Address code review comments.
diff --git a/compiler/back_end/cpp/testcode/next_keyword_test.cc b/compiler/back_end/cpp/testcode/next_keyword_test.cc
index c4990f4..3dc2be3 100644
--- a/compiler/back_end/cpp/testcode/next_keyword_test.cc
+++ b/compiler/back_end/cpp/testcode/next_keyword_test.cc
@@ -28,13 +28,14 @@
 namespace test {
 namespace {
 
+// For reference in the code below, the NextKeyword structure is defined as:
+//
 // [$default byte_order: "LittleEndian"]
 // struct NextKeyword:
 //   0       [+4]  UInt  value32
 //   $next   [+2]  UInt  value16
 //   $next   [+1]  UInt  value8
 //   $next+3 [+1]  UInt  value8_offset
-
 TEST(NextKeyword, FieldsAreCorrectlyLocated) {
   ::std::array<char, NextKeyword::IntrinsicSizeInBytes()> values = {
     1, 0, 0, 0,
diff --git a/compiler/front_end/dependency_checker.py b/compiler/front_end/dependency_checker.py
index fa2d719..538a679 100644
--- a/compiler/front_end/dependency_checker.py
+++ b/compiler/front_end/dependency_checker.py
@@ -224,9 +224,10 @@
 
 def _find_object_dependency_cycles(ir):
   """Finds dependency cycles in types in the ir."""
-  dependencies, errors = _find_dependencies(ir)
-  if errors:
-    return errors
+  dependencies, find_dependency_errors = _find_dependencies(ir)
+  if find_dependency_errors:
+    return find_dependency_errors
+  errors = []
   cycles = _find_cycles(dict(dependencies))
   for cycle in cycles:
     # TODO(bolms): This lists the entire strongly-connected component in a
diff --git a/compiler/front_end/synthetics.py b/compiler/front_end/synthetics.py
index aebc7e5..7080527 100644
--- a/compiler/front_end/synthetics.py
+++ b/compiler/front_end/synthetics.py
@@ -239,7 +239,6 @@
   expression.function.args[0].CopyFrom(last_location.start)
   expression.function.args[1].CopyFrom(last_location.size)
   expression.source_location.CopyFrom(original_location)
-  # DO NOT SUBMIT: Error messages for circular references?
   _mark_as_synthetic(expression.function)
 
 
@@ -311,7 +310,7 @@
 def desugar(ir):
   """Translates pure syntactic sugar to its desugared form.
 
-  Replaces `$then` symbols with the start+length of the previous physical
+  Replaces `$next` symbols with the start+length of the previous physical
   field.
 
   Adds aliases for all fields in anonymous `bits` to the enclosing structure.
diff --git a/compiler/util/traverse_ir.py b/compiler/util/traverse_ir.py
index ce2c94f..b1e33f8 100644
--- a/compiler/util/traverse_ir.py
+++ b/compiler/util/traverse_ir.py
@@ -294,13 +294,13 @@
   It does not have any built-in incidental actions.
 
   Arguments:
-    ir: An ir_pb2.Ir object to walk.
+    node: An ir_pb2.Ir object to walk.
     pattern: A list of node types to match.
     action: A callable, which will be called on nodes matching `pattern`.
     incidental_actions: A dict of node types to callables, which can be used to
         set new parameters for `action` for part of the IR tree.
     skip_descendants_of: A list of types whose children should be skipped when
-        traversing `ir`.
+        traversing `node`.
     parameters: A list of top-level parameters.
 
   Returns: