The text of Gal. 3:18 is verbless: εἰ γὰρ ἐκ νόμου ἡ κληρονομία [?????], οὐκέτι ἐξ ἐπαγγελίας [?????] · τῷ δὲ Ἀβραὰμ δι᾿ ἐπαγγελίας κεχάρισται ὁ θεός.
κατὰ Smyth: A Greek Grammar
Smyth §2292. Only one class of conditional sentences distinctly expresses non-fulfilment of the action
1. Present or Past
Protasis: εἰ with the imperfect indicative.
Apodosis: ἄν with the imperfect indicative.
εἰ ταῦτα ἐποίεις, καλῶς ἂν ἐποίεις if you were (now) doing this, you would be doing well; if you had been doing this, you would have been doing well.
2. Past
Protasis: εἰ with the aorist indicative.
Apodosis: ἄν with the aorist indicative.
εἰ ταῦτα ἐποίησας, καλῶς ἂν ἐποίησας if you had done this, you would have done well.
Present: Gal. 3:18 εἰ γὰρ ἐκ νόμου ἡ κληρονομία [ἦν], οὐκέτι ἐξ ἐπαγγελίας [ἂν ἦν]· τῷ δὲ Ἀβραὰμ δι᾿ ἐπαγγελίας κεχάρισται ὁ θεός.
Past: Gal. 3:18 εἰ γὰρ ἐκ νόμου ἡ κληρονομία [ἐγένετο] , οὐκέτι ἐξ ἐπαγγελίας [ἂν ἐγένετο] · τῷ δὲ Ἀβραὰμ δι᾿ ἐπαγγελίας κεχάρισται ὁ θεός.
οὐκέτι in the apodosis would imply the indicative, but the presence of ἂν brings the whole contingency into the realm of possiblity/impossibility - and hence seem to imply the subjunctive. But Greek used the indicative. But are there any examples of contrary to fact statements which have mixed moods?