is Unlifted Type == Primitive Type?

Hello, According to GHC Wiki https://gitlab.haskell.org/ghc/ghc/wikis/commentary/compiler/type-type#Class... it seems that only primitive types can be unlifted. Is this true in general? (i.e. no user type can be unlifted) [image: image.png] Does the Stg to Cmm codegen support compilation for a variable of user defined ADT as unlifted? i.e. some analysis proved that it is always a constructor and never a thunk. Thanks, Csaba