Fix rebase breakage

Author: odersky

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

@@ -829,7 +829,7 @@ object desugar {
         case Some(DefDef(name, _, (vparam :: _) :: _, _, _)) =>
           s"${name}_of_${inventTypeName(vparam.tpt)}"
         case _ =>
-          ctx.error(i"anonymous instance must have `for` part or must define at least one extension method", impl.pos)
+          ctx.error(i"anonymous instance must have `for` part or must define at least one extension method", impl.sourcePos)
           nme.ERROR.toString
       }
     else
@@ -1015,7 +1015,7 @@ object desugar {
    *      def $anonfun(params) = body
    *      Closure($anonfun)
    */
-  def makeClosure(params: List[ValDef], body: Tree, tpt: Tree = TypeTree(), isContextual: Boolean)(implicit ctx: Context): Block = {
+  def makeClosure(params: List[ValDef], body: Tree, tpt: Tree = null, isContextual: Boolean)(implicit ctx: Context): Block = {
     val span = params.headOption.fold(body.span)(_.span.union(body.span))
     Block(
       DefDef(nme.ANON_FUN, Nil, params :: Nil, if (tpt == null) TypeTree() else tpt, body)

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

@@ -106,7 +106,7 @@ object untpd extends Trees.Instance[Untyped] with UntypedTreeInfo {
   case class PatDef(mods: Modifiers, pats: List[Tree], tpt: Tree, rhs: Tree)(implicit @constructorOnly src: SourceFile) extends DefTree
   case class DependentTypeTree(tp: List[Symbol] => Type)(implicit @constructorOnly src: SourceFile) extends Tree
 
-  @sharable object EmptyTypeIdent extends Ident(tpnme.EMPTY) with WithoutTypeOrPos[Untyped] {
+  @sharable object EmptyTypeIdent extends Ident(tpnme.EMPTY)(NoSource) with WithoutTypeOrPos[Untyped] {
     override def isEmpty: Boolean = true
   }
 

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

@@ -2546,7 +2546,7 @@ object Parsers {
      *                   |  id ‘=’ Expr
      *  InstanceParams ::=  [DefTypeParamClause] {‘with’ ‘(’ [DefParams] ‘)}
      */
-    def instanceDef(start: Offset, mods: Modifiers, instanceMod: Mod) = atPos(start, nameStart) {
+    def instanceDef(start: Offset, mods: Modifiers, instanceMod: Mod) = atSpan(start, nameStart) {
       val name = if (isIdent && !isIdent(nme.of)) ident() else EmptyTermName
       val tparams = typeParamClauseOpt(ParamOwner.Def)
       val vparamss = paramClauses(ofInstance = true)