1 //===--- UniqueptrDeleteReleaseCheck.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 "UniqueptrDeleteReleaseCheck.h"
10 #include "clang/AST/ASTContext.h"
11 #include "clang/ASTMatchers/ASTMatchFinder.h"
12 #include "clang/Lex/Lexer.h"
13
14 using namespace clang::ast_matchers;
15
16 namespace clang {
17 namespace tidy {
18 namespace readability {
19
registerMatchers(MatchFinder * Finder)20 void UniqueptrDeleteReleaseCheck::registerMatchers(MatchFinder *Finder) {
21 auto IsSusbstituted = qualType(anyOf(
22 substTemplateTypeParmType(), hasDescendant(substTemplateTypeParmType())));
23
24 auto UniquePtrWithDefaultDelete = classTemplateSpecializationDecl(
25 hasName("std::unique_ptr"),
26 hasTemplateArgument(1, refersToType(qualType(hasDeclaration(cxxRecordDecl(
27 hasName("std::default_delete")))))));
28
29 Finder->addMatcher(
30 cxxDeleteExpr(has(ignoringParenImpCasts(cxxMemberCallExpr(
31 on(expr(hasType(UniquePtrWithDefaultDelete),
32 unless(hasType(IsSusbstituted)))
33 .bind("uptr")),
34 callee(cxxMethodDecl(hasName("release")))))))
35 .bind("delete"),
36 this);
37 }
38
check(const MatchFinder::MatchResult & Result)39 void UniqueptrDeleteReleaseCheck::check(
40 const MatchFinder::MatchResult &Result) {
41 const auto *PtrExpr = Result.Nodes.getNodeAs<Expr>("uptr");
42 const auto *DeleteExpr = Result.Nodes.getNodeAs<Expr>("delete");
43
44 if (PtrExpr->getBeginLoc().isMacroID())
45 return;
46
47 // Ignore dependent types.
48 // It can give us false positives, so we go with false negatives instead to
49 // be safe.
50 if (PtrExpr->getType()->isDependentType())
51 return;
52
53 SourceLocation AfterPtr = Lexer::getLocForEndOfToken(
54 PtrExpr->getEndLoc(), 0, *Result.SourceManager, getLangOpts());
55
56 diag(DeleteExpr->getBeginLoc(),
57 "prefer '= nullptr' to 'delete x.release()' to reset unique_ptr<> "
58 "objects")
59 << FixItHint::CreateRemoval(CharSourceRange::getCharRange(
60 DeleteExpr->getBeginLoc(), PtrExpr->getBeginLoc()))
61 << FixItHint::CreateReplacement(
62 CharSourceRange::getTokenRange(AfterPtr, DeleteExpr->getEndLoc()),
63 " = nullptr");
64 }
65
66 } // namespace readability
67 } // namespace tidy
68 } // namespace clang
69