🐛 Fix CoreXY plus extra axes

See #22490

Marlin/src/inc/SanityCheck.h

 #if LINEAR_AXES >= 4
   #if AXIS4_NAME != 'A' && AXIS4_NAME != 'B' && AXIS4_NAME != 'C' && AXIS4_NAME != 'U' && AXIS4_NAME != 'V' && AXIS4_NAME != 'W'
     #error "AXIS4_NAME can only be one of 'A', 'B', 'C', 'U', 'V', or 'W'."
+  #elif !defined(I_MIN_POS) || !defined(I_MAX_POS)
+    #error "I_MIN_POS and I_MAX_POS are required with LINEAR_AXES >= 4."
+  #elif !defined(I_HOME_DIR)
+    #error "I_HOME_DIR is required with LINEAR_AXES >= 4."
+  #elif HAS_I_ENABLE && !defined(I_ENABLE_ON)
+    #error "I_ENABLE_ON is required for your I driver with LINEAR_AXES >= 4."
   #endif
 #endif
 #if LINEAR_AXES >= 5
     #error "AXIS5_NAME must be different from AXIS4_NAME and AXIS6_NAME"
   #elif AXIS5_NAME != 'A' && AXIS5_NAME != 'B' && AXIS5_NAME != 'C' && AXIS5_NAME != 'U' && AXIS5_NAME != 'V' && AXIS5_NAME != 'W'
     #error "AXIS5_NAME can only be one of 'A', 'B', 'C', 'U', 'V', or 'W'."
+  #elif !defined(J_MIN_POS) || !defined(J_MAX_POS)
+    #error "J_MIN_POS and J_MAX_POS are required with LINEAR_AXES >= 5."
+  #elif !defined(J_HOME_DIR)
+    #error "J_HOME_DIR is required with LINEAR_AXES >= 5."
+  #elif HAS_J_ENABLE && !defined(J_ENABLE_ON)
+    #error "J_ENABLE_ON is required for your J driver with LINEAR_AXES >= 5."
   #endif
 #endif
 #if LINEAR_AXES >= 6
     #error "AXIS6_NAME must be different from AXIS5_NAME and AXIS4_NAME."
   #elif AXIS6_NAME != 'A' && AXIS6_NAME != 'B' && AXIS6_NAME != 'C' && AXIS6_NAME != 'U' && AXIS6_NAME != 'V' && AXIS6_NAME != 'W'
     #error "AXIS6_NAME can only be one of 'A', 'B', 'C', 'U', 'V', or 'W'."
+  #elif !defined(K_MIN_POS) || !defined(K_MAX_POS)
+    #error "K_MIN_POS and K_MAX_POS are required with LINEAR_AXES >= 6."
+  #elif !defined(K_HOME_DIR)
+    #error "K_HOME_DIR is required with LINEAR_AXES >= 6."
+  #elif HAS_K_ENABLE && !defined(K_ENABLE_ON)
+    #error "K_ENABLE_ON is required for your K driver with LINEAR_AXES >= 6."
   #endif
 #endif
 

Marlin/src/module/planner.cpp

       " A:", target.a, " (", da, " steps)"
       " B:", target.b, " (", db, " steps)"
       " C:", target.c, " (", dc, " steps)"
+      #if LINEAR_AXES >= 4
+        " " AXIS4_STR ":", target.i, " (", di, " steps)"
+      #endif
+      #if LINEAR_AXES >= 5
+        " " AXIS5_STR ":", target.j, " (", dj, " steps)"
+      #endif
+      #if LINEAR_AXES >= 6
+        " " AXIS6_STR ":", target.k, " (", dk, " steps)"
+      #endif
       #if HAS_EXTRUDERS
         " E:", target.e, " (", de, " steps)"
       #endif
       if (dk < 0) SBI(dm, K_AXIS)
     );
   #endif
+
+  #if IS_CORE
+    #if LINEAR_AXES >= 4
+      if (di < 0) SBI(dm, I_AXIS);
+    #endif
+    #if LINEAR_AXES >= 5
+      if (dj < 0) SBI(dm, J_AXIS);
+    #endif
+    #if LINEAR_AXES >= 6
+      if (dk < 0) SBI(dm, K_AXIS);
+    #endif
+  #endif
+
   #if HAS_EXTRUDERS
     if (de < 0) SBI(dm, E_AXIS);
   #endif
    */
   struct DistanceMM : abce_float_t {
     #if EITHER(IS_CORE, MARKFORGED_XY)
-      xyz_pos_t head;
+      struct { float x, y, z; } head;
     #endif
   } steps_dist_mm;
   #if IS_CORE
       steps_dist_mm.b      = (db + dc) * steps_to_mm[B_AXIS];
       steps_dist_mm.c      = CORESIGN(db - dc) * steps_to_mm[C_AXIS];
     #endif
+    #if LINEAR_AXES >= 4
+      steps_dist_mm.i = di * steps_to_mm[I_AXIS];
+    #endif
+    #if LINEAR_AXES >= 5
+      steps_dist_mm.j = dj * steps_to_mm[J_AXIS];
+    #endif
+    #if LINEAR_AXES >= 6
+      steps_dist_mm.k = dk * steps_to_mm[K_AXIS];
+    #endif
   #elif ENABLED(MARKFORGED_XY)
     steps_dist_mm.head.x = da * steps_to_mm[A_AXIS];
     steps_dist_mm.head.y = db * steps_to_mm[B_AXIS];