Add missing -Yexplicit-nulls for presentation compiler (#18776)

With a new definition of untyped trees, it is now required to have
`-Yexplicit-nulls` flag in modules that use them in order to have proper
type checking. This PR adds the missing flag.

Without the flag, it was possible to first assign untyped trees to typed
trees, and secondly use extension methods for typed trees which can be
seen at `KeywordsCompletions.scala` with usage of
`untpdTree.filterSubtrees`.

It is also blocked by: #18775

I can also make a workaround in the unmanaged module, but it will
require a dependency on nightly version / a new release from metals.
[Cherry-picked e149e4c]

Author: rochala

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

@@ -23,7 +23,7 @@ object AutoImports:
     def renameConfigMap(config: PresentationCompilerConfig)(using
         Context
     ): Map[Symbol, String] =
-      config.symbolPrefixes.asScala.flatMap { (from, to) =>
+      config.symbolPrefixes().nn.asScala.flatMap { (from, to) =>
         val pkg = SemanticdbSymbols.inverseSemanticdbSymbol(from)
         val rename = to.stripSuffix(".").stripSuffix("#")
         List(pkg, pkg.map(_.moduleClass)).flatten
@@ -246,7 +246,7 @@ object AutoImports:
         // see WorksheetProvider.worksheetScala3AdjustmentsForPC
         val indent =
           if pos.source.path.isWorksheet &&
-            editPos.getStart().getCharacter() == 0
+            editPos.getStart().nn.getCharacter() == 0
           then indent0.drop(2)
           else indent0
         val topPadding =

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

@@ -29,13 +29,12 @@ final class AutoImportsProvider(
 )(using ReportContext):
 
   def autoImports(isExtension: Boolean): List[AutoImportsResult] =
-    val uri = params.uri
+    val uri = params.uri().nn
+    val text = params.text().nn
     val filePath = Paths.get(uri)
-    driver.run(
-      uri,
-      SourceFile.virtual(filePath.toString, params.text)
-    )
-    val unit = driver.currentCtx.run.units.head
+    driver.run(uri, SourceFile.virtual(filePath.toString, text))
+
+    val unit = driver.currentCtx.run.nn.units.head
     val tree = unit.tpdTree
 
     val pos = driver.sourcePosition(params)
@@ -81,7 +80,7 @@ final class AutoImportsProvider(
             val generator =
               AutoImports.generator(
                 correctedPos,
-                params.text,
+                text,
                 tree,
                 unit.comments,
                 indexedContext.importContext,

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

@@ -17,7 +17,7 @@ class CompilerSearchVisitor(
 )(using ctx: Context, reports: ReportContext)
     extends SymbolSearchVisitor:
 
-  val logger: Logger = Logger.getLogger(classOf[CompilerSearchVisitor].getName)
+  val logger: Logger = Logger.getLogger(classOf[CompilerSearchVisitor].getName().nn).nn
 
   private def isAccessible(sym: Symbol): Boolean = try
     sym != NoSymbol && sym.isPublic && sym.isStatic
@@ -68,7 +68,7 @@ class CompilerSearchVisitor(
       .split("\\$")
 
     val added =
-      try toSymbols(pkg, innerPath.toList).filter(visitSymbol)
+      try toSymbols(pkg, innerPath.nn.toList.map(_.nn)).filter(visitSymbol)
       catch
         case NonFatal(e) =>
           logger.log(Level.WARNING, e.getMessage(), e)
@@ -95,6 +95,6 @@ class CompilerSearchVisitor(
   override def isCancelled: Boolean = false
 
   private def normalizePackage(pkg: String): String =
-    pkg.replace("/", ".").stripSuffix(".")
+    pkg.replace("/", ".").nn.stripSuffix(".")
 
