From 481b2e2f3f4484f589157accfc17cf11cbf7dbd6 Mon Sep 17 00:00:00 2001
From: Preetham Gujjula <gitcommit@mail.preetham.io>
Date: Wed, 22 May 2024 16:51:51 -0400
Subject: [PATCH 1/6] Warn when there are unused imports

---
 pqueue.cabal | 3 ---
 1 file changed, 3 deletions(-)

diff --git a/pqueue.cabal b/pqueue.cabal
index f006f9d..db6a922 100644
--- a/pqueue.cabal
+++ b/pqueue.cabal
@@ -74,9 +74,6 @@ library
     -fspec-constr
     -fdicts-strict
     -Wall
-  if impl(ghc >= 8.0)
-    ghc-options:
-      -fno-warn-unused-imports
 
 test-suite test
   hs-source-dirs: src, tests

From c14f33613f8a160e1e3eb4b03891f4fe4c1835e4 Mon Sep 17 00:00:00 2001
From: Preetham Gujjula <gitcommit@mail.preetham.io>
Date: Wed, 22 May 2024 14:47:08 -0400
Subject: [PATCH 2/6] Remove unused imports

---
 benchmarks/HeapSort.hs              |  1 -
 benchmarks/KWay/PrioMergeAlg.hs     |  1 -
 benchmarks/KWay/RandomIncreasing.hs |  1 -
 benchmarks/PHeapSort.hs             |  1 -
 src/BinomialQueue/Max.hs            | 15 +--------------
 src/BinomialQueue/Min.hs            | 14 +-------------
 src/Data/PQueue/Internals.hs        |  3 ---
 src/Data/PQueue/Min.hs              | 14 +-------------
 src/Data/PQueue/Prio/Internals.hs   |  6 +++++-
 src/Data/PQueue/Prio/Min.hs         |  4 ----
 10 files changed, 8 insertions(+), 52 deletions(-)

diff --git a/benchmarks/HeapSort.hs b/benchmarks/HeapSort.hs
index 7179e87..89bd6fe 100644
--- a/benchmarks/HeapSort.hs
+++ b/benchmarks/HeapSort.hs
@@ -1,6 +1,5 @@
 module HeapSort where
 
-import Data.PQueue.Min (MinQueue)
 import qualified Data.PQueue.Min as P
 import System.Random
 
diff --git a/benchmarks/KWay/PrioMergeAlg.hs b/benchmarks/KWay/PrioMergeAlg.hs
index 9ccb7ca..fef8dd9 100644
--- a/benchmarks/KWay/PrioMergeAlg.hs
+++ b/benchmarks/KWay/PrioMergeAlg.hs
@@ -7,7 +7,6 @@ module KWay.PrioMergeAlg
   ) where
 
 import qualified Data.PQueue.Prio.Min as P
-import System.Random (StdGen)
 import Data.Word
 import Data.List (unfoldr)
 import KWay.RandomIncreasing
diff --git a/benchmarks/KWay/RandomIncreasing.hs b/benchmarks/KWay/RandomIncreasing.hs
index bb6d6a2..40354a2 100644
--- a/benchmarks/KWay/RandomIncreasing.hs
+++ b/benchmarks/KWay/RandomIncreasing.hs
@@ -5,7 +5,6 @@ module KWay.RandomIncreasing where
 
 import System.Random
 import Data.Word
-import Data.List (unfoldr)
 
 data Stream = Stream !Word64 {-# UNPACK #-} !StdGen
 
diff --git a/benchmarks/PHeapSort.hs b/benchmarks/PHeapSort.hs
index 6c4b9a5..66a93b6 100644
--- a/benchmarks/PHeapSort.hs
+++ b/benchmarks/PHeapSort.hs
@@ -1,6 +1,5 @@
 module PHeapSort where
 
-import Data.PQueue.Prio.Min (MinPQueue)
 import qualified Data.PQueue.Prio.Min as P
 import System.Random
 
diff --git a/src/BinomialQueue/Max.hs b/src/BinomialQueue/Max.hs
index c379579..f21c0cc 100644
--- a/src/BinomialQueue/Max.hs
+++ b/src/BinomialQueue/Max.hs
@@ -88,26 +88,13 @@ module BinomialQueue.Max (
 import Prelude hiding (null, take, drop, takeWhile, dropWhile, splitAt, span, break, (!!), filter, map)
 
 import Data.Coerce (coerce)
-import Data.Foldable (foldl')
-import Data.Maybe (fromMaybe)
 import Data.Bifunctor (bimap)
-
-#if MIN_VERSION_base(4,9,0)
-import Data.Semigroup (Semigroup((<>)))
-#endif
-
 import qualified Data.List as List
+import Data.Maybe (fromMaybe)
 
 import qualified BinomialQueue.Min as MinQ
 import Data.PQueue.Internals.Down
 
-#ifdef __GLASGOW_HASKELL__
-import GHC.Exts (build)
-#else
-build :: ((a -> [a] -> [a]) -> [a] -> [a]) -> [a]
-build f = f (:) []
-#endif
-
 newtype MaxQueue a = MaxQueue { unMaxQueue :: MinQ.MinQueue (Down a) }
 
