SI-2405 Confer implicit privileges to renamed imports.

Yin and yang would be pleased: A fix in two parts.

1. Use the name of the imported symbol, rather than the alias, in the generated `Select(qual, name)` tree.
2. Do the opposite in `isQualifyingImplicit`, which performs one part of the shadowing check.

But there is still work to do. The second part of the shadowing check, `nonImplicitSynonymInScope`,
fails to notice this case (irrespective of aliased imports).

  // Expecting shadowing #2. Alas, none is cast!
  object Test1 {
    object A { implicit val x: Int = 1 }
    import A.x
    def x: Int = 0
    implicitly[Int]
  }

I'm hitching the residual problem to SI-4270's wagon.

1 files changed, 5 insertions, 1 deletions

diff --git a/src/compiler/scala/tools/nsc/typechecker/Implicits.scala b/src/compiler/scala/tools/nsc/typechecker/Implicits.scala
index 8f025336bb..b2d373593f 100644
--- a/src/compiler/scala/tools/nsc/typechecker/Implicits.scala
+++ b/src/compiler/scala/tools/nsc/typechecker/Implicits.scala
@@ -554,7 +554,11 @@ trait Implicits {
 
       val itree = atPos(pos.focus) {
         if (info.pre == NoPrefix) Ident(info.name)
-        else Select(gen.mkAttributedQualifier(info.pre), info.name)
+        else {
+          // SI-2405 Not info.name, which might be an aliased import
+          val implicitMemberName = info.sym.name
+          Select(gen.mkAttributedQualifier(info.pre), implicitMemberName)
+        }
       }
       printTyping("typedImplicit1 %s, pt=%s, from implicit %s:%s".format(
         typeDebug.ptTree(itree), wildPt, info.name, info.tpe)