diff --git a/Makefile b/Makefile
index 9496ce5983..cc30814b44 100644
--- a/Makefile
+++ b/Makefile
@@ -74,10 +74,15 @@ python: $(LIBUPB_PIC)
 	cd lang_ext/python && python setup.py build
 
 # Tests
+tests/test.proto.pb: tests/test.proto
+	# TODO: replace with upbc
+	protoc tests/test.proto -otests/test.proto.pb
+
 tests: tests/tests \
     tests/test_table \
     tests/t.test_vs_proto2.googlemessage1 \
-    tests/t.test_vs_proto2.googlemessage2
+    tests/t.test_vs_proto2.googlemessage2 \
+    tests/test.proto.pb
 
 #VALGRIND=valgrind --leak-check=full --error-exitcode=1 
 VALGRIND=
diff --git a/src/upb_def.c b/src/upb_def.c
index 08140e4c17..bc4f293196 100644
--- a/src/upb_def.c
+++ b/src/upb_def.c
@@ -27,8 +27,9 @@ static int div_round_up(int numerator, int denominator) {
 //
 // Our scheme is as follows.  First we give each def a flag indicating whether
 // it is part of a cycle or not.  Because defs are immutable, this flag will
-// never change.  For acyclic defs, we can use a naive algorithm and avoid
-// the overhead of dealing with cycles.  Most defs will be acyclic.
+// never change.  For acyclic defs, we can use a naive algorithm and avoid the
+// overhead of dealing with cycles.  Most defs will be acyclic, and most cycles
+// will be very short.
 //
 // For defs that participate in cycles we keep two reference counts.  One
 // tracks references that come from outside the cycle (we call these external
diff --git a/tests/test_vs_proto2.cc b/tests/test_vs_proto2.cc
index 926d731073..58c8e50c30 100644
--- a/tests/test_vs_proto2.cc
+++ b/tests/test_vs_proto2.cc
@@ -131,8 +131,8 @@ void compare(const google::protobuf::Message& proto2_msg,
   const google::protobuf::Descriptor *d = proto2_msg.GetDescriptor();
   struct upb_msgdef *def = upb_msg->def;
 
-  ASSERT((uint32_t)d->field_count() == def->num_fields);
-  for(uint32_t i = 0; i < def->num_fields; i++) {
+  ASSERT((upb_field_count_t)d->field_count() == def->num_fields);
+  for(upb_field_count_t i = 0; i < def->num_fields; i++) {
     struct upb_fielddef *upb_f = &def->fields[i];
     const google::protobuf::FieldDescriptor *proto2_f =
         d->FindFieldByNumber(upb_f->number);
diff --git a/tests/tests.c b/tests/tests.c
index 9fbfa3af20..3580c2ef36 100644
--- a/tests/tests.c
+++ b/tests/tests.c
@@ -228,9 +228,18 @@ static void test_get_f_uint32_t()
 }
 
 static void test_upb_symtab() {
-  struct upb_symtab *c = upb_symtab_new();
-  ASSERT(c);
-  upb_symtab_unref(c);
+  struct upb_symtab *s = upb_symtab_new();
+  ASSERT(s);
+  struct upb_string *descriptor = upb_strreadfile("tests/test.proto.pb");
+  if(!descriptor) {
+    fprintf(stderr, "Couldn't read input file tests/test.proto.pb\n");
+    exit(1);
+  }
+  struct upb_status status = UPB_STATUS_INIT;
+  upb_symtab_add_desc(s, descriptor, &status);
+  ASSERT(upb_ok(&status));
+  upb_string_unref(descriptor);
+  upb_symtab_unref(s);
 }
 
 
diff --git a/tools/upbc.c b/tools/upbc.c
index cb41eccc0a..8d41abc792 100644
--- a/tools/upbc.c
+++ b/tools/upbc.c
@@ -708,6 +708,7 @@ int main(int argc, char *argv[])
 
   int symcount;
   struct upb_def **defs = upb_symtab_getandref_defs(s, &symcount);
+  upb_symtab_unref(s);
   write_h(defs, symcount, h_filename, cident, h_file);
   write_const_h(defs, symcount, h_filename, h_const_file);
   for (int i = 0; i < symcount; i++) upb_def_unref(defs[i]);
@@ -719,7 +720,6 @@ int main(int argc, char *argv[])
     fclose(c_file);
   }
   upb_msg_unref(fds_msg);
-  upb_symtab_unref(s);
   upb_string_unref(descriptor);
   fclose(h_file);
   fclose(h_const_file);