chore: Backport changes from Metals

This includes:
- scalameta/metals#5956
- scalameta/metals#5979
- scalameta/metals#5994
- scalameta/metals#5995
- scalameta/metals#5998
- scalameta/metals#5999
- scalameta/metals#6000

compiler/src/dotty/tools/dotc/interactive/Interactive.scala

@@ -282,12 +282,10 @@ object Interactive {
     case nested :: encl :: rest =>
       val outer = contextOfPath(encl :: rest)
       try encl match {
-        case tree @ PackageDef(pkg, stats) =>
-          assert(tree.symbol.exists)
+        case tree @ PackageDef(pkg, stats) if tree.symbol.exists =>
           if (nested `eq` pkg) outer
           else contextOfStat(stats, nested, pkg.symbol.moduleClass, outer.packageContext(tree, tree.symbol))
-        case tree: DefDef =>
-          assert(tree.symbol.exists)
+        case tree: DefDef if tree.symbol.exists =>
           val localCtx = outer.localContext(tree, tree.symbol).setNewScope
           for params <- tree.paramss; param <- params do localCtx.enter(param.symbol)
             // Note: this overapproximates visibility a bit, since value parameters are only visible

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

@@ -58,6 +58,7 @@ class CompilerSearchVisitor(
               .filter(denot => denot.exists)
               .map(_.symbol)
               .filter(isAccessible)
+              .filter(!_.is(Flags.Given))
           }
           loop(next, tl)
         case Nil => owners

presentation-compiler/src/main/dotty/tools/pc/completions/CompletionPos.scala

@@ -15,6 +15,7 @@ import dotty.tools.dotc.util.Spans
 import dotty.tools.pc.utils.MtagsEnrichments.*
 
 import org.eclipse.lsp4j as l
+import scala.annotation.tailrec
 
 enum CompletionKind:
   case Empty, Scope, Members
@@ -55,8 +56,10 @@ object CompletionPos:
     val prevIsDot =
       if start - 1 >= 0 then text.charAt(start - 1) == '.' else false
     val kind =
-      if query.nn.isEmpty() && !prevIsDot then CompletionKind.Empty
-      else if prevIsDot then CompletionKind.Members
+      if prevIsDot then CompletionKind.Members
+      else if isImportOrExportSelect(cursorPos, treePath) then
+        CompletionKind.Members
+      else if query.nn.isEmpty then CompletionKind.Empty
       else CompletionKind.Scope
 
     CompletionPos(kind, start, end, query.nn, cursorPos, uri)
@@ -84,6 +87,21 @@ object CompletionPos:
     (i, tabIndented)
   end inferIndent
 
+  private def isImportOrExportSelect(
+      pos: SourcePosition,
+      path: List[Tree],
+  )(using Context): Boolean =
+    @tailrec
+    def loop(enclosing: List[Tree]): Boolean =
+      enclosing match
+        case head :: tl if !head.sourcePos.contains(pos) => loop(tl)
+        case (tree: (Import | Export)) :: _ =>
+          tree.selectors.exists(_.imported.sourcePos.contains(pos))
+        case _ => false
+
+    loop(path)
+
+
   /**
    * Returns the start offset of the identifier starting as the given offset position.
    */

presentation-compiler/src/main/dotty/tools/pc/completions/Completions.scala

@@ -72,8 +72,8 @@ class Completions(
       case _ :: (withcursor @ Select(fun, name)) :: (appl: GenericApply) :: _
           if appl.fun == withcursor && name.decoded == Cursor.value =>
         false
-      case (_: Import) :: _ => false
-      case _ :: (_: Import) :: _ => false
+      case (_: (Import | Export)) :: _ => false
+      case _ :: (_: (Import | Export)) :: _ => false
       case (_: Ident) :: (_: SeqLiteral) :: _ => false
       case _ => true
 
@@ -140,7 +140,8 @@ class Completions(
 
     val application = CompletionApplication.fromPath(path)
     val ordering = completionOrdering(application)
-    val values = application.postProcess(all.sorted(ordering))
+    val sorted = all.sorted(ordering)
+    val values = application.postProcess(sorted)
     (values, result)
   end completions
 
@@ -441,6 +442,10 @@ class Completions(
           true,
         )
 
+      case (tree: (Import | Export)) :: _
+          if tree.selectors.exists(_.renamed.sourcePos.contains(pos)) =>
+        (List.empty, true)
+
       // From Scala 3.1.3-RC3 (as far as I know), path contains
       // `Literal(Constant(null))` on head for an incomplete program, in this case, just ignore the head.
       case Literal(Constant(null)) :: tl =>
@@ -791,7 +796,8 @@ class Completions(
       val fuzzyCache = mutable.Map.empty[CompletionValue, Int]
 
       def compareLocalSymbols(s1: Symbol, s2: Symbol): Int =
-        if s1.isLocal && s2.isLocal then
+        if s1.isLocal && s2.isLocal && s1.sourcePos.exists && s2.sourcePos.exists
+        then
           val firstIsAfter = s1.srcPos.isAfter(s2.srcPos)
           if firstIsAfter then -1 else 1
         else 0
@@ -833,6 +839,16 @@ class Completions(
         priority(o1) - priority(o2)
       end compareInApplyParams
 
