Clean up a bit more in Constructors.

Comment about my poor naming choice in Types.
NullaryMethodType sounds like the method has one empty argument list,
whereas it really has no argument lists at all.

Author: adriaanm

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

@@ -359,7 +359,7 @@ abstract class Constructors extends Statics with Transform with ast.TreeDSL {
       }
 
       log("merging: " + originalStats.mkString("\n") + "\nwith\n" + specializedStats.mkString("\n"))
-      val res = for (s <- originalStats; stat = s.duplicate) yield {
+      for (s <- originalStats; stat = s.duplicate) yield {
         log("merge: looking at " + stat)
         val stat1 = stat match {
           case Assign(sel @ Select(This(_), field), _) =>
@@ -389,9 +389,8 @@ abstract class Constructors extends Statics with Transform with ast.TreeDSL {
         } else
           stat1
       }
-      if (specBuf.nonEmpty)
-        println("residual specialized constructor statements: " + specBuf)
-      res
+//      if (specBuf.nonEmpty)
+//        println("residual specialized constructor statements: " + specBuf)
     }
 
     /* Add an 'if' around the statements coming after the super constructor. This
@@ -591,7 +590,7 @@ abstract class Constructors extends Statics with Transform with ast.TreeDSL {
           case ValDef(mods, name, _, _) if mods hasFlag PRESUPER =>
             // stat is the constructor-local definition of the field value
             val fields = presupers filter (_.getterName == name)
-            assert(fields.length == 1)
+            assert(fields.length == 1, s"expected exactly one field by name $name in $presupers of $clazz's early initializers")
             val to = fields.head.symbol
 
             if (memoizeValue(to)) constrStatBuf += mkAssign(to, Ident(stat.symbol))
@@ -607,9 +606,9 @@ abstract class Constructors extends Statics with Transform with ast.TreeDSL {
         // it goes before the superclass constructor call, otherwise it goes after.
         // A lazy val's effect is not moved to the constructor, as it is delayed.
         // Returns `true` when a `ValDef` is needed.
-        def moveEffectToCtor(mods: Modifiers, rhs: Tree, memoized: Boolean): Unit = {
+        def moveEffectToCtor(mods: Modifiers, rhs: Tree, assignSym: Symbol): Unit = {
           val initializingRhs =
-            if (!memoized || statSym.isLazy) EmptyTree // not memoized, or effect delayed (for lazy val)
+            if ((assignSym eq NoSymbol) || statSym.isLazy) EmptyTree // not memoized, or effect delayed (for lazy val)
             else if (!mods.hasStaticFlag) intoConstructor(statSym, primaryConstr.symbol)(rhs)
             else rhs
 
@@ -619,7 +618,7 @@ abstract class Constructors extends Statics with Transform with ast.TreeDSL {
               else if (mods hasFlag PRESUPER | PARAMACCESSOR) constrPrefixBuf
               else constrStatBuf
 
-            initPhase += mkAssign(statSym, initializingRhs)
+            initPhase += mkAssign(assignSym, initializingRhs)
           }
         }
 
@@ -640,10 +639,11 @@ abstract class Constructors extends Statics with Transform with ast.TreeDSL {
           //   - the constructor, before the super call (early initialized or a parameter accessor),
           //   - the constructor, after the super call (regular val).
           case ValDef(mods, _, _, rhs) =>
-            val emitField = memoizeValue(statSym)
-            moveEffectToCtor(mods, rhs, emitField)
-
-            if (emitField) defBuf += deriveValDef(stat)(_ => EmptyTree)
+            if (rhs ne EmptyTree) {
+              val emitField = memoizeValue(statSym)
+              moveEffectToCtor(mods, rhs, if (emitField) statSym else NoSymbol)
+              if (emitField) defBuf += deriveValDef(stat)(_ => EmptyTree)
+            } else defBuf += stat
 
           // all other statements go into the constructor
           case _ => constrStatBuf += intoConstructor(impl.symbol, primaryConstr.symbol)(stat)

src/reflect/scala/reflect/internal/Types.scala

@@ -2496,6 +2496,8 @@ trait Types
     override def isJava = true
   }
 
+  // TODO: rename so it's more appropriate for the type that is for a method without argument lists
+  // ("nullary" erroneously implies it has an argument list with zero arguments, it actually has zero argument lists)
   case class NullaryMethodType(override val resultType: Type) extends Type with NullaryMethodTypeApi {
     override def isTrivial = resultType.isTrivial && (resultType eq resultType.withoutAnnotations)
     override def prefix: Type = resultType.prefix