improvement: Don't dealias named tuples for type hints

presentation-compiler/src/main/dotty/tools/pc/HoverProvider.scala

@@ -110,22 +110,23 @@ object HoverProvider:
             if symbol.name == nme.selectDynamic || symbol.name == nme.applyDynamic =>
           fallbackToDynamics(path, printer, contentType)
         case symbolTpes @ ((symbol, tpe, None) :: _) =>
-          val exprTpw = tpe.widenTermRefExpr.deepDealias
+          val exprTpw = dealiased(tpe.widenTermRefExpr)
           val hoverString =
             tpw match
               // https://github.com/scala/scala3/issues/8891
               case tpw: ImportType =>
                 printer.hoverSymbol(symbol, symbol.paramRef)
               case _ =>
-                val (tpe, sym) =
+                val (innerTpe, sym) =
                   if symbol.isType then (symbol.typeRef, symbol)
                   else enclosing.head.seenFrom(symbol)
 
                 val finalTpe =
-                  if tpe != NoType then tpe
+                  if tpe.isNamedTupleType then tpe.widenTermRefExpr
+                  else if innerTpe != NoType then innerTpe
                   else tpw
 
-                printer.hoverSymbol(sym, finalTpe.deepDealias)
+                printer.hoverSymbol(sym, dealiased(finalTpe))
             end match
           end hoverString
 
@@ -134,7 +135,7 @@ object HoverProvider:
             .map(_.docstring())
             .mkString("\n")
 
-          val expresionTypeOpt = 
+          val expresionTypeOpt =
             if symbol.name == StdNames.nme.??? then
               InferExpectedType(search, driver, params).infer()
             else printer.expressionType(exprTpw)
@@ -161,7 +162,7 @@ object HoverProvider:
               ju.Optional.empty().nn
           end match
         case (_, tpe, Some(namedTupleArg)) :: _ =>
-          val exprTpw = tpe.widenTermRefExpr.deepDealias
+          val exprTpw = dealiased(tpe.widenTermRefExpr)
           printer.expressionType(exprTpw) match
             case Some(tpe) =>
               ju.Optional.of(
@@ -179,6 +180,8 @@ object HoverProvider:
     end if
   end hover
 
+  private def dealiased(tpe: Type)(using Context): Type = if tpe.isNamedTupleType then tpe.deepDealias.simplified else tpe.deepDealias
+
   extension (pos: SourcePosition)
     private def isPoint: Boolean = pos.start == pos.end
 
@@ -194,7 +197,7 @@ object HoverProvider:
             val resultType =
               rest match
                 case Select(_, asInstanceOf) :: TypeApply(_, List(tpe)) :: _ if asInstanceOf == nme.asInstanceOfPM =>
-                    tpe.tpe.widenTermRefExpr.deepDealias
+                  dealiased(tpe.tpe.widenTermRefExpr)
                 case _ if n == nme.selectDynamic => tpe.resultType
                 case _ => tpe
 
@@ -220,9 +223,9 @@ object HoverProvider:
             findRefinement(parent)
           case _ => None
 
-      val refTpe = sel.typeOpt.widen.deepDealias match
+      val refTpe = dealiased(sel.typeOpt.widen) match
         case r: RefinedType => Some(r)
-        case t: (TermRef | TypeProxy) => Some(t.termSymbol.info.deepDealias)
+        case t: (TermRef | TypeProxy) => Some(dealiased(t.termSymbol.info))
         case _ => None
 
       refTpe.flatMap(findRefinement).asJava

presentation-compiler/src/main/dotty/tools/pc/InferredTypeProvider.scala

@@ -99,8 +99,8 @@ final class InferredTypeProvider(
           case AppliedType(tycon, args) =>
             isInScope(tycon) && args.forall(isInScope)
           case _ => true
-      if isInScope(tpe)
-      then tpe
+      if isInScope(tpe) then tpe
+      else if tpe.isNamedTupleType then tpe.dealias.simplified
       else tpe.deepDealias
 
     val printer = ShortenedTypePrinter(

presentation-compiler/src/main/dotty/tools/pc/MetalsInteractive.scala

@@ -206,7 +206,7 @@ object MetalsInteractive:
       // Handle select on named tuples
       case (Apply(Apply(TypeApply(fun, List(t1, t2)), List(ddef)), List(Literal(Constant(i: Int))))) :: _
         if fun.symbol.exists && fun.symbol.name == nme.apply &&
-            fun.symbol.owner.exists && fun.symbol.owner == getModuleIfDefined("scala.NamedTuple").moduleClass =>
+            fun.symbol.owner.exists && fun.symbol.owner == defn.NamedTupleModule.moduleClass =>
         def getIndex(t: Tree): Option[Type] =
           t.tpe.dealias match
             case AppliedType(_, args) => args.get(i)

presentation-compiler/src/main/dotty/tools/pc/PcInlayHintsProvider.scala

@@ -142,7 +142,7 @@ class PcInlayHintsProvider(
       if isInScope(tpe) then tpe
       else tpe.deepDealias(using indexedCtx.ctx)
 
-    val dealiased = optDealias(tpe)
+    val dealiased = if tpe.isNamedTupleType then optDealias(tpe).simplified else optDealias(tpe)
     val tpeStr = printer.tpe(dealiased)
     val usedRenames = printer.getUsedRenames
     val parts = partsFromType(dealiased, usedRenames)

presentation-compiler/src/main/dotty/tools/pc/printer/ShortenedTypePrinter.scala

@@ -214,7 +214,9 @@ class ShortenedTypePrinter(
       case ConstantType(const) => toText(const)
       case _ => toTextRef(tp) ~ ".type"
 
