fix warnings: missing cast, unreachable code

src/ble/att_server.c

@@ -548,9 +548,10 @@ static void att_server_handle_can_send_now(void){
     hci_con_handle_t request_con_handle   = HCI_CON_HANDLE_INVALID;
     hci_con_handle_t last_send_con_handle = HCI_CON_HANDLE_INVALID;
     int can_send_now = 1;
-    int phase;
+    int phase_index;
 
-    for (phase = ATT_SERVER_RUN_PHASE_1_REQUESTS; phase <= ATT_SERVER_RUN_PHASE_3_NOTIFICATIONS; phase++){
+    for (phase_index = ATT_SERVER_RUN_PHASE_1_REQUESTS; phase_index <= ATT_SERVER_RUN_PHASE_3_NOTIFICATIONS; phase_index++){
+        att_server_run_phase_t phase = (att_server_run_phase_t) phase_index;
         hci_con_handle_t skip_connections_until = att_server_last_can_send_now;
         while (1){
             btstack_linked_list_iterator_t it;

src/ble/sm.c

@@ -3184,7 +3184,6 @@ static int sm_validate_stk_generation_method(void){
             return (sm_accepted_stk_generation_methods & SM_STK_GENERATION_METHOD_OOB) != 0;
         case NUMERIC_COMPARISON:
             return (sm_accepted_stk_generation_methods & SM_STK_GENERATION_METHOD_NUMERIC_COMPARISON) != 0;
-            return 1;
         default:
             return 0;
     }

src/btstack_crypto.c

@@ -670,9 +670,11 @@ static void btstack_crypto_run(void){
 #else
             btstack_crypto_wait_for_hci_result = 1;
             hci_send_cmd(&hci_le_generate_dhkey, &btstack_crypto_ec_p192->public_key[0], &btstack_crypto_ec_p192->public_key[32]);
-#endif
 #endif
             break;
+
+#endif /* ENABLE_ECC_P256 */
+
         default:
             break;
     }

src/btstack_slip.c

@@ -113,9 +113,9 @@ uint8_t btstack_slip_encoder_get_byte(void){
 					encoder_state = SLIP_ENCODER_SEND_DD;
 					return 0xdb;
 				default:
-					return next_byte;
-			}
                     break;
+			}
+			return next_byte;
 		case SLIP_ENCODER_SEND_DC:
 			encoder_state = SLIP_ENCODER_DEFAULT;
 			return 0x0dc;