Move more logic from RefinedPrinter to DecompilerPrinter

RefinedPrinter cannot make use of symbols in order to be able to print
after all phases (e.g. Parser).

Author: allanrenucci

compiler/src/dotty/tools/dotc/printing/DecompilerPrinter.scala

@@ -1,7 +1,7 @@
 package dotty.tools.dotc.printing
 
 import dotty.tools.dotc.ast.Trees._
-import dotty.tools.dotc.ast.untpd.{PackageDef, Template, TypeDef}
+import dotty.tools.dotc.ast.untpd.{Tree, PackageDef, Template, TypeDef}
 import dotty.tools.dotc.ast.{Trees, untpd}
 import dotty.tools.dotc.printing.Texts._
 import dotty.tools.dotc.core.Contexts._
@@ -54,16 +54,22 @@ class DecompilerPrinter(_ctx: Context) extends RefinedPrinter(_ctx) {
     decl ~~ typeText(nameIdText(tree)) ~ withEnclosingDef(tree) { toTextTemplate(impl) } ~ ""
   }
 
-  override protected def selfToText(impl: Template): Text =
-    super.selfToText(impl).provided(!impl.constr.symbol.owner.is(Module))
-
   override protected def toTextTemplate(impl: Template, ofNew: Boolean = false): Text = {
-    def isSyntheticParent(sym: Symbol): Boolean = {
+    def isSynthetic(parent: Tree): Boolean = {
+      val sym = parent.symbol
       sym.maybeOwner == defn.ObjectClass ||
       (sym == defn.ProductClass && impl.symbol.owner.is(Case))
     }
-    val impl1 = impl.copy(parents = impl.parents.filterNot(p => isSyntheticParent(p.symbol)))
-    super.toTextTemplate(impl1, ofNew)
+    val parents = impl.parents.filterNot(isSynthetic)
+
+    // We don't print self type and constructor for objects
+    val isObject = impl.constr.symbol.owner.is(Module)
+    if (isObject) {
+      val parentsText = keywordText(" extends") ~~ Text(parents.map(constrText), keywordStr(" with "))
+      val bodyText = " {" ~~ toTextGlobal(impl.body, "\n") ~ "}"
+      parentsText.provided(parents.nonEmpty) ~ bodyText
+    }
+    else super.toTextTemplate(impl.copy(parents = parents), ofNew)
   }
 
   override protected def typeApplyText[T >: Untyped](tree: TypeApply[T]): Text = {

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

@@ -640,16 +640,18 @@ class RefinedPrinter(_ctx: Context) extends PlainPrinter(_ctx) {
     val tparamsTxt = withEnclosingDef(constr) { tparamsText(tparams) }
     val primaryConstrs = if (constr.rhs.isEmpty) Nil else constr :: Nil
     val prefix: Text =
-      if (constr.symbol.owner.is(Module)) ""
-      else if (vparamss.isEmpty || primaryConstrs.nonEmpty) tparamsTxt
+      if (vparamss.isEmpty || primaryConstrs.nonEmpty) tparamsTxt
       else {
         var modsText = modText(constr.mods, "")
         if (!modsText.isEmpty) modsText = " " ~ modsText
         if (constr.mods.hasAnnotations && !constr.mods.hasFlags) modsText = modsText ~~ " this"
         withEnclosingDef(constr) { addVparamssText(tparamsTxt ~~ modsText, vparamss) }
       }
     val parentsText = Text(parents map constrText, keywordStr(" with "))
-    val selfText = selfToText(impl)
+    val selfText = {
+      val selfName = if (self.name == nme.WILDCARD) keywordStr("this") else self.name.toString
+      (selfName ~ optText(self.tpt)(": " ~ _) ~ " =>").close
+    }.provided(!self.isEmpty)
     val body = if (ctx.settings.YtestPickler.value) {
       // Pickling/unpickling reorders the body members, so we need to homogenize
       val (params, rest) = impl.body partition {
@@ -661,17 +663,9 @@ class RefinedPrinter(_ctx: Context) extends PlainPrinter(_ctx) {
       params ::: rest
     } else impl.body
 
-    val bodyText =
-      (if (constr.symbol.owner.is(Module)) " {" else "{") ~~
-      selfText ~~ toTextGlobal(primaryConstrs ::: body, "\n") ~ "}"
-
-    prefix ~ (keywordText(" extends") provided (!ofNew && parents.nonEmpty)) ~~ parentsText ~~ bodyText
-  }
+    val bodyText = " {" ~~ selfText ~~ toTextGlobal(primaryConstrs ::: body, "\n") ~ "}"
 
-  protected def selfToText(impl: Template): Text = {
-    val self = impl.self
-    val selfName = if (self.name == nme.WILDCARD) keywordStr("this") else self.name.toString
-    (selfName ~ optText(self.tpt)(": " ~ _) ~ " =>").close provided (!self.isEmpty)
+    prefix ~ keywordText(" extends").provided(!ofNew && parents.nonEmpty) ~~ parentsText ~ bodyText
   }
 
   protected def templateText(tree: TypeDef, impl: Template): Text = {