1 //===--- RedundantMemberInitCheck.cpp - clang-tidy-------------------------===//
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 "RedundantMemberInitCheck.h"
10 #include "../utils/Matchers.h"
11 #include "clang/AST/ASTContext.h"
12 #include "clang/ASTMatchers/ASTMatchFinder.h"
13 #include "clang/Lex/Lexer.h"
14 #include <algorithm>
15 
16 using namespace clang::ast_matchers;
17 using namespace clang::tidy::matchers;
18 
19 namespace clang {
20 namespace tidy {
21 namespace readability {
22 
storeOptions(ClangTidyOptions::OptionMap & Opts)23 void RedundantMemberInitCheck::storeOptions(ClangTidyOptions::OptionMap &Opts) {
24   Options.store(Opts, "IgnoreBaseInCopyConstructors",
25                 IgnoreBaseInCopyConstructors);
26 }
27 
registerMatchers(MatchFinder * Finder)28 void RedundantMemberInitCheck::registerMatchers(MatchFinder *Finder) {
29   auto Construct =
30       cxxConstructExpr(
31           hasDeclaration(cxxConstructorDecl(hasParent(
32               cxxRecordDecl(unless(isTriviallyDefaultConstructible()))))))
33           .bind("construct");
34 
35   Finder->addMatcher(
36       traverse(
37           TK_AsIs,
38           cxxConstructorDecl(
39               unless(isDelegatingConstructor()),
40               ofClass(unless(
41                   anyOf(isUnion(), ast_matchers::isTemplateInstantiation()))),
42               forEachConstructorInitializer(
43                   cxxCtorInitializer(
44                       isWritten(), withInitializer(ignoringImplicit(Construct)),
45                       unless(forField(hasType(isConstQualified()))),
46                       unless(forField(hasParent(recordDecl(isUnion())))))
47                       .bind("init")))
48               .bind("constructor")),
49       this);
50 }
51 
check(const MatchFinder::MatchResult & Result)52 void RedundantMemberInitCheck::check(const MatchFinder::MatchResult &Result) {
53   const auto *Init = Result.Nodes.getNodeAs<CXXCtorInitializer>("init");
54   const auto *Construct = Result.Nodes.getNodeAs<CXXConstructExpr>("construct");
55   const auto *ConstructorDecl =
56       Result.Nodes.getNodeAs<CXXConstructorDecl>("constructor");
57 
58   if (IgnoreBaseInCopyConstructors && ConstructorDecl->isCopyConstructor() &&
59       Init->isBaseInitializer())
60     return;
61 
62   if (Construct->getNumArgs() == 0 ||
63       Construct->getArg(0)->isDefaultArgument()) {
64     if (Init->isAnyMemberInitializer()) {
65       diag(Init->getSourceLocation(), "initializer for member %0 is redundant")
66           << Init->getAnyMember()
67           << FixItHint::CreateRemoval(Init->getSourceRange());
68     } else {
69       diag(Init->getSourceLocation(),
70            "initializer for base class %0 is redundant")
71           << Construct->getType()
72           << FixItHint::CreateRemoval(Init->getSourceRange());
73     }
74   }
75 }
76 
77 } // namespace readability
78 } // namespace tidy
79 } // namespace clang
80