diff --git a/compiler/daml-lf-tools/src/DA/Daml/LF/TypeChecker/NameCollision.hs b/compiler/daml-lf-tools/src/DA/Daml/LF/TypeChecker/NameCollision.hs
index f7d6e9b7bd3b..99a3f4f7e762 100644
--- a/compiler/daml-lf-tools/src/DA/Daml/LF/TypeChecker/NameCollision.hs
+++ b/compiler/daml-lf-tools/src/DA/Daml/LF/TypeChecker/NameCollision.hs
@@ -33,7 +33,7 @@ data Name
     | NRecordType ModuleName TypeConName
     | NVariantType ModuleName TypeConName
     | NEnumType ModuleName TypeConName
-    | NTypeSynonym ModuleName TypeConName
+    | NTypeSynonym ModuleName TypeSynName
     | NVariantCon ModuleName TypeConName VariantConName
     | NEnumCon ModuleName TypeConName VariantConName
     | NField ModuleName TypeConName FieldName
@@ -58,7 +58,7 @@ displayName = \case
         T.concat ["variant ", dot m, ":", dot t]
     NEnumType (ModuleName m) (TypeConName t) ->
         T.concat ["enum ", dot m, ":", dot t]
-    NTypeSynonym (ModuleName m) (TypeConName t) ->
+    NTypeSynonym (ModuleName m) (TypeSynName t) ->
         T.concat ["synonym ", dot m, ":", dot t]
     NVariantCon (ModuleName m) (TypeConName t) (VariantConName v) ->
         T.concat ["variant constructor ", dot m, ":", dot t, ".", v]
@@ -112,7 +112,7 @@ fullyResolve = FRName . map T.toLower . \case
         m ++ t
     NEnumType (ModuleName m) (TypeConName t) ->
         m ++ t
-    NTypeSynonym (ModuleName m) (TypeConName t) ->
+    NTypeSynonym (ModuleName m) (TypeSynName t) ->
         m ++ t
     NVariantCon (ModuleName m) (TypeConName t) (VariantConName v) ->
         m ++ t ++ [v]
@@ -193,6 +193,10 @@ checkTemplate moduleName Template{..} = do
     forM_ tplChoices $ \TemplateChoice{..} ->
         checkName (NChoice moduleName tplTypeCon chcName)
 
+checkSynonym :: ModuleName -> DefTypeSyn -> NCMonad ()
+checkSynonym moduleName DefTypeSyn{..} =
+    checkName (NTypeSynonym moduleName synName)
+
 checkModuleName :: Module -> NCMonad ()
 checkModuleName m =
     checkName (NModule (moduleName m))
@@ -207,6 +211,8 @@ checkModuleBody m = do
         checkDataType (moduleName m) dataType
     forM_ (moduleTemplates m) $ \tpl ->
         checkTemplate (moduleName m) tpl
+    forM_ (moduleSynonyms m) $ \synonym ->
+        checkSynonym (moduleName m) synonym
 
 checkModule :: Module -> NCMonad ()
 checkModule m = do
@@ -238,13 +244,12 @@ isAscendant (ModuleName xs) (ModuleName ys) =
 -- name collision condition.
 checkModuleDeps :: World -> Module -> NCMonad ()
 checkModuleDeps world mod0 = do
-    -- TODO #3616:  check for collisions with TypeSynonyms
     let package = getWorldSelf world
         modules = NM.toList (packageModules package)
         name0 = moduleName mod0
         ascendants = filter (flip isAscendant name0 . moduleName) modules
         descendants = filter (isAscendant name0 . moduleName) modules
-    mapM_ checkModuleBody ascendants -- only need type names
+    mapM_ checkModuleBody ascendants -- only need type and synonym names
     mapM_ checkModuleName descendants -- only need module names
     mapM_ checkVirtualModuleName (concatMap virtualModuleNames descendants)
     checkModule mod0