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 = '1.36';
  +const String version = '1.37';
   
   // Restriction on statements and expressions.
   const int stmtLength = 2;
  
positive.code: 
    void emitCollectionElement(int depth, DartType tp) {
      int r = depth <= exprDepth ? rand.nextInt(10) : 10;
      switch (r + 3) {
        // TODO(ajcbik): enable when on by default
        // Favors elements over control-flow collections.
        case 0:
          emit('...'); // spread
  
negative.code: 
      emitLn('try {');
      indent += 2;
      emitLn('X${classFields.length - 1}().run();');
      indent -= 2;
      emitLn('} catch (exception, stackTrace) {');
      indent += 2;
      emitLn("print('X${classFields.length - 1}().run() throws');");
      indent -= 2;
      emitLn('} finally {');
      indent += 2;
  