Deduplicate exported symbols.

Author: phischu

src/Language/Haskell/Names/Exports.hs

@@ -16,16 +16,16 @@ import Language.Haskell.Names.ScopeUtils
 import Language.Haskell.Names.SyntaxUtils
 import Language.Haskell.Names.ModuleSymbols
 import Language.Haskell.Names.GlobalSymbolTable as Global
-import Data.List (nub)
+import qualified Data.Set as Set (fromList, toList)
 
 
 -- | Compute the list of symbols the given module exports using the given
 -- table of symbols that are in scope in that module.
 exportedSymbols :: (Data l, Eq l) => Global.Table -> Module l -> [Symbol]
-exportedSymbols globalTable modul = case getExportSpecList modul of
+exportedSymbols globalTable modul = nubSymbols (case getExportSpecList modul of
   Nothing -> moduleSymbols globalTable modul
   Just (ExportSpecList _ exportSpecs) ->
-    concatMap (exportSpecSymbols globalTable) exportSpecs
+    concatMap (exportSpecSymbols globalTable) exportSpecs)
 
 exportSpecSymbols :: Global.Table -> ExportSpec l -> [Symbol]
 exportSpecSymbols globalTable exportSpec =
@@ -70,7 +70,7 @@ annotateExportSpec globalTable exportSpec =
       [] -> scopeError (ENotInScope qn) exportSpec
       [symbol] ->
         let
-          subSymbols = nub (do
+          subSymbols = nubSymbols (do
               subSymbol <- concat (Map.elems globalTable)
               Just subSymbolParentName <- return $ symbolParent subSymbol
               guard (subSymbolParentName == symbolName symbol)
@@ -109,3 +109,11 @@ annotateExportSpec globalTable exportSpec =
           (UnQual _ _, symbols) <- Map.toList globalTable
           symbols)
 
+
+nubSymbols :: [Symbol] -> [Symbol]
+nubSymbols = loop Set.empty where
+  loop _ [] = []
+  loop a (b : c) = if Set.member b a
+    then loop a c
+    else b : loop (Set.insert b a) c
+

tests/exports/DataFamilies.hs.golden

@@ -17,11 +17,6 @@
     , symbolName = Ident () "method1"
     , className = Ident () "ListLike"
     }
-, DataFam
-    { symbolModule = ModuleName () "DataFamilies"
-    , symbolName = Ident () "Vector"
-    , associate = Nothing
-    }
 , Constructor
     { symbolModule = ModuleName () "DataFamilies"
     , symbolName = Ident () "U_Vector"

tests/exports/DuplicateExports.hs

@@ -0,0 +1,4 @@
+module DuplicateExports (A(A), A) where
+
+data A = A
+

tests/exports/DuplicateExports.hs.golden

@@ -0,0 +1,10 @@
+[ Data
+    { symbolModule = ModuleName () "DuplicateExports"
+    , symbolName = Ident () "A"
+    }
+, Constructor
+    { symbolModule = ModuleName () "DuplicateExports"
+    , symbolName = Ident () "A"
+    , typeName = Ident () "A"
+    }
+]