clang-tools  9.0.0
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  // Only register the matchers for C++; the functionality currently does not
22  // provide any benefit to other languages, despite being benign.
23  if (!getLangOpts().CPlusPlus)
24  return;
25 
26  const auto HasGoodReturnType = cxxMethodDecl(returns(lValueReferenceType(
27  pointee(unless(isConstQualified()),
28  anyOf(autoType(), hasDeclaration(equalsBoundNode("class")))))));
29 
30  const auto IsSelf = qualType(
31  anyOf(hasDeclaration(equalsBoundNode("class")),
32  referenceType(pointee(hasDeclaration(equalsBoundNode("class"))))));
33  const auto IsAssign =
34  cxxMethodDecl(unless(anyOf(isDeleted(), isPrivate(), isImplicit())),
35  hasName("operator="), ofClass(recordDecl().bind("class")))
36  .bind("method");
37  const auto IsSelfAssign =
38  cxxMethodDecl(IsAssign, hasParameter(0, parmVarDecl(hasType(IsSelf))))
39  .bind("method");
40 
41  Finder->addMatcher(
42  cxxMethodDecl(IsAssign, unless(HasGoodReturnType)).bind("ReturnType"),
43  this);
44 
45  const auto BadSelf = referenceType(
46  anyOf(lValueReferenceType(pointee(unless(isConstQualified()))),
47  rValueReferenceType(pointee(isConstQualified()))));
48 
49  Finder->addMatcher(
50  cxxMethodDecl(IsSelfAssign,
51  hasParameter(0, parmVarDecl(hasType(BadSelf))))
52  .bind("ArgumentType"),
53  this);
54 
55  Finder->addMatcher(
56  cxxMethodDecl(IsSelfAssign, anyOf(isConst(), isVirtual())).bind("cv"),
57  this);
58 
59  const auto IsBadReturnStatement = returnStmt(unless(has(ignoringParenImpCasts(
60  anyOf(unaryOperator(hasOperatorName("*"), hasUnaryOperand(cxxThisExpr())),
61  cxxOperatorCallExpr(argumentCountIs(1),
62  callee(unresolvedLookupExpr()),
63  hasArgument(0, cxxThisExpr())))))));
64  const auto IsGoodAssign = cxxMethodDecl(IsAssign, HasGoodReturnType);
65 
66  Finder->addMatcher(returnStmt(IsBadReturnStatement, forFunction(IsGoodAssign))
67  .bind("returnStmt"),
68  this);
69 }
70 
71 void UnconventionalAssignOperatorCheck::check(
72  const MatchFinder::MatchResult &Result) {
73  if (const auto *RetStmt = Result.Nodes.getNodeAs<ReturnStmt>("returnStmt")) {
74  diag(RetStmt->getBeginLoc(), "operator=() should always return '*this'");
75  } else {
76  static const char *const Messages[][2] = {
77  {"ReturnType", "operator=() should return '%0&'"},
78  {"ArgumentType", "operator=() should take '%0 const&', '%0&&' or '%0'"},
79  {"cv", "operator=() should not be marked '%1'"}};
80 
81  const auto *Method = Result.Nodes.getNodeAs<CXXMethodDecl>("method");
82  for (const auto &Message : Messages) {
83  if (Result.Nodes.getNodeAs<Decl>(Message[0]))
84  diag(Method->getBeginLoc(), Message[1])
85  << Method->getParent()->getName()
86  << (Method->isConst() ? "const" : "virtual");
87  }
88  }
89 }
90 
91 } // namespace misc
92 } // namespace tidy
93 } // namespace clang
constexpr llvm::StringLiteral Message
===– Representation.cpp - ClangDoc Representation --------—*- C++ -*-===//
llvm::Optional< llvm::Expected< tooling::AtomicChanges > > Result
Definition: Rename.cpp:36