anchor.diff:  // Version of DartFuzz. Increase this each time changes are made
   // to preserve the property that a given version of DartFuzz yields
   // the same fuzzed program for a deterministic random seed.
  -const String version = '1.42';
  +const String version = '1.43';
   
   // Restriction on statements and expressions.
   const int stmtLength = 2;
  
positive.code:           final int i = localVars.length;
            emit('for (int $localName$i ');
            // For-loop (induction, list, set).
            switch (rand.nextInt(3)) {
              case 0:
                emit('= 0; $localName$i < ');
  
negative.code:   bool emitForIn(int depth) {
      final int i = localVars.length;
      emitLn('for (int $localName$i in ', newline: false);
      localVars.add(null); // declared, but don't use
      emitExpr(0, rand.nextBool() ? DartType.INT_LIST : DartType.INT_SET);
      localVars.removeLast(); // will get type
      emit(') {', newline: true);
      indent += 2;
      nest++;
  