[PATCH] D47554: [analyzer] Check for dead/impossible status checks

[Alexander Kornienko via Phabricator via cfe-commits]

alexfh added inline comments.


================
Comment at: lib/StaticAnalyzer/Checkers/DeadStatusChecker.cpp:33
+
+    const Expr *hasNullptr(const BinaryOperator *BO) const {
+      const Expr *ret = nullptr;
----------------
george.karpenkov wrote:
> Could this be rewritten as a matcher instead? Surely there must be one comparing the literal to null?
For this particular part a matchers-based solution might be a bit wordy:

  binaryOperator(anyOf(
    allOf(hasLHS(ignoringParenCasts(nullPointerConstant())), hasRHS(expr().bind("other"))),
    allOf(hasRHS(ignoringParenCasts(nullPointerConstant())), hasLHS(expr().bind("other")))))

But maybe it's time to add a helper matcher similar to hasEitherOperand, for example:
  inline internal::Matcher<BinaryOperator> hasOperands(
      const internal::Matcher<Expr> &One, const internal::Matcher<Expr> &Another) {
    return anyOf(allOf(hasLHS(One), hasRHS(Another)), allOf(hasRHS(One), hasLHS(Another)));
  }

This can be done locally, but I wouldn't object adding it to ASTMatchers.h, since it could already be used a few times in the existing code (at least in clang-tidy/bugprone/IncorrectRoundingsCheck.cpp and clang-tidy/misc/RedundantExpressionCheck.cpp).


Repository:
  rC Clang

https://reviews.llvm.org/D47554