 -- | \(O(\log n)\). Returns the minimum element. Throws an error on an empty queue.
diff --git a/src/BinomialQueue/Min.hs b/src/BinomialQueue/Min.hs
index 2eee2b7..fd6910d 100644
--- a/src/BinomialQueue/Min.hs
+++ b/src/BinomialQueue/Min.hs
@@ -89,23 +89,11 @@ module BinomialQueue.Min (
 import Prelude hiding (null, take, drop, takeWhile, dropWhile, splitAt, span, break, (!!), filter, map)
 
 import Data.Foldable (foldl')
-import Data.Maybe (fromMaybe)
-
-#if MIN_VERSION_base(4,9,0)
-import Data.Semigroup (Semigroup((<>)))
-#endif
-
 import qualified Data.List as List
+import Data.Maybe (fromMaybe)
 
 import BinomialQueue.Internals
 
-#ifdef __GLASGOW_HASKELL__
-import GHC.Exts (build)
-#else
-build :: ((a -> [a] -> [a]) -> [a] -> [a]) -> [a]
-build f = f (:) []
-#endif
-
 -- | \(O(\log n)\). Returns the minimum element. Throws an error on an empty queue.
 findMin :: Ord a => MinQueue a -> a
 findMin = fromMaybe (error "Error: findMin called on empty queue") . getMin
diff --git a/src/Data/PQueue/Internals.hs b/src/Data/PQueue/Internals.hs
index 78d0d1d..a4ce5b1 100644
--- a/src/Data/PQueue/Internals.hs
+++ b/src/Data/PQueue/Internals.hs
@@ -45,8 +45,6 @@ import BinomialQueue.Internals
   , BinomTree (..)
   , Succ (..)
   , Zero (..)
-  , Extract (..)
-  , MExtract (..)
   )
 import qualified BinomialQueue.Internals as BQ
 import Control.DeepSeq (NFData(rnf), deepseq)
@@ -55,7 +53,6 @@ import Data.Foldable (foldl')
 import Data.Semigroup (Semigroup(..), stimesMonoid)
 #endif
 
-import Data.PQueue.Internals.Foldable
 #ifdef __GLASGOW_HASKELL__
 import Data.Data
 import Text.Read (Lexeme(Ident), lexP, parens, prec,
diff --git a/src/Data/PQueue/Min.hs b/src/Data/PQueue/Min.hs
index 02b6e35..1fbea31 100644
--- a/src/Data/PQueue/Min.hs
+++ b/src/Data/PQueue/Min.hs
@@ -95,13 +95,8 @@ module Data.PQueue.Min (
 import Prelude hiding (null, take, drop, takeWhile, dropWhile, splitAt, span, break, (!!), filter, map)
 
 import Data.Foldable (foldl')
-import Data.Maybe (fromMaybe)
-
-#if MIN_VERSION_base(4,9,0)
-import Data.Semigroup (Semigroup((<>)))
-#endif
-
 import qualified Data.List as List
+import Data.Maybe (fromMaybe)
 
 import Data.PQueue.Internals hiding (MinQueue (..))
 import Data.PQueue.Internals (MinQueue (MinQueue))
@@ -109,13 +104,6 @@ import qualified Data.PQueue.Internals as Internals
 import qualified BinomialQueue.Internals as BQ
 import qualified Data.PQueue.Prio.Internals as Prio
 
-#ifdef __GLASGOW_HASKELL__
-import GHC.Exts (build)
-#else
-build :: ((a -> [a] -> [a]) -> [a] -> [a]) -> [a]
-build f = f (:) []
-#endif
-
 #ifdef __GLASGOW_HASKELL__
 -- | A bidirectional pattern synonym for an empty priority queue.
 --
diff --git a/src/Data/PQueue/Prio/Internals.hs b/src/Data/PQueue/Prio/Internals.hs
index 4afaede..85c1dde 100644
--- a/src/Data/PQueue/Prio/Internals.hs
+++ b/src/Data/PQueue/Prio/Internals.hs
@@ -52,7 +52,11 @@ module Data.PQueue.Prio.Internals (
   unions
   ) where
 
