Internal type error regarding internalisation

[Unigurd]

I get a compile error when I try to compile the following with futhark c:

type sometype 't = #someval t
entry crash : sometype ([]i32) = #someval [1]

The error message is as follows:

Warning at bug.fut:2:1-45:
  Entry point return type
  
    #someval [1]i32
  
  will have an opaque type, so the result will likely not be usable.
Internal compiler error.
Please report this at https://github.com/diku-dk/futhark/issues.
After internalisation:
In function crash
Type error:
payload_4041 was invalidly consumed.
Nothing can be consumed here.

If I change sometype to sometype 't = t and all instances of constructor #someval, then I simply get a normal type error.

Additionally, the following will also crash when I try to load it into futhark repl:

type sometype 't = #someval t

let unwrap 't (n : sometype t) : t
  = match n case #someval m -> m

let geni32 (maxsize : i32) : sometype i32 = #someval maxsize

let genarr 'elm
           (genelm: i32 -> sometype elm)
           (ownsize : i32)
           : sometype ([ownsize]elm) =
  let rngs = replicate ownsize ownsize
  in #someval (map (unwrap <-< genelm) rngs)

entry crash : sometype ([][]i32)=
  genarr (genarr geni32) 1

The error message:

Loading bug.fut
Warning at bug.fut:15:1-16:26:
  Entry point return type
  
    #someval [1][1]i32
  
  will have an opaque type, so the result will likely not be usable.

Internal compiler error (unhandled IO exception).
Please report this at https://github.com/diku-dk/futhark/issues
Bad return type: *[][ownsize]i32
CallStack (from HasCallStack):
  error, called at src/Language/Futhark/Interpreter.hs:1312:15 in futhark-0.16.0-5e4b2caa8c56347058172608c41910e8fcef137fed5a05bf88d6af351cfcef7:Language.Futhark.Interpreter                                   

This one stop crashing if I change the body of crash to genarr geni32 1 and its type accordingly.