clang-tools  15.0.0git
UnconventionalAssignOperatorCheck.cpp
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1 //===--- UnconventionalAssignOperatorCheck.cpp - clang-tidy -----*- C++ -*-===//
2 //
3 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
4 // See https://llvm.org/LICENSE.txt for license information.
5 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
6 //
7 //===----------------------------------------------------------------------===//
8 
10 #include "clang/ASTMatchers/ASTMatchFinder.h"
11 #include "clang/ASTMatchers/ASTMatchers.h"
12 
13 using namespace clang::ast_matchers;
14 
15 namespace clang {
16 namespace tidy {
17 namespace misc {
18 
19 void UnconventionalAssignOperatorCheck::registerMatchers(
20  ast_matchers::MatchFinder *Finder) {
21  const auto HasGoodReturnType =
22  cxxMethodDecl(returns(hasCanonicalType(lValueReferenceType(pointee(
23  unless(isConstQualified()),
24  anyOf(autoType(), hasDeclaration(equalsBoundNode("class"))))))));
25 
26  const auto IsSelf = qualType(hasCanonicalType(
27  anyOf(hasDeclaration(equalsBoundNode("class")),
28  referenceType(pointee(hasDeclaration(equalsBoundNode("class")))))));
29  const auto IsAssign =
30  cxxMethodDecl(unless(anyOf(isDeleted(), isPrivate(), isImplicit())),
31  hasName("operator="), ofClass(recordDecl().bind("class")))
32  .bind("method");
33  const auto IsSelfAssign =
34  cxxMethodDecl(IsAssign, hasParameter(0, parmVarDecl(hasType(IsSelf))))
35  .bind("method");
36 
37  Finder->addMatcher(
38  cxxMethodDecl(IsAssign, unless(HasGoodReturnType)).bind("ReturnType"),
39  this);
40 
41  const auto BadSelf = qualType(hasCanonicalType(referenceType(
42  anyOf(lValueReferenceType(pointee(unless(isConstQualified()))),
43  rValueReferenceType(pointee(isConstQualified()))))));
44 
45  Finder->addMatcher(
46  cxxMethodDecl(IsSelfAssign,
47  hasParameter(0, parmVarDecl(hasType(BadSelf))))
48  .bind("ArgumentType"),
49  this);
50 
51  Finder->addMatcher(
52  cxxMethodDecl(IsSelfAssign, anyOf(isConst(), isVirtual())).bind("cv"),
53  this);
54 
55  const auto IsBadReturnStatement = returnStmt(unless(has(ignoringParenImpCasts(
56  anyOf(unaryOperator(hasOperatorName("*"), hasUnaryOperand(cxxThisExpr())),
57  cxxOperatorCallExpr(argumentCountIs(1),
58  callee(unresolvedLookupExpr()),
59  hasArgument(0, cxxThisExpr())),
60  cxxOperatorCallExpr(
61  hasOverloadedOperatorName("="),
62  hasArgument(
63  0, unaryOperator(hasOperatorName("*"),
64  hasUnaryOperand(cxxThisExpr())))))))));
65  const auto IsGoodAssign = cxxMethodDecl(IsAssign, HasGoodReturnType);
66 
67  Finder->addMatcher(returnStmt(IsBadReturnStatement, forFunction(IsGoodAssign))
68  .bind("returnStmt"),
69  this);
70 }
71 
73  const MatchFinder::MatchResult &Result) {
74  if (const auto *RetStmt = Result.Nodes.getNodeAs<ReturnStmt>("returnStmt")) {
75  diag(RetStmt->getBeginLoc(), "operator=() should always return '*this'");
76  } else {
77  const auto *Method = Result.Nodes.getNodeAs<CXXMethodDecl>("method");
78  if (Result.Nodes.getNodeAs<CXXMethodDecl>("ReturnType"))
79  diag(Method->getBeginLoc(), "operator=() should return '%0&'")
80  << Method->getParent()->getName();
81  if (Result.Nodes.getNodeAs<CXXMethodDecl>("ArgumentType"))
82  diag(Method->getBeginLoc(),
83  "operator=() should take '%0 const&'%select{|, '%0&&'}1 or '%0'")
84  << Method->getParent()->getName() << getLangOpts().CPlusPlus11;
85  if (Result.Nodes.getNodeAs<CXXMethodDecl>("cv"))
86  diag(Method->getBeginLoc(),
87  "operator=() should not be marked '%select{const|virtual}0'")
88  << !Method->isConst();
89  }
90 }
91 
92 } // namespace misc
93 } // namespace tidy
94 } // namespace clang
clang::clangd::check
bool check(llvm::StringRef File, llvm::Optional< Range > LineRange, const ThreadsafeFS &TFS, const ClangdLSPServer::Options &Opts, bool EnableCodeCompletion)
Definition: Check.cpp:268
clang::ast_matchers
Definition: AbseilMatcher.h:14
clang
===– Representation.cpp - ClangDoc Representation --------—*- C++ -*-===//
Definition: ApplyReplacements.h:27
UnconventionalAssignOperatorCheck.h