diff --git a/libraries/tools/idl2k/src/main/kotlin/config.kt b/libraries/tools/idl2k/src/main/kotlin/config.kt
index 0ad9df73c73..b49b7fa2c39 100644
--- a/libraries/tools/idl2k/src/main/kotlin/config.kt
+++ b/libraries/tools/idl2k/src/main/kotlin/config.kt
@@ -73,3 +73,7 @@ val requiredArguments = setOf(
         "DOMPoint.constructor.point",
         "DOMQuad.constructor.rect"
 )
+
+val inheritanceExclude = mapOf(
+        "SVGAElement" to setOf("HTMLHyperlinkElementUtils")
+)
\ No newline at end of file
diff --git a/libraries/tools/idl2k/src/main/kotlin/gen.kt b/libraries/tools/idl2k/src/main/kotlin/gen.kt
index bf3f91e12eb..0237205ca97 100644
--- a/libraries/tools/idl2k/src/main/kotlin/gen.kt
+++ b/libraries/tools/idl2k/src/main/kotlin/gen.kt
@@ -95,8 +95,7 @@ private val EMPTY_CONSTRUCTOR = ExtendedAttribute(null, "Constructor", emptyList
 
 fun generateTrait(repository: Repository, iface: InterfaceDefinition): GenerateTraitOrClass {
     val superClasses = iface.superTypes
-            .map { repository.interfaces[it] }
-            .filterNotNull()
+            .mapNotNull { repository.interfaces[it] }
             .filter {
                 when (resolveDefinitionKind(repository, it)) {
                     GenerateDefinitionKind.CLASS,
@@ -111,7 +110,7 @@ fun generateTrait(repository: Repository, iface: InterfaceDefinition): GenerateT
 
     val declaredConstructors = iface.findConstructors()
     val entityKind = resolveDefinitionKind(repository, iface, declaredConstructors)
-    val extensions = repository.externals[iface.name]?.map { repository.interfaces[it] }?.filterNotNull() ?: emptyList()
+    val extensions = repository.externals[iface.name]?.mapNotNull { repository.interfaces[it] } ?: emptyList()
 
     val primaryConstructor = when {
         declaredConstructors.size == 1 -> declaredConstructors.single()
@@ -141,9 +140,9 @@ fun generateTrait(repository: Repository, iface: InterfaceDefinition): GenerateT
         ConstructorWithSuperTypeCall(constructorAsFunction, secondaryConstructor, initCall)
     }
 
-    return GenerateTraitOrClass(iface.name, iface.namespace, entityKind, iface.superTypes,
-            memberAttributes = (iface.mapAttributes(repository) + extensions.flatMap { it.mapAttributes(repository) }).distinct().toList(),
-            memberFunctions = (iface.mapOperations(repository) + extensions.flatMap { it.mapOperations(repository) }).distinct().toList(),
+    return GenerateTraitOrClass(iface.name, iface.namespace, entityKind, (iface.superTypes + extensions.map { it.name }).distinct(),
+            memberAttributes = iface.mapAttributes(repository),
+            memberFunctions = iface.mapOperations(repository),
             constants = (iface.constants.map { it.mapConstant(repository) } + extensions.flatMap { it.constants.map { it.mapConstant(repository) } }.distinct().toList()),
             primaryConstructor = primaryConstructorWithCall,
             secondaryConstructors = secondaryConstructorsWithCall,
diff --git a/libraries/tools/idl2k/src/main/kotlin/render.kt b/libraries/tools/idl2k/src/main/kotlin/render.kt
index f3cd1cd5b6f..93d4a9ed707 100644
--- a/libraries/tools/idl2k/src/main/kotlin/render.kt
+++ b/libraries/tools/idl2k/src/main/kotlin/render.kt
@@ -131,10 +131,11 @@ fun Appendable.render(allTypes: Map<String, GenerateTraitOrClass>, typeNamesToUn
         renderArgumentsDeclaration(primary.constructor.fixRequiredArguments(iface.name).arguments.dynamicIfUnknownType(allTypes.keys), false)
     }
 
+    val superTypesExclude = inheritanceExclude[iface.name] ?: emptySet()
     val superCallName = primary?.initTypeCall?.name
     val superTypesWithCalls =
             (primary?.initTypeCall?.let { listOf(renderCall(it)) } ?: emptyList()) +
-                    iface.superTypes.filter { it != superCallName && it in allSuperTypesNames } +
+                    iface.superTypes.filter { it != superCallName && it in allSuperTypesNames }.filter { it !in superTypesExclude } +
                     (typeNamesToUnions[iface.name] ?: emptyList())
 
     if (superTypesWithCalls.isNotEmpty()) {
@@ -164,22 +165,33 @@ fun Appendable.render(allTypes: Map<String, GenerateTraitOrClass>, typeNamesToUn
     iface.memberAttributes
         .filter { it !in superAttributes && !it.static && (it.isVar || (it.isVal && superAttributesByName[it.name]?.hasNoVars() ?: true)) }
         .map { it.dynamicIfUnknownType(allTypes.keys) }
-        .groupBy { it.name }.reduceValues(::merge).values.forEach { arg ->
+        .groupBy { it.name }
+        .reduceValues(::merge).values.forEach { attribute ->
             val modality = when {
-                arg.signature in superSignatures -> MemberModality.OVERRIDE
-                iface.kind == GenerateDefinitionKind.CLASS && arg.isVal -> MemberModality.OPEN
+                attribute.signature in superSignatures -> MemberModality.OVERRIDE
+                iface.kind == GenerateDefinitionKind.CLASS && attribute.isVal -> MemberModality.OPEN
                 iface.kind == GenerateDefinitionKind.ABSTRACT_CLASS -> when {
-                    arg.initializer != null || arg.getterSetterNoImpl -> MemberModality.OPEN
+                    attribute.initializer != null || attribute.getterSetterNoImpl -> MemberModality.OPEN
                     else -> MemberModality.ABSTRACT
                 }
                 else -> MemberModality.FINAL
             }
-            renderAttributeDeclarationAsProperty(arg,
-                modality = modality,
-                commented = arg.isCommented(iface.name),
-                omitDefaults = iface.kind == GenerateDefinitionKind.INTERFACE,
-                level = 1
-        )
+
+            if (attribute.name in superAttributesByName && attribute.signature !in superSignatures) {
+                System.err.println("Property ${iface.name}.${attribute.name} has different type in super type(s) so will not be generated: ")
+                for ((superTypeName, attributes) in allSuperTypes.map { it.name to it.memberAttributes.filter { it.name == attribute.name }.distinct() }) {
+                    for (superAttribute in attributes) {
+                        System.err.println("  $superTypeName.${attribute.name}: ${superAttribute.type.render()}")
+                    }
+                }
+            } else {
+                renderAttributeDeclarationAsProperty(attribute,
+                        modality = modality,
+                        commented = attribute.isCommented(iface.name),
+                        omitDefaults = iface.kind == GenerateDefinitionKind.INTERFACE,
+                        level = 1
+                )
+            }
     }
     iface.memberFunctions.filter { it !in superFunctions && !it.static }.map { it.dynamicIfUnknownType(allTypes.keys) }.groupBy { it.signature }.reduceValues(::betterFunction).values.forEach {
         renderFunctionDeclaration(it.fixRequiredArguments(iface.name), it.signature in superSignatures, commented = it.isCommented(iface.name))