@value interface Object1<#x|> {}

@value interface Object2<|#y> {}

@value interface Object3<#w|#z> {
  refines Object1<#w>
  refines Object2<#z>
}

@value interface Object4<#t> {
  refines Object3<#t,#t>
}

@value interface Object5<|#q> {
  // Variance reversed twice by Object1.
  refines Object1<Object1<#q>>
}

@type interface Object6<|#x> {}

concrete Object7<|#s> {
  // Variance reversed twice by Object1.
  defines Object6<Object1<Object1<#s>>>
}