use a spellscript instead
check this:
```code
class spell_yogg_saron_diminsh_power : public SpellScriptLoader
{
    public:
        spell_yogg_saron_diminsh_power() : SpellScriptLoader("spell_yogg_saron_diminsh_power") { }

        class spell_yogg_saron_diminsh_power_AuraScript : public AuraScript
        {
            PrepareAuraScript(spell_yogg_saron_diminsh_power_AuraScript);

            void HandleProc(AuraEffect const* /*aurEff*/, ProcEventInfo& /*eventInfo*/)
            {
                PreventDefaultAction();
                GetTarget()->InterruptSpell(CURRENT_CHANNELED_SPELL);
            }

            void Register()
            {
                OnEffectProc += AuraEffectProcFn(spell_devourer_of_souls_mirrored_soul_proc_AuraScript::HandleProc, EFFECT_0, SPELL_AURA_PROC_TRIGGER_SPELL);
            }
        };

        AuraScript* GetAuraScript() const
        {
            return new spell_yogg_saron_diminsh_power_AuraScript();
        }
};
```