build: bump deepseq minimum version and remove workaround

Author: e-kwsm

ShellCheck.cabal

@@ -52,7 +52,7 @@ library
       base                 >= 4.8.0.0 && < 5,
       bytestring           >= 0.10.6 && < 0.13,
       containers           >= 0.5.6 && < 0.9,
-      deepseq              >= 1.4.1 && < 1.6,
+      deepseq              >= 1.4.2 && < 1.6,
       Diff                 >= 0.4.0 && < 1.1,
       fgl                  (>= 5.7.0 && < 5.8.1.0) || (>= 5.8.1.1 && < 5.9),
       filepath             >= 1.4.0 && < 1.6,

src/ShellCheck/CFGAnalysis.hs

@@ -20,7 +20,6 @@
 {-# LANGUAGE TemplateHaskell #-}
 {-# LANGUAGE RankNTypes #-}
 {-# LANGUAGE DeriveAnyClass, DeriveGeneric #-}
-{-# LANGUAGE CPP #-}
 
 {-
     Data Flow Analysis on a Control Flow Graph.
@@ -449,14 +448,6 @@ data StackEntry s = StackEntry {
 }
     deriving (Eq, Generic, NFData)
 
-#if MIN_VERSION_deepseq(1,4,2)
--- Our deepseq already has a STRef instance
-#else
--- Older deepseq (for GHC < 8) lacks this instance
-instance NFData (STRef s a) where
-    rnf = (`seq` ())
-#endif
-
 -- Overwrite a base state with the contents of a diff state
 -- This is unrelated to join/merge.
 patchState :: InternalState -> InternalState -> InternalState