From 5bfe1494648980d7822084c4aeb50ac5126103ae Mon Sep 17 00:00:00 2001
From: Som Snytt <som.snytt@gmail.com>
Date: Fri, 15 Nov 2019 05:06:38 -0800
Subject: [PATCH] Exclude universal members from root module import

---
 .../scala/tools/nsc/ast/TreeGen.scala         |  2 +-
 .../tools/nsc/typechecker/Contexts.scala      | 23 ++++++++++++-------
 .../scala/reflect/internal/Trees.scala        |  1 +
 test/files/neg/t5389.check                    |  4 ++++
 test/files/neg/t5389.scala                    |  4 ++++
 5 files changed, 25 insertions(+), 9 deletions(-)
 create mode 100644 test/files/neg/t5389.check
 create mode 100644 test/files/neg/t5389.scala

diff --git a/src/compiler/scala/tools/nsc/ast/TreeGen.scala b/src/compiler/scala/tools/nsc/ast/TreeGen.scala
index 4b7b87bfe30d..64430eacd2e0 100644
--- a/src/compiler/scala/tools/nsc/ast/TreeGen.scala
+++ b/src/compiler/scala/tools/nsc/ast/TreeGen.scala
@@ -39,7 +39,7 @@ abstract class TreeGen extends scala.reflect.internal.TreeGen with TreeDSL {
   def mkImport(qualSym: Symbol, name: Name, toName: Name): Import =
     mkImportFromSelector(qualSym, ImportSelector(name, 0, toName, 0) :: Nil)
 
-  private def mkImportFromSelector(qualSym: Symbol, selector: List[ImportSelector]): Import = {
+  def mkImportFromSelector(qualSym: Symbol, selector: List[ImportSelector]): Import = {
     assert(qualSym ne null, this)
     val qual = gen.mkAttributedStableRef(qualSym)
     val importSym = (
diff --git a/src/compiler/scala/tools/nsc/typechecker/Contexts.scala b/src/compiler/scala/tools/nsc/typechecker/Contexts.scala
index 2c3fc08d8bb9..a34f5f4aec11 100644
--- a/src/compiler/scala/tools/nsc/typechecker/Contexts.scala
+++ b/src/compiler/scala/tools/nsc/typechecker/Contexts.scala
@@ -13,16 +13,17 @@
 package scala.tools.nsc
 package typechecker
 
-import scala.collection.{immutable, mutable}
 import scala.annotation.tailrec
-import scala.reflect.internal.util.{ ReusableInstance, shortClassOfInstance, ListOfNil, SomeOfNil }
+import scala.collection.{immutable, mutable}
+import scala.reflect.internal.util.{ReusableInstance, shortClassOfInstance, ListOfNil, SomeOfNil}
+import scala.util.chaining._
 
 /**
  *  @author  Martin Odersky
  */
 trait Contexts { self: Analyzer =>
   import global._
-  import definitions.{JavaLangPackage, ScalaPackage, PredefModule, ScalaXmlTopScope, ScalaXmlPackage}
+  import definitions.{JavaLangPackage, ScalaPackage, PredefModule, ScalaXmlTopScope, ScalaXmlPackage, isUniversalMember}
   import ContextMode._
   import scala.reflect.internal.Flags._
 
@@ -137,7 +138,16 @@ trait Contexts { self: Analyzer =>
   }
 
   def rootContext(unit: CompilationUnit, tree: Tree = EmptyTree, throwing: Boolean = false, checking: Boolean = false): Context = {
-    val rootImportsContext = rootImports(unit).foldLeft(startContext)((c, sym) => c.make(gen.mkWildcardImport(sym), unit = unit))
+    val rootImportsContext = rootImports(unit).foldLeft(startContext) { (c, sym) =>
+      if (sym.isPackage) c.make(gen.mkWildcardImport(sym), unit = unit)
+      else {
+        val universals = sym.typeSignature.members.filter(isUniversalMember).map(_.name).toSet
+        val sels = universals.iterator
+          .map(ImportSelector.mask).toList
+          .appended(ImportSelector.wild)
+        c.make(gen.mkImportFromSelector(sym, sels), unit = unit)
+      }
+    }
 
     // there must be a scala.xml package when xml literals were parsed in this unit
     if (unit.hasXml && ScalaXmlPackage == NoSymbol)
@@ -150,10 +160,7 @@ trait Contexts { self: Analyzer =>
       if (!unit.hasXml || ScalaXmlTopScope == NoSymbol) rootImportsContext
       else rootImportsContext.make(gen.mkImport(ScalaXmlPackage, nme.TopScope, nme.dollarScope))
 
-    val c = contextWithXML.make(tree, unit = unit)
-
-    c.initRootContext(throwing, checking)
-    c
+    contextWithXML.make(tree, unit = unit).tap(_.initRootContext(throwing, checking))
   }
 
   def rootContextPostTyper(unit: CompilationUnit, tree: Tree = EmptyTree): Context =
diff --git a/src/reflect/scala/reflect/internal/Trees.scala b/src/reflect/scala/reflect/internal/Trees.scala
index c0d71586c334..fabe8f9cef1f 100644
--- a/src/reflect/scala/reflect/internal/Trees.scala
+++ b/src/reflect/scala/reflect/internal/Trees.scala
@@ -498,6 +498,7 @@ trait Trees extends api.Trees {
     val wild     = ImportSelector(nme.WILDCARD, -1, null, -1)
     val wildList = List(wild) // OPT This list is shared for performance.
     def wildAt(pos: Int) = ImportSelector(nme.WILDCARD, pos, null, -1)
+    def mask(name: Name) = ImportSelector(name, -1, nme.WILDCARD, -1)
   }
 
   case class Import(expr: Tree, selectors: List[ImportSelector])
diff --git a/test/files/neg/t5389.check b/test/files/neg/t5389.check
new file mode 100644
index 000000000000..8911ebd57abe
--- /dev/null
+++ b/test/files/neg/t5389.check
@@ -0,0 +1,4 @@
+t5389.scala:2: error: not found: object ne
+import ne.scala
+       ^
+one error found
diff --git a/test/files/neg/t5389.scala b/test/files/neg/t5389.scala
new file mode 100644
index 000000000000..bb83d7a563d7
--- /dev/null
+++ b/test/files/neg/t5389.scala
@@ -0,0 +1,4 @@
+
+import ne.scala
+
+class C