add failing test for type converter being composed
add failing test for type converter being composed

fable-compiler/Fable,ncave/Fable,ncave/Fable,ncave/Fable,ncave/Fable,ncave/Fable,fable-compiler/Fable,fable-compiler/Fable,ncave/Fable,inosik/Fable,fable-compiler/Fable,fable-compiler/Fable,inosik/Fable,fable-compiler/Fable,ncave/Fable,fable-compiler/Fable