Drop ImplicitShadowing mode

Author: odersky

compiler/src/dotty/tools/dotc/core/Mode.scala

@@ -60,11 +60,6 @@ object Mode {
    */
   val Printing: Mode = newMode(10, "Printing")
 
-  /** We are currently typechecking an ident to determine whether some implicit
-   *  is shadowed - don't do any other shadowing tests.
-   */
-  val ImplicitShadowing: Mode = newMode(11, "ImplicitShadowing")
-
   /** We are currently in a `viewExists` check. In that case, ambiguous
    *  implicits checks are disabled and we succeed with the first implicit
    *  found.

compiler/src/dotty/tools/dotc/typer/Typer.scala

@@ -2029,7 +2029,6 @@ class Typer extends Namer
         val result = if (ifpt.exists &&
             xtree.isTerm &&
             !untpd.isContextualClosure(xtree) &&
-            !ctx.mode.is(Mode.ImplicitShadowing) &&
             !ctx.mode.is(Mode.Pattern) &&
             !ctx.isAfterTyper)
           makeContextualFunction(xtree, ifpt)
@@ -2598,7 +2597,6 @@ class Typer extends Namer
           !untpd.isContextualClosure(tree) &&
           !isApplyProto(pt) &&
           !ctx.mode.is(Mode.Pattern) &&
-          !ctx.mode.is(Mode.ImplicitShadowing) &&
           !ctx.isAfterTyper) {
         typr.println(i"insert apply on implicit $tree")
         typed(untpd.Select(untpd.TypedSplice(tree), nme.apply), pt, locked)