r196464 - Per [dcl.meaning]p1, a name in an inline namespace can be redeclared using a

Richard Smith richard-llvm at metafoo.co.uk
Wed Dec 4 20:30:04 PST 2013


Author: rsmith
Date: Wed Dec  4 22:30:04 2013
New Revision: 196464

URL: http://llvm.org/viewvc/llvm-project?rev=196464&view=rev
Log:
Per [dcl.meaning]p1, a name in an inline namespace can be redeclared using a
name from the enclosing namespace set if the name is specified as a
qualified-id.

Modified:
    cfe/trunk/include/clang/Sema/IdentifierResolver.h
    cfe/trunk/include/clang/Sema/Sema.h
    cfe/trunk/lib/Sema/IdentifierResolver.cpp
    cfe/trunk/lib/Sema/SemaDecl.cpp
    cfe/trunk/lib/Sema/SemaTemplate.cpp
    cfe/trunk/test/CXX/dcl.decl/dcl.meaning/p1-0x.cpp

Modified: cfe/trunk/include/clang/Sema/IdentifierResolver.h
URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/include/clang/Sema/IdentifierResolver.h?rev=196464&r1=196463&r2=196464&view=diff
==============================================================================
--- cfe/trunk/include/clang/Sema/IdentifierResolver.h (original)
+++ cfe/trunk/include/clang/Sema/IdentifierResolver.h Wed Dec  4 22:30:04 2013
@@ -150,11 +150,14 @@ public:
   /// if 'D' is in Scope 'S', otherwise 'S' is ignored and isDeclInScope returns
   /// true if 'D' belongs to the given declaration context.
   ///
-  /// \param ExplicitInstantiationOrSpecialization When true, we are checking
-  /// whether the declaration is in scope for the purposes of explicit template
-  /// instantiation or specialization. The default is false.
+  /// \param AllowInlineNamespace If \c true, we are checking whether a prior
+  ///        declaration is in scope in a declaration that requires a prior
+  ///        declaration (because it is either explicitly qualified or is a
+  ///        template instantiation or specialization). In this case, a
+  ///        declaration is in scope if it's in the inline namespace set of the
+  ///        context.
   bool isDeclInScope(Decl *D, DeclContext *Ctx, Scope *S = 0,
-                     bool ExplicitInstantiationOrSpecialization = false) const;
+                     bool AllowInlineNamespace = false) const;
 
   /// AddDecl - Link the decl to its shadowed decl chain.
   void AddDecl(NamedDecl *D);

Modified: cfe/trunk/include/clang/Sema/Sema.h
URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/include/clang/Sema/Sema.h?rev=196464&r1=196463&r2=196464&view=diff
==============================================================================
--- cfe/trunk/include/clang/Sema/Sema.h (original)
+++ cfe/trunk/include/clang/Sema/Sema.h Wed Dec  4 22:30:04 2013
@@ -1823,11 +1823,11 @@ public:
   /// if 'D' is in Scope 'S', otherwise 'S' is ignored and isDeclInScope returns
   /// true if 'D' belongs to the given declaration context.
   ///
-  /// \param ExplicitInstantiationOrSpecialization When true, we are checking
-  /// whether the declaration is in scope for the purposes of explicit template
-  /// instantiation or specialization. The default is false.
+  /// \param AllowInlineNamespace If \c true, allow the declaration to be in the
+  ///        enclosing namespace set of the context, rather than contained
+  ///        directly within it.
   bool isDeclInScope(NamedDecl *D, DeclContext *Ctx, Scope *S = 0,
-                     bool ExplicitInstantiationOrSpecialization = false);
+                     bool AllowInlineNamespace = false);
 
