Fix increment on nullable

test/codegen/expect/DeltaBlue.js

 var DeltaBlue;
 (function(exports) {
   'use strict';
   // Function main: () → dynamic
   function main() {
     new DeltaBlue().report();
   }
   class DeltaBlue extends BenchmarkBase.BenchmarkBase {
     DeltaBlue() {
       super.BenchmarkBase("DeltaBlue");
@@ skipping 257 matching lines @@
       for (let overridden = c.satisfy(mark); overridden !== null; overridden = overridden.satisfy(mark))
         ;
     }
     incrementalRemove(c) {
       let out = c.output();
       c.markUnsatisfied();
       c.removeFromGraph();
       let unsatisfied = this.removePropagateFrom(out);
       let strength = REQUIRED;
       do {
-        for (let i = 0; dart.notNull(i) < dart.notNull(unsatisfied.length); dart.notNull(i)++) {
+        for (let i = 0; dart.notNull(i) < dart.notNull(unsatisfied.length); i = dart.notNull(i) + 1) {
           let u = unsatisfied.get(i);
           if (dart.equals(u.strength, strength))
             this.incrementalAdd(u);
         }
         strength = strength.nextWeaker();
       } while (!dart.equals(strength, WEAKEST));
     }
     newMark() {
-      return ++dart.notNull(this.currentMark);
+      return this.currentMark = dart.notNull(this.currentMark) + 1;
     }
     makePlan(sources) {
       let mark = this.newMark();
       let plan = new Plan();
       let todo = sources;
       while (dart.notNull(todo.length) > 0) {
         let c = todo.removeLast();
         if (c.output().mark !== mark && dart.notNull(c.inputsKnown(mark))) {
           plan.addConstraint(c);
           c.output().mark = mark;
           this.addConstraintsConsumingTo(c.output(), todo);
         }
       }
       return plan;
     }
     extractPlanFromConstraints(constraints) {
       let sources = new List.from([]);
-      for (let i = 0; dart.notNull(i) < dart.notNull(constraints.length); dart.notNull(i)++) {
+      for (let i = 0; dart.notNull(i) < dart.notNull(constraints.length); i = dart.notNull(i) + 1) {
         let c = constraints.get(i);
         if (dart.notNull(c.isInput()) && dart.notNull(c.isSatisfied()))
           sources.add(c);
       }
       return this.makePlan(sources);
     }
     addPropagate(c, mark) {
       let todo = new List.from([c]);
       while (dart.notNull(todo.length) > 0) {
         let d = todo.removeLast();
         if (d.output().mark === mark) {
           this.incrementalRemove(c);
           return false;
         }
         d.recalculate();
         this.addConstraintsConsumingTo(d.output(), todo);
       }
       return true;
     }
     removePropagateFrom(out) {
       out.determinedBy = null;
       out.walkStrength = WEAKEST;
       out.stay = true;
       let unsatisfied = new List.from([]);
       let todo = new List.from([out]);
       while (dart.notNull(todo.length) > 0) {
         let v = todo.removeLast();
-        for (let i = 0; dart.notNull(i) < dart.notNull(v.constraints.length); dart.notNull(i)++) {
+        for (let i = 0; dart.notNull(i) < dart.notNull(v.constraints.length); i = dart.notNull(i) + 1) {
           let c = v.constraints.get(i);
           if (!dart.notNull(c.isSatisfied()))
             unsatisfied.add(c);
         }
         let determining = v.determinedBy;
-        for (let i = 0; dart.notNull(i) < dart.notNull(v.constraints.length); dart.notNull(i)++) {
+        for (let i = 0; dart.notNull(i) < dart.notNull(v.constraints.length); i = dart.notNull(i) + 1) {
           let next = v.constraints.get(i);
           if (dart.notNull(!dart.equals(next, determining)) && dart.notNull(next.isSatisfied())) {
             next.recalculate();
             todo.add(next.output());
           }
         }
       }
       return unsatisfied;
     }
     addConstraintsConsumingTo(v, coll) {
       let determining = v.determinedBy;
-      for (let i = 0; dart.notNull(i) < dart.notNull(v.constraints.length); dart.notNull(i)++) {
+      for (let i = 0; dart.notNull(i) < dart.notNull(v.constraints.length); i = dart.notNull(i) + 1) {
         let c = v.constraints.get(i);
