Add an instance for untagging values

source/library/Witch/Instances.hs

@@ -1278,6 +1278,9 @@ instance From.From Time.ZonedTime Time.UTCTime where
 -- | Uses @coerce@. Essentially the same as 'Tagged.Tagged'.
 instance From.From a (Tagged.Tagged t a)
 
+-- | Uses @coerce@. Essentially the same as 'Tagged.unTagged'.
+instance From.From (Tagged.Tagged t a) a
+
 --
 
 realFloatToRational ::

source/test-suite/Main.hs

@@ -2076,6 +2076,11 @@ spec = describe "Witch" $ do
       it "works" $ do
         f False `shouldBe` Tagged.Tagged False
 
+    describe "From (Tagged t a) a" $ do
+      let f = Witch.from @(Tagged.Tagged () Bool) @Bool
+      it "works" $ do
+        f (Tagged.Tagged False) `shouldBe` False
+
 newtype Age
   = Age Int.Int8
   deriving (Eq, Show)