A bug in auto extending import

[berberman]

Your environment

Output of haskell-language-server --probe-tools or haskell-language-server-wrapper --probe-tools:

haskell-language-server version: 0.9.0.0 (GHC: 8.10.3) (PATH: /home/berberman/.cabal/store/ghc-8.10.3/haskell-language-server-0.9.0.0-fc3fc5c6bb9dbe9d059eeb2e8438fa71dbd18c178e95fd1b51ebde0ab2e9d440/bin/haskell-language-server)
Tool versions found on the $PATH
cabal:          3.2.0.0
stack:          Not found
ghc:            8.10.3

Which lsp-client do you use:
vscode

Steps to reproduce

Create A.hs:

module A where

data TyCon = DataConA | DataConB

And import TyCon(..) in another module:

module Test where

import A (TyCon (..))

Expected behaviour

DataConA is already in scope, so there's no need to extend the import list.

Actual behaviour