wip

Author: sjrd

compiler/src/dotty/tools/dotc/transform/Constructors.scala

@@ -205,6 +205,16 @@ class Constructors extends MiniPhase with IdentityDenotTransformer { thisPhase =
                 owner = constr.symbol).installAfter(thisPhase)
               constrStats += intoConstr(stat, sym)
             }
+          case stat @ DefDef(name, _, _, tpt, _)
+              if stat.symbol.isGetter && stat.symbol.owner.is(Trait) && !stat.symbol.is(Lazy) =>
+            val sym = stat.symbol
+            assert(isRetained(sym), sym)
+            if (!stat.rhs.isEmpty && !isWildcardArg(stat.rhs))
+              val setter =
+                if (sym.setter.exists) sym.setter
+                else sym.accessorNamed(Mixin.traitSetterName(sym.asTerm))
+              constrStats += Apply(ref(setter), intoConstr(stat.rhs, sym).withSpan(stat.span) :: Nil)
+            clsStats += cpy.DefDef(stat)(rhs = EmptyTree)
           case DefDef(nme.CONSTRUCTOR, _, ((outerParam @ ValDef(nme.OUTER, _, _)) :: _) :: Nil, _, _) =>
             clsStats += mapOuter(outerParam.symbol).transform(stat)
           case _: DefTree =>

compiler/src/dotty/tools/dotc/transform/Mixin.scala

@@ -12,13 +12,19 @@ import Types._
 import Decorators._
 import DenotTransformers._
 import StdNames._
+import Names._
 import NameKinds._
 import NameOps._
 import ast.Trees._
 import collection.mutable
 
 object Mixin {
   val name: String = "mixin"
+
+  def traitSetterName(getter: TermSymbol)(implicit ctx: Context): TermName =
+    getter.ensureNotPrivate.name
+      .expandedName(getter.owner, TraitSetterName)
+      .asTermName.setterName
 }
 
 /** This phase performs the following transformations:
@@ -155,9 +161,7 @@ class Mixin extends MiniPhase with SymTransformer { thisPhase =>
 
   private def traitSetter(getter: TermSymbol)(implicit ctx: Context): Symbol =
     getter.copy(
-      name = getter.ensureNotPrivate.name
-        .expandedName(getter.owner, TraitSetterName)
-        .asTermName.setterName,
+      name = Mixin.traitSetterName(getter),
       flags = Method | Accessor | Deferred,
       info = MethodType(getter.info.resultType :: Nil, defn.UnitType))