Add IsString instance

Add `instance IsString (Seq Char)` when compiling with GHC.

Author: treeowl

Data/Sequence.hs

@@ -1,6 +1,8 @@
 {-# LANGUAGE CPP #-}
 #if __GLASGOW_HASKELL__
-{-# LANGUAGE DeriveDataTypeable, StandaloneDeriving #-}
+{-# LANGUAGE DeriveDataTypeable #-}
+{-# LANGUAGE StandaloneDeriving #-}
+{-# LANGUAGE FlexibleInstances #-}
 #endif
 #if __GLASGOW_HASKELL__ >= 703
 {-# LANGUAGE Trustworthy #-}
@@ -182,6 +184,7 @@ import GHC.Exts (build)
 import Text.Read (Lexeme(Ident), lexP, parens, prec,
     readPrec, readListPrec, readListPrecDefault)
 import Data.Data
+import Data.String (IsString(..))
 #endif
 
 -- Array stuff, with GHC.Arr on GHC
@@ -2137,6 +2140,11 @@ instance GHC.Exts.IsList (Seq a) where
     toList = toList
 #endif
 
+#ifdef __GLASGOW_HASKELL__
+instance IsString (Seq Char) where
+    fromString = fromList
+#endif
+
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 -- Reverse
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