 end CompilerSearchVisitor

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

@@ -30,7 +30,7 @@ object CompletionItemResolver extends ItemResolver:
           .orElse(
             search.symbolDocumentation(gsym.companion)
           ) match
-          case Some(info) if item.getDetail != null =>
+          case Some(info) if item.getDetail() != null =>
             enrichDocs(
               item,
               info,
@@ -50,7 +50,7 @@ object CompletionItemResolver extends ItemResolver:
       Context
   ): String =
     def docs(gsym: Symbol): String =
-      search.symbolDocumentation(gsym).fold("")(_.docstring())
+      search.symbolDocumentation(gsym).fold("")(_.docstring().nn)
     val gsymDoc = docs(gsym)
     def keyword(gsym: Symbol): String =
       if gsym.isClass then "class"
@@ -60,7 +60,7 @@ object CompletionItemResolver extends ItemResolver:
       else ""
     val companion = gsym.companion
     if companion == NoSymbol || gsym.is(JavaDefined) then
-      if gsymDoc.isEmpty then
+      if gsymDoc.isEmpty() then
         if gsym.isAliasType then
           fullDocstring(gsym.info.metalsDealias.typeSymbol, search)
         else if gsym.is(Method) then
@@ -73,8 +73,8 @@ object CompletionItemResolver extends ItemResolver:
       else gsymDoc
     else
       val companionDoc = docs(companion)
-      if companionDoc.isEmpty then gsymDoc
-      else if gsymDoc.isEmpty then companionDoc
+      if companionDoc.isEmpty() then gsymDoc
+      else if gsymDoc.isEmpty() then companionDoc
       else
         List(
           s"""|### ${keyword(companion)} ${companion.name}

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

@@ -23,13 +23,12 @@ final class ConvertToNamedArgumentsProvider(
 ):
 
   def convertToNamedArguments: Either[String, List[l.TextEdit]] =
-    val uri = params.uri
+    val uri = params.uri().nn
+    val text = params.text().nn
     val filePath = Paths.get(uri)
-    driver.run(
-      uri,
-      SourceFile.virtual(filePath.toString, params.text)
-    )
-    val unit = driver.currentCtx.run.units.head
+    driver.run(uri, SourceFile.virtual(filePath.toString, text))
+
+    val unit = driver.currentCtx.run.nn.units.head
     val newctx = driver.currentCtx.fresh.setCompilationUnit(unit)
     val pos = driver.sourcePosition(params)
     val trees = driver.openedTrees(uri)

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

@@ -38,12 +38,12 @@ final class ExtractMethodProvider(
     extends ExtractMethodUtils:
 
   def extractMethod(): List[TextEdit] =
-    val text = range.text()
-    val uri = range.uri
+    val text = range.text().nn
+    val uri = range.uri().nn
     val filePath = Paths.get(uri)
     val source = SourceFile.virtual(filePath.toString, text)
     driver.run(uri, source)
-    val unit = driver.currentCtx.run.units.head
+    val unit = driver.currentCtx.run.nn.units.head
     val pos = driver.sourcePosition(range).startPos
     val path =
       Interactive.pathTo(driver.openedTrees(uri), pos)(using driver.currentCtx)
@@ -145,7 +145,7 @@ final class ExtractMethodProvider(
         val oldIndentLen = head.startPos.startColumnPadding.length()
         val toExtract =
           textToExtract(
-            range.text(),
+            text,
             head.startPos.start,
             expr.endPos.end,
             newIndent,

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

@@ -32,8 +32,9 @@ object HoverProvider:
       driver: InteractiveDriver,
       search: SymbolSearch
   )(implicit reportContext: ReportContext): ju.Optional[HoverSignature] =
-    val uri = params.uri
-    val sourceFile = SourceFile.virtual(params.uri, params.text)
+    val uri = params.uri().nn
+    val text = params.text().nn
+    val sourceFile = SourceFile.virtual(uri, text)
     driver.run(uri, sourceFile)
 
     given ctx: Context = driver.currentCtx
@@ -54,7 +55,7 @@ object HoverProvider:
     then
       def report =
         val posId =
-          if path.isEmpty || path.head.sourcePos == null || !path.head.sourcePos.exists
+          if path.isEmpty || !path.head.sourcePos.exists
           then pos.start
           else path.head.sourcePos.start
         Report(
@@ -77,7 +78,7 @@ object HoverProvider:
         )
       end report
       reportContext.unsanitized.create(report, ifVerbose = true)
-      ju.Optional.empty()
+      ju.Optional.empty().nn
     else
       val skipCheckOnName =
         !pos.isPoint // don't check isHoveringOnName for RangeHover
@@ -125,7 +126,7 @@ object HoverProvider:
 
