improvement: Also don't dealias when inserting type or on hover

Author: tgodzik

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

@@ -110,7 +110,7 @@ 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
@@ -125,7 +125,7 @@ object HoverProvider:
                   if tpe != NoType then tpe
                   else tpw
 
-                printer.hoverSymbol(sym, finalTpe.deepDealias)
+                printer.hoverSymbol(sym, dealiased(finalTpe))
             end match
           end hoverString
 
@@ -134,7 +134,7 @@ 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 +161,7 @@ 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 +179,8 @@ object HoverProvider:
     end if
   end hover
 
+  private def dealiased(tpe: Type)(using Context): Type = if tpe.isNamedTupleType then tpe else tpe.deepDealias
+
   extension (pos: SourcePosition)
     private def isPoint: Boolean = pos.start == pos.end
 
@@ -194,7 +196,7 @@ 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 +222,9 @@ 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
       else tpe.deepDealias
 
     val printer = ShortenedTypePrinter(

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

@@ -970,6 +970,27 @@ 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,
+      """|import scala.NamedTuple.Concat
+         |def hello = (path = ".", num = 5)
+         |
+         |def test: Concat[(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 +745,35 @@ 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: Concat[(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 `value-of`: Unit =
     check(
       """|enum Foo(val key: String) {