Remove artificial CURSOR added for the completions

compiler/src/dotty/tools/dotc/ast/NavigateAST.scala

@@ -3,6 +3,7 @@ package ast
 
 import core.Contexts.*
 import core.Decorators.*
+import core.StdNames
 import util.Spans.*
 import Trees.{Closure, MemberDef, DefTree, WithLazyFields}
 import dotty.tools.dotc.core.Types.AnnotatedType
@@ -76,6 +77,8 @@ object NavigateAST {
       var bestFit: List[Positioned] = path
       while (it.hasNext) {
         val path1 = it.next() match {
+          // FIXME this has to be changed to deterministicaly find recoveed tree
+          case untpd.Select(qual, name) if name == StdNames.nme.??? => path
           case p: Positioned if !p.isInstanceOf[Closure[?]] => singlePath(p, path)
           case m: untpd.Modifiers => childPath(m.productIterator, path)
           case xs: List[?] => childPath(xs.iterator, path)
@@ -84,11 +87,17 @@ object NavigateAST {
         if ((path1 ne path) &&
             ((bestFit eq path) ||
              bestFit.head.span != path1.head.span &&
-             bestFit.head.span.contains(path1.head.span)))
+             envelops(bestFit.head.span, path1.head.span)))
           bestFit = path1
       }
       bestFit
     }
+
+    def envelops(a: Span, b: Span): Boolean =
+      !b.exists || a.exists && (
+        (a.start < b.start && a.end >= b.end ) || (a.start <= b.start && a.end > b.end)
+      )
+
     /*
      * Annotations trees are located in the Type
      */

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

@@ -119,16 +119,17 @@ object Completion:
       case _ =>
         ""
 
+  def naiveCompletionPrefix(text: String, offset: Int): String =
+    var i = offset - 1
+    while i >= 0 && text(i).isUnicodeIdentifierPart do i -= 1
+    i += 1 // move to first character
+    text.slice(i, offset)
+
   /**
    * Inspect `path` to determine the completion prefix. Only symbols whose name start with the
    * returned prefix should be considered.
    */
   def completionPrefix(path: List[untpd.Tree], pos: SourcePosition)(using Context): String =
-    def fallback: Int =
-      var i = pos.point - 1
-      while i >= 0 && Character.isUnicodeIdentifierPart(pos.source.content()(i)) do i -= 1
-      i + 1
-
     path match
       case GenericImportSelector(sel) =>
         if sel.isGiven then completionPrefix(sel.bound :: Nil, pos)
@@ -146,7 +147,7 @@ object Completion:
       case (tree: untpd.RefTree) :: _ if tree.name != nme.ERROR =>
         tree.name.toString.take(pos.span.point - tree.span.point)
 
-      case _ => pos.source.content.slice(fallback, pos.point).mkString
+      case _ => naiveCompletionPrefix(pos.source.content().mkString, pos.point)
 
 
   end completionPrefix

compiler/src/dotty/tools/dotc/parsing/Parsers.scala

@@ -1725,7 +1725,7 @@ object Parsers {
             case arg =>
               arg
           val args1 = args.mapConserve(sanitize)
-          
+
           if in.isArrow || isPureArrow || erasedArgs.contains(true) then
             functionRest(args)
           else

language-server/test/dotty/tools/languageserver/CompletionTest.scala

@@ -1705,6 +1705,15 @@ class CompletionTest {
        ("getOrElse", Method, "[V1 >: String](key: Int, default: => V1): V1"),
      ))
 
+  @Test def testtest: Unit =
+    code"""|object M {
+           |  def sel$m1
+           |}
+           |"""
+     .completion(m1, Set(
+       ("getOrElse", Method, "[V1 >: String](key: Int, default: => V1): V1"),
+     ))
+
   @Test def noEnumCompletionInNewContext: Unit =
     code"""|enum TestEnum:
            |  case TestCase

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

@@ -67,7 +67,7 @@ final class AutoImportsProvider(
     val results = symbols.result.filter(isExactMatch(_, name))
 
     if results.nonEmpty then
-      val correctedPos = CompletionPos.infer(pos, params, path).toSourcePosition
+      val correctedPos = CompletionPos.infer(pos, params, path, false).toSourcePosition
       val mkEdit =
         path match
           // if we are in import section just specify full name

