Move this to a helper method and add missing cases

src/main/java/baritone/pathing/movement/MovementHelper.java

@@ -374,6 +374,26 @@ public interface MovementHelper extends ActionCosts, Helper {
                 && ((Integer) state.getValue(BlockLiquid.LEVEL)) == 0;
     }
 
+    /**
+     * If movements make us stand/walk on this block, will it have a top to walk on?
+     */
+    static boolean mustBeSolidToWalkOn(CalculationContext context, int x, int y, int z, IBlockState state) {
+        Block block = state.getBlock();
+        if (block == Blocks.LADDER || block == Blocks.VINE) {
+            return false;
+        }
+        if (block instanceof BlockLiquid) {
+            if (context.assumeWalkOnWater) {
+                return false;
+            }
+            Block blockAbove = context.getBlock(x, y+1, z);
+            if (blockAbove instanceof BlockLiquid) {
+                return false;
+            }
+        }
+        return true;
+    }
+
     static boolean canPlaceAgainst(BlockStateInterface bsi, int x, int y, int z) {
         return canPlaceAgainst(bsi, x, y, z, bsi.get0(x, y, z));
     }

src/main/java/baritone/pathing/movement/movements/MovementDiagonal.java

@@ -127,7 +127,7 @@ public class MovementDiagonal extends Movement {
             destWalkOn = destInto;
         } else {
             destWalkOn = context.get(destX, y - 1, destZ);
-            boolean standingOnABlock = !(context.getBlock(x, y - 1, z) instanceof BlockLiquid) || (!context.assumeWalkOnWater && !(context.getBlock(x, y, z) instanceof BlockLiquid));
+            boolean standingOnABlock = MovementHelper.mustBeSolidToWalkOn(context, x, y-1, z, context.get(x, y-1, z));
             frostWalker = standingOnABlock && MovementHelper.canUseFrostWalker(context, destWalkOn);
             if (!MovementHelper.canWalkOn(context.bsi, destX, y - 1, destZ, destWalkOn) && !frostWalker) {
                 descend = true;

src/main/java/baritone/pathing/movement/movements/MovementTraverse.java

@@ -73,8 +73,7 @@ public class MovementTraverse extends Movement {
         IBlockState pb1 = context.get(destX, y, destZ);
         IBlockState destOn = context.get(destX, y - 1, destZ);
         Block srcDown = context.getBlock(x, y - 1, z);
-        // if we are on water but are neither in water nor can stand on water we must have placed a block to get here
+        boolean standingOnABlock = MovementHelper.mustBeSolidToWalkOn(context, x, y-1, z, context.get(x, y-1, z));
-        boolean standingOnABlock = !(srcDown instanceof BlockLiquid) || (!context.assumeWalkOnWater && !(context.getBlock(x, y, z) instanceof BlockLiquid));
         boolean frostWalker = standingOnABlock && MovementHelper.canUseFrostWalker(context, destOn);
         if (MovementHelper.canWalkOn(context.bsi, destX, y - 1, destZ, destOn) || frostWalker) { //this is a walk, not a bridge
             double WC = WALK_ONE_BLOCK_COST;