elab4b.lean:9:7: 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
  f 0 1

error for boo.f
function expected at
  f 0 1 2
Additional information:
elab4b.lean:9:7: context: switched to basic overload resolution where arguments are elaborated without any information about the expected type because expected type was not available
elab4b.lean:11:7: error: ambiguous overload, possible interpretations
  foo.f 0 1
  boo.f 0 1
Additional information:
elab4b.lean:11:7: context: switched to basic overload resolution where arguments are elaborated without any information about the expected type because expected type was not available
elab4b.lean:13:7: error: ambiguous overload, possible interpretations
  bla.f bool.tt bool.ff
  foo.f bool.tt bool.ff
Additional information:
elab4b.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