boo.f 0 1 2 : ℕ
elab4.lean:13:7: error: none of the overloads are applicable
error for bla.f
failed to synthesize type class instance for
⊢ has_add bool

error for foo.f
function expected at
  foo.f 0 1

error for boo.f
function expected at
  boo.f 0 1 2
Additional information:
elab4.lean:13:7: context: switched to basic overload resolution where arguments are elaborated without any information about the expected type because expected type was not available
elab4.lean:15:7: error: ambiguous overload, possible interpretations
  foo.f 0 1
  boo.f 0 1
Additional information:
elab4.lean:15:7: context: switched to basic overload resolution where arguments are elaborated without any information about the expected type because expected type was not available
foo.f bool.tt 2 : bool
bla.f bool.tt bool.ff bool.tt : bool → bool
elab4.lean:21:7: error: ambiguous overload, possible interpretations
  bla.f bool.tt bool.ff
  foo.f bool.tt bool.ff
Additional information:
elab4.lean:21:7: context: switched to basic overload resolution where arguments are elaborated without any information about the expected type because expected type was not available
foo.f 0 1 : ℕ