@value interface Type1<#a> {}

@value interface Type2<#b> {
  refines Type1<#b>
}

@value interface Type3<#c> {
  refines Type2<#c>
}

@value interface Interface1<#j> {
  something<#x,#y>
    #x requires Type2<#j>
    #y allows Type1<#j>
  (#x) -> (#y)
}

@value interface Interface2<#k> {
  something<#w,#z>
    #w requires Type3<#k>
    #z allows Type3<#k>
  (#w) -> (#z)
}

concrete Test<#q> {
  refines Interface1<#q>
  refines Interface2<#q>

  @value something<#r,#s>
    #r requires Type2<#q>
    #s allows Type2<#q>
  (#r) -> (#s)
}