Build failure with template-haskell-2.17, bound not revisable on hackage

[andreasabel]

Build with GHC 9.0 fails because of a change in template-haskell (see below).
A bound template-haskell < 2.17 would be necessary for the versions already released on hackage.
Unfortunately, template-haskell is only a build-depends in conditionals in the cabal file and those cannot be revised.
(Due to this limitation, it is best practice to mention all dependencies in an unconditional build-depends, and add additional constraints on these dependencies in the conditionals.)

$ cabal install lenses

Build profile: -w ghc-9.0.1 -O1
In order, the following will be built (use -v for more details):
 - lenses-0.1.8 (lib:lenses) (requires build)
...
[2 of 2] Compiling Data.Lenses.Template ( src-26/Data/Lenses/Template.hs, dist/build/Data/Lenses/Template.o, dist/build/Data/Lenses/Template.dyn_o )

src-26/Data/Lenses/Template.hs:110:18: error:
    • Expecting one more argument to ‘TyVarBndr’
      Expected a type, but ‘TyVarBndr’ has kind ‘* -> *’
    • In the type signature:
        makeAccs :: [TyVarBndr] -> [VarStrictType] -> Q [Dec]
      In an equation for ‘nameDeriveLenses’:
...

[andreasabel]

In my role has hackage trustee, I revised lenses-0.1.6/7/8 with upper bounds on base serving as proxy for upper bounds on template-haskell.

[jvranish]

Makes sense, thanks!