Remove unused packages and make unused packages error

templatise.cabal

@@ -46,13 +46,13 @@ common initialise-common
     , network-uri           ^>=2.6.4.1  || ^>=2.7.0.0
     , optparse-applicative  ^>=0.18.1.0
     , process               ^>=1.6.13.2
-    , regex-tdfa            ^>=1.3.2.2
     , text                  ^>=1.2.5.0  || ^>=2.0.1    || ^>=2.1
     , time                  ^>=1.11.1.1 || ^>=1.12.2   || ^>=1.13     || ^>=1.14
 
   ghc-options:
     -Wall -Werror=missing-fields -Werror=unused-imports
-    -Werror=unused-matches -Werror=unused-top-binds
+    -Werror=unused-matches -Werror=unused-top-binds -Wunused-packages
+    -Werror=unused-packages
 
 library initialise-library
   import:           initialise-common
@@ -75,7 +75,10 @@ library initialise-library
     , extra         ^>=1.7.14
     , http-client   ^>=0.7.14
     , http-conduit  ^>=2.3.8.3
-    , parsec        ^>=3.1.15.0
+    , regex-tdfa    ^>=1.3.2.2
+
+  if impl(ghc <9.8)
+    build-depends: parsec ^>=3.1.15.0
 
   hs-source-dirs:   lib/initialise
 
@@ -84,7 +87,7 @@ library initialise-library
   default-language: Haskell2010
 
 --build-tool-depends:
---ghc-options:      -Wall
+--ghc-options:
 
 test-suite initialise-test
   import:           initialise-common
@@ -116,13 +119,12 @@ test-suite initialise-test
   default-language: Haskell2010
 
   -- build-tool-depends:
-  ghc-options:      -threaded -Wall
+  ghc-options:      -threaded
 
 executable initialise
   main-is:          Main.hs
   build-depends:
-    , base                  ^>=4.16.3.0 || ^>=4.17.0.0 || ^>=4.18.0.0 || ^>=4.19.0.0
-    , filepath              ^>=1.4.2.2  || ^>=1.5.0
+    , base                  ^>=4.16.3.0 || ^>=4.17.0.0 || ^>=4.18.0.0 || ^>=4.19.0.0 || ^>=4.20
     , initialise-library
     , optparse-applicative  ^>=0.18.1.0
 
@@ -133,4 +135,5 @@ executable initialise
   default-language: Haskell2010
 
   -- build-tool-depends:
-  ghc-options:      -threaded -Wall
+  ghc-options:
+    -threaded -Wall -Wunused-packages -Werror=unused-packages