           val docString = symbolTpes
             .flatMap(symTpe => search.symbolDocumentation(symTpe._1))
-            .map(_.docstring)
+            .map(_.docstring())
             .mkString("\n")
           printer.expressionType(exprTpw) match
             case Some(expressionType) =>
@@ -143,9 +144,9 @@ object HoverProvider:
                   docstring = Some(docString),
                   forceExpressionType = forceExpressionType
                 )
-              )
+              ).nn
             case _ =>
-              ju.Optional.empty
+              ju.Optional.empty().nn
           end match
       end match
     end if
@@ -188,7 +189,7 @@ object HoverProvider:
 
       refTpe.flatMap(findRefinement).asJava
     case _ =>
-      ju.Optional.empty()
+      ju.Optional.empty().nn
 
 end HoverProvider
 

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

@@ -7,6 +7,7 @@ import dotty.tools.dotc.core.Contexts.*
 import dotty.tools.dotc.core.Flags.*
 import dotty.tools.dotc.core.NameOps.moduleClassName
 import dotty.tools.dotc.core.Names.*
+import dotty.tools.dotc.core.Scopes.EmptyScope
 import dotty.tools.dotc.core.Symbols.*
 import dotty.tools.dotc.core.Types.*
 import dotty.tools.dotc.typer.ImportInfo
@@ -82,7 +83,6 @@ object IndexedContext:
 
   def apply(ctx: Context): IndexedContext =
     ctx match
-      case null => Empty
       case NoContext => Empty
       case _ => LazyWrapper(using ctx)
 
@@ -205,14 +205,14 @@ object IndexedContext:
     val (symbols, renames) =
       if ctx.isImportContext then
         val (syms, renames) =
-          fromImportInfo(ctx.importInfo)
+          fromImportInfo(ctx.importInfo.nn)
             .map((sym, rename) => (sym, rename.map(r => sym -> r.decoded)))
             .unzip
         (syms, renames.flatten.toMap)
       else if ctx.owner.isClass then
         val site = ctx.owner.thisType
         (accesibleMembers(site), Map.empty)
-      else if ctx.scope != null then (ctx.scope.toList, Map.empty)
+      else if ctx.scope != EmptyScope then (ctx.scope.toList, Map.empty)
       else (List.empty, Map.empty)
 
     val initial = Map.empty[String, List[Symbol]]

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

@@ -62,14 +62,14 @@ final class InferredTypeProvider(
       adjustOpt: Option[AdjustTypeOpts] = None
   ): List[TextEdit] =
     val retryType = adjustOpt.isEmpty
-    val uri = params.uri
-    val filePath = Paths.get(uri)
+    val uri = params.uri().nn
+    val filePath = Paths.get(uri).nn
 
-    val sourceText = adjustOpt.map(_.text).getOrElse(params.text)
+    val sourceText = adjustOpt.map(_.text).getOrElse(params.text().nn)
     val source =
-      SourceFile.virtual(filePath.toString, sourceText)
+      SourceFile.virtual(filePath.toString(), sourceText)
     driver.run(uri, source)
-    val unit = driver.currentCtx.run.units.head
+    val unit = driver.currentCtx.run.nn.units.head
     val pos = driver.sourcePosition(params)
     val path =
       Interactive.pathTo(driver.openedTrees(uri), pos)(using driver.currentCtx)
@@ -78,15 +78,15 @@ final class InferredTypeProvider(
     val indexedCtx = IndexedContext(locatedCtx)
     val autoImportsGen = AutoImports.generator(
       pos,
-      params.text,
+      sourceText,
       unit.tpdTree,
       unit.comments,
       indexedCtx,
       config
     )
 
     def removeType(nameEnd: Int, tptEnd: Int) =
-      sourceText.substring(0, nameEnd) +
+      sourceText.substring(0, nameEnd).nn +
         sourceText.substring(tptEnd + 1, sourceText.length())
 
