UnconventionalAssignOperatorCheck.cpp
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//===--- UnconventionalAssignOperatorCheck.cpp - clang-tidy -----*- C++ -*-===//
//
// 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 "UnconventionalAssignOperatorCheck.h"
#include "clang/ASTMatchers/ASTMatchFinder.h"
#include "clang/ASTMatchers/ASTMatchers.h"
using namespace clang::ast_matchers;
namespace clang {
namespace tidy {
namespace misc {
void UnconventionalAssignOperatorCheck::registerMatchers(
ast_matchers::MatchFinder *Finder) {
const auto HasGoodReturnType = cxxMethodDecl(returns(lValueReferenceType(
pointee(unless(isConstQualified()),
anyOf(autoType(), hasDeclaration(equalsBoundNode("class")))))));
const auto IsSelf = qualType(
anyOf(hasDeclaration(equalsBoundNode("class")),
referenceType(pointee(hasDeclaration(equalsBoundNode("class"))))));
const auto IsAssign =
cxxMethodDecl(unless(anyOf(isDeleted(), isPrivate(), isImplicit())),
hasName("operator="), ofClass(recordDecl().bind("class")))
.bind("method");
const auto IsSelfAssign =
cxxMethodDecl(IsAssign, hasParameter(0, parmVarDecl(hasType(IsSelf))))
.bind("method");
Finder->addMatcher(
cxxMethodDecl(IsAssign, unless(HasGoodReturnType)).bind("ReturnType"),
this);
const auto BadSelf = referenceType(
anyOf(lValueReferenceType(pointee(unless(isConstQualified()))),
rValueReferenceType(pointee(isConstQualified()))));
Finder->addMatcher(
cxxMethodDecl(IsSelfAssign,
hasParameter(0, parmVarDecl(hasType(BadSelf))))
.bind("ArgumentType"),
this);
Finder->addMatcher(
cxxMethodDecl(IsSelfAssign, anyOf(isConst(), isVirtual())).bind("cv"),
this);
const auto IsBadReturnStatement = returnStmt(unless(has(ignoringParenImpCasts(
anyOf(unaryOperator(hasOperatorName("*"), hasUnaryOperand(cxxThisExpr())),
cxxOperatorCallExpr(argumentCountIs(1),
callee(unresolvedLookupExpr()),
hasArgument(0, cxxThisExpr())),
cxxOperatorCallExpr(
hasOverloadedOperatorName("="),
hasArgument(
0, unaryOperator(hasOperatorName("*"),
hasUnaryOperand(cxxThisExpr())))))))));
const auto IsGoodAssign = cxxMethodDecl(IsAssign, HasGoodReturnType);
Finder->addMatcher(returnStmt(IsBadReturnStatement, forFunction(IsGoodAssign))
.bind("returnStmt"),
this);
}
void UnconventionalAssignOperatorCheck::check(
const MatchFinder::MatchResult &Result) {
if (const auto *RetStmt = Result.Nodes.getNodeAs<ReturnStmt>("returnStmt")) {
diag(RetStmt->getBeginLoc(), "operator=() should always return '*this'");
} else {
static const char *const Messages[][2] = {
{"ReturnType", "operator=() should return '%0&'"},
{"ArgumentType",
getLangOpts().CPlusPlus11
? "operator=() should take '%0 const&', '%0&&' or '%0'"
: "operator=() should take '%0 const&' or '%0'"},
{"cv", "operator=() should not be marked '%1'"}};
const auto *Method = Result.Nodes.getNodeAs<CXXMethodDecl>("method");
for (const auto &Message : Messages) {
if (Result.Nodes.getNodeAs<Decl>(Message[0]))
diag(Method->getBeginLoc(), Message[1])
<< Method->getParent()->getName()
<< (Method->isConst() ? "const" : "virtual");
}
}
}
} // namespace misc
} // namespace tidy
} // namespace clang