Optimize splitting lines with many rules.

lib/src/debug.dart

Index: lib/src/debug.dart
diff --git a/lib/src/debug.dart b/lib/src/debug.dart
index 47ca7fe41cbf7d1e0d82a582cd69006e4e826733..e091f37b7189087e6a0144521603f456ad3312f0 100644
--- a/lib/src/debug.dart
+++ b/lib/src/debug.dart
@@ -118,8 +118,10 @@ void dumpChunks(int start, List<Chunk> chunks) {
     if (chunk.rule != null) {
       row.add(chunk.isHardSplit ? "" : chunk.rule.toString());
 
-      var outerRules = chunk.rule.outerRules.toSet().intersection(rules);
-      writeIf(outerRules.isNotEmpty, () => "-> ${outerRules.join(" ")}");
+      var constrainedRules =
+          chunk.rule.constrainedRules.toSet().intersection(rules);
+      writeIf(constrainedRules.isNotEmpty,
+          () => "-> ${constrainedRules.join(" ")}");
     } else {
       row.add("(no rule)");