TH Generates dupicate pattern synonyms if type is in AST multiple times

[arianvp]

When a datatype occurs multiple times within another datatype,
multiple pattern synonyms are generated, leading to invalid haskell code

see b0818ae for triggering the bug

[arianvp]

[nix-shell:~/Projects/generics/lol]$ runhaskell Setup.hs build --ghc-options="-ddump-splices -ddump-to-file"
Preprocessing library for generics-mrsop-1.1.1..
Building library for generics-mrsop-1.1.1..
[17 of 18] Compiling Generics.MRSOP.Examples.SimpTH ( src/Generics/MRSOP/Examples/SimpTH.hs, dist/build/Generics/MRSOP/Examples/SimpTH.o )

src/Generics/MRSOP/Examples/SimpTH.hs:65:1: error:
    Multiple declarations of ‘Nothing_’
    Declared at: src/Generics/MRSOP/Examples/SimpTH.hs:65:1
                 src/Generics/MRSOP/Examples/SimpTH.hs:65:1
   |
65 | deriveFamilyWith ''Singl [t| Stmt String |]
   | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^

src/Generics/MRSOP/Examples/SimpTH.hs:65:1: error:
    Multiple declarations of ‘Just_’
    Declared at: src/Generics/MRSOP/Examples/SimpTH.hs:65:1
                 src/Generics/MRSOP/Examples/SimpTH.hs:65:1
   |
65 | deriveFamilyWith ''Singl [t| Stmt String |]
   | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^

Generated splice:

    pattern SAssign_ p_a8S9 p_a8Sa = Tag CZ
                                         (NA_K p_a8S9 :* (NA_I p_a8Sa :* NP0))
    pattern SIf_ p_a8Sb p_a8Sc p_a8Sd = Tag (CS CZ)
                                            (NA_I p_a8Sb :* (NA_I p_a8Sc :* (NA_I p_a8Sd :* NP0)))
    pattern SSeq_ p_a8Se p_a8Sf = Tag (CS (CS CZ))
                                      (NA_I p_a8Se :* (NA_I p_a8Sf :* NP0))
    pattern SReturn_ p_a8Sg = Tag (CS (CS (CS CZ)))
                                  (NA_I p_a8Sg :* NP0)
    pattern SDecl_ p_a8Sh = Tag (CS (CS (CS (CS CZ))))
                                (NA_I p_a8Sh :* NP0)
    pattern SSkip_ = Tag (CS (CS (CS (CS (CS CZ))))) NP0
    pattern EVar_ p_a8Si = Tag CZ (NA_K p_a8Si :* NP0)
    pattern ECall_ p_a8Sj p_a8Sk = Tag (CS CZ)
                                       (NA_K p_a8Sj :* (NA_I p_a8Sk :* NP0))
    pattern EAdd_ p_a8Sl p_a8Sm = Tag (CS (CS CZ))
                                      (NA_I p_a8Sl :* (NA_I p_a8Sm :* NP0))
    pattern ESub_ p_a8Sn p_a8So = Tag (CS (CS (CS CZ)))
                                      (NA_I p_a8Sn :* (NA_I p_a8So :* NP0))
    pattern Foo_ p_a8Sp = Tag (CS (CS (CS (CS CZ))))
                              (NA_I p_a8Sp :* NP0)
    pattern BBar_ p_a8Sq = Tag (CS (CS (CS (CS (CS CZ)))))
                               (NA_I p_a8Sq :* NP0)
    pattern ELit_ p_a8Sr = Tag (CS (CS (CS (CS (CS (CS CZ))))))
                               (NA_K p_a8Sr :* NP0)
    pattern DVar_ p_a8Ss = Tag CZ (NA_K p_a8Ss :* NP0)
    pattern DFun_ p_a8St p_a8Su p_a8Sv = Tag (CS CZ)
                                             (NA_K p_a8St :* (NA_K p_a8Su :* (NA_I p_a8Sv :* NP0)))
    pattern Bar_ p_a8Sw = Tag (CS (CS CZ)) (NA_I p_a8Sw :* NP0)
    pattern Lol_ p_a8Sx = Tag (CS (CS (CS CZ))) (NA_I p_a8Sx :* NP0)
    pattern Nothing_ = Tag CZ NP0
    pattern Just_ p_a8Sy = Tag (CS CZ) (NA_I p_a8Sy :* NP0)
    pattern Nothing_ = Tag CZ NP0
    pattern Just_ p_a8Sz = Tag (CS CZ) (NA_I p_a8Sz :* NP0)