diff --git a/lightup.c b/lightup.c
index 854d28a..3db47f7 100644
--- a/lightup.c
+++ b/lightup.c
@@ -416,6 +416,8 @@ static void debug_state(game_state *state)
     int x, y;
     char c = '?';
 
+    (void)c; /* placate -Wunused-but-set-variable if debug() does nothing */
+
     for (y = 0; y < state->h; y++) {
         for (x = 0; x < state->w; x++) {
             c = '.';
diff --git a/loopy.c b/loopy.c
index 18da2e8..3545976 100644
--- a/loopy.c
+++ b/loopy.c
@@ -2713,7 +2713,6 @@ static int loop_deductions(solver_state *sstate)
     game_state *state = sstate->state;
     grid *g = state->game_grid;
     int shortest_chainlen = g->num_dots;
-    bool loop_found = false;
     int dots_connected;
     bool progress = false;
     int i;
@@ -2726,7 +2725,7 @@ static int loop_deductions(solver_state *sstate)
      */
     for (i = 0; i < g->num_edges; i++) {
         if (state->lines[i] == LINE_YES) {
-            loop_found |= merge_dots(sstate, i);
+            merge_dots(sstate, i);
             edgecount++;
         }
     }