clang-tools  10.0.0git
RedundantDeclarationCheck.cpp
Go to the documentation of this file.
1 //===--- RedundantDeclarationCheck.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 
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 
20 AST_MATCHER(FunctionDecl, doesDeclarationForceExternallyVisibleDefinition) {
21  return Node.doesDeclarationForceExternallyVisibleDefinition();
22 }
23 
24 RedundantDeclarationCheck::RedundantDeclarationCheck(StringRef Name,
25  ClangTidyContext *Context)
26  : ClangTidyCheck(Name, Context),
27  IgnoreMacros(Options.getLocalOrGlobal("IgnoreMacros", true)) {}
28 
30  Finder->addMatcher(
31  namedDecl(anyOf(varDecl(unless(isDefinition())),
32  functionDecl(unless(anyOf(
33  isDefinition(), isDefaulted(),
34  doesDeclarationForceExternallyVisibleDefinition(),
35  hasParent(friendDecl()))))))
36  .bind("Decl"),
37  this);
38 }
39 
40 void RedundantDeclarationCheck::check(const MatchFinder::MatchResult &Result) {
41  const auto *D = Result.Nodes.getNodeAs<NamedDecl>("Decl");
42  const auto *Prev = D->getPreviousDecl();
43  if (!Prev)
44  return;
45  if (!Prev->getLocation().isValid())
46  return;
47  if (Prev->getLocation() == D->getLocation())
48  return;
49  if (IgnoreMacros &&
50  (D->getLocation().isMacroID() || Prev->getLocation().isMacroID()))
51  return;
52  // Don't complain when the previous declaration is a friend declaration.
53  for (const auto &Parent : Result.Context->getParents(*Prev))
54  if (Parent.get<FriendDecl>())
55  return;
56 
57  const SourceManager &SM = *Result.SourceManager;
58 
59  const bool DifferentHeaders =
60  !SM.isInMainFile(D->getLocation()) &&
61  !SM.isWrittenInSameFile(Prev->getLocation(), D->getLocation());
62 
63  bool MultiVar = false;
64  if (const auto *VD = dyn_cast<VarDecl>(D)) {
65  // Is this a multivariable declaration?
66  for (const auto Other : VD->getDeclContext()->decls()) {
67  if (Other != D && Other->getBeginLoc() == VD->getBeginLoc()) {
68  MultiVar = true;
69  break;
70  }
71  }
72  }
73 
74  SourceLocation EndLoc = Lexer::getLocForEndOfToken(
75  D->getSourceRange().getEnd(), 0, SM, Result.Context->getLangOpts());
76  {
77  auto Diag = diag(D->getLocation(), "redundant %0 declaration") << D;
78  if (!MultiVar && !DifferentHeaders)
79  Diag << FixItHint::CreateRemoval(
80  SourceRange(D->getSourceRange().getBegin(), EndLoc));
81  }
82  diag(Prev->getLocation(), "previously declared here", DiagnosticIDs::Note);
83 }
84 
85 } // namespace readability
86 } // namespace tidy
87 } // namespace clang
const Node * Parent
Base class for all clang-tidy checks.
static constexpr llvm::StringLiteral Name
===– Representation.cpp - ClangDoc Representation --------—*- C++ -*-===//
void check(const ast_matchers::MatchFinder::MatchResult &Result) override
ClangTidyChecks that register ASTMatchers should do the actual work in here.
Every ClangTidyCheck reports errors through a DiagnosticsEngine provided by this context.
DiagnosticBuilder diag(SourceLocation Loc, StringRef Description, DiagnosticIDs::Level Level=DiagnosticIDs::Warning)
Add a diagnostic with the check&#39;s name.
void registerMatchers(ast_matchers::MatchFinder *Finder) override
Override this to register AST matchers with Finder.