title: source() doesn't work ("node stack overflow")
body: <p>I have the following few lines of code in my R script called <code>assign1.R</code>:</p>
  
  <pre><code>(u &lt;- c(1, 1, 0, 1, 0)) # a)
  u[3] # b)
  ones_u &lt;- which(u == 1) # c)
  ones_u
  source("assign1.R")
  </code></pre>
  
  <p>Only, the <code>source()</code> function does not work. R shows me the following error message:</p>
  
  <pre><code>Error in match(x, table, nomatch = 0L) : node stack overflow
  Error during wrapup: node stack overflow
  </code></pre>
  
  <p>What is the problem?</p>