diff --git a/src/pmc/filehandle.pmc b/src/pmc/filehandle.pmc
index 972406c278..ca66c5b8c1 100644
--- a/src/pmc/filehandle.pmc
+++ b/src/pmc/filehandle.pmc
@@ -359,6 +359,7 @@ Read a line from the filehandle and return it in a string.
     METHOD readline_interactive(STRING *prompt :optional, INTVAL got_prompt :opt_flag) {
         STRING *string_result = NULL;
 #ifdef PARROT_HAS_READLINE
+    /* 4-column indent to get c_indent.t to DTRT */
         char * const r = readline(got_prompt ? prompt->strstart : NULL);
 
         if (r) {