+      def prioritizeKeywords(o1: CompletionValue, o2: CompletionValue): Int =
+        def priority(v: CompletionValue): Int =
+          v match
+            case _: CompletionValue.CaseKeyword => 0
+            case _: CompletionValue.NamedArg => 1
+            case _: CompletionValue.Keyword => 2
+            case _ => 3
+
+        priority(o1) - priority(o2)
+      end prioritizeKeywords
       /**
        * Some completion values should be shown first such as CaseKeyword and
        * NamedArg
@@ -909,7 +925,10 @@ class Completions(
           case _ =>
             val byApplyParams = compareInApplyParams(o1, o2)
             if byApplyParams != 0 then byApplyParams
-            else compareByRelevance(o1, o2)
+            else
+              val keywords = prioritizeKeywords(o1, o2)
+              if keywords != 0 then keywords
+              else compareByRelevance(o1, o2)
       end compare
 
 end Completions

presentation-compiler/src/main/dotty/tools/pc/completions/InterpolatorCompletions.scala

@@ -83,14 +83,13 @@ object InterpolatorCompletions:
           case _: Select => true
           case _ => false
         } =>
-      val allLiterals = parent match
-        case SeqLiteral(elems, _) =>
-          elems
-        case _ => Nil
-      expr.elems.zip(allLiterals.tail).collectFirst {
-        case (i: (Ident | Select), literal) if literal == lit =>
-          i
-      }
+      parent match
+        case SeqLiteral(elems, _) if elems.size > 0 =>
+          expr.elems.zip(elems.tail).collectFirst {
+            case (i: (Ident | Select), literal) if literal == lit =>
+              i
+          }
+        case _ => None
   end interpolatorMemberArg
 
   /**

presentation-compiler/src/main/dotty/tools/pc/completions/NamedArgCompletions.scala

@@ -17,6 +17,7 @@ import dotty.tools.dotc.core.Names.Name
 import dotty.tools.dotc.core.StdNames.*
 import dotty.tools.dotc.core.SymDenotations.NoDenotation
 import dotty.tools.dotc.core.Symbols
+import dotty.tools.dotc.core.Symbols.defn
 import dotty.tools.dotc.core.Symbols.NoSymbol
 import dotty.tools.dotc.core.Symbols.Symbol
 import dotty.tools.dotc.core.Types.AndType
@@ -309,15 +310,17 @@ object NamedArgCompletions:
 
     val completionSymbols = indexedContext.scopeSymbols
     def matchingTypesInScope(paramType: Type): List[String] =
-      completionSymbols
-        .collect {
-          case sym
-              if sym.info <:< paramType && sym.isTerm && !sym.info.isErroneous && !sym.info.isNullType && !sym.info.isNothingType && !sym
-                .is(Flags.Method) && !sym.is(Flags.Synthetic) =>
-            sym.decodedName
-        }
-        .filter(name => name != "Nil" && name != "None")
-        .sorted
+      if paramType != defn.AnyType then
+        completionSymbols
+          .collect {
+            case sym
+                if sym.info <:< paramType && sym.isTerm && !sym.info.isErroneous && !sym.info.isNullType && !sym.info.isNothingType && !sym
+                  .is(Flags.Method) && !sym.is(Flags.Synthetic) =>
+              sym.decodedName
+          }
+          .filter(name => name != "Nil" && name != "None")
+          .sorted
+      else Nil
 
     def findDefaultValue(param: ParamSymbol): String =
       val matchingType = matchingTypesInScope(param.info)

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

@@ -1047,7 +1047,7 @@ class CompletionArgSuite extends BaseCompletionSuite:
          |    bbb = 123,
          |    aa@@
          |  )
-         |} 
+         |}
          |""".stripMargin,
       """|aaa = : Int
          |""".stripMargin,
@@ -1063,7 +1063,7 @@ class CompletionArgSuite extends BaseCompletionSuite:
          |    ccc = 123,
          |    aa@@
          |  )
-         |} 
+         |}
          |""".stripMargin,
       """|aaa = : Int
          |""".stripMargin,
@@ -1079,7 +1079,7 @@ class CompletionArgSuite extends BaseCompletionSuite:
          |    ccc = 123,
          |    aa@@
          |  )
-         |} 
+         |}
          |""".stripMargin,
       """|aaa = : Int
          |""".stripMargin,
@@ -1105,4 +1105,18 @@ class CompletionArgSuite extends BaseCompletionSuite:
       """|str = : String
          | """.stripMargin,
       topLines = Some(1),
+    )
+
+  @Test def `comparison` =
+    check(
+      """package a
+        |object w {
+        |  abstract class T(x: Int) {
+        |    def met(x: Int): Unit = {
+        |      println(x@@)
+        |    }
+        |  }}
+        |""".stripMargin,
+      """x: Int
+        |x = : Any""".stripMargin,
     )

