For exactprint 1.5.0 / ghc-9.2.5, makeDeltaAst' seems to just break things

[lspitzner]

I am trying to exactprint individual decls. On the untransformed parsed source, exactprinting one decl works, but it inserts newlines corresponding to the position of the decl in the original source file, i.e. if you have

> module Foo where
> 
> import Prelude
> 
> blah :: Int

and if you pretty-print just the type signature you get

> 
> 
> 
> 
> blah :: Int

which is a bit annoying/confusing. Trying to solve this I thought I'd be able to make use of the makeDeltaAst helper, but with that, things completely break, and you get output similar to (not exactly with the above input, but the problem should be apparent):

       from anc:Anchor local/Sample.hs:7:8-10 UnchangedAnchor
 EpAnnNotUsed:from anc:Anchor local/Sample.hs:8:1-3 UnchangedAnchorEpAnnNotUsed:from anc:Anchor local/Sample.hs:8:1-8 UnchangedAnchorEpAnnNotUsed:from anc:Anchor local/Sample.hs:8:1-8 UnchangedAnchorfoo =EpAnnNotUsed:from anc:Anchor local/Sample.hs:8:1-3 UnchangedAnchor      42






      from anc:Anchor local/Sample.hs:8:7-8 UnchangedAnchor

Is that function just broken? Intended for a different purpose? Is it meant to be applied recursively? Fixed in 9.4.x?