diff --git a/shared/src/main/scala/io/kaitai/struct/ClassCompiler.scala b/shared/src/main/scala/io/kaitai/struct/ClassCompiler.scala
index 3de1fc6c8..f4d3826f2 100644
--- a/shared/src/main/scala/io/kaitai/struct/ClassCompiler.scala
+++ b/shared/src/main/scala/io/kaitai/struct/ClassCompiler.scala
@@ -324,7 +324,7 @@ class ClassCompiler(
 
     if (!lang.innerDocstrings)
       compileInstanceDoc(instName, instSpec)
-    lang.instanceHeader(className, instName, dataType, instSpec.isNullable)
+    lang.instanceHeader(className, instName, instSpec)
     if (lang.innerDocstrings)
       compileInstanceDoc(instName, instSpec)
     lang.instanceCheckCacheAndReturn(instName, dataType)
@@ -344,7 +344,7 @@ class ClassCompiler(
   }
 
   def compileInstanceDeclaration(instName: InstanceIdentifier, instSpec: InstanceSpec): Unit =
-    lang.instanceDeclaration(instName, instSpec.dataTypeComposite, instSpec.isNullable)
+    lang.instanceDeclaration(instName, instSpec)
 
   def compileEnum(curClass: ClassSpec, enumColl: EnumSpec): Unit =
     lang.enumDeclaration(curClass.name, enumColl.name.last, enumColl.sortedSeq)
diff --git a/shared/src/main/scala/io/kaitai/struct/GoClassCompiler.scala b/shared/src/main/scala/io/kaitai/struct/GoClassCompiler.scala
index 9c5af1597..4efebc6b1 100644
--- a/shared/src/main/scala/io/kaitai/struct/GoClassCompiler.scala
+++ b/shared/src/main/scala/io/kaitai/struct/GoClassCompiler.scala
@@ -65,7 +65,7 @@ class GoClassCompiler(
 
     if (!instSpec.doc.isEmpty)
       lang.attributeDoc(instName, instSpec.doc)
-    lang.instanceHeader(className, instName, dataType, instSpec.isNullable)
+    lang.instanceHeader(className, instName, instSpec)
     lang.instanceCheckCacheAndReturn(instName, dataType)
 
     instSpec match {
diff --git a/shared/src/main/scala/io/kaitai/struct/RustClassCompiler.scala b/shared/src/main/scala/io/kaitai/struct/RustClassCompiler.scala
index a148abc43..3c75039e2 100644
--- a/shared/src/main/scala/io/kaitai/struct/RustClassCompiler.scala
+++ b/shared/src/main/scala/io/kaitai/struct/RustClassCompiler.scala
@@ -29,15 +29,15 @@ class RustClassCompiler(
 
     // Basic struct declaration
     lang.classHeader(curClass.name)
-    
+
     compileAttrDeclarations(curClass.seq ++ extraAttrs)
     curClass.instances.foreach { case (instName, instSpec) =>
       compileInstanceDeclaration(instName, instSpec)
     }
-    
+
     // Constructor = Read() function
     compileReadFunction(curClass)
-    
+
     compileInstances(curClass)
 
     compileAttrReaders(curClass.seq ++ extraAttrs)
@@ -63,9 +63,9 @@ class RustClassCompiler(
       case Some(fe: FixedEndian) => Some(fe)
       case _ => None
     }
-    
+
     lang.readHeader(defEndian, false)
-    
+
     compileSeq(curClass.seq, defEndian)
     lang.classConstructorFooter
   }
@@ -85,7 +85,7 @@ class RustClassCompiler(
 
     if (!instSpec.doc.isEmpty)
       lang.attributeDoc(instName, instSpec.doc)
-    lang.instanceHeader(className, instName, dataType, instSpec.isNullable)
+    lang.instanceHeader(className, instName, instSpec)
     lang.instanceCheckCacheAndReturn(instName, dataType)
 
     instSpec match {
diff --git a/shared/src/main/scala/io/kaitai/struct/languages/CSharpCompiler.scala b/shared/src/main/scala/io/kaitai/struct/languages/CSharpCompiler.scala
index 905de245d..c356c0265 100644
--- a/shared/src/main/scala/io/kaitai/struct/languages/CSharpCompiler.scala
+++ b/shared/src/main/scala/io/kaitai/struct/languages/CSharpCompiler.scala
@@ -479,13 +479,13 @@ class CSharpCompiler(val typeProvider: ClassTypeProvider, config: RuntimeConfig)
 
