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| //===--- BoolPointerImplicitConversionCheck.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 "BoolPointerImplicitConversionCheck.h"
using namespace clang::ast_matchers;
namespace clang {
namespace tidy {
namespace bugprone {
void BoolPointerImplicitConversionCheck::registerMatchers(MatchFinder *Finder) {
// Look for ifs that have an implicit bool* to bool conversion in the
// condition. Filter negations.
Finder->addMatcher(
ifStmt(hasCondition(findAll(implicitCastExpr(
unless(hasParent(unaryOperator(hasOperatorName("!")))),
hasSourceExpression(
expr(hasType(pointerType(pointee(booleanType()))),
ignoringParenImpCasts(declRefExpr().bind("expr")))),
hasCastKind(CK_PointerToBoolean)))),
unless(isInTemplateInstantiation()))
.bind("if"),
this);
}
void BoolPointerImplicitConversionCheck::check(
const MatchFinder::MatchResult &Result) {
auto *If = Result.Nodes.getNodeAs<IfStmt>("if");
auto *Var = Result.Nodes.getNodeAs<DeclRefExpr>("expr");
// Ignore macros.
if (Var->getBeginLoc().isMacroID())
return;
// Only allow variable accesses for now, no function calls or member exprs.
// Check that we don't dereference the variable anywhere within the if. This
// avoids false positives for checks of the pointer for nullptr before it is
// dereferenced. If there is a dereferencing operator on this variable don't
// emit a diagnostic. Also ignore array subscripts.
const Decl *D = Var->getDecl();
auto DeclRef = ignoringParenImpCasts(declRefExpr(to(equalsNode(D))));
if (!match(findAll(
unaryOperator(hasOperatorName("*"), hasUnaryOperand(DeclRef))),
*If, *Result.Context)
.empty() ||
!match(findAll(arraySubscriptExpr(hasBase(DeclRef))), *If,
*Result.Context)
.empty() ||
// FIXME: We should still warn if the paremater is implicitly converted to
// bool.
!match(findAll(callExpr(hasAnyArgument(ignoringParenImpCasts(DeclRef)))),
*If, *Result.Context)
.empty() ||
!match(findAll(cxxDeleteExpr(has(ignoringParenImpCasts(expr(DeclRef))))),
*If, *Result.Context)
.empty())
return;
diag(Var->getBeginLoc(), "dubious check of 'bool *' against 'nullptr', did "
"you mean to dereference it?")
<< FixItHint::CreateInsertion(Var->getBeginLoc(), "*");
}
} // namespace bugprone
} // namespace tidy
} // namespace clang
|