Custom-setups completion in cabal files

Author: vidit-od

plugins/hls-cabal-plugin/src/Ide/Plugin/Cabal/Completion/Data.hs

@@ -88,7 +88,8 @@ stanzaKeywordMap =
       ("common", libExecTestBenchCommons Library),
       ("common", libExecTestBenchCommons Common),
       ("flag", flagFields),
-      ("source-repository", sourceRepositoryFields)
+      ("source-repository", sourceRepositoryFields),
+      ("custom-setup", customSetupFields)
     ]
 
 libraryFields :: Map KeyWordName Completer
@@ -236,6 +237,15 @@ libExecTestBenchCommons st =
         -- but not have erased the "common" stanza.
         noopCompleter
 
+customSetupFields :: Map KeyWordName Completer
+customSetupFields =
+  Map.fromList
+    [ ("setup-depends:", noopCompleter)
+    , ("build-depends:", noopCompleter)
+    , ("build-tools:", noopCompleter)
+    , ("default-language:", constantCompleter ["GHC2021", "Haskell2010", "Haskell98"])
+    ]
+
 -- | Returns all possible language extensions including disabled ones.
 allExtensions :: [Extension]
 allExtensions =