   //</editor-fold>
 
-  override def instanceDeclaration(attrName: InstanceIdentifier, attrType: DataType, isNullable: Boolean): Unit = {
-    out.puts(s"private bool ${flagForInstName(attrName)};")
-    out.puts(s"private ${kaitaiType2NativeTypeNullable(attrType, isNullable)} ${privateMemberName(attrName)};")
+  override def instanceDeclaration(instName: InstanceIdentifier, instSpec: InstanceSpec): Unit = {
+    out.puts(s"private bool ${flagForInstName(instName)};")
+    out.puts(s"private ${kaitaiType2NativeTypeNullable(instSpec.dataTypeComposite, instSpec.isNullable)} ${privateMemberName(instName)};")
   }
 
-  override def instanceHeader(className: String, instName: InstanceIdentifier, dataType: DataType, isNullable: Boolean): Unit = {
-    out.puts(s"public ${kaitaiType2NativeTypeNullable(dataType, isNullable)} ${publicMemberName(instName)}")
+  override def instanceHeader(className: String, instName: InstanceIdentifier, instSpec: InstanceSpec): Unit = {
+    out.puts(s"public ${kaitaiType2NativeTypeNullable(instSpec.dataTypeComposite, instSpec.isNullable)} ${publicMemberName(instName)}")
     out.puts("{")
     out.inc
     out.puts("get")
diff --git a/shared/src/main/scala/io/kaitai/struct/languages/CppCompiler.scala b/shared/src/main/scala/io/kaitai/struct/languages/CppCompiler.scala
index 901eadd88..fc32492f4 100644
--- a/shared/src/main/scala/io/kaitai/struct/languages/CppCompiler.scala
+++ b/shared/src/main/scala/io/kaitai/struct/languages/CppCompiler.scala
@@ -817,19 +817,19 @@ class CppCompiler(
 
   override def switchBytesOnlyAsRaw = true
 
-  override def instanceDeclaration(attrName: InstanceIdentifier, attrType: DataType, isNullable: Boolean): Unit = {
+  override def instanceDeclaration(instName: InstanceIdentifier, instSpec: InstanceSpec): Unit = {
     ensureMode(PrivateAccess)
-    outHdr.puts(s"bool ${calculatedFlagForName(attrName)};")
-    outHdr.puts(s"${kaitaiType2NativeType(attrType)} ${privateMemberName(attrName)};")
-    declareNullFlag(attrName, isNullable)
+    outHdr.puts(s"bool ${calculatedFlagForName(instName)};")
+    outHdr.puts(s"${kaitaiType2NativeType(instSpec.dataTypeComposite)} ${privateMemberName(instName)};")
+    declareNullFlag(instName, instSpec.isNullable)
   }
 
-  override def instanceHeader(className: List[String], instName: InstanceIdentifier, dataType: DataType, isNullable: Boolean): Unit = {
+  override def instanceHeader(className: List[String], instName: InstanceIdentifier, instSpec: InstanceSpec): Unit = {
     ensureMode(PublicAccess)
-    outHdr.puts(s"${kaitaiType2NativeType(dataType.asNonOwning)} ${publicMemberName(instName)}();")
+    outHdr.puts(s"${kaitaiType2NativeType(instSpec.dataTypeComposite.asNonOwning)} ${publicMemberName(instName)}();")
 
     outSrc.puts
-    outSrc.puts(s"${kaitaiType2NativeType(dataType.asNonOwning, true)} ${types2class(className)}::${publicMemberName(instName)}() {")
+    outSrc.puts(s"${kaitaiType2NativeType(instSpec.dataTypeComposite.asNonOwning, true)} ${types2class(className)}::${publicMemberName(instName)}() {")
     outSrc.inc
   }
 
diff --git a/shared/src/main/scala/io/kaitai/struct/languages/GoCompiler.scala b/shared/src/main/scala/io/kaitai/struct/languages/GoCompiler.scala
index ed965db3e..b00d41722 100644
--- a/shared/src/main/scala/io/kaitai/struct/languages/GoCompiler.scala
+++ b/shared/src/main/scala/io/kaitai/struct/languages/GoCompiler.scala
@@ -441,15 +441,15 @@ class GoCompiler(typeProvider: ClassTypeProvider, config: RuntimeConfig)
     out.inc
   }
 
