
 		markersToCheck.add(new MarkerToCheck("Constant must be initialized",  lineNum, IMarker.SEVERITY_ERROR));
@@ -71,10 +71,13 @@ public class OOP_Semantic_tests {
 		lineNum += 10;
 		markersToCheck.add(new MarkerToCheck("Type mismatch: a value of type `integer' was expected instead of `charstring'",  lineNum, IMarker.SEVERITY_ERROR));
 		markersToCheck.add(new MarkerToCheck("Type mismatch: a value of type `charstring' was expected instead of `integer'",  ++lineNum, IMarker.SEVERITY_ERROR));
-		lineNum += 12;
-		markersToCheck.add(new MarkerToCheck("Type mismatch: a value of type `charstring' was expected instead of `integer'",  lineNum, IMarker.SEVERITY_ERROR));
+		lineNum += 11;
+		markersToCheck.add(new MarkerToCheck("Unknown field reference",  lineNum, IMarker.SEVERITY_ERROR));
+		markersToCheck.add(new MarkerToCheck("Type mismatch: a value of type `charstring' was expected instead of `integer'",  ++lineNum, IMarker.SEVERITY_ERROR));
 		lineNum += 8;
 		markersToCheck.add(new MarkerToCheck("integer value was expected",  lineNum, IMarker.SEVERITY_ERROR));
+		lineNum += 4;
+		markersToCheck.add(new MarkerToCheck("Type mismatch: a value of type `octetstring' was expected instead of `charstring'",  lineNum, IMarker.SEVERITY_ERROR));
 
 		
 		return markersToCheck;