         if (dart.notNull(!dart.equals(c, determining)) && dart.notNull(c.isSatisfied()))
           coll.add(c);
       }
     }
   }
   class Plan extends dart.Object {
     Plan() {
       this.list = new List.from([]);
     }
     addConstraint(c) {
       this.list.add(c);
     }
     size() {
       return this.list.length;
     }
     execute() {
-      for (let i = 0; dart.notNull(i) < dart.notNull(this.list.length); dart.notNull(i)++) {
+      for (let i = 0; dart.notNull(i) < dart.notNull(this.list.length); i = dart.notNull(i) + 1) {
         this.list.get(i).execute();
       }
     }
   }
   // Function chainTest: (int) → void
   function chainTest(n) {
     exports.planner = new Planner();
     let prev = null, first = null, last = null;
-    for (let i = 0; dart.notNull(i) <= dart.notNull(n); dart.notNull(i)++) {
+    for (let i = 0; dart.notNull(i) <= dart.notNull(n); i = dart.notNull(i) + 1) {
       let v = new Variable("v", 0);
       if (prev !== null)
         new EqualityConstraint(prev, v, REQUIRED);
       if (i === 0)
         first = v;
       if (i === n)
         last = v;
       prev = v;
     }
     new StayConstraint(last, STRONG_DEFAULT);
     let edit = new EditConstraint(first, PREFERRED);
     let plan = exports.planner.extractPlanFromConstraints(new List.from([edit]));
-    for (let i = 0; dart.notNull(i) < 100; dart.notNull(i)++) {
+    for (let i = 0; dart.notNull(i) < 100; i = dart.notNull(i) + 1) {
       first.value = i;
       plan.execute();
       if (last.value !== i) {
         core.print("Chain test failed:");
         core.print(`Expected last value to be ${i} but it was ${last.value}.`);
       }
     }
   }
   // Function projectionTest: (int) → void
   function projectionTest(n) {
     exports.planner = new Planner();
     let scale = new Variable("scale", 10);
     let offset = new Variable("offset", 1000);
     let src = null, dst = null;
     let dests = new List.from([]);
-    for (let i = 0; dart.notNull(i) < dart.notNull(n); dart.notNull(i)++) {
+    for (let i = 0; dart.notNull(i) < dart.notNull(n); i = dart.notNull(i) + 1) {
       src = new Variable("src", i);
       dst = new Variable("dst", i);
       dests.add(dst);
       new StayConstraint(src, NORMAL);
       new ScaleConstraint(src, scale, offset, dst, REQUIRED);
     }
     change(src, 17);
     if (dst.value !== 1170)
       core.print("Projection 1 failed");
     change(dst, 1050);
     if (src.value !== 5)
       core.print("Projection 2 failed");
     change(scale, 5);
-    for (let i = 0; dart.notNull(i) < dart.notNull(n) - 1; dart.notNull(i)++) {
+    for (let i = 0; dart.notNull(i) < dart.notNull(n) - 1; i = dart.notNull(i) + 1) {
       if (dests.get(i).value !== dart.notNull(i) * 5 + 1000)
         core.print("Projection 3 failed");
     }
     change(offset, 2000);
-    for (let i = 0; dart.notNull(i) < dart.notNull(n) - 1; dart.notNull(i)++) {
+    for (let i = 0; dart.notNull(i) < dart.notNull(n) - 1; i = dart.notNull(i) + 1) {
       if (dests.get(i).value !== dart.notNull(i) * 5 + 2000)
         core.print("Projection 4 failed");
     }
   }
   // Function change: (Variable, int) → void
   function change(v, newValue) {
     let edit = new EditConstraint(v, PREFERRED);
     let plan = exports.planner.extractPlanFromConstraints(new List.from([edit]));
-    for (let i = 0; dart.notNull(i) < 10; dart.notNull(i)++) {
+    for (let i = 0; dart.notNull(i) < 10; i = dart.notNull(i) + 1) {
       v.value = newValue;
       plan.execute();
     }
     edit.destroyConstraint();
   }
   exports.planner = null;
   // Exports:
   exports.main = main;
   exports.DeltaBlue = DeltaBlue;
   exports.Strength = Strength;
@@ skipping 14 matching lines @@
   exports.BinaryConstraint = BinaryConstraint;
   exports.ScaleConstraint = ScaleConstraint;
   exports.EqualityConstraint = EqualityConstraint;
   exports.Variable = Variable;
   exports.Planner = Planner;
   exports.Plan = Plan;
   exports.chainTest = chainTest;
   exports.projectionTest = projectionTest;
   exports.change = change;
 })(DeltaBlue || (DeltaBlue = {}));