unit-typed lazy vals should never receive a field

this need was unmasked by test/files/run/t7843-jsr223-service.scala,
which no longer printed the output expected from the `0 to 10 foreach`

Author: adriaanm

src/compiler/scala/tools/nsc/typechecker/MethodSynthesis.scala

@@ -488,12 +488,10 @@ trait MethodSynthesis {
       // as the symbol info is in the process of being created then.
       // TODO: harmonize tree & symbol creation
       // TODO: the `def field` call-site breaks when you add `|| vd.symbol.owner.isTrait` (detected in test suite)
-      def noFieldFor(vd: ValDef) = vd.mods.isDeferred || (owner.isTrait && !traitFieldFor(vd))
-
-      // TODO: remove need for this as we moved over all kinds of field to the getter-based encoding
-      private def traitFieldFor(vd: ValDef): Boolean =
-        (vd.mods.isLazy && !isUnitType(vd.symbol.info)) || vd.mods.hasFlag(PRESUPER)
+      def noFieldFor(vd: ValDef) = vd.mods.isDeferred || (vd.mods.isLazy && isUnitType(vd.symbol.info)) || (owner.isTrait && !traitFieldFor(vd))
 
+      // TODO: never emit any fields in traits -- only use getter for lazy/presuper ones as well
+      private def traitFieldFor(vd: ValDef): Boolean = vd.mods.hasFlag(PRESUPER)
     }
 
     case class Field(tree: ValDef) extends DerivedFromValDef {