Merge pull request #1094 from j2rodrig/master

Change nested typer creation to allow creation of derived typers

Author: odersky

src/dotty/tools/dotc/typer/Namer.scala

@@ -508,7 +508,7 @@ class Namer { typer: Typer =>
         if (sym is Module) moduleValSig(sym)
         else valOrDefDefSig(original, sym, Nil, Nil, identity)(localContext(sym).setNewScope)
       case original: DefDef =>
-        val typer1 = new Typer
+        val typer1 = ctx.typer.newLikeThis
         nestedTyper(sym) = typer1
         typer1.defDefSig(original, sym)(localContext(sym).setTyper(typer1))
       case original: TypeDef =>

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

@@ -68,6 +68,8 @@ class Typer extends Namer with TypeAssigner with Applications with Implicits wit
    */
   private var importedFromRoot: Set[Symbol] = Set()
 
+  def newLikeThis: Typer = new Typer
+
   /** Attribute an identifier consisting of a simple name or wildcard
    *
    *  @param tree      The tree representing the identifier.