Commit 7b938627 authored by Tom Stellard's avatar Tom Stellard
Browse files

Merging r314733: 

------------------------------------------------------------------------
r314733 | rsmith | 2017-10-02 15:43:36 -0700 (Mon, 02 Oct 2017) | 5 lines

PR33839: Fix -Wunused handling for structured binding declarations.

We warn about a structured binding declaration being unused only if none of its
bindings are used.

------------------------------------------------------------------------

llvm-svn: 319847
parent adb004d9

clang/lib/Sema/SemaDecl.cpp

+21 −5
Original line number Diff line number Diff line
@@ -1603,7 +1603,24 @@ static bool ShouldDiagnoseUnusedDecl(const NamedDecl *D) { 
  if (D->isInvalidDecl())

    return false;













  if (D->isReferenced() || D->isUsed() || D->hasAttr<UnusedAttr>() ||













  bool Referenced = false;













  if (auto *DD = dyn_cast<DecompositionDecl>(D)) {













    // For a decomposition declaration, warn if none of the bindings are













    // referenced, instead of if the variable itself is referenced (which













    // it is, by the bindings' expressions).













    for (auto *BD : DD->bindings()) {













      if (BD->isReferenced()) {













        Referenced = true;













        break;













      }













    }













  } else if (!D->getDeclName()) {













    return false;













  } else if (D->isReferenced() || D->isUsed()) {













    Referenced = true;













  }

























  if (Referenced || D->hasAttr<UnusedAttr>() ||















      D->hasAttr<ObjCPreciseLifetimeAttr>())















    return false;
























@@ -1726,7 +1743,7 @@ void Sema::DiagnoseUnusedDecl(const NamedDecl *D) {













  else















    DiagID = diag::warn_unused_variable;



























  Diag(D->getLocation(), DiagID) << D->getDeclName() << Hint;













  Diag(D->getLocation(), DiagID) << D << Hint;















}





























static void CheckPoppedLabel(LabelDecl *L, Sema &S) {










@@ -1756,8 +1773,6 @@ void Sema::ActOnPopScope(SourceLocation Loc, Scope *S) {













    assert(isa<NamedDecl>(TmpD) && "Decl isn't NamedDecl?");















    NamedDecl *D = cast<NamedDecl>(TmpD);



























    if (!D->getDeclName()) continue;



























    // Diagnose unused variables in this scope.















    if (!S->hasUnrecoverableErrorOccurred()) {















      DiagnoseUnusedDecl(D);









@@ -1765,6 +1780,8 @@ void Sema::ActOnPopScope(SourceLocation Loc, Scope *S) {













        DiagnoseUnusedNestedTypedefs(RD);















    }



























    if (!D->getDeclName()) continue;



























    // If this was a forward reference to a label, verify it was defined.















    if (LabelDecl *LD = dyn_cast<LabelDecl>(D))















      CheckPoppedLabel(LD, *this);










@@ -6155,7 +6172,6 @@ NamedDecl *Sema::ActOnVariableDeclarator(













  IdentifierInfo *II = Name.getAsIdentifierInfo();





























  if (D.isDecompositionDeclarator()) {













    AddToScope = false;















    // Take the name of the first declarator as our name for diagnostic















    // purposes.















    auto &Decomp = D.getDecompositionDeclarator();

































clang/lib/Sema/SemaDeclCXX.cpp



+4
−1






























Original line number
Diff line number
Diff line








@@ -826,7 +826,10 @@ Sema::ActOnDecompositionDeclarator(Scope *S, Declarator &D,













  NamedDecl *New =















      ActOnVariableDeclarator(S, D, DC, TInfo, Previous,















                              MultiTemplateParamsArg(), AddToScope, Bindings);













  if (AddToScope) {













    S->AddDecl(New);















    CurContext->addHiddenDecl(New);













  }





























  if (isInOpenMPDeclareTargetContext())















    checkDeclIsAllowedInOpenMPTarget(nullptr, New);

































clang/lib/Sema/SemaTemplateInstantiateDecl.cpp



+1
−0






























Original line number
Diff line number
Diff line








@@ -677,6 +677,7 @@ TemplateDeclInstantiator::VisitTypeAliasTemplateDecl(TypeAliasTemplateDecl *D) {













Decl *TemplateDeclInstantiator::VisitBindingDecl(BindingDecl *D) {















  auto *NewBD = BindingDecl::Create(SemaRef.Context, Owner, D->getLocation(),















                                    D->getIdentifier());













  NewBD->setReferenced(D->isReferenced());















  SemaRef.CurrentInstantiationScope->InstantiatedLocal(D, NewBD);















  return NewBD;















}

































clang/test/SemaCXX/unused.cpp



+46
−4






























Original line number
Diff line number
Diff line













// RUN: %clang_cc1 -fsyntax-only -verify %s













// RUN: %clang_cc1 -fsyntax-only -verify -std=c++98 %s













// RUN: %clang_cc1 -fsyntax-only -verify -std=c++11 %s













// RUN: %clang_cc1 -fsyntax-only -verify -Wunused %s













// RUN: %clang_cc1 -fsyntax-only -verify -std=c++98 -Wunused %s













// RUN: %clang_cc1 -fsyntax-only -verify -std=c++11 -Wunused %s













// RUN: %clang_cc1 -fsyntax-only -verify -std=c++17 -Wunused %s































// PR4103 : Make sure we don't get a bogus unused expression warning















namespace PR4103 {









@@ -8,7 +9,7 @@ namespace PR4103 {













    char foo;















  };















  class APSInt : public APInt {













    char bar;













    char bar; // expected-warning {{private field 'bar' is not used}}















  public:















    APSInt &operator=(const APSInt &RHS);















  };










@@ -69,3 +70,44 @@ namespace UnresolvedLookup {













    }















  };















}



























#if __cplusplus >= 201703L













namespace PR33839 {













  void a() {













    struct X { int a, b; } x;













    auto [a, b] = x; // expected-warning {{unused variable '[a, b]'}}













    auto [c, d] = x;













    (void)d;













  }



























  template<typename T> void f() {













    struct A { int n; } a[1];













    for (auto [x] : a) {













      (void)x;













    }













    auto [y] = a[0]; // expected-warning {{unused}}













  }













  template<bool b> void g() {













    struct A { int n; } a[1];













    for (auto [x] : a) {













      if constexpr (b)













        (void)x;













    }



























    auto [y] = a[0];













    if constexpr (b)













      (void)y; // ok, even when b == false













  }













  template<typename T> void h() {













    struct A { int n; } a[1];













    for (auto [x] : a) { // expected-warning {{unused variable '[x]'}}













    }













  }













  void use() { 













    f<int>(); // expected-note {{instantiation of}}













    g<true>();













    g<false>();













    h<int>(); // expected-note {{instantiation of}}













  }













}













#endif