From 86c112538084f7718252966f5f9d9278c4837fb2 Mon Sep 17 00:00:00 2001
From: Scott Lahteine <github@thinkyhead.com>
Date: Sun, 10 May 2020 04:52:51 -0500
Subject: [PATCH] Sanity check 3-point defines

Fixes #17870
---
 Marlin/src/inc/Conditionals_post.h | 6 +++++-
 1 file changed, 5 insertions(+), 1 deletion(-)

diff --git a/Marlin/src/inc/Conditionals_post.h b/Marlin/src/inc/Conditionals_post.h
index 26cad8797..fe8778590 100644
--- a/Marlin/src/inc/Conditionals_post.h
+++ b/Marlin/src/inc/Conditionals_post.h
@@ -2338,9 +2338,13 @@
   #undef MESH_MAX_Y
 #endif
 
-#if defined(PROBE_PT_1_X) && defined(PROBE_PT_2_X) && defined(PROBE_PT_3_X) && defined(PROBE_PT_1_Y) && defined(PROBE_PT_2_Y) && defined(PROBE_PT_3_Y)
+#define _POINT_COUNT (defined(PROBE_PT_1_X) + defined(PROBE_PT_2_X) + defined(PROBE_PT_3_X) + defined(PROBE_PT_1_Y) + defined(PROBE_PT_2_Y) + defined(PROBE_PT_3_Y))
+#if _POINT_COUNT == 6
   #define HAS_FIXED_3POINT 1
+#elif _POINT_COUNT > 0
+  #error "For 3-Point Leveling all XY points must be defined (or none for the defaults)."
 #endif
+#undef _POINT_COUNT
 
 /**
  * Buzzer/Speaker