Spec - comments on reviews

[haxscramper]

To-dos that were uncovered when during PR reviews

• Specification tests PR2 #43 (comment)

• Specification tests PR2 #43 (comment)

• Specification tests PR2 #43 (comment)

• Specification tests PR2 #43 (comment)

• Specification tests PR3 #59 (comment) - discussion about

  user-defined typeclass breaks overload resolution. Moving A or B in a separate generic typeclass fails overload resolution. type Q = A or B is not the same as A or B written directly in the proc parameter

  Potentially a known issue - Distinct generic parameter types nim-lang/Nim#1385, [generic] T:seq wrong type inference: can't instantiate proc fun1[T1:seq, T2:seq](a1:T1, a2:T2) with fun1(@[1], @[1.0]) nim-lang/Nim#8435 - related. Not clear what the correct approach is, right now it was decided to leave the current behavior intact.