-import Control.Applicative (liftA2, liftA3, Const (..))
+#if MIN_VERSION_base(4,18,0)
+import Control.Applicative (Const (..))
+#else
+import Control.Applicative (liftA2, Const (..))
+#endif
 import Control.DeepSeq (NFData(rnf), deepseq)
 import Data.Coerce (coerce)
 import Data.Functor.Identity (Identity(Identity, runIdentity))
diff --git a/src/Data/PQueue/Prio/Min.hs b/src/Data/PQueue/Prio/Min.hs
index ca026ca..5db11ee 100644
--- a/src/Data/PQueue/Prio/Min.hs
+++ b/src/Data/PQueue/Prio/Min.hs
@@ -132,10 +132,6 @@ module Data.PQueue.Prio.Min (
 import qualified Data.List as List
 import Data.Maybe (fromMaybe)
 
-#if MIN_VERSION_base(4,9,0)
-import Data.Semigroup (Semigroup((<>)))
-#endif
-
 import Data.PQueue.Prio.Internals hiding (MinPQueue (..))
 import Data.PQueue.Prio.Internals (MinPQueue)
 import qualified Data.PQueue.Prio.Internals as Internals

From a5b9e46d3670cbdef2e13fa28b89b70977a80e37 Mon Sep 17 00:00:00 2001
From: Preetham Gujjula <gitcommit@mail.preetham.io>
Date: Wed, 22 May 2024 16:02:21 -0400
Subject: [PATCH 3/6] Only import foldl' when base < 4.20

---
 src/BinomialQueue/Internals.hs | 2 ++
 src/BinomialQueue/Min.hs       | 2 ++
 src/Data/PQueue/Internals.hs   | 2 ++
 src/Data/PQueue/Max.hs         | 6 +++---
 src/Data/PQueue/Min.hs         | 2 ++
 5 files changed, 11 insertions(+), 3 deletions(-)

diff --git a/src/BinomialQueue/Internals.hs b/src/BinomialQueue/Internals.hs
index aa4dcd4..0168c70 100644
--- a/src/BinomialQueue/Internals.hs
+++ b/src/BinomialQueue/Internals.hs
@@ -46,7 +46,9 @@ module BinomialQueue.Internals (
   ) where
 
 import Control.DeepSeq (NFData(rnf), deepseq)
+#if !MIN_VERSION_base(4,20,0)
 import Data.Foldable (foldl')
+#endif
 import Data.Function (on)
 #if MIN_VERSION_base(4,9,0)
 import Data.Semigroup (Semigroup(..), stimesMonoid)
diff --git a/src/BinomialQueue/Min.hs b/src/BinomialQueue/Min.hs
index fd6910d..4885fd7 100644
--- a/src/BinomialQueue/Min.hs
+++ b/src/BinomialQueue/Min.hs
@@ -88,7 +88,9 @@ module BinomialQueue.Min (
 
 import Prelude hiding (null, take, drop, takeWhile, dropWhile, splitAt, span, break, (!!), filter, map)
 
+#if !MIN_VERSION_base(4,20,0)
 import Data.Foldable (foldl')
+#endif
 import qualified Data.List as List
 import Data.Maybe (fromMaybe)
 
diff --git a/src/Data/PQueue/Internals.hs b/src/Data/PQueue/Internals.hs
index a4ce5b1..0e5ed51 100644
--- a/src/Data/PQueue/Internals.hs
+++ b/src/Data/PQueue/Internals.hs
@@ -48,7 +48,9 @@ import BinomialQueue.Internals
   )
 import qualified BinomialQueue.Internals as BQ
 import Control.DeepSeq (NFData(rnf), deepseq)
+#if !MIN_VERSION_base(4,20,0)
 import Data.Foldable (foldl')
+#endif
 #if MIN_VERSION_base(4,9,0)
 import Data.Semigroup (Semigroup(..), stimesMonoid)
 #endif
diff --git a/src/Data/PQueue/Max.hs b/src/Data/PQueue/Max.hs
index fe98ae1..53986d3 100644
--- a/src/Data/PQueue/Max.hs
+++ b/src/Data/PQueue/Max.hs
@@ -86,14 +86,14 @@ module Data.PQueue.Max (
 import Control.DeepSeq (NFData(rnf))
 
 import Data.Coerce (coerce)
+#if !MIN_VERSION_base(4,20,0)
+import Data.Foldable (foldl')
+#endif
 import Data.Maybe (fromMaybe)
-
 #if MIN_VERSION_base(4,9,0)
 import Data.Semigroup (Semigroup(..), stimesMonoid)
 #endif
 
