title: Vim syntax error highlight
body: <p>I'm vim newbie, and I been using someone's vim configuration(I've cloned his <code>.vim</code> directory to my home directory).</p>
  
  <p>It seems that his configuration has a bug about syntax checking. As you can see:</p>
  
  <p><a href="https://i.stack.imgur.com/8JT5b.png" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/8JT5b.png" alt="enter image description here"></a></p>
  
  <p>The bracket should not be highlighted, cause there is not error there.</p>
  
  <p>So my question is, which part of the <code>vim</code> configuration should I check for this issue.</p>
  
  <p>Thanks</p>
  
  <p><strong>UPDATE: 0</strong></p>
  
  <p>I think I found the line that cause this bug.</p>
  
  <p>I have a extra.vim file in <code>~/.vim/syntax/c/extra.vim</code> the file is looks like:</p>
  
  <pre><code>"========================================================
  " Highlight All Function
  "========================================================
  syn match   cFunction "\&lt;[a-zA-Z_][a-zA-Z_0-9]*\&gt;[^()]*)("me=e-2
  syn match   cFunction "\&lt;[a-zA-Z_][a-zA-Z_0-9]*\&gt;\s*("me=e-1
  
  "========================================================
  " Highlight All Math Operator
  "========================================================
  " C math operators
  syn match       cMathOperator     display "[-+\*/%=]"
  "" C pointer operators
  syn match       cPointerOperator  display "-&gt;\|\."
  "" C logical   operators - boolean results
  syn match       cLogicalOperator  display "[!&lt;&gt;]=\="
  syn match       cLogicalOperator  display "=="
  "" C bit operators
  syn match       cBinaryOperator   display "\(&amp;\||\|\^\|&lt;&lt;\|&gt;&gt;\)=\="
  syn match       cBinaryOperator   display "\~"
  syn match       cBinaryOperatorError display "\~="
  "" More C logical operators - highlight in preference to binary
  syn match       cLogicalOperator  display "&amp;&amp;\|||"
  syn match       cLogicalOperatorError display "\(&amp;&amp;\|||\)="
  
  " Math Operator
  hi def link cMathOperator            cOperator
  hi def link cPointerOperator         cOperator
  hi def link cLogicalOperator         cOperator
  hi def link cBinaryOperator          cOperator
  hi def link cBinaryOperatorError     cOperator
  hi def link cLogicalOperator         cOperator
  hi def link cLogicalOperatorError    cOperator
  
  
  hi def link cFunction Function
  hi def link cOperator Operator
  
  " hi Operator guifg=LightGoldenrod
  </code></pre>
  
  <p>When I comment out the line below:</p>
  
  <pre><code>syn match       cMathOperator     display "[-+\*/%=]"
  </code></pre>
  
  <p>The issue is gone.</p>
  
  <p>So how can I fix this, and why ?</p>