-  override def instanceDeclaration(attrName: InstanceIdentifier, attrType: DataType, isNullable: Boolean): Unit = {
-    out.puts(s"${calculatedFlagForName(attrName)} bool")
-    out.puts(s"${idToStr(attrName)} ${kaitaiType2NativeType(attrType)}")
+  override def instanceDeclaration(instName: InstanceIdentifier, instSpec: InstanceSpec): Unit = {
+    out.puts(s"${calculatedFlagForName(instName)} bool")
+    out.puts(s"${idToStr(instName)} ${kaitaiType2NativeType(instSpec.dataTypeComposite)}")
   }
 
-  override def instanceHeader(className: List[String], instName: InstanceIdentifier, dataType: DataType, isNullable: Boolean): Unit = {
-    out.puts(s"func (this *${types2class(className)}) ${publicMemberName(instName)}() (v ${kaitaiType2NativeType(dataType)}, err error) {")
+  override def instanceHeader(className: List[String], instName: InstanceIdentifier, instSpec: InstanceSpec): Unit = {
+    out.puts(s"func (this *${types2class(className)}) ${publicMemberName(instName)}() (v ${kaitaiType2NativeType(instSpec.dataTypeComposite)}, err error) {")
     out.inc
-    translator.returnRes = Some(dataType match {
+    translator.returnRes = Some(instSpec.dataTypeComposite match {
       case _: IntType => "0"
       case _: BooleanType => "false"
       case _: StrType => "\"\""
diff --git a/shared/src/main/scala/io/kaitai/struct/languages/JavaCompiler.scala b/shared/src/main/scala/io/kaitai/struct/languages/JavaCompiler.scala
index d48ac11d1..3cea44586 100644
--- a/shared/src/main/scala/io/kaitai/struct/languages/JavaCompiler.scala
+++ b/shared/src/main/scala/io/kaitai/struct/languages/JavaCompiler.scala
@@ -615,12 +615,12 @@ class JavaCompiler(val typeProvider: ClassTypeProvider, config: RuntimeConfig)
 
   //</editor-fold>
 
-  override def instanceDeclaration(attrName: InstanceIdentifier, attrType: DataType, isNullable: Boolean): Unit = {
-    out.puts(s"private ${kaitaiType2JavaTypeBoxed(attrType)} ${idToStr(attrName)};")
+  override def instanceDeclaration(instName: InstanceIdentifier, instSpec: InstanceSpec): Unit = {
+    out.puts(s"private ${kaitaiType2JavaTypeBoxed(instSpec.dataTypeComposite)} ${idToStr(instName)};")
   }
 
-  override def instanceHeader(className: String, instName: InstanceIdentifier, dataType: DataType, isNullable: Boolean): Unit = {
-    out.puts(s"public ${kaitaiType2JavaTypeBoxed(dataType)} ${idToStr(instName)}() {")
+  override def instanceHeader(className: String, instName: InstanceIdentifier, instSpec: InstanceSpec): Unit = {
+    out.puts(s"public ${kaitaiType2JavaTypeBoxed(instSpec.dataTypeComposite)} ${idToStr(instName)}() {")
     out.inc
   }
 
diff --git a/shared/src/main/scala/io/kaitai/struct/languages/JavaScriptCompiler.scala b/shared/src/main/scala/io/kaitai/struct/languages/JavaScriptCompiler.scala
index 3810ae767..3a916f420 100644
--- a/shared/src/main/scala/io/kaitai/struct/languages/JavaScriptCompiler.scala
+++ b/shared/src/main/scala/io/kaitai/struct/languages/JavaScriptCompiler.scala
@@ -487,7 +487,7 @@ class JavaScriptCompiler(val typeProvider: ClassTypeProvider, config: RuntimeCon
 
   //</editor-fold>
 
-  override def instanceHeader(className: List[String], instName: InstanceIdentifier, dataType: DataType, isNullable: Boolean): Unit = {
+  override def instanceHeader(className: List[String], instName: InstanceIdentifier, instSpec: InstanceSpec): Unit = {
     out.puts(s"Object.defineProperty(${type2class(className.last)}.prototype, '${publicMemberName(instName)}', {")
     out.inc
     out.puts("get: function() {")
diff --git a/shared/src/main/scala/io/kaitai/struct/languages/LuaCompiler.scala b/shared/src/main/scala/io/kaitai/struct/languages/LuaCompiler.scala
index 34d774810..6c538404a 100644
--- a/shared/src/main/scala/io/kaitai/struct/languages/LuaCompiler.scala
+++ b/shared/src/main/scala/io/kaitai/struct/languages/LuaCompiler.scala
@@ -251,7 +251,7 @@ class LuaCompiler(typeProvider: ClassTypeProvider, config: RuntimeConfig)
   override def alignToByte(io: String): Unit =
     out.puts(s"$io:align_to_byte()")
 