   /// Finds the scope corresponding to the given decl context, if it
   /// happens to be an enclosing scope.  Otherwise return NULL.
@@ -2528,8 +2528,7 @@ public:
                                    AssociatedClassSet &AssociatedClasses);
 
   void FilterLookupForScope(LookupResult &R, DeclContext *Ctx, Scope *S,
-                            bool ConsiderLinkage,
-                            bool ExplicitInstantiationOrSpecialization);
+                            bool ConsiderLinkage, bool AllowInlineNamespace);
 
   void DiagnoseAmbiguousLookup(LookupResult &Result);
   //@}

Modified: cfe/trunk/lib/Sema/IdentifierResolver.cpp
URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/lib/Sema/IdentifierResolver.cpp?rev=196464&r1=196463&r2=196464&view=diff
==============================================================================
--- cfe/trunk/lib/Sema/IdentifierResolver.cpp (original)
+++ cfe/trunk/lib/Sema/IdentifierResolver.cpp Wed Dec  4 22:30:04 2013
@@ -95,7 +95,7 @@ IdentifierResolver::~IdentifierResolver(
 /// if 'D' is in Scope 'S', otherwise 'S' is ignored and isDeclInScope returns
 /// true if 'D' belongs to the given declaration context.
 bool IdentifierResolver::isDeclInScope(Decl *D, DeclContext *Ctx, Scope *S,
-                             bool ExplicitInstantiationOrSpecialization) const {
+                                       bool AllowInlineNamespace) const {
   Ctx = Ctx->getRedeclContext();
 
   if (Ctx->isFunctionOrMethod() || S->isFunctionPrototypeScope()) {
@@ -131,9 +131,8 @@ bool IdentifierResolver::isDeclInScope(D
   }
 
   DeclContext *DCtx = D->getDeclContext()->getRedeclContext();
-  return ExplicitInstantiationOrSpecialization
-           ? Ctx->InEnclosingNamespaceSetOf(DCtx)
-           : Ctx->Equals(DCtx);
+  return AllowInlineNamespace ? Ctx->InEnclosingNamespaceSetOf(DCtx)
+                              : Ctx->Equals(DCtx);
 }
 
 /// AddDecl - Link the decl to its shadowed decl chain.

Modified: cfe/trunk/lib/Sema/SemaDecl.cpp
URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/lib/Sema/SemaDecl.cpp?rev=196464&r1=196463&r2=196464&view=diff
==============================================================================
--- cfe/trunk/lib/Sema/SemaDecl.cpp (original)
+++ cfe/trunk/lib/Sema/SemaDecl.cpp Wed Dec  4 22:30:04 2013
@@ -1086,9 +1086,8 @@ void Sema::pushExternalDeclIntoScope(Nam
 }
 
 bool Sema::isDeclInScope(NamedDecl *D, DeclContext *Ctx, Scope *S,
-                         bool ExplicitInstantiationOrSpecialization) {
-  return IdResolver.isDeclInScope(D, Ctx, S,
-                                  ExplicitInstantiationOrSpecialization);
+                         bool AllowInlineNamespace) {
+  return IdResolver.isDeclInScope(D, Ctx, S, AllowInlineNamespace);
 }
 
 Scope *Sema::getScopeForDeclContext(Scope *S, DeclContext *DC) {
@@ -1108,21 +1107,19 @@ static bool isOutOfScopePreviousDeclarat
 
 /// Filters out lookup results that don't fall within the given scope
 /// as determined by isDeclInScope.
-void Sema::FilterLookupForScope(LookupResult &R,
-                                DeclContext *Ctx, Scope *S,
+void Sema::FilterLookupForScope(LookupResult &R, DeclContext *Ctx, Scope *S,
                                 bool ConsiderLinkage,
-                                bool ExplicitInstantiationOrSpecialization) {
+                                bool AllowInlineNamespace) {
   LookupResult::Filter F = R.makeFilter();
   while (F.hasNext()) {
     NamedDecl *D = F.next();
 
-    if (isDeclInScope(D, Ctx, S, ExplicitInstantiationOrSpecialization))
+    if (isDeclInScope(D, Ctx, S, AllowInlineNamespace))
       continue;
 
-    if (ConsiderLinkage &&
-        isOutOfScopePreviousDeclaration(D, Ctx, Context))
+    if (ConsiderLinkage && isOutOfScopePreviousDeclaration(D, Ctx, Context))
       continue;
-    
+
     F.erase();
   }
 
