From 2a8d00e81e583c84967596ff863ebca6039c6350 Mon Sep 17 00:00:00 2001
From: Katarzyna Marek <kasia@marek.net>
Date: Thu, 5 Oct 2023 09:41:12 +0200
Subject: [PATCH] bugfix: match completions for type aliases scala 3

---
 .../pc/completions/MatchCaseCompletions.scala |  7 ++-
 .../scala/tests/pc/CompletionMatchSuite.scala | 48 +++++++++++++++++++
 2 files changed, 51 insertions(+), 4 deletions(-)

diff --git a/mtags/src/main/scala-3/scala/meta/internal/pc/completions/MatchCaseCompletions.scala b/mtags/src/main/scala-3/scala/meta/internal/pc/completions/MatchCaseCompletions.scala
index 0d701c94cc2..e256a137618 100644
--- a/mtags/src/main/scala-3/scala/meta/internal/pc/completions/MatchCaseCompletions.scala
+++ b/mtags/src/main/scala-3/scala/meta/internal/pc/completions/MatchCaseCompletions.scala
@@ -39,7 +39,6 @@ object CaseKeywordCompletion:
    * @param selector `selector` of `selector match { cases }`  or `EmptyTree` when
    *                 not in a match expression (for example `List(1).foreach { case@@ }`.
    * @param completionPos the position of the completion
-   * @param typedtree typed tree of the file, used for generating auto imports
    * @param indexedContext
    * @param config
    * @param parent the parent tree node of the pattern match, for example `Apply(_, _)` when in
@@ -88,7 +87,7 @@ object CaseKeywordCompletion:
             new Parents(NoType, definitions)
       case sel => new Parents(sel.tpe, definitions)
 
-    val selectorSym = parents.selector.typeSymbol
+    val selectorSym = parents.selector.metalsDealias.typeSymbol
 
     // Special handle case when selector is a tuple or `FunctionN`.
     if definitions.isTupleClass(selectorSym) || definitions.isFunctionClass(
@@ -240,8 +239,8 @@ object CaseKeywordCompletion:
       clientSupportsSnippets,
     )
     val tpe = selector.tpe.widen.bounds.hi match
-      case tr @ TypeRef(_, _) => tr.underlying
-      case t => t
+      case tr @ TypeRef(_, _) => tr.underlying.metalsDealias
+      case t => t.metalsDealias
 
     val sortedSubclasses =
       val subclasses =
diff --git a/tests/cross/src/test/scala/tests/pc/CompletionMatchSuite.scala b/tests/cross/src/test/scala/tests/pc/CompletionMatchSuite.scala
index 256a67c920b..3ff6f65ac1b 100644
--- a/tests/cross/src/test/scala/tests/pc/CompletionMatchSuite.scala
+++ b/tests/cross/src/test/scala/tests/pc/CompletionMatchSuite.scala
@@ -734,4 +734,52 @@ class CompletionMatchSuite extends BaseCompletionSuite {
     filter = _.contains("exhaustive"),
   )
 
+  checkEdit(
+    "type-alias".tag(IgnoreScala2),
+    s"""|object O {
+        | type Id[A] = A
+        |
+        | enum Animal:
+        |   case Cat, Dog
+        | 
+        | val animal: Id[Animal] = ???
+        |
+        | animal ma@@
+        |}
+        |""".stripMargin,
+    s"""object O {
+       | type Id[A] = A
+       |
+       | enum Animal:
+       |   case Cat, Dog
+       | 
+       | val animal: Id[Animal] = ???
+       |
+       | animal match
+       |\tcase Animal.Cat => $$0
+       |\tcase Animal.Dog =>
+       |
+       |}
+       |""".stripMargin,
+    filter = _.contains("exhaustive"),
+  )
+
+  check(
+    "type-alias2".tag(IgnoreScala2),
+    s"""|object O {
+        | type Id[A] = A
+        |
+        | enum Animal:
+        |   case Cat, Dog
+        | 
+        | val animal: Id[Animal] = ???
+        |
+        |  animal match {
+        |  \tcase Animal.C@@
+        |  }
+        |}
+        |""".stripMargin,
+    "Cat: Animal",
+  )
+
 }