Add instance: Hashable SomeLspId (#424)

* Add instance: Hashable SomeLspId

* Add separate Hashable (LspId m) and use for Hashable SomeLspId

Author: thomasjm

lsp-types/src/Language/LSP/Types/LspId.hs

@@ -7,9 +7,10 @@
 module Language.LSP.Types.LspId where
 
 import qualified Data.Aeson                                 as A
-import           Data.Text                                  (Text)
+import           Data.Hashable
 import           Data.Int (Int32)
 import           Data.IxMap
+import           Data.Text                                  (Text)
 
 import           Language.LSP.Types.Method
 
@@ -30,6 +31,10 @@ instance IxOrd LspId where
   type Base LspId = SomeLspId
   toBase = SomeLspId
 
+instance Hashable (LspId m) where
+  hashWithSalt n (IdInt i) = hashWithSalt n i
+  hashWithSalt n (IdString t) = hashWithSalt n t
+
 data SomeLspId where
   SomeLspId :: !(LspId m) -> SomeLspId
 
@@ -45,3 +50,6 @@ instance Ord SomeLspId where
       go (IdString a) (IdString b) = a `compare` b
       go (IdInt    _) (IdString _) = LT
       go (IdString _) (IdInt    _) = GT
+
+instance Hashable SomeLspId where
+  hashWithSalt n (SomeLspId lspId) = hashWithSalt n lspId