Boo.Lang.Compiler.Steps.PreProcessExtensionMethods.CheckExtensionSemantics C# (CSharp) Method

        void CheckExtensionSemantics(Method node)
        {
            if (!((IMethod)node.Entity).IsExtension) return;
            if (NodeType.Method == node.NodeType && (node.IsStatic || node.DeclaringType is Module)) return;
            Errors.Add(CompilerErrorFactory.InvalidExtensionDefinition(node));
        }