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

@@ -22,7 +22,8 @@ case class CompletionPos(
   identEnd: Int,
   query: String,
   originalCursorPosition: SourcePosition,
-  sourceUri: URI
+  sourceUri: URI,
+  withCURSOR: Boolean
 ):
   def queryEnd: Int = originalCursorPosition.point
   def stripSuffixEditRange: l.Range = new l.Range(originalCursorPosition.offsetToPos(queryStart), originalCursorPosition.offsetToPos(identEnd))
@@ -34,17 +35,19 @@ object CompletionPos:
   def infer(
       sourcePos: SourcePosition,
       offsetParams: OffsetParams,
-      adjustedPath: List[Tree]
+      adjustedPath: List[Tree],
+      wasCursorApplied: Boolean
   )(using Context): CompletionPos =
     val identEnd = adjustedPath match
       case (refTree: RefTree) :: _ if refTree.name.toString.contains(Cursor.value) =>
         refTree.span.end - Cursor.value.length
+      case (refTree: RefTree) :: _  => refTree.span.end
       case _ => sourcePos.end
 
     val query = Completion.completionPrefix(adjustedPath, sourcePos)
     val start = sourcePos.end - query.length()
 
-    CompletionPos(start, identEnd, query.nn, sourcePos, offsetParams.uri.nn)
+    CompletionPos(start, identEnd, query.nn, sourcePos, offsetParams.uri.nn, wasCursorApplied)
 
   /**
    * Infer the indentation by counting the number of spaces in the given line.

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

@@ -14,9 +14,12 @@ import dotty.tools.dotc.ast.tpd.*
 import dotty.tools.dotc.core.Constants.Constant
 import dotty.tools.dotc.core.Contexts.Context
 import dotty.tools.dotc.core.Phases
-import dotty.tools.dotc.core.StdNames
+import dotty.tools.dotc.core.StdNames.nme
+import dotty.tools.dotc.core.Flags
 import dotty.tools.dotc.interactive.Interactive
+import dotty.tools.dotc.interactive.Completion
 import dotty.tools.dotc.interactive.InteractiveDriver
+import dotty.tools.dotc.parsing.Tokens
 import dotty.tools.dotc.util.SourceFile
 import dotty.tools.pc.AutoImports.AutoImportEdits
 import dotty.tools.pc.AutoImports.AutoImportsGenerator
@@ -45,23 +48,31 @@ class CompletionProvider(
     val uri = params.uri().nn
     val text = params.text().nn
 
-    val code = applyCompletionCursor(params)
+    val (wasCursorApplied, code) = applyCompletionCursor(params)
     val sourceFile = SourceFile.virtual(uri, code)
     driver.run(uri, sourceFile)
 
-    val ctx = driver.currentCtx
+    given ctx: Context = driver.currentCtx
     val pos = driver.sourcePosition(params)
     val (items, isIncomplete) = driver.compilationUnits.get(uri) match
       case Some(unit) =>
-
         val newctx = ctx.fresh.setCompilationUnit(unit).withPhase(Phases.typerPhase(using ctx))
-        val tpdPath = Interactive.pathTo(newctx.compilationUnit.tpdTree, pos.span)(using newctx)
-        val adjustedPath = Interactive.resolveTypedOrUntypedPath(tpdPath, pos)(using newctx)
+        val tpdPath0 = Interactive.pathTo(unit.tpdTree, pos.span)(using newctx)
+        val adjustedPath = Interactive.resolveTypedOrUntypedPath(tpdPath0, pos)(using newctx)
+
+        val tpdPath = tpdPath0 match
+          // $1$ // FIXME add check for a $1$ name to make sure we only do the below in lifting case
+          case Select(qual, name) :: tail if qual.symbol.is(Flags.Synthetic) =>
+            qual.symbol.defTree match
+              case valdef: ValDef => Select(valdef.rhs, name) :: tail
+              case _ => tpdPath0
+          case _ => tpdPath0
+
 
         val locatedCtx = Interactive.contextOfPath(tpdPath)(using newctx)
         val indexedCtx = IndexedContext(locatedCtx)
 