     def optDealias(tpe: Type): Type =
@@ -134,7 +134,7 @@ final class InferredTypeProvider(
         def baseEdit(withParens: Boolean): TextEdit =
           val keywordOffset = if isParam then 0 else 4
           val endPos =
-            findNamePos(params.text, vl, keywordOffset).endPos.toLsp
+            findNamePos(sourceText, vl, keywordOffset).endPos.toLsp
           adjustOpt.foreach(adjust => endPos.setEnd(adjust.adjustedEndPos))
           new TextEdit(
             endPos,
@@ -148,11 +148,10 @@ final class InferredTypeProvider(
             toCheckFor: Char,
             blockStartPos: SourcePosition
         ) =
-          val text = params.text
-          val isParensFunction: Boolean = text(applyEndingPos) == toCheckFor
+          val isParensFunction: Boolean = sourceText(applyEndingPos) == toCheckFor
 
           val alreadyHasParens =
-            text(blockStartPos.start) == '('
+            sourceText(blockStartPos.start) == '('
 
           if isParensFunction && !alreadyHasParens then
             new TextEdit(blockStartPos.toLsp, "(") :: baseEdit(withParens =
@@ -188,7 +187,7 @@ final class InferredTypeProvider(
               Some(
                 AdjustTypeOpts(
                   removeType(vl.namePos.end, tpt.sourcePos.end - 1),
-                  tpt.sourcePos.toLsp.getEnd()
+                  tpt.sourcePos.toLsp.getEnd().nn
                 )
               )
             )
@@ -227,7 +226,7 @@ final class InferredTypeProvider(
               Some(
                 AdjustTypeOpts(
                   removeType(lastColon, tpt.sourcePos.end - 1),
-                  tpt.sourcePos.toLsp.getEnd()
+                  tpt.sourcePos.toLsp.getEnd().nn
                 )
               )
             )
@@ -256,8 +255,8 @@ final class InferredTypeProvider(
             val firstEnd = patterns(0).endPos.end
             val secondStart = patterns(1).startPos.start
             val hasDot = params
-              .text()
-              .substring(firstEnd, secondStart)
+              .text().nn
+              .substring(firstEnd, secondStart).nn
               .exists(_ == ',')
             if !hasDot then
               val leftParen = new TextEdit(body.startPos.toLsp, "(")
@@ -309,7 +308,7 @@ final class InferredTypeProvider(
           val end = if withBacktick then idx + 1 else idx
           val pos = tree.source.atSpan(Span(start, end, start))
           Some(pos)
-        case None if idx < text.length =>
+        case None if idx < text.length() =>
           val ch = text.charAt(idx)
           if ch == realName.head then
             lookup(idx + 1, Some((idx, realName.tail)), withBacktick)

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

@@ -48,7 +48,7 @@ class MetalsDriver(
 
   override def run(uri: URI, sourceCode: String): List[Diagnostic] =
     val diags =
-      if alreadyCompiled(uri, sourceCode.toCharArray()) then Nil
+      if alreadyCompiled(uri, sourceCode.toCharArray().nn) then Nil
       else super.run(uri, sourceCode)
     lastCompiledURI = uri
     diags

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

@@ -33,24 +33,23 @@ abstract class PcCollector[T](
     params: VirtualFileParams
 ):
   private val caseClassSynthetics: Set[Name] = Set(nme.apply, nme.copy)
-  val uri = params.uri()
-  val filePath = Paths.get(uri)
-  val sourceText = params.text
+  val uri = params.uri().nn
+  val filePath = Paths.get(uri).nn
+  val sourceText = params.text().nn
   val source =
-    SourceFile.virtual(filePath.toString, sourceText)
+    SourceFile.virtual(filePath.toString(), sourceText)
   driver.run(uri, source)
   given ctx: Context = driver.currentCtx
 
-  val unit = driver.currentCtx.run.units.head
+  val unit = driver.currentCtx.run.nn.units.head
   val compilatonUnitContext = ctx.fresh.setCompilationUnit(unit)
   val offset = params match
     case op: OffsetParams => op.offset()
     case _ => 0
   val offsetParams =
     params match
       case op: OffsetParams => op
-      case _ =>
-        CompilerOffsetParams(params.uri(), params.text(), 0, params.token())
+      case _ => CompilerOffsetParams(uri, sourceText, 0, params.token().nn)
   val pos = driver.sourcePosition(offsetParams)
   val rawPath =
     Interactive