-  override def instanceHeader(className: List[String], instName: InstanceIdentifier, dataType: DataType, isNullable: Boolean): Unit = {
+  override def instanceHeader(className: List[String], instName: InstanceIdentifier, instSpec: InstanceSpec): Unit = {
     out.puts(s"${types2class(className)}.property.${publicMemberName(instName)} = {}")
     out.puts(s"function ${types2class(className)}.property.${publicMemberName(instName)}:get()")
     out.inc
diff --git a/shared/src/main/scala/io/kaitai/struct/languages/PHPCompiler.scala b/shared/src/main/scala/io/kaitai/struct/languages/PHPCompiler.scala
index 14212d406..07f420292 100644
--- a/shared/src/main/scala/io/kaitai/struct/languages/PHPCompiler.scala
+++ b/shared/src/main/scala/io/kaitai/struct/languages/PHPCompiler.scala
@@ -383,7 +383,7 @@ class PHPCompiler(typeProvider: ClassTypeProvider, config: RuntimeConfig)
 
   override def switchEnd(): Unit = universalFooter
 
-  override def instanceHeader(className: List[String], instName: InstanceIdentifier, dataType: DataType, isNullable: Boolean): Unit = {
+  override def instanceHeader(className: List[String], instName: InstanceIdentifier, instSpec: InstanceSpec): Unit = {
     out.puts(s"public function ${idToStr(instName)}() {")
     out.inc
   }
diff --git a/shared/src/main/scala/io/kaitai/struct/languages/PerlCompiler.scala b/shared/src/main/scala/io/kaitai/struct/languages/PerlCompiler.scala
index d2735bc2b..687eb6630 100644
--- a/shared/src/main/scala/io/kaitai/struct/languages/PerlCompiler.scala
+++ b/shared/src/main/scala/io/kaitai/struct/languages/PerlCompiler.scala
@@ -356,7 +356,7 @@ class PerlCompiler(typeProvider: ClassTypeProvider, config: RuntimeConfig)
   def onComparisonExpr(condition: Ast.expr) =
     Ast.expr.Compare(Ast.expr.Name(Ast.identifier("_on")), Ast.cmpop.Eq, condition)
 
-  override def instanceHeader(className: List[String], instName: InstanceIdentifier, dataType: DataType, isNullable: Boolean): Unit = {
+  override def instanceHeader(className: List[String], instName: InstanceIdentifier, instSpec: InstanceSpec): Unit = {
     out.puts
     out.puts(s"sub ${instName.name} {")
     out.inc
diff --git a/shared/src/main/scala/io/kaitai/struct/languages/PythonCompiler.scala b/shared/src/main/scala/io/kaitai/struct/languages/PythonCompiler.scala
index fd1d65d7c..cebccf72f 100644
--- a/shared/src/main/scala/io/kaitai/struct/languages/PythonCompiler.scala
+++ b/shared/src/main/scala/io/kaitai/struct/languages/PythonCompiler.scala
@@ -419,7 +419,7 @@ class PythonCompiler(typeProvider: ClassTypeProvider, config: RuntimeConfig)
 
   override def switchEnd(): Unit = {}
 
-  override def instanceHeader(className: String, instName: InstanceIdentifier, dataType: DataType, isNullable: Boolean): Unit = {
+  override def instanceHeader(className: String, instName: InstanceIdentifier, instSpec: InstanceSpec): Unit = {
     out.puts("@property")
     out.puts(s"def ${publicMemberName(instName)}(self):")
     out.inc
diff --git a/shared/src/main/scala/io/kaitai/struct/languages/RubyCompiler.scala b/shared/src/main/scala/io/kaitai/struct/languages/RubyCompiler.scala
index 838f403ad..5b48413e9 100644
--- a/shared/src/main/scala/io/kaitai/struct/languages/RubyCompiler.scala
+++ b/shared/src/main/scala/io/kaitai/struct/languages/RubyCompiler.scala
@@ -398,7 +398,7 @@ class RubyCompiler(typeProvider: ClassTypeProvider, config: RuntimeConfig)
   override def switchEnd(): Unit =
     out.puts("end")
 
