diff --git a/src/proto.h b/src/proto.h
index 330685f1..bd6fd72a 100644
--- a/src/proto.h
+++ b/src/proto.h
@@ -644,7 +644,7 @@ void do_cursorpos_void(void);
 int help_line_len(const char *ptr);
 void do_help(void);
 #endif
-void do_replace_highlight(int highlight_flag, const char *word);
+void do_replace_highlight(bool highlight_flag, const char *word);
 #ifdef DEBUG
 void dump_buffer(const filestruct *inptr);
 void dump_buffer_reverse(void);
diff --git a/src/winio.c b/src/winio.c
index 1378d3a5..79e2f16e 100644
--- a/src/winio.c
+++ b/src/winio.c
@@ -3976,7 +3976,7 @@ void do_help(void)
 
 /* Highlight the current word being replaced or spell checked.  We
  * expect word to have tabs and control characters expanded. */
-void do_replace_highlight(int highlight_flag, const char *word)
+void do_replace_highlight(bool highlight_flag, const char *word)
 {
     size_t y = xplustabs();
     size_t word_len = strlen(word);