SI-7335 Remove special case for import of Predef._ in Predef.scala

Perhaps this once was problematic, but in our modern age we can
bootstrap perfectly well with this import.

Author: retronym

src/reflect/scala/reflect/internal/TreeInfo.scala

@@ -663,19 +663,9 @@ abstract class TreeInfo {
       unapply(dissectApplied(tree))
   }
 
-  /** Does list of trees start with a definition of
-   *  a class of module with given name (ignoring imports)
-   */
-  def firstDefinesClassOrObject(trees: List[Tree], name: Name): Boolean = trees match {
-    case Import(_, _) :: xs             => firstDefinesClassOrObject(xs, name)
-    case Annotated(_, tree1) :: _       => firstDefinesClassOrObject(List(tree1), name)
-    case ModuleDef(_, `name`, _) :: _   => true
-    case ClassDef(_, `name`, _, _) :: _ => true
-    case _                              => false
-  }
-
   /** Is this file the body of a compilation unit which should not
-   *  have Predef imported?
+   *  have Predef imported? This is the case iff the first import in the
+   *  unit explicitly refers to Predef.
    */
   def noPredefImportForUnit(body: Tree) = {
     // Top-level definition whose leading imports include Predef.
@@ -684,13 +674,7 @@ abstract class TreeInfo {
       case Import(expr, _)      => isReferenceToPredef(expr)
       case _                    => false
     }
-    // Compilation unit is class or object 'name' in package 'scala'
-    def isUnitInScala(tree: Tree, name: Name) = tree match {
-      case PackageDef(Ident(nme.scala_), defs) => firstDefinesClassOrObject(defs, name)
-      case _                                   => false
-    }
-
-    isUnitInScala(body, nme.Predef) || isLeadingPredefImport(body)
+    isLeadingPredefImport(body)
   }
 
   def isAbsTypeDef(tree: Tree) = tree match {