-import Data.Foldable (foldl')
-
 import qualified Data.PQueue.Min as Min
 import qualified Data.PQueue.Prio.Max.Internals as Prio
 import Data.PQueue.Internals.Down (Down(..))
diff --git a/src/Data/PQueue/Min.hs b/src/Data/PQueue/Min.hs
index 1fbea31..5b668de 100644
--- a/src/Data/PQueue/Min.hs
+++ b/src/Data/PQueue/Min.hs
@@ -94,7 +94,9 @@ module Data.PQueue.Min (
 
 import Prelude hiding (null, take, drop, takeWhile, dropWhile, splitAt, span, break, (!!), filter, map)
 
+#if !MIN_VERSION_base(4,20,0)
 import Data.Foldable (foldl')
+#endif
 import qualified Data.List as List
 import Data.Maybe (fromMaybe)
 

From 4112883e2b6e61471d6a9ed0dc13a3d468a716d0 Mon Sep 17 00:00:00 2001
From: Preetham Gujjula <gitcommit@mail.preetham.io>
Date: Wed, 22 May 2024 16:06:51 -0400
Subject: [PATCH 4/6] Only import unsafeCoerce when necessary

---
 src/Nattish.hs | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/src/Nattish.hs b/src/Nattish.hs
index 925f8b3..a52c4fe 100644
--- a/src/Nattish.hs
+++ b/src/Nattish.hs
@@ -18,7 +18,9 @@ module Nattish
   ( Nattish (Zeroy, Succy)
   )
   where
+#if __GLASGOW_HASKELL__ >= 904
 import Unsafe.Coerce (unsafeCoerce)
+#endif
 #if __GLASGOW_HASKELL__ >= 800
 import Data.Kind (Type)
 #endif

From 0b38aebd3598f3749f6b4faea5cacdf2d131303d Mon Sep 17 00:00:00 2001
From: Preetham Gujjula <gitcommit@mail.preetham.io>
Date: Wed, 22 May 2024 16:17:42 -0400
Subject: [PATCH 5/6] Only use Type when it's defined

---
 src/Nattish.hs | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/src/Nattish.hs b/src/Nattish.hs
index a52c4fe..c782e72 100644
--- a/src/Nattish.hs
+++ b/src/Nattish.hs
@@ -40,7 +40,11 @@ import Data.Kind (Type)
 -- it is very fast to work with.
 
 #if __GLASGOW_HASKELL__ < 904
+#if __GLASGOW_HASKELL__ >= 800
+data Nattish :: k -> (k -> k) -> k -> Type where
+#else
 data Nattish :: k -> (k -> k) -> k -> * where
+#endif
   Zeroy :: Nattish zero succ zero
   Succy :: !(Nattish zero succ n) -> Nattish zero succ (succ n)
 

From 45f128e45e6818b0bb7a26947820abc02ad0bfe5 Mon Sep 17 00:00:00 2001
From: Preetham Gujjula <gitcommit@mail.preetham.io>
Date: Wed, 22 May 2024 16:35:08 -0400
Subject: [PATCH 6/6] Use COMPLETE pragma only when ghc >= 8.2

---
 src/Data/PQueue/Min.hs      | 2 ++
 src/Data/PQueue/Prio/Min.hs | 2 ++
 2 files changed, 4 insertions(+)

diff --git a/src/Data/PQueue/Min.hs b/src/Data/PQueue/Min.hs
index 5b668de..c824457 100644
--- a/src/Data/PQueue/Min.hs
+++ b/src/Data/PQueue/Min.hs
@@ -136,7 +136,9 @@ pattern a :< q <- (minView -> Just (a, q))
 {-# INLINE (:<) #-}
 # endif
 
+# if __GLASGOW_HASKELL__ >= 820
 {-# COMPLETE Empty, (:<) #-}
+# endif
 #endif
 
 -- | \(O(1)\). Returns the minimum element. Throws an error on an empty queue.
diff --git a/src/Data/PQueue/Prio/Min.hs b/src/Data/PQueue/Prio/Min.hs
index 5db11ee..bf39e3e 100644
--- a/src/Data/PQueue/Prio/Min.hs
+++ b/src/Data/PQueue/Prio/Min.hs
@@ -168,7 +168,9 @@ pattern ka :< q <- (minViewWithKey -> Just (ka, q))
 {-# INLINE (:<) #-}
 # endif
 
+# if __GLASGOW_HASKELL__ >= 820
 {-# COMPLETE Empty, (:<) #-}
+# endif
 #endif
 
 (.:) :: (c -> d) -> (a -> b -> c) -> a -> b -> d