Better printing of import symbols

Had duplications of `import` before.
Also: add import info when printing contexts.

Author: odersky

src/dotty/tools/dotc/core/Contexts.scala

@@ -422,9 +422,11 @@ object Contexts {
     final def withOwner(owner: Symbol): Context =
       if (owner ne this.owner) fresh.setOwner(owner) else this
 
-    override def toString =
+    override def toString = {
+      def iinfo(implicit ctx: Context) = if (ctx.importInfo == null) "" else i"${ctx.importInfo.selectors}%, %"
       "Context(\n" +
-      (outersIterator map ( ctx => s"  owner = ${ctx.owner}, scope = ${ctx.scope}") mkString "\n")
+      (outersIterator map ( ctx => s"  owner = ${ctx.owner}, scope = ${ctx.scope}, import = ${iinfo(ctx)}") mkString "\n")
+    }
   }
 
   /** A condensed context provides only a small memory footprint over

src/dotty/tools/dotc/printing/RefinedPrinter.scala

@@ -351,7 +351,7 @@ class RefinedPrinter(_ctx: Context) extends PlainPrinter(_ctx) {
       case SeqLiteral(elems, elemtpt) =>
         "[" ~ toTextGlobal(elems, ",") ~ " : " ~ toText(elemtpt) ~ "]"
       case tree @ Inlined(call, bindings, body) =>
-        (("/* inlined from " ~ toText(call) ~ "*/ ") provided !homogenizedView) ~ 
+        (("/* inlined from " ~ toText(call) ~ "*/ ") provided !homogenizedView) ~
         blockText(bindings :+ body)
       case tpt: untpd.DerivedTypeTree =>
         "<derived typetree watching " ~ summarized(toText(tpt.watched)) ~ ">"
@@ -525,11 +525,11 @@ class RefinedPrinter(_ctx: Context) extends PlainPrinter(_ctx) {
       if (tree.isType) txt = toText(tp)
       else if (!tree.isDef) txt = ("<" ~ txt ~ ":" ~ toText(tp) ~ ">").close
     }
-    else if (homogenizedView && tree.isType) 
+    else if (homogenizedView && tree.isType)
       txt = toText(tree.typeOpt)
     if (ctx.settings.Yprintpos.value && !tree.isInstanceOf[WithoutTypeOrPos[_]]) {
-      val pos = 
-        if (homogenizedView && !tree.isInstanceOf[MemberDef]) tree.pos.toSynthetic 
+      val pos =
+        if (homogenizedView && !tree.isInstanceOf[MemberDef]) tree.pos.toSynthetic
         else tree.pos
       val clsStr = "" // DEBUG: if (tree.isType) tree.getClass.toString else ""
       txt = (txt ~ "@" ~ pos.toString ~ clsStr).close
@@ -559,14 +559,12 @@ class RefinedPrinter(_ctx: Context) extends PlainPrinter(_ctx) {
       (sym.allOverriddenSymbols exists (_ is TypeParam))
 
   override def toText(sym: Symbol): Text = {
-    if (sym.isImport) {
-      def importString(tree: untpd.Tree) = s"import ${tree.show}"
+    if (sym.isImport)
       sym.infoOrCompleter match {
-        case info: Namer#Completer => return importString(info.original)
-        case info: ImportType => return importString(info.expr)
+        case info: Namer#Completer => return info.original.show
+        case info: ImportType => return s"import $info.expr.show"
         case _ =>
       }
-    }
     if (sym.is(ModuleClass))
       kindString(sym) ~~ (nameString(sym.name.stripModuleClassSuffix) + idString(sym))
     else