Better printing of anonymous classes.

Used to be just $anon, now is `Ps { ... }`, where `Ps` are
the instantiated parents of the anonymous class.

3 files changed, 18 insertions, 11 deletions

diff --git a/src/dotty/tools/dotc/core/Types.scala b/src/dotty/tools/dotc/core/Types.scala
index 36b546230..89facfee5 100644
--- a/src/dotty/tools/dotc/core/Types.scala
+++ b/src/dotty/tools/dotc/core/Types.scala
@@ -2002,12 +2002,23 @@ object Types {
     // cached because baseType needs parents
     private var parentsCache: List[TypeRef] = null
 
+    /** The parent type refs as seen from the given prefix */
     override def parents(implicit ctx: Context): List[TypeRef] = {
       if (parentsCache == null)
         parentsCache = cls.classParents.mapConserve(rebase(_).asInstanceOf[TypeRef])
       parentsCache
     }
 
+    /** The parent types with all type arguments */
+    def instantiatedParents(implicit ctx: Context): List[Type] =
+      parents mapConserve { pref =>
+        ((pref: Type) /: pref.classSymbol.typeParams) { (parent, tparam) =>
+          val targSym = decls.lookup(tparam.name)
+          if (targSym.exists) RefinedType(parent, targSym.name, targSym.info)
+          else parent
+        }
+      }
+
     def derivedClassInfo(prefix: Type)(implicit ctx: Context) =
       if (prefix eq this.prefix) this
       else ClassInfo(prefix, cls, classParents, decls, selfInfo)
diff --git a/src/dotty/tools/dotc/printing/PlainPrinter.scala b/src/dotty/tools/dotc/printing/PlainPrinter.scala
index 308470885..3a322648a 100644
--- a/src/dotty/tools/dotc/printing/PlainPrinter.scala
+++ b/src/dotty/tools/dotc/printing/PlainPrinter.scala
@@ -251,22 +251,21 @@ class PlainPrinter(_ctx: Context) extends Printer {
           case sym: Symbol if !sym.isCompleted => "this: ? =>"
           case _ => "this: " ~ atPrec(InfixPrec) { toText(tp.selfType) } ~ " =>"
         }
-        val parentsText = Text(cparents.map(p =>
-          toTextLocal(reconstituteParent(cls, p))), " with ")
         val trueDecls = otherDecls.filterNot(treatAsTypeArg)
         val declsText =
           if (trueDecls.isEmpty || !ctx.settings.debug.value) Text()
           else dclsText(trueDecls)
-        tparamsText ~ " extends " ~ parentsText ~ "{" ~ selfText ~ declsText ~
+        tparamsText ~ " extends " ~ toTextParents(tp.parents) ~ "{" ~ selfText ~ declsText ~
           "} at " ~ preText
       case _ =>
         ": " ~ toTextGlobal(tp)
     }
   }
 
+  protected def toTextParents(parents: List[Type]): Text = Text(parents.map(toTextLocal), " with ")
+
   protected def treatAsTypeParam(sym: Symbol): Boolean = false
   protected def treatAsTypeArg(sym: Symbol): Boolean = false
-  protected def reconstituteParent(cls: ClassSymbol, parent: Type): Type = parent
 
   /** String representation of symbol's kind. */
   def kindString(sym: Symbol): String = {
diff --git a/src/dotty/tools/dotc/printing/RefinedPrinter.scala b/src/dotty/tools/dotc/printing/RefinedPrinter.scala
index c20598bb3..d0a681f90 100644
--- a/src/dotty/tools/dotc/printing/RefinedPrinter.scala
+++ b/src/dotty/tools/dotc/printing/RefinedPrinter.scala
@@ -115,8 +115,12 @@ class RefinedPrinter(_ctx: Context) extends PlainPrinter(_ctx) {
             case _ => nameString(tp.symbol)
           }
         }
+        else if (tp.symbol.isAnonymousClass)
+          return toText(tp.info)
       case ExprType(result) =>
         return "=> " ~ toText(result)
+      case tp: ClassInfo =>
+        return toTextParents(tp.instantiatedParents) ~ "{...}"
       case tp: SelectionProto =>
         return toText(RefinedType(WildcardType, tp.name, tp.memberProto))
       case tp: ViewProto =>
@@ -437,13 +441,6 @@ class RefinedPrinter(_ctx: Context) extends PlainPrinter(_ctx) {
     sym.isType && (sym is ProtectedLocal) &&
       (sym.allOverriddenSymbols exists (_ is TypeParam))
 
-  override protected def reconstituteParent(cls: ClassSymbol, parent: Type): Type =
-    (parent /: parent.classSymbol.typeParams) { (parent, tparam) =>
-      val targSym = cls.decls.lookup(tparam.name)
-      if (targSym.exists) RefinedType(parent, targSym.name, targSym.info)
-      else parent
-    }
-
   override def toText(sym: Symbol): Text = {
     if (sym.name == nme.IMPORT) {
       def importString(tree: untpd.Tree) = s"import ${tree.show}"