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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(hasCanonicalType(lValueReferenceType(pointee(
unless(isConstQualified()),
anyOf(autoType(), hasDeclaration(equalsBoundNode("class"))))))));
const auto IsSelf = qualType(hasCanonicalType(
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 = qualType(hasCanonicalType(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 {
const auto *Method = Result.Nodes.getNodeAs<CXXMethodDecl>("method");
if (Result.Nodes.getNodeAs<CXXMethodDecl>("ReturnType"))
diag(Method->getBeginLoc(), "operator=() should return '%0&'")
<< Method->getParent()->getName();
if (Result.Nodes.getNodeAs<CXXMethodDecl>("ArgumentType"))
diag(Method->getBeginLoc(),
"operator=() should take '%0 const&'%select{|, '%0&&'}1 or '%0'")
<< Method->getParent()->getName() << getLangOpts().CPlusPlus11;
if (Result.Nodes.getNodeAs<CXXMethodDecl>("cv"))
diag(Method->getBeginLoc(),
"operator=() should not be marked '%select{const|virtual}0'")
<< !Method->isConst();
}
}
} // namespace misc
} // namespace tidy
} // namespace clang
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