don't suppress field for unit-typed vals

it affects the memory model -- even a write of unit to a field is relevant...

Author: adriaanm

src/compiler/scala/tools/nsc/transform/Fields.scala

@@ -137,13 +137,8 @@ abstract class Fields extends InfoTransform with ast.TreeDSL with TypingTransfor
     // not stored, no side-effect
     val pureConstant = tp.isInstanceOf[ConstantType]
 
-    val stored = !(pureConstant || isUnitType(tp))
+    val stored = !(pureConstant) // || isUnitType(tp))
 
-    //  - setter (for var) or getter (for val) that isn't stored
-    // (pureConstant already shortcircuits this, but it may still be a unit-typed val)
-    def deriveStoredAccessor(stat: Tree)(deriveUnitDef: Tree => Tree) =
-      if (!stored) deriveUnitDef(stat)
-      else stat
 
     //    println(s"fieldMemoizationIn $sym $site = $tp")
     def assignSym: Symbol =
@@ -448,7 +443,11 @@ abstract class Fields extends InfoTransform with ast.TreeDSL with TypingTransfor
 
           def dropRhs = deriveDefDef(stat)(_ => EmptyTree)
           implicit val fieldMemoization = fieldMemoizationIn(statSym, clazz)
-          def deriveStoredAccessor(tree: Tree) = fieldMemoization.deriveStoredAccessor(tree)(deriveUnitDef)
+
+          def deriveStoredAccessor(stat: Tree) = stat
+          // if we decide to have non-stored fields with initialization effects:
+//            if (!fieldMemoization.stored) deriveUnitDef(stat)
+//            else stat
 
           if (clazz.isTrait)
             if (fieldMemoization.pureConstant) stat :: Nil
@@ -464,7 +463,7 @@ abstract class Fields extends InfoTransform with ast.TreeDSL with TypingTransfor
           // drop the val for (a) constant (pure & not-stored) and (b) not-stored (but still effectful) fields
           if (fieldMemoization.pureConstant) Nil // (a)
           else if (fieldMemoization.stored) dropRhs :: init(rhs)
-          else init(rhs) // (b)
+          else init(rhs) // (b) -- not used currently
 
         case tree => List (
           if (exprOwner != currentOwner && tree.isTerm) atOwner(exprOwner)(super.transform(tree))