-  def tpe(tpe: Type): String = toText(tpe).mkString(defaultWidth, false)
+  def tpe(tpe: Type): String =
+    val dealiased = if (tpe.isNamedTupleType) tpe.deepDealias.simplified else tpe
+    toText(dealiased).mkString(defaultWidth, false)
 
   def hoverSymbol(sym: Symbol, info: Type)(using Context): String =
     val typeSymbol = info.typeSymbol

presentation-compiler/test/dotty/tools/pc/tests/completion/CompletionSuite.scala

@@ -2041,6 +2041,21 @@ class CompletionSuite extends BaseCompletionSuite:
       filter = _.contains("name")
     )
 
+  @Test def `namedTuple-completions-2` =
+    check(
+      """|import scala.NamedTuple.*
+         |
+         |def hello = (path = ".", num = 5)++ (line = 1)
+         |val hello2 = (path = ".", num = 5)++ (line = 1)
+         |
+         |@main def bla =
+         |   hello@@
+         |""".stripMargin,
+      """|hello2: (path : String, num : Int, line : Int)
+         |hello: (path : String, num : Int, line : Int)
+      """.stripMargin,
+    )
+
   @Test def `Selectable with namedTuple Fields member` =
     check(
       """|import scala.NamedTuple.*

presentation-compiler/test/dotty/tools/pc/tests/edit/InsertInferredTypeSuite.scala

@@ -970,6 +970,26 @@ class InsertInferredTypeSuite extends BaseCodeActionSuite:
          |""".stripMargin
     )
 
+  @Test def `named-tuples` =
+    checkEdit(
+      """|def hello = (path = ".", num = 5)
+         |
+         |def <<test>> =
+         |  hello ++ (line = 1)
+         |
+         |@main def bla =
+         |   val x: (path: String, num: Int, line: Int) = test
+         |""".stripMargin,
+      """|def hello = (path = ".", num = 5)
+         |
+         |def test: (path : String, num : Int, line : Int) =
+         |  hello ++ (line = 1)
+         |
+         |@main def bla =
+         |   val x: (path: String, num: Int, line: Int) = test
+         |""".stripMargin
+    )
+
   def checkEdit(
       original: String,
       expected: String

presentation-compiler/test/dotty/tools/pc/tests/hover/HoverTermSuite.scala

@@ -745,6 +745,47 @@ class HoverTermSuite extends BaseHoverSuite:
       "name: String".hover
     )
 
+
+  @Test def `named-tuples3`: Unit =
+    check(
+      """|def hello = (path = ".", num = 5)
+         |
+         |def test =
+         |  hello ++ (line = 1)
+         |
+         |@main def bla =
+         |   val x: (path: String, num: Int, line: Int) = t@@est
+         |""".stripMargin,
+      "def test: (path : String, num : Int, line : Int)".hover
+    )
+
+
+  @Test def `named-tuples4`: Unit =
+    check(
+      """|def hello = (path = ".", num = 5)
+         |
+         |def test =
+         |  hel@@lo ++ (line = 1)
+         |
+         |@main def bla =
+         |   val x: (path: String, num: Int, line: Int) = test
+         |""".stripMargin,
+      "def hello: (path : String, num : Int)".hover
+    )
+
+  @Test def `named-tuples5`: Unit =
+    check(
+      """|def hello = (path = ".", num = 5)
+         |
+         |def test(x: (path: String, num: Int)) =
+         |  x ++ (line = 1)
+         |
+         |@main def bla =
+         |   val x: (path: String, num: Int, line: Int) = t@@est(hello)
+         |""".stripMargin,
+      "def test(x: (path : String, num : Int)): (path : String, num : Int, line : Int)".hover
+    )
+
   @Test def `value-of`: Unit =
     check(
       """|enum Foo(val key: String) {

presentation-compiler/test/dotty/tools/pc/tests/inlayHints/InlayHintsSuite.scala

@@ -1055,4 +1055,24 @@ class InlayHintsSuite extends BaseInlayHintsSuite {
          |}
          |""".stripMargin
     )
+
+  @Test def `named-tuples` =
+    check(
+      """|def hello = (path = ".", num = 5)
+         |
+         |def test =
+         |  hello ++ (line = 1)
+         |
+         |@main def bla =
+         |   val x: (path: String, num: Int, line: Int) = test
+         |""".stripMargin,
+      """|def hello/*: (path : String<<java/lang/String#>>, num : Int<<scala/Int#>>)*/ = (path = ".", num = 5)/*[(String<<java/lang/String#>>, Int<<scala/Int#>>)]*/
+         |
+         |def test/*: (path : String<<java/lang/String#>>, num : Int<<scala/Int#>>, line : Int<<scala/Int#>>)*/ =
+         |  hello ++/*[Tuple1<<scala/Tuple1#>>["line"], Tuple1<<scala/Tuple1#>>[Int<<scala/Int#>>]]*/ (line = 1)/*(using refl<<scala/`<:<`.refl().>>)*//*[Tuple1<<scala/Tuple1#>>[Int<<scala/Int#>>]]*/
+         |
+         |@main def bla/*: Unit<<scala/Unit#>>*/ =
+         |   val x: (path: String, num: Int, line: Int) = test
+         |""".stripMargin
+    )
 }