bugfix: Fix enumeration issues when Value is imported (#23124)

This is still not a perfect fix, since we add the full prefix, but
that's the current status quo. Making prefixes shorter is something we
need to work on separately.

Author: tgodzik

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

@@ -23,13 +23,13 @@ sealed trait IndexedContext:
   given ctx: Context
   def scopeSymbols: List[Symbol]
   def rename(sym: Symbol): Option[String]
-  def findSymbol(name: Name): Option[List[Symbol]]
+  def findSymbol(name: Name, fromPrefix: Option[Type] = None): Option[List[Symbol]]
   def findSymbolInLocalScope(name: String): Option[List[Symbol]]
 
-  final def lookupSym(sym: Symbol): Result =
+  final def lookupSym(sym: Symbol, fromPrefix: Option[Type] = None): Result =
     def all(symbol: Symbol): Set[Symbol] = Set(symbol, symbol.companionModule, symbol.companionClass, symbol.companion).filter(_ != NoSymbol)
     val isRelated = all(sym) ++ all(sym.dealiasType)
-    findSymbol(sym.name) match
+    findSymbol(sym.name, fromPrefix) match
       case Some(symbols) if symbols.exists(isRelated) => Result.InScope
       case Some(symbols) if symbols.exists(isTermAliasOf(_, sym)) => Result.InScope
       case Some(symbols) if symbols.map(_.dealiasType).exists(isRelated) => Result.InScope
@@ -81,7 +81,7 @@ object IndexedContext:
 
   case object Empty extends IndexedContext:
     given ctx: Context = NoContext
-    def findSymbol(name: Name): Option[List[Symbol]] = None
+    def findSymbol(name: Name, fromPrefix: Option[Type]): Option[List[Symbol]] = None
     def findSymbolInLocalScope(name: String): Option[List[Symbol]] = None
     def scopeSymbols: List[Symbol] = List.empty
     def rename(sym: Symbol): Option[String] = None
@@ -111,11 +111,31 @@ object IndexedContext:
 
     override def findSymbolInLocalScope(name: String): Option[List[Symbol]] =
       names.get(name).map(_.map(_.symbol).toList).filter(_.nonEmpty)
-    def findSymbol(name: Name): Option[List[Symbol]] =
+    def findSymbol(name: Name, fromPrefix: Option[Type]): Option[List[Symbol]] =
       names
         .get(name.show)
-        .map(_.map(_.symbol).toList)
-        .orElse(defaultScopes(name))
+        .map { denots =>
+          def skipThisType(tp: Type): Type = tp match
+            case ThisType(prefix) => skipThisType(prefix)
+            case _ => tp
+
+          val filteredDenots = fromPrefix match
+            case Some(prefix) =>
+              val target = skipThisType(prefix)
+              denots.filter { denot =>
+                denot.prefix == NoPrefix ||
+                (denot.prefix match
+                  case tref: TermRef =>
+                    tref.termSymbol.info <:< target
+                  case otherPrefix =>
+                    otherPrefix <:< target
+                )
+              }
+            case None => denots
+
+          filteredDenots.map(_.symbol).toList
+        }
+        .orElse(defaultScopes(name)).filter(_.nonEmpty)
 
     def scopeSymbols: List[Symbol] =
       names.values.flatten.map(_.symbol).toList

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

@@ -94,7 +94,8 @@ final class InferredTypeProvider(
         tpe match
           case tref: TypeRef =>
             indexedCtx.lookupSym(
-              tref.currentSymbol
+              tref.currentSymbol,
+              Some(tref.prefix)
             ) == IndexedContext.Result.InScope
           case AppliedType(tycon, args) =>
             isInScope(tycon) && args.forall(isInScope)
@@ -136,7 +137,6 @@ final class InferredTypeProvider(
             findNamePos(sourceText, vl, keywordOffset).endPos.toLsp
           adjustOpt.foreach(adjust => endPos.setEnd(adjust.adjustedEndPos))
           val spaceBefore = name.isOperatorName
-
           new TextEdit(
             endPos,
             printTypeAscription(optDealias(tpt.typeOpt), spaceBefore) + {

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

@@ -174,14 +174,13 @@ class ShortenedTypePrinter(
         res.toPrefixText
     }
 
-
   override def toTextPrefixOf(tp: NamedType): Text = controlled {
     val maybeRenamedPrefix: Option[Text] = findRename(tp)
     def trimmedPrefix: Text =
       if !tp.designator.isInstanceOf[Symbol] && tp.typeSymbol == NoSymbol then
         super.toTextPrefixOf(tp)
       else
-        indexedCtx.lookupSym(tp.symbol) match
+        indexedCtx.lookupSym(tp.symbol, Some(tp.prefix)) match
           case _ if indexedCtx.rename(tp.symbol).isDefined => Text()
           // symbol is missing and is accessible statically, we can import it and add proper prefix
           case Result.Missing if isAccessibleStatically(tp.symbol) =>

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

@@ -990,6 +990,72 @@ class InsertInferredTypeSuite extends BaseCodeActionSuite:
          |""".stripMargin
     )
 
+  @Test def `enums` =
+    checkEdit(
+      """|object EnumerationValue:
+         |  object Day extends Enumeration {
+         |    type Day = Value
+         |    val Weekday, Weekend = Value
+         |  }
+         |  object Bool extends Enumeration {
+         |    type Bool = Value
+         |    val True, False = Value
+         |  }
+         |  import Bool._
+         |  def day(d: Day.Value): Unit = ???
+         |  val <<d>> =
+         |    if (true) Day.Weekday
+         |    else Day.Weekend
+         |""".stripMargin,
+      """|object EnumerationValue:
+         |  object Day extends Enumeration {
+         |    type Day = Value
+         |    val Weekday, Weekend = Value
+         |  }
+         |  object Bool extends Enumeration {
+         |    type Bool = Value
+         |    val True, False = Value
+         |  }
+         |  import Bool._
+         |  def day(d: Day.Value): Unit = ???
+         |  val d: EnumerationValue.Day.Value =
+         |    if (true) Day.Weekday
+         |    else Day.Weekend
+         |""".stripMargin
+    )
+
+  @Test def `enums2` =
+    checkEdit(
+      """|object EnumerationValue:
+         |  object Day extends Enumeration {
+         |    type Day = Value
+         |    val Weekday, Weekend = Value
+         |  }
+         |  object Bool extends Enumeration {
+         |    type Bool = Value
+         |    val True, False = Value
+         |  }
+         |  import Bool._
+         |  val <<b>> =
+         |    if (true) True
+         |    else False
+         |""".stripMargin,
+      """|object EnumerationValue:
+         |  object Day extends Enumeration {
+         |    type Day = Value
+         |    val Weekday, Weekend = Value
+         |  }
+         |  object Bool extends Enumeration {
+         |    type Bool = Value
+         |    val True, False = Value
+         |  }
+         |  import Bool._
+         |  val b: Value =
+         |    if (true) True
+         |    else False
+         |""".stripMargin
+    )
+
   def checkEdit(
       original: String,
       expected: String