clang-tools 6.0.0

UnconventionalAssignOperatorCheck.cpp
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1 //===--- UnconventionalAssignOperatorCheck.cpp - clang-tidy -----*- C++ -*-===//
2 //
3 // The LLVM Compiler Infrastructure
4 //
5 // This file is distributed under the University of Illinois Open Source
6 // License. See LICENSE.TXT for details.
7 //
8 //===----------------------------------------------------------------------===//
9
10 #include "UnconventionalAssignOperatorCheck.h"
11 #include "clang/ASTMatchers/ASTMatchFinder.h"
12 #include "clang/ASTMatchers/ASTMatchers.h"
13
14 using namespace clang::ast_matchers;
15
16 namespace clang {
17 namespace tidy {
18 namespace misc {
19
20 void UnconventionalAssignOperatorCheck::registerMatchers(
21 ast_matchers::MatchFinder *Finder) {
22 // Only register the matchers for C++; the functionality currently does not
23 // provide any benefit to other languages, despite being benign.
24 if (!getLangOpts().CPlusPlus)
25 return;
26
27 const auto HasGoodReturnType = cxxMethodDecl(returns(
28 lValueReferenceType(pointee(unless(isConstQualified()),
29 hasDeclaration(equalsBoundNode("class"))))));
30
31 const auto IsSelf = qualType(
32 anyOf(hasDeclaration(equalsBoundNode("class")),
33 referenceType(pointee(hasDeclaration(equalsBoundNode("class"))))));
34 const auto IsAssign =
35 cxxMethodDecl(unless(anyOf(isDeleted(), isPrivate(), isImplicit())),
36 hasName("operator="), ofClass(recordDecl().bind("class")))
37 .bind("method");
38 const auto IsSelfAssign =
39 cxxMethodDecl(IsAssign, hasParameter(0, parmVarDecl(hasType(IsSelf))))
40 .bind("method");
41
42 Finder->addMatcher(
43 cxxMethodDecl(IsAssign, unless(HasGoodReturnType)).bind("ReturnType"),
44 this);
45
46 const auto BadSelf = referenceType(
47 anyOf(lValueReferenceType(pointee(unless(isConstQualified()))),
48 rValueReferenceType(pointee(isConstQualified()))));
49
50 Finder->addMatcher(
51 cxxMethodDecl(IsSelfAssign,
52 hasParameter(0, parmVarDecl(hasType(BadSelf))))
53 .bind("ArgumentType"),
54 this);
55
56 Finder->addMatcher(
57 cxxMethodDecl(IsSelfAssign, anyOf(isConst(), isVirtual())).bind("cv"),
58 this);
59
60 const auto IsBadReturnStatement = returnStmt(unless(has(ignoringParenImpCasts(
61 anyOf(unaryOperator(hasOperatorName("*"), hasUnaryOperand(cxxThisExpr())),
62 cxxOperatorCallExpr(argumentCountIs(1),
63 callee(unresolvedLookupExpr()),
64 hasArgument(0, cxxThisExpr())))))));
65 const auto IsGoodAssign = cxxMethodDecl(IsAssign, HasGoodReturnType);
66
67 Finder->addMatcher(returnStmt(IsBadReturnStatement, forFunction(IsGoodAssign))
68 .bind("returnStmt"),
69 this);
70 }
71
72 void UnconventionalAssignOperatorCheck::check(
73 const MatchFinder::MatchResult &Result) {
74 if (const auto *RetStmt = Result.Nodes.getNodeAs<ReturnStmt>("returnStmt")) {
75 diag(RetStmt->getLocStart(), "operator=() should always return '*this'");
76 } else {
77 static const char *const Messages[][2] = {
78 {"ReturnType", "operator=() should return '%0&'"},
79 {"ArgumentType", "operator=() should take '%0 const&', '%0&&' or '%0'"},
80 {"cv", "operator=() should not be marked '%1'"}};
81
82 const auto *Method = Result.Nodes.getNodeAs<CXXMethodDecl>("method");
83 for (const auto &Message : Messages) {
84 if (Result.Nodes.getNodeAs<Decl>(Message[0]))
85 diag(Method->getLocStart(), Message[1])
86 << Method->getParent()->getName()
87 << (Method->isConst() ? "const" : "virtual");
88 }
89 }
90 }
91
92 } // namespace misc
93 } // namespace tidy
94 } // namespace clang
clang::ast_matchers
Definition: ClangTidyDiagnosticConsumer.h:27
UnconventionalAssignOperatorCheck.h
clang::tidy::modernize::Message
static const StringRef Message
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clang
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