Change conditionals in .cabal file to use base version

OneTuple.cabal

@@ -1,6 +1,6 @@
 cabal-version:      1.12
 name:               OneTuple
-version:            0.4.2.1
+version:            0.4.3
 synopsis:           Singleton Tuple
 category:           Data
 description:
@@ -40,6 +40,14 @@ source-repository head
   type:     git
   location: https://github.com/phadej/OneTuple.git
 
+flag base-ge-4-15
+  default: True
+  manual:  False
+
+flag base-ge-4-16
+  default: True
+  manual:  False
+
 library
   default-language: Haskell98
   exposed-modules:
@@ -52,17 +60,31 @@ library
       base              >=4.12 && <4.23
     , template-haskell
 
-  if impl(ghc >=9.0)
+  if flag(base-ge-4-15)
     build-depends: ghc-prim
+
   else
     build-depends: hashable >=1.3.5.0 && <1.6
 
-  if !impl(ghc >=9.0)
+  if !flag(base-ge-4-15)
     build-depends: foldable1-classes-compat >=0.1 && <0.2
 
-  if !impl(ghc >=9.2)
+  if !flag(base-ge-4-16)
     build-depends: base-orphans >=0.8.6
 
+  -- flag selection forcing conditionals
+  if flag(base-ge-4-15)
+    build-depends: base >=4.15
+
+  else
+    build-depends: base <4.15
+
+  if flag(base-ge-4-16)
+    build-depends: base >=4.16
+
+  else
+    build-depends: base <4.16
+
 test-suite instances
   type:             exitcode-stdio-1.0
   default-language: Haskell98

src/Data/Tuple/OneTuple.hs

@@ -1,7 +1,4 @@
-{-# LANGUAGE CPP             #-}
-#if __GLASGOW_HASKELL__ >= 708
 {-# LANGUAGE PatternSynonyms #-}
-#endif
 -- | This is a module to help migration from @OneTuple@ to @Solo@.
 -- Migrate to use "Data.Tuple" from @base-4.16@ or "Data.Tuple.Solo" with all GHCs.
 --
@@ -10,9 +7,7 @@ module Data.Tuple.OneTuple
 {-# DEPRECATED "Use Data.Tuple.Solo" #-}
 (
     OneTuple,
-#if __GLASGOW_HASKELL__ >= 708
     pattern OneTuple,
-#endif
     only,
 ) where
 
@@ -23,13 +18,7 @@ type OneTuple = Solo
 only :: OneTuple a -> a
 only = getSolo
 
-#if __GLASGOW_HASKELL__ >= 708
-#if __GLASGOW_HASKELL__ >= 710
 pattern OneTuple :: a -> Solo a
-#endif
 pattern OneTuple a = MkSolo a
-#endif
 
-#if __GLASGOW_HASKELL__ >= 800
 {-# COMPLETE OneTuple #-}
-#endif

src/Data/Tuple/Solo.hs

@@ -54,6 +54,7 @@ pattern MkSolo a = Solo a
 
 {-# COMPLETE MkSolo #-}
 
+-- !MIN_VERSION_base(4,15,0)
 #else
 
 import Control.Applicative (Applicative (..))

test/instances.hs

@@ -1,9 +1,6 @@
 {-# LANGUAGE CPP #-}
-#if __GLASGOW_HASKELL__ >= 800
 {-# OPTIONS_GHC -Wincomplete-patterns -Werror=incomplete-patterns #-}
-#else
 {-# OPTIONS_GHC -fwarn-incomplete-patterns -Werror #-}
-#endif
 module Main where
 
 import Control.Applicative  (Applicative (..))
@@ -66,9 +63,7 @@ hasApplicative :: Applicative f => f a -> f a; hasApplicative x = x; testApplica
 hasMonad :: Monad f => f a -> f a; hasMonad x = x; testMonad = hasMonad tup1
 hasMonadFix :: MonadFix f => f a -> f a; hasMonadFix x = x; testMonadFix = hasMonadFix tup1
 
-#if MIN_VERSION_base(4,4,0)
 hasMonadZip :: MonadZip f => f a -> f a; hasMonadZip x = x; testMonadZip = hasMonadZip tup1
-#endif
 
 hasEq1 :: Eq1 f => f a -> f a; hasEq1 x = x; testEq1 = hasEq1 tup1
 hasOrd1 :: Ord1 f => f a -> f a; hasOrd1 x = x; testOrd1 = hasOrd1 tup1