Properly handle conditionals in assignment

Author: kddnewton

lib/syntax_tree/node.rb

@@ -5173,7 +5173,7 @@ def self.call(parent)
 
       while (node = queue.shift)
         return true if [Assign, MAssign, OpAssign].include?(node.class)
-        queue += node.child_nodes
+        queue += node.child_nodes.compact
       end
 
       false

test/fixtures/if.rb

@@ -59,3 +59,7 @@
     baz
   end
 )
+%
+if (x = x + 1).to_i
+  x
+end