Merge branch 'master' into fix-parsing-message-header

Author: saitmilk

README.md

@@ -24,6 +24,7 @@ typescript definitions laid out in the specification
 - [haskell-language-server](https://github.com/haskell/haskell-language-server)
 - [dhall-lsp-server](https://github.com/dhall-lang/dhall-haskell/tree/master/dhall-lsp-server#readme)
 - [swarm](https://github.com/byorgey/swarm/blob/main/src/Swarm/Language/LSP.hs)
+- [curry-language-server](https://github.com/fwcd/curry-language-server)
 
 ## Example language servers
 There are two example language servers in the `lsp/example/` folder. `Simple.hs` provides a minimal example:

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

@@ -138,7 +138,7 @@ instance ToJSON SomeRegistration where
 instance FromJSON SomeRegistration where
   parseJSON = withObject "Registration" $ \o -> do
     SomeClientMethod m <- o .: "method"
-    r <- Registration <$> o .: "id" <*> pure m <*> regHelper m (o .: "registerOptions")
+    r <- Registration <$> o .: "id" <*> pure m <*> regHelper m (o .:? "registerOptions")
     pure (SomeRegistration r)
 
 instance Eq SomeRegistration where