fails to typecheck with inferred type

[stew]

Input:

```unison:hide
structural type Holder g
  = Holder ('{g} () ->{g} ())


Holder.wrap : ('{g} () ->{g} ()) -> Holder g
Holder.wrap  = Holder 
```

```
  The expression in red
  
                needs the abilities: {g5}
    but was assumed to only require: {}
  
  This is likely a result of using an un-annotated function as an argument with concrete abilities. Try adding an annotation to the function definition whose body is red.
  
      7 | Holder.wrap  = Holder 
```

Holder.wrap in the above fails to typecheck if you include the type signature, it works without, The type signature given is the one inferred, however.