Crash related to missing name in name signature

[janmasrovira]

module bug;

type T := mkT;

fun {_ : T} : {A : Type} -> T := mkT;

x : T := fun@{A := T};

typechecking the above gives

juvix: (^?!): empty Fold
CallStack (from HasCallStack):
  error, called at src/Control/Lens/Fold.hs:1315:28 in lens-5.2.3-D5GlV5Um12X6NDUMVTaXJq:Control.Lens.Fold
  ^?!, called at src/Juvix/Compiler/Internal/Translation/FromConcrete/NamedArguments.hs:207:54 in juvix-0.6.6-IA4XJn6GhdOJDSjvPUJz6T:Juvix.Compiler.Internal.Translation.FromConcrete.NamedArguments