 the analyzer core 
by calling <a href = "http://clang.llvm.org/doxygen/classclang_1_1ento_1_1CheckerContext.html#ae7738af2cbfd1d713edec33d3203dff5">CheckerContext::emitReport</a>.

<h2 id=ast>AST Visitors</h2>
  Some checks might not require path-sensitivity to be effective. Simple AST walk 
  might be sufficient. If that is the case, consider implementing a Clang 
  compiler warning. On the other hand, a check might not be acceptable as a compiler 
  warning; for example, because of a relatively high fals