-  override def instanceHeader(className: String, instName: InstanceIdentifier, dataType: DataType, isNullable: Boolean): Unit = {
+  override def instanceHeader(className: String, instName: InstanceIdentifier, instSpec: InstanceSpec): Unit = {
     out.puts(s"def ${instName.name}")
     out.inc
   }
diff --git a/shared/src/main/scala/io/kaitai/struct/languages/RustCompiler.scala b/shared/src/main/scala/io/kaitai/struct/languages/RustCompiler.scala
index 73969ac78..f9599a935 100644
--- a/shared/src/main/scala/io/kaitai/struct/languages/RustCompiler.scala
+++ b/shared/src/main/scala/io/kaitai/struct/languages/RustCompiler.scala
@@ -57,7 +57,7 @@ class RustCompiler(typeProvider: ClassTypeProvider, config: RuntimeConfig)
   override def opaqueClassDeclaration(classSpec: ClassSpec): Unit = {
     val name = type2class(classSpec.name.last)
     val pkg = type2classAbs(classSpec.name)
-    
+
     importList.add(s"$pkg::$name")
   }
 
@@ -77,7 +77,7 @@ class RustCompiler(typeProvider: ClassTypeProvider, config: RuntimeConfig)
 
     out.puts(s"impl KaitaiStruct for ${type2class(name)} {")
     out.inc
-    
+
     // Parameter names
     val pIo = paramName(IoIdentifier)
     val pParent = paramName(ParentIdentifier)
@@ -113,7 +113,7 @@ class RustCompiler(typeProvider: ClassTypeProvider, config: RuntimeConfig)
   }
 
   override def runReadCalc(): Unit = {
-  
+
   }
 
   override def readHeader(endian: Option[FixedEndian], isEmpty: Boolean) = {
@@ -146,7 +146,7 @@ class RustCompiler(typeProvider: ClassTypeProvider, config: RuntimeConfig)
   }
 
   override def attributeReader(attrName: Identifier, attrType: DataType, isNullable: Boolean): Unit = {
-  
+
   }
 
   override def universalDoc(doc: DocSpec): Unit = {
@@ -422,8 +422,8 @@ class RustCompiler(typeProvider: ClassTypeProvider, config: RuntimeConfig)
 
   override def switchEnd(): Unit = universalFooter
 
-  override def instanceDeclaration(attrName: InstanceIdentifier, attrType: DataType, isNullable: Boolean): Unit = {
-    out.puts(s"    pub ${idToStr(attrName)}: Option<${kaitaiType2NativeType(attrType)}>,")
+  override def instanceDeclaration(instName: InstanceIdentifier, instSpec: InstanceSpec): Unit = {
+    out.puts(s"    pub ${idToStr(instName)}: Option<${kaitaiType2NativeType(instSpec.dataTypeComposite)}>,")
   }
 
   override def instanceDeclHeader(className: List[String]): Unit = {
@@ -435,8 +435,8 @@ class RustCompiler(typeProvider: ClassTypeProvider, config: RuntimeConfig)
     out.inc
   }
 
-  override def instanceHeader(className: List[String], instName: InstanceIdentifier, dataType: DataType, isNullable: Boolean): Unit = {
-    out.puts(s"fn ${idToStr(instName)}(&mut self) -> ${kaitaiType2NativeType(dataType)} {")
+  override def instanceHeader(className: List[String], instName: InstanceIdentifier, instSpec: InstanceSpec): Unit = {
+    out.puts(s"fn ${idToStr(instName)}(&mut self) -> ${kaitaiType2NativeType(instSpec.dataTypeComposite)} {")
     out.inc
   }
 
@@ -458,7 +458,7 @@ class RustCompiler(typeProvider: ClassTypeProvider, config: RuntimeConfig)
 
     out.puts(s"enum $enumClass {")
     out.inc
-    
+
     enumColl.foreach { case (id, label) =>
       universalDoc(label.doc)
       out.puts(s"${value2Const(label.name)},")
@@ -494,7 +494,7 @@ class RustCompiler(typeProvider: ClassTypeProvider, config: RuntimeConfig)
   override def localTemporaryName(id: Identifier): String = s"$$_t_${idToStr(id)}"
 
   override def paramName(id: Identifier): String = s"${idToStr(id)}"
-    
+
   def kaitaiType2NativeType(attrType: DataType): String = {
     attrType match {
       case Int1Type(false) => "u8"
@@ -523,7 +523,7 @@ class RustCompiler(typeProvider: ClassTypeProvider, config: RuntimeConfig)
         case Some(cs) => s"Box<${type2class(cs.name)}>"
         case None => s"Box<${type2class(t.name)}>"
       }
-      
+
       case t: EnumType => t.enumSpec match {
         case Some(cs) => s"Box<${type2class(cs.name)}>"
         case None => s"Box<${type2class(t.name)}>"
@@ -533,11 +533,11 @@ class RustCompiler(typeProvider: ClassTypeProvider, config: RuntimeConfig)
 
