clang-tools  8.0.0
RedundantDeclarationCheck.cpp
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1 //===--- RedundantDeclarationCheck.cpp - clang-tidy------------------------===//
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 
11 #include "clang/AST/ASTContext.h"
12 #include "clang/ASTMatchers/ASTMatchFinder.h"
13 #include "clang/Lex/Lexer.h"
14 
15 using namespace clang::ast_matchers;
16 
17 namespace clang {
18 namespace tidy {
19 namespace readability {
20 
21 RedundantDeclarationCheck::RedundantDeclarationCheck(StringRef Name,
22  ClangTidyContext *Context)
23  : ClangTidyCheck(Name, Context),
24  IgnoreMacros(Options.getLocalOrGlobal("IgnoreMacros", true)) {}
25 
27  Finder->addMatcher(
28  namedDecl(anyOf(varDecl(unless(isDefinition())),
29  functionDecl(unless(anyOf(isDefinition(), isDefaulted(),
30  hasParent(friendDecl()))))))
31  .bind("Decl"),
32  this);
33 }
34 
35 void RedundantDeclarationCheck::check(const MatchFinder::MatchResult &Result) {
36  const auto *D = Result.Nodes.getNodeAs<NamedDecl>("Decl");
37  const auto *Prev = D->getPreviousDecl();
38  if (!Prev)
39  return;
40  if (!Prev->getLocation().isValid())
41  return;
42  if (Prev->getLocation() == D->getLocation())
43  return;
44  if (IgnoreMacros &&
45  (D->getLocation().isMacroID() || Prev->getLocation().isMacroID()))
46  return;
47  // Don't complain when the previous declaration is a friend declaration.
48  for (const auto &Parent : Result.Context->getParents(*Prev))
49  if (Parent.get<FriendDecl>())
50  return;
51 
52  const SourceManager &SM = *Result.SourceManager;
53 
54  const bool DifferentHeaders =
55  !SM.isInMainFile(D->getLocation()) &&
56  !SM.isWrittenInSameFile(Prev->getLocation(), D->getLocation());
57 
58  bool MultiVar = false;
59  if (const auto *VD = dyn_cast<VarDecl>(D)) {
60  // Is this a multivariable declaration?
61  for (const auto Other : VD->getDeclContext()->decls()) {
62  if (Other != D && Other->getBeginLoc() == VD->getBeginLoc()) {
63  MultiVar = true;
64  break;
65  }
66  }
67  }
68 
69  SourceLocation EndLoc = Lexer::getLocForEndOfToken(
70  D->getSourceRange().getEnd(), 0, SM, Result.Context->getLangOpts());
71  {
72  auto Diag = diag(D->getLocation(), "redundant %0 declaration") << D;
73  if (!MultiVar && !DifferentHeaders)
74  Diag << FixItHint::CreateRemoval(
75  SourceRange(D->getSourceRange().getBegin(), EndLoc));
76  }
77  diag(Prev->getLocation(), "previously declared here", DiagnosticIDs::Note);
78 }
79 
80 } // namespace readability
81 } // namespace tidy
82 } // namespace clang
Base class for all clang-tidy checks.
Definition: ClangTidy.h:127
static constexpr llvm::StringLiteral Name
const Decl * D
Definition: XRefs.cpp:79
llvm::Optional< llvm::Expected< tooling::AtomicChanges > > Result
===– 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.
Definition: ClangTidy.cpp:438
void registerMatchers(ast_matchers::MatchFinder *Finder) override
Override this to register AST matchers with Finder.