Set: pp::colors
  Assumed: T
  Assumed: R
  Assumed: f
  Coercion f
Variable f : T → R
Coercion f
  Assumed: g
Error (line: 9, pos: 0) invalid coercion declaration, frontend already has a coercion for the given types
  Assumed: h
Error (line: 11, pos: 0) invalid coercion declaration, a coercion must have an arrow type (i.e., a non-dependent functional type)
  Defined: T2
  Defined: R2
  Assumed: f2
Error (line: 15, pos: 0) invalid coercion declaration, frontend already has a coercion for the given types
  Assumed: id
Error (line: 17, pos: 0) invalid coercion declaration, 'from' and 'to' types are the same