       case KaitaiStreamType => s"Option<Box<KaitaiStream>>"
       case KaitaiStructType | CalcKaitaiStructType => s"Option<Box<KaitaiStruct>>"
-      
+
       case st: SwitchType => kaitaiType2NativeType(st.combinedType)
     }
   }
-  
+
   def kaitaiType2Default(attrType: DataType): String = {
     attrType match {
       case Int1Type(false) => "0"
@@ -569,12 +569,12 @@ class RustCompiler(typeProvider: ClassTypeProvider, config: RuntimeConfig)
 
       case KaitaiStreamType => "None"
       case KaitaiStructType => "None"
-      
+
       case _: SwitchType => ""
       // TODO
     }
   }
-  
+
   def type2class(names: List[String]) = types2classRel(names)
 
   def type2classAbs(names: List[String]) =
diff --git a/shared/src/main/scala/io/kaitai/struct/languages/components/LanguageCompiler.scala b/shared/src/main/scala/io/kaitai/struct/languages/components/LanguageCompiler.scala
index 229cbdabd..fb3797aaa 100644
--- a/shared/src/main/scala/io/kaitai/struct/languages/components/LanguageCompiler.scala
+++ b/shared/src/main/scala/io/kaitai/struct/languages/components/LanguageCompiler.scala
@@ -124,8 +124,8 @@ abstract class LanguageCompiler(
   def instanceDeclHeader(className: List[String]): Unit = {}
   def instanceClear(instName: InstanceIdentifier): Unit = {}
   def instanceSetCalculated(instName: InstanceIdentifier): Unit = {}
-  def instanceDeclaration(attrName: InstanceIdentifier, attrType: DataType, isNullable: Boolean): Unit = attributeDeclaration(attrName, attrType, isNullable)
-  def instanceHeader(className: List[String], instName: InstanceIdentifier, dataType: DataType, isNullable: Boolean): Unit
+  def instanceDeclaration(instName: InstanceIdentifier, instSpec: InstanceSpec): Unit = attributeDeclaration(instName, instSpec.dataTypeComposite, instSpec.isNullable)
+  def instanceHeader(className: List[String], instName: InstanceIdentifier, instSpec: InstanceSpec): Unit
   def instanceFooter: Unit
   def instanceCheckCacheAndReturn(instName: InstanceIdentifier, dataType: DataType): Unit
   def instanceReturn(instName: InstanceIdentifier, attrType: DataType): Unit
diff --git a/shared/src/main/scala/io/kaitai/struct/languages/components/NoNeedForFullClassPath.scala b/shared/src/main/scala/io/kaitai/struct/languages/components/NoNeedForFullClassPath.scala
index 63be66119..4e427eab5 100644
--- a/shared/src/main/scala/io/kaitai/struct/languages/components/NoNeedForFullClassPath.scala
+++ b/shared/src/main/scala/io/kaitai/struct/languages/components/NoNeedForFullClassPath.scala
@@ -16,9 +16,9 @@ trait NoNeedForFullClassPath {
     classConstructorHeader(name.last, parentType, rootClassName.last, isHybrid, params)
   def classConstructorHeader(name: String, parentType: DataType, rootClassName: String, isHybrid: Boolean, params: List[ParamDefSpec]): Unit
 
-  def instanceHeader(className: List[String], instName: InstanceIdentifier, dataType: DataType, isNullable: Boolean): Unit =
-    instanceHeader(className.last, instName, dataType, isNullable)
-  def instanceHeader(className: String, instName: InstanceIdentifier, dataType: DataType, isNullable: Boolean): Unit
+  def instanceHeader(className: List[String], instName: InstanceIdentifier, instSpec: InstanceSpec): Unit =
+    instanceHeader(className.last, instName, instSpec)
+  def instanceHeader(className: String, instName: InstanceIdentifier, instSpec: InstanceSpec): Unit
 
   def enumDeclaration(curClass: List[String], enumName: String, enumColl: Seq[(Long, EnumValueSpec)]): Unit =
     enumDeclaration(curClass.last, enumName, enumColl.map((x) => (x._1, x._2.name)))