function getBaseConstructorTypeOfClass(type) {
            if (!type.resolvedBaseConstructorType) {
                var baseTypeNode = getBaseTypeNodeOfClass(type);
                if (!baseTypeNode) {
                    return type.resolvedBaseConstructorType = undefinedType;
                }
                if (!pushTypeResolution(type, 1 /* ResolvedBaseConstructorType */)) {
                    return unknownType;
                }
                var baseConstructorType = checkExpression(baseTypeNode.expression);
                if (baseConstructorType.flags & 80896 /* ObjectType */) {
                    // Resolving the members of a class requires us to resolve the base class of that class.
                    // We force resolution here such that we catch circularities now.
                    resolveStructuredTypeMembers(baseConstructorType);
                }
                if (!popTypeResolution()) {
                    error(type.symbol.valueDeclaration, ts.Diagnostics._0_is_referenced_directly_or_indirectly_in_its_own_base_expression, symbolToString(type.symbol));
                    return type.resolvedBaseConstructorType = unknownType;
                }
                if (baseConstructorType !== unknownType && baseConstructorType !== nullType && !isConstructorType(baseConstructorType)) {
                    error(baseTypeNode.expression, ts.Diagnostics.Type_0_is_not_a_constructor_function_type, typeToString(baseConstructorType));
                    return type.resolvedBaseConstructorType = unknownType;
                }
                type.resolvedBaseConstructorType = baseConstructorType;
            }
            return type.resolvedBaseConstructorType;
        }