From f31ad61adabe59da9006acc79334ccec453bf95d Mon Sep 17 00:00:00 2001
From: Katarzyna Marek <kasia@marek.net>
Date: Tue, 30 Apr 2024 14:07:54 +0200
Subject: [PATCH] fix: delias type members in hover

---
 .../meta/internal/pc/HoverProvider.scala      |  6 +-
 .../internal/mtags/MtagsEnrichments.scala     | 10 +++-
 .../scala/tests/hover/HoverDefnSuite.scala    | 10 +++-
 .../scala/tests/hover/HoverTermSuite.scala    | 55 +++++++++++++++++++
 4 files changed, 77 insertions(+), 4 deletions(-)

diff --git a/mtags/src/main/scala-2/scala/meta/internal/pc/HoverProvider.scala b/mtags/src/main/scala-2/scala/meta/internal/pc/HoverProvider.scala
index 714e6f3e75e..1dbe9cbfed6 100644
--- a/mtags/src/main/scala-2/scala/meta/internal/pc/HoverProvider.scala
+++ b/mtags/src/main/scala-2/scala/meta/internal/pc/HoverProvider.scala
@@ -238,7 +238,8 @@ class HoverProvider(
           lookupSymbol = name => context.lookupSymbol(name, _ => true) :: Nil,
           renames = re
         )
-        val prettyType = metalsToLongString(tpe.widen.finalResultType, history)
+        val prettyType =
+          metalsToLongString(tpe.widen.finalResultType.map(_.dealias), history)
         val lspRange = if (range.isRange) Some(range.toLsp) else None
         Some(
           new ScalaHover(
@@ -282,7 +283,8 @@ class HoverProvider(
         val flags = List(symbolFlagString(symbol), keyword, name)
           .filterNot(_.isEmpty)
           .mkString(" ")
-        val prettyType = metalsToLongString(tpe.widen.finalResultType, history)
+        val prettyType =
+          metalsToLongString(tpe.widen.finalResultType.map(_.dealias), history)
         val macroSuffix =
           if (symbol.isMacro) " = macro"
           else ""
diff --git a/mtags/src/main/scala-3/scala/meta/internal/mtags/MtagsEnrichments.scala b/mtags/src/main/scala-3/scala/meta/internal/mtags/MtagsEnrichments.scala
index 7cccab7d877..fa70710f208 100644
--- a/mtags/src/main/scala-3/scala/meta/internal/mtags/MtagsEnrichments.scala
+++ b/mtags/src/main/scala-3/scala/meta/internal/mtags/MtagsEnrichments.scala
@@ -21,8 +21,11 @@ import dotty.tools.dotc.core.Names.*
 import dotty.tools.dotc.core.StdNames.*
 import dotty.tools.dotc.core.SymDenotations.NoDenotation
 import dotty.tools.dotc.core.Symbols.*
+import dotty.tools.dotc.core.Types.AliasingBounds
 import dotty.tools.dotc.core.Types.AppliedType
+import dotty.tools.dotc.core.Types.RefinedType
 import dotty.tools.dotc.core.Types.Type
+import dotty.tools.dotc.core.Types.TypeBounds
 import dotty.tools.dotc.interactive.Interactive
 import dotty.tools.dotc.interactive.InteractiveDriver
 import dotty.tools.dotc.util.SourcePosition
@@ -375,8 +378,13 @@ object MtagsEnrichments extends ScalametaCommonEnrichments:
     def metalsDealias(using Context): Type =
       tpe.dealias match
         case app @ AppliedType(tycon, params) =>
-          // we dealias applied type params by hand, because `dealias` doesn't do it
           AppliedType(tycon, params.map(_.metalsDealias))
+        case aliasingBounds: AliasingBounds =>
+          aliasingBounds.derivedAlias(aliasingBounds.alias.dealias)
+        case TypeBounds(lo, hi) =>
+          TypeBounds(lo.dealias, hi.dealias)
+        case RefinedType(parent, name, refinedInfo) =>
+          RefinedType(parent.dealias, name, refinedInfo.metalsDealias)
         case dealised => dealised
 
 end MtagsEnrichments
diff --git a/tests/cross/src/test/scala/tests/hover/HoverDefnSuite.scala b/tests/cross/src/test/scala/tests/hover/HoverDefnSuite.scala
index cc78de43532..151ba57bbd1 100644
--- a/tests/cross/src/test/scala/tests/hover/HoverDefnSuite.scala
+++ b/tests/cross/src/test/scala/tests/hover/HoverDefnSuite.scala
@@ -167,7 +167,15 @@ class HoverDefnSuite extends BaseHoverSuite {
     """|object a {
        |  type <<M@@yType>> = Int
        |}""".stripMargin,
-    "type MyType: MyType".hover
+    """|**Expression type**:
+       |```scala
+       |Int
+       |```
+       |**Symbol signature**:
+       |```scala
+       |type MyType: MyType
+       |```
+       |""".stripMargin
   )
 
   check(
diff --git a/tests/cross/src/test/scala/tests/hover/HoverTermSuite.scala b/tests/cross/src/test/scala/tests/hover/HoverTermSuite.scala
index 38f5f11a210..38e90114900 100644
--- a/tests/cross/src/test/scala/tests/hover/HoverTermSuite.scala
+++ b/tests/cross/src/test/scala/tests/hover/HoverTermSuite.scala
@@ -718,4 +718,59 @@ class HoverTermSuite extends BaseHoverSuite {
       |""".stripMargin,
     "".stripMargin
   )
+
+  check(
+    "dealias type members in val definition",
+    """object Obj {
+      |  trait A extends Sup { self =>
+      |    type T
+      |    def member : T 
+      |  }
+      |  val x: A { type T = Int} = ???
+      |
+      |  <<x.mem@@ber>>
+      |
+      |}""".stripMargin,
+    """def member: Int""".stripMargin.hover
+  )
+
+  check(
+    "dealias-type-members-in-argument-of-anonymous-function",
+    """object Obj {
+      |  trait A extends Sup { self =>
+      |    type T
+      |    def fun(
+      |        body: A { type T = self.T} => Unit
+      |    ) =
+      |      ()
+      |  }
+      |  val x: A { type T = Int} = ???
+      |
+      |  x.fun { <<y@@y>> =>
+      |  ()
+      |  }
+      |
+      |}""".stripMargin,
+    """|**Expression type**:
+       |```scala
+       |A{type T = Int}
+       |```
+       |**Symbol signature**:
+       |```scala
+       |yy: A{type T = dealias-type-members-in-argument-of-anonymous-function.Obj.x.T}
+       |```
+       |""".stripMargin,
+    compat = Map(
+      "3" -> """|**Expression type**:
+                |```scala
+                |A{type T = Int}
+                |```
+                |**Symbol signature**:
+                |```scala
+                |yy: A{type T = x.T}
+                |```
+                |""".stripMargin
+    )
+  )
+
 }