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

@@ -38,7 +38,8 @@ class CompletionKeywordSuite extends BaseCompletionSuite:
         |  // tr@@
         |}
         |""".stripMargin,
-      "",
+      """|transient scala (commit: '')
+         |transparentTrait - scala.annotation (commit: '')""".stripMargin,
       includeCommitCharacter = true
     )
 
@@ -57,7 +58,8 @@ class CompletionKeywordSuite extends BaseCompletionSuite:
         |  **/
         |}
         |""".stripMargin,
-      "",
+     """|transient scala (commit: '')
+        |transparentTrait - scala.annotation (commit: '')""".stripMargin,
       includeCommitCharacter = true
     )
 
@@ -151,6 +153,8 @@ class CompletionKeywordSuite extends BaseCompletionSuite:
       """|value: Int
          |val
          |var
+         |varargs(): varargs
+         |varargs - scala.annotation
          |""".stripMargin
     )
 
@@ -167,6 +171,8 @@ class CompletionKeywordSuite extends BaseCompletionSuite:
         |""".stripMargin,
       """|val
          |var
+         |varargs(): varargs
+         |varargs - scala.annotation
          |""".stripMargin
     )
 
@@ -181,9 +187,10 @@ class CompletionKeywordSuite extends BaseCompletionSuite:
         |  }
         |}
         |""".stripMargin,
-      """|given (commit: '')
-         |""".stripMargin,
-      includeCommitCharacter = true
+      """given (commit: '')
+        |""".stripMargin,
+      includeCommitCharacter = true,
+      topLines = Some(5)
     )
 
   @Test def `val-arg` =
@@ -198,8 +205,8 @@ class CompletionKeywordSuite extends BaseCompletionSuite:
         |}
         |""".stripMargin,
       """|value: Int
-         |""".stripMargin,
-      topLines = Some(1)
+         |varargs(): varargs
+         |varargs - scala.annotation""".stripMargin
     )
 
   @Test def `val-trailing-space` =
@@ -406,7 +413,13 @@ class CompletionKeywordSuite extends BaseCompletionSuite:
         |  protected de@@
         |}
       """.stripMargin,
-      "def"
+      """|def
+         |deprecated scala
+         |deprecatedInheritance scala
+         |deprecatedName scala
+         |deprecatedOverriding scala
+         |""".stripMargin,
+      topLines = Some(5)
     )
 
   @Test def `protected-val` =
@@ -418,9 +431,10 @@ class CompletionKeywordSuite extends BaseCompletionSuite:
         |  protected va@@
         |}
       """.stripMargin,
-      """val
-        |var
-        |""".stripMargin
+      """|val
+         |var
+         |varargs - scala.annotation
+         |""".stripMargin
     )
 
   @Test def `topLevel` =
@@ -458,16 +472,26 @@ class CompletionKeywordSuite extends BaseCompletionSuite:
          |  def hello(u@@)
          |}""".stripMargin,
       """|using (commit: '')
+         |unsafeExceptions scala (commit: '')
+         |unchecked scala (commit: '')
+         |unsafe - scala.caps (commit: '')
+         |unsafeNulls - scala.runtime.stdLibPatches.language (commit: '')
          |""".stripMargin,
-      includeCommitCharacter = true
+      includeCommitCharacter = true,
+      topLines = Some(5)
     )
 
   @Test def `not-using` =
     check(
       """|object A{
          |  def hello(a: String, u@@)
          |}""".stripMargin,
-      ""
+      """|unsafeExceptions scala
+         |unchecked scala
+         |unsafe - scala.caps
+         |unsafeNulls - scala.runtime.stdLibPatches.language
+         |unused - scala.annotation """.stripMargin,
+      topLines = Some(5)
     )
 
   @Test def `extends-class` =

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

@@ -54,7 +54,10 @@ class CompletionPatternSuite extends BaseCompletionSuite:
         |    case ma@@
         |  }
         |}""".stripMargin,
-      ""
+      """|main scala
+         |macros - scala.languageFeature.experimental
+         |macroImpl - scala.reflect.macros.internal
+         |""".stripMargin
     )
 
   @Test def `bind2` =

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

@@ -323,7 +323,8 @@ class CompletionSnippetSuite extends BaseCompletionSuite:
          |Widget($0) - (age: Int): Widget
          |Widget($0) - (name: String, age: Int): Widget
          |""".stripMargin,
-      includeDetail = true
+      includeDetail = true,
+      topLines = Some(4)
     )
 
   @Test def `no-apply` =
@@ -335,8 +336,13 @@ class CompletionSnippetSuite extends BaseCompletionSuite:
           |  Wi@@
           |}
           |""".stripMargin,
-      "Widget -  example",
-      includeDetail = true
+      """|Widget -  example
+         |Window -  java.awt
+         |WindowPeer -  java.awt.peer
+         |WithFilter -  scala.collection
+         |""".stripMargin,
+      includeDetail = true,
+      topLines = Some(4)
     )
 
   // https://github.com/scalameta/metals/issues/4004