-        val completionPos = CompletionPos.infer(pos, params, adjustedPath)(using locatedCtx)
+        val completionPos = CompletionPos.infer(pos, params, adjustedPath, wasCursorApplied)(using locatedCtx)
 
         val autoImportsGen = AutoImports.generator(
           completionPos.toSourcePosition,
@@ -111,6 +122,10 @@ class CompletionProvider(
     )
   end completions
 
+  val allKeywords =
+    val softKeywords = Tokens.softModifierNames + nme.as + nme.derives + nme.extension + nme.throws + nme.using
+    Tokens.keywords.toList.map(Tokens.tokenString) ++ softKeywords.map(_.toString)
+
   /**
    * In case if completion comes from empty line like:
    * {{{
@@ -123,23 +138,30 @@ class CompletionProvider(
    * Otherwise, completion poisition doesn't point at any tree
    * because scala parser trim end position to the last statement pos.
    */
-  private def applyCompletionCursor(params: OffsetParams): String =
+  private def applyCompletionCursor(params: OffsetParams): (Boolean, String) =
     val text = params.text().nn
     val offset = params.offset().nn
+    val query = Completion.naiveCompletionPrefix(text, offset)
 
-    val isStartMultilineComment =
-      val i = params.offset()
-      i >= 3 && (text.charAt(i - 1) match
-        case '*' =>
-          text.charAt(i - 2) == '*' &&
-          text.charAt(i - 3) == '/'
-        case _ => false
-      )
-    if isStartMultilineComment then
-      // Insert potentially missing `*/` to avoid comment out all codes after the "/**".
-      text.substring(0, offset).nn + Cursor.value + "*/" + text.substring(offset)
+    if offset > 0 && text.charAt(offset - 1).isUnicodeIdentifierPart && !allKeywords.contains(query) then
+      false -> text
     else
-      text.substring(0, offset).nn + Cursor.value + text.substring(offset)
+      val isStartMultilineComment =
+
+        val i = params.offset()
+        i >= 3 && (text.charAt(i - 1) match
+          case '*' =>
+            text.charAt(i - 2) == '*' &&
+            text.charAt(i - 3) == '/'
+          case _ => false
+        )
+      true -> (
+        if isStartMultilineComment then
+          // Insert potentially missing `*/` to avoid comment out all codes after the "/**".
+          text.substring(0, offset).nn + Cursor.value + "*/" + text.substring(offset)
+        else
+          text.substring(0, offset).nn + Cursor.value + text.substring(offset)
+      )
   end applyCompletionCursor
 
   private def completionItems(
@@ -172,7 +194,7 @@ class CompletionProvider(
               Select(Apply(Select(Select(_, name), _), _), _),
               _
             ) :: _ =>
-          name == StdNames.nme.StringContext
+          name == nme.StringContext
         // "My name is $name"
         case Literal(Constant(_: String)) :: _ =>
           true

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

@@ -63,11 +63,9 @@ class Completions(
       /* In case of `method@@()` we should not add snippets and the path
        * will contain apply as the parent of the current tree.
        */
-      case (fun) :: (appl: GenericApply) :: _ if appl.fun == fun =>
-        false
-      case _ :: (withcursor @ Select(fun, name)) :: (appl: GenericApply) :: _
-          if appl.fun == withcursor && name.decoded == Cursor.value =>
-        false
+      case (fun) :: (appl: GenericApply) :: _ if appl.fun == fun => false
+      case sel  :: (funSel @ Select(fun, name)) :: (appl: GenericApply) :: _
+        if appl.fun == funSel && sel == fun => false
       case (_: (Import | Export)) :: _ => false
       case _ :: (_: (Import | Export)) :: _ => false
       case _ => true
@@ -479,14 +477,8 @@ class Completions(
           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 =>
-        advancedCompletions(tl, completionPos)
-
       case _ =>
         val args = NamedArgCompletions.contribute(
-          pos,
           path,
           adjustedPath,
           indexedContext,

