This question was posed by Thomas Pullman on Gaeilge-B on 12 Bealtaine, 2002

Maidir leis an gceist:

>>>Now my question - do impersonal forms get lenited after the relative
pronoun as I've done (-- "in 1917 a fhoilsíodh" -- ), and eclipsed after
indirect relatives in the present, or are they immune from mutation?

It should be " i 1917 a foilsíodh" because ...

Of the six tenses Aimsir Láithreach; A. Gnáth-láithreach, A. Chaite, A. Ghnáth-chaite, A. Fháistineach, Modh Choinníollach, only one resists aspiration / lenition / séimhiú in the "impersonal form" or "briathar saor" and that is An Aimsir Chaite / The Past Tense. You can treat all the others as you would in any of the "persons" -- an té a chuirfidh -- an té a chuirfear -- an uaigh ina gcuirfear ... etc.

But "an té a chuir an crann" -- an crann a cuireadh --- an talamh inar cuireadh an crann etc. No aspiration on "cuireadh" -- briathar saor aimsir chaite.

I notice some writers have got this wrong and apply the aimsir chaite rule to all the tenses leaving out the séimhiú / aspiration. Aspirate "an briathar saor" in five tenses leave it out in one.

Look at the negative: Ní chuirtear; ní chuirfear; ní chuirfí; and ní chuirtí -- but"níor cuireadh".

In reported speechdearfach / diúltach -- go / nach gcuirtear;go / nach gcuirfear; go / nach gcuirfí; go / nach gcuirtí --- but -- gur/ nár cuireadh.

Finally look at one of the irregular verbs:

faightear / ní fhaightear / ... go / nach bhfaightear;

gheofar: .... ní/ go / nach bhfaighfear;

gheobhfaí: ní / go / nach bhfaighfí;

d'fhaightí: ní / go / nach bhfaightí

--- ach fuarthas: ní / go / nach bhfuarthas --- so you can put an "urú" on it in the Past Tense [I cannot think of another example unless "go ndeachthas" ] but do not put a séimhiú on the "briathar saor" of the Past Tense -- you can in all the other tenses. [Unfortunately there is one exception "ní dheachthas" but that is it -- at least I think so until someone points out others to me.:-)]

I am talking about Standard Written Irish here. I am not concerned with what may or may not be said in this dialect or that in this message. Almost every variable will be heard somewhere in one dialect or another.