diff --git a/src/regex_impl.cc b/src/regex_impl.cc
index 957f993b..09c8cc02 100644
--- a/src/regex_impl.cc
+++ b/src/regex_impl.cc
@@ -745,12 +745,12 @@ private:
             case ParsedRegex::ResetStart:
                 return true;
             case ParsedRegex::LookAhead:
-                if (node->children.empty())
+                if (not node->children.empty())
                     compute_start_chars(m_forward ? node->children.front() : node->children.back(),
                                         accepted, rejected);
                 return true;
             case ParsedRegex::NegativeLookAhead:
-                if (node->children.empty())
+                if (not node->children.empty())
                     compute_start_chars(m_forward ? node->children.front() : node->children.back(),
                                         rejected, accepted);
                 return true;
@@ -1124,6 +1124,11 @@ auto test_regex = UnitTest{[]{
         kak_assert(vm.exec("# foo bar", RegexExecFlags::Search));
         kak_assert(*vm.captures()[0] == '#');
     }
+
+    {
+        TestVM<> vm{R"((?=))"};
+        kak_assert(vm.exec(""));
+    }
 }};
 
 }