Fix use of exported prefix

compiler/src/dotty/tools/dotc/ast/tpd.scala

@@ -1383,7 +1383,11 @@ object tpd extends Trees.Instance[Type] with TypedTreeInfo {
   /** Recover identifier prefix (e.g. this) if it exists */
   def desugarIdentPrefix(tree: Ident)(using Context): Tree = tree.tpe match {
     case TermRef(prefix: TermRef, _) =>
-      ref(prefix)
+      prefix.info match
+        case mt: MethodType if mt.paramInfos.isEmpty && mt.resultType.typeSymbol.is(Module) =>
+          ref(mt.resultType.typeSymbol.sourceModule)
+        case _ =>
+          ref(prefix)
     case TermRef(prefix: ThisType, _) =>
       This(prefix.cls)
     case _ =>

tests/pos/i13490.scala

@@ -0,0 +1,17 @@
+object MyApi {
+  enum MyEnum(a: Int) {
+    case A extends MyEnum(1)
+  }
+  case class Foo(a: MyEnum)
+}
+
+object Test {
+  export MyApi.*
+  import MyEnum.*
+  Foo(MyEnum.A) match {
+    case Foo(a) =>
+      a match {
+        case A =>
+      }
+  }
+}

tests/run/i13490.min.scala

@@ -0,0 +1,13 @@
+object MyTypes:
+  enum MyEnum:
+    case Foo
+    case Bar
+
+object MyApi:
+  export MyTypes.*
+
+object MyUse:
+  import MyApi.MyEnum.Foo
+  def foo = Foo
+
+@main def Test = assert(MyUse.foo.toString == "Foo")