CastingThroughVoidCheck.cpp

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//===--- CastingThroughVoidCheck.cpp - clang-tidy -------------------------===//
//
// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
// See https://llvm.org/LICENSE.txt for license information.
// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
//
//===----------------------------------------------------------------------===//
 
#include "CastingThroughVoidCheck.h"
#include "clang/AST/Expr.h"
#include "clang/AST/Type.h"
#include "clang/ASTMatchers/ASTMatchFinder.h"
#include "clang/ASTMatchers/ASTMatchers.h"
 
using namespace clang::ast_matchers;
 
namespace clang::tidy::bugprone {
 
void CastingThroughVoidCheck::registerMatchers(MatchFinder *Finder) {
  Finder->addMatcher(
      explicitCastExpr(
          hasDestinationType(
              qualType(unless(hasCanonicalType(pointsTo(voidType()))))
                  .bind("target_type")),
          hasSourceExpression(
              explicitCastExpr(
                  hasSourceExpression(
                      expr(hasType(qualType(unless(pointsTo(voidType())))
                                       .bind("source_type")))),
                  hasDestinationType(
                      qualType(pointsTo(voidType())).bind("void_type")))
                  .bind("cast"))),
      this);
}
 
void CastingThroughVoidCheck::check(const MatchFinder::MatchResult &Result) {
  const auto TT = *Result.Nodes.getNodeAs<QualType>("target_type");
  const auto ST = *Result.Nodes.getNodeAs<QualType>("source_type");
  const auto VT = *Result.Nodes.getNodeAs<QualType>("void_type");
  const auto *CE = Result.Nodes.getNodeAs<ExplicitCastExpr>("cast");
  diag(CE->getExprLoc(), "do not cast %0 to %1 through %2") << ST << TT << VT;
}
 
} // namespace clang::tidy::bugprone