@@ -4671,8 +4668,8 @@ Sema::ActOnTypedefNameDecl(Scope *S, Dec
                            LookupResult &Previous, bool &Redeclaration) {
   // Merge the decl with the existing one if appropriate. If the decl is
   // in an outer scope, it isn't the same thing.
-  FilterLookupForScope(Previous, DC, S, /*ConsiderLinkage*/ false,
-                       /*ExplicitInstantiationOrSpecialization=*/false);
+  FilterLookupForScope(Previous, DC, S, /*ConsiderLinkage*/false,
+                       /*AllowInlineNamespace*/false);
   filterNonConflictingPreviousDecls(Context, NewTD, Previous);
   if (!Previous.empty()) {
     Redeclaration = true;
@@ -5400,15 +5397,16 @@ Sema::ActOnVariableDeclarator(Scope *S,
   }
 
   // Diagnose shadowed variables before filtering for scope.
-  if (!D.getCXXScopeSpec().isSet())
+  if (D.getCXXScopeSpec().isEmpty())
     CheckShadow(S, NewVD, Previous);
 
   // Don't consider existing declarations that are in a different
   // scope and are out-of-semantic-context declarations (if the new
   // declaration has linkage).
-  FilterLookupForScope(
-      Previous, OriginalDC, S, shouldConsiderLinkage(NewVD),
-      IsExplicitSpecialization || IsVariableTemplateSpecialization);
+  FilterLookupForScope(Previous, OriginalDC, S, shouldConsiderLinkage(NewVD),
+                       D.getCXXScopeSpec().isNotEmpty() ||
+                       IsExplicitSpecialization ||
+                       IsVariableTemplateSpecialization);
 
   // Check whether the previous declaration is in the same block scope. This
   // affects whether we merge types with it, per C++11 [dcl.array]p3.
@@ -6886,6 +6884,7 @@ Sema::ActOnFunctionDeclarator(Scope *S,
 
   // Filter out previous declarations that don't match the scope.
   FilterLookupForScope(Previous, OriginalDC, S, shouldConsiderLinkage(NewFD),
+                       D.getCXXScopeSpec().isNotEmpty() ||
                        isExplicitSpecialization ||
                        isFunctionTemplateSpecialization);
 
@@ -10683,7 +10682,8 @@ Decl *Sema::ActOnTag(Scope *S, unsigned
       // in the same scope (so that the definition/declaration completes or
       // rementions the tag), reuse the decl.
       if (TUK == TUK_Reference || TUK == TUK_Friend ||
-          isDeclInScope(PrevDecl, SearchDC, S, isExplicitSpecialization)) {
+          isDeclInScope(PrevDecl, SearchDC, S,
+                        SS.isNotEmpty() || isExplicitSpecialization)) {
         // Make sure that this wasn't declared as an enum and now used as a
         // struct or something similar.
         if (!isAcceptableTagRedeclaration(PrevTagDecl, Kind,
@@ -10844,8 +10844,8 @@ Decl *Sema::ActOnTag(Scope *S, unsigned
         Invalid = true;
 
       // Otherwise, only diagnose if the declaration is in scope.
-      } else if (!isDeclInScope(PrevDecl, SearchDC, S, 
-                                isExplicitSpecialization)) {
+      } else if (!isDeclInScope(PrevDecl, SearchDC, S,
+                                SS.isNotEmpty() || isExplicitSpecialization)) {
         // do nothing
 
       // Diagnose implicit declarations introduced by elaborated types.

Modified: cfe/trunk/lib/Sema/SemaTemplate.cpp
URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/lib/Sema/SemaTemplate.cpp?rev=196464&r1=196463&r2=196464&view=diff
==============================================================================
--- cfe/trunk/lib/Sema/SemaTemplate.cpp (original)
+++ cfe/trunk/lib/Sema/SemaTemplate.cpp Wed Dec  4 22:30:04 2013
@@ -968,7 +968,8 @@ Sema::CheckClassTemplate(Scope *S, unsig
           PrevDecl = (*Previous.begin())->getUnderlyingDecl();
       }
     }
-  } else if (PrevDecl && !isDeclInScope(PrevDecl, SemanticContext, S))
+  } else if (PrevDecl &&
+             !isDeclInScope(PrevDecl, SemanticContext, S, SS.isValid()))
     PrevDecl = PrevClassTemplate = 0;
 