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

@@ -224,7 +224,7 @@ object InterpolatorCompletions:
       buildTargetIdentifier: String
   )(using ctx: Context, reportsContext: ReportContext): List[CompletionValue] =
     val litStartPos = lit.span.start
-    val litEndPos = lit.span.end - Cursor.value.length()
+    val litEndPos = lit.span.end - (if completionPos.withCURSOR then Cursor.value.length else 0)
     val position = completionPos.originalCursorPosition
     val span = position.span
     val nameStart =

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

@@ -35,9 +35,8 @@ import scala.annotation.tailrec
 object NamedArgCompletions:
 
   def contribute(
-      pos: SourcePosition,
       path: List[Tree],
-      untypedPath: => List[untpd.Tree],
+      untypedPath: List[untpd.Tree],
       indexedContext: IndexedContext,
       clientSupportsSnippets: Boolean,
   )(using ctx: Context): List[CompletionValue] =
@@ -64,12 +63,13 @@ object NamedArgCompletions:
           for
             app <- getApplyForContextFunctionParam(rest)
             if !app.fun.isInfix
-          yield contribute(
-            Some(ident),
-            app,
-            indexedContext,
-            clientSupportsSnippets,
-          )
+          yield
+            contribute(
+              Some(ident),
+              app,
+              indexedContext,
+              clientSupportsSnippets,
+            )
         contribution.getOrElse(Nil)
       case (app: Apply) :: _ =>
         /**
@@ -156,10 +156,11 @@ object NamedArgCompletions:
           case _ => None
       val matchingMethods =
         for
-          (name, indxContext) <- maybeNameAndIndexedContext(method)
-          potentialMatches <- indxContext.findSymbol(name)
-        yield potentialMatches.collect {
-          case m
+          (name, indexedContext) <- maybeNameAndIndexedContext(method)
+          potentialMatches <- indexedContext.findSymbol(name)
+        yield
+          potentialMatches.collect {
+            case m
               if m.is(Flags.Method) &&
                 m.vparamss.length >= argss.length &&
                 Try(m.isAccessibleFrom(apply.symbol.info)).toOption
@@ -179,8 +180,7 @@ object NamedArgCompletions:
     end fallbackFindMatchingMethods
 
     val matchingMethods: List[Symbols.Symbol] =
-      if method.symbol.paramSymss.nonEmpty
-      then
+      if method.symbol.paramSymss.nonEmpty then
         val allArgsAreSupplied =
           val vparamss = method.symbol.vparamss
           vparamss.length == argss.length && vparamss
@@ -295,6 +295,7 @@ object NamedArgCompletions:
       )
     }
 
+    // FIXME pass query here
     val prefix = ident
       .map(_.name.toString)
       .getOrElse("")
@@ -391,7 +392,7 @@ class FuzzyArgMatcher(tparams: List[Symbols.Symbol])(using Context):
     (expectedArgs.length == actualArgs.length ||
       (!allArgsProvided && expectedArgs.length >= actualArgs.length)) &&
       actualArgs.zipWithIndex.forall {
-        case (Ident(name), _) if name.endsWith(Cursor.value) => true
+        case (Ident(name), _) => true
         case (NamedArg(name, arg), _) =>
           expectedArgs.exists { expected =>
             expected.name == name && (!arg.hasType || arg.typeOpt.unfold

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

@@ -573,7 +573,7 @@ object OverrideCompletions:
             )
           )
         // class Main extends Val:
-        //    he@@
+        //   he@@
         case (id: Ident) :: (t: Template) :: (td: TypeDef) :: _
             if t.parents.nonEmpty =>
           Some(
@@ -586,6 +586,20 @@ object OverrideCompletions:
             )
           )
 
+        // class Main extends Val:
+        //   hello@ // this transforms into this.hello, thus is a Select
+        case (sel @ Select(th: This, name)) :: (t: Template) :: (td: TypeDef) :: _
+            if t.parents.nonEmpty && th.qual.name == td.name =>
+          Some(
+            (
+              td,
+              None,
+              sel.sourcePos.start,
+              false,
+              Some(name.show),
+            )
+          )
+
         case _ => None
 
   end OverrideExtractor