llvm-project/clang-tools-extra/clang-tidy/misc/UnconventionalAssignOperato...

90 lines
3.3 KiB
C++

//===--- UnconventionalAssignOperatorCheck.cpp - clang-tidy -----*- C++ -*-===//
//
// The LLVM Compiler Infrastructure
//
// This file is distributed under the University of Illinois Open Source
// License. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//
#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) {
// Only register the matchers for C++; the functionality currently does not
// provide any benefit to other languages, despite being benign.
if (!getLangOpts().CPlusPlus)
return;
const auto HasGoodReturnType = cxxMethodDecl(returns(
lValueReferenceType(pointee(unless(isConstQualified()),
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(
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->getLocStart(), "operator=() should always return '*this'");
} else {
static const char *const Messages[][2] = {
{"ReturnType", "operator=() should return '%0&'"},
{"ArgumentType", "operator=() should take '%0 const&', '%0&&' 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->getLocStart(), Message[1])
<< Method->getParent()->getName()
<< (Method->isConst() ? "const" : "virtual");
}
}
}
} // namespace misc
} // namespace tidy
} // namespace clang