NoUnused.Exports: Fixed types being incorrectly reported

CHANGELOG.md

@@ -2,6 +2,8 @@
 
 ## [Unreleased]
 
+Fixed issues in [`NoUnused.Exports`] where type aliases and custom types would incorrectly be reported. Thanks Eric from the Elm Slack for reporting!
+
 ## [1.2.1] - 2024-04-01
 
 - [`NoUnused.Exports`] now reports (and removes using `--fix`) elements even if the module is exposing everything (`module X exposing (..)`) if the element is unused both locally and across the project. Thanks [@tfausak](https://github.com/tfausak).

src/NoUnused/Exports.elm

@@ -1655,7 +1655,12 @@ expressionVisitor node moduleContext =
                         []
                         declarations
             in
-            { moduleContext | used = List.foldl Set.insert moduleContext.used used }
+            List.foldl
+                (\( moduleName, name ) ctx ->
+                    registerLocalValueWithRealModuleName moduleName name ctx
+                )
+                moduleContext
+                used
 
         Expression.CaseExpression { cases } ->
             let
@@ -1666,7 +1671,12 @@ expressionVisitor node moduleContext =
                         (List.map Tuple.first cases)
                         []
             in
-            { moduleContext | used = List.foldl Set.insert moduleContext.used usedConstructors }
+            List.foldl
+                (\( moduleName, name ) ctx ->
+                    registerLocalValueWithRealModuleName moduleName name ctx
+                )
+                moduleContext
+                usedConstructors
 
         _ ->
             moduleContext
@@ -1675,7 +1685,17 @@ expressionVisitor node moduleContext =
 registerLocalValue : Range -> String -> ModuleContext -> ModuleContext
 registerLocalValue range name moduleContext =
     case ModuleNameLookupTable.moduleNameAt moduleContext.lookupTable range of
-        Just [] ->
+        Just moduleName ->
+            registerLocalValueWithRealModuleName (String.join "." moduleName) name moduleContext
+
+        Nothing ->
+            moduleContext
+
+
+registerLocalValueWithRealModuleName : String -> String -> ModuleContext -> ModuleContext
+registerLocalValueWithRealModuleName realModuleName name moduleContext =
+    case realModuleName of
+        "" ->
             case Dict.get name moduleContext.constructorNameToTypeName of
                 Just typeName ->
                     { moduleContext | exposed = Dict.remove typeName moduleContext.exposed }
@@ -1693,11 +1713,8 @@ registerLocalValue range name moduleContext =
                     else
                         moduleContext
 
-        Just moduleName ->
-            registerAsUsed ( String.join "." moduleName, name ) moduleContext
-
-        Nothing ->
-            moduleContext
+        moduleName ->
+            registerAsUsed ( moduleName, name ) moduleContext
 
 
 findUsedConstructors : ModuleNameLookupTable -> List (Node Pattern) -> List ( ModuleNameStr, String ) -> List ( ModuleNameStr, String )

tests/NoUnused/ExportsTest.elm

@@ -1877,6 +1877,78 @@ main = NotReported.used
                 , """
 port module NotReported exposing (..)
 port used : ()
+"""
+                ]
+                    |> Review.Test.runOnModulesWithProjectData application rule
+                    |> Review.Test.expectNoErrors
+        , test "should not remove a type alias used in a local let binding type annotation" <|
+            \() ->
+                [ """
+module Main exposing (main)
+import Tertiary
+main = Tertiary.func 1 2
+"""
+                , """
+module Tertiary exposing (..)
+
+type alias Tertiary = {}
+
+func : Int -> Int -> Int
+func a b =
+    let
+        perhapsTertiary : Int -> Maybe Tertiary
+        perhapsTertiary a =
+            if a > 5 then
+                Just {}
+            else
+                Nothing
+    in
+    case perhapsTertiary 4 of
+        Just _ ->
+            a + b
+
+        Nothing ->
+            a - 4
+"""
+                ]
+                    |> Review.Test.runOnModulesWithProjectData application rule
+                    |> Review.Test.expectNoErrors
+        , test "should not remove a type used in a local let destructuring" <|
+            \() ->
+                [ """
+module Main exposing (main)
+import Tertiary
+main = Tertiary.func 1
+"""
+                , """
+module Tertiary exposing (..)
+
+type Wrapper = WrapperConstructor Int
+
+func foo =
+    let
+        (WrapperConstructor int) = foo
+    in
+    int
+"""
+                ]
+                    |> Review.Test.runOnModulesWithProjectData application rule
+                    |> Review.Test.expectNoErrors
+        , test "should not custom type that is being pattern matched on locally" <|
+            \() ->
+                [ """
+module Main exposing (main)
+import Tertiary
+main = Tertiary.func foo
+"""
+                , """
+module Tertiary exposing (..)
+
+type Used = X
+
+func foo =
+    case foo of
+        X -> 1
 """
                 ]
                     |> Review.Test.runOnModulesWithProjectData application rule