clang-tools 10.0.0

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
9 #include "UnconventionalAssignOperatorCheck.h"
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
clang::ast_matchers
Definition: AbseilMatcher.h:14
Decl
const FunctionDecl * Decl
Definition: AvoidBindCheck.cpp:93
UnconventionalAssignOperatorCheck.h
clang::tidy::modernize::Message
constexpr llvm::StringLiteral Message
Definition: UseTrailingReturnTypeCheck.cpp:101
clang
===– Representation.cpp - ClangDoc Representation --------—*- C++ -*-===//
Definition: ApplyReplacements.h:27