   if (PrevClassTemplate) {

Modified: cfe/trunk/test/CXX/dcl.decl/dcl.meaning/p1-0x.cpp
URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/test/CXX/dcl.decl/dcl.meaning/p1-0x.cpp?rev=196464&r1=196463&r2=196464&view=diff
==============================================================================
--- cfe/trunk/test/CXX/dcl.decl/dcl.meaning/p1-0x.cpp (original)
+++ cfe/trunk/test/CXX/dcl.decl/dcl.meaning/p1-0x.cpp Wed Dec  4 22:30:04 2013
@@ -22,3 +22,82 @@ int decltype(tfoo<T>())::i; // expected-
 template<typename T>
 void decltype(tfoo<T>())::func() { // expected-error{{nested name specifier 'decltype(tfoo<T>())::' for declaration does not refer into a class, class template or class template partial specialization}}
 }
+
+// An init-declarator named with a qualified-id can refer to an element of the
+// inline namespace set of the named namespace.
+namespace inline_namespaces {
+  namespace N {
+    inline namespace M {
+      void f(); // expected-note {{possible target}}
+      void g();
+      extern int m, n;
+      struct S; struct T;
+      enum E : int; enum F : int;
+      template<typename T> void ft(); // expected-note {{here}}
+      template<typename T> void gt(); // expected-note {{here}}
+      template<typename T> extern int mt; // expected-note {{here}} expected-warning {{extension}}
+      template<typename T> extern int nt; // expected-note {{here}} expected-warning {{extension}}
+      template<typename T> struct U; // expected-note {{here}}
+      template<typename T> struct V; // expected-note {{here}}
+    }
+
+    // When named by unqualified-id, we do *not* look in the inline namespace
+    // set.
+    void f() {} // expected-note {{possible target}}
+    int m;
+    struct S {};
+    enum E : int {};
+
+    static_assert(&f != &M::f, ""); // expected-error {{reference to overloaded function could not be resolved}}
+    static_assert(&m != &M::m, "");
+    typedef S X; // expected-note {{previous}}
+    typedef M::S X; // expected-error {{different type}}
+    typedef E Y; // expected-note {{previous}}
+    typedef M::E Y; // expected-error {{different type}}
+
+    // When named by (unqualified) template-id, we do look in the inline
+    // namespace set.  See [namespace.def]p8, [temp.explicit]p3,
+    // [temp.expl.spec]p2.
+    //
+    // This is not explicitly specified for partial specializations, but
+    // that is just a language defect.
+    template<> void ft<int>() {}
+    template void ft<char>(); // expected-error {{undefined}}
+
+    template<typename T> int mt<T*>; // expected-warning {{extension}}
+    template<> int mt<int>; // expected-warning {{extension}}
+    template int mt<int*>;
+    template int mt<char>; // expected-error {{undefined}}
+
+    template<typename T> struct U<T*> {};
+    template<> struct U<int> {};
+    template struct U<int*>;
+    template struct U<char>; // expected-error {{undefined}}
+  }
+
+  // When named by qualified-id, we *do* look in the inline namespace set.
+  void N::g() {}
+  int N::n;
+  struct N::T {};
+  enum N::F : int {};
+
+  static_assert(&N::g == &N::M::g, "");
+  static_assert(&N::n == &N::M::n, "");
+  typedef N::T X;
+  typedef N::M::T X;
+  typedef N::F Y;
+  typedef N::M::F Y;
+
+  template<> void N::gt<int>() {}
+  template void N::gt<char>(); // expected-error {{undefined}}
+
+  template<typename T> int N::nt<T*>; // expected-warning {{extension}}
+  template<> int N::nt<int>; // expected-warning {{extension}}
+  template int N::nt<int*>;
+  template int N::nt<char>; // expected-error {{undefined}}
+
+  template<typename T> struct N::V<T*> {};
+  template<> struct N::V<int> {};
+  template struct N::V<int*>;
+  template struct N::V<char>; // expected-error {{undefined}}
+}





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