Revert "[clang] Fix missing diagnostic of declaration use when accessing TypeDecls through typename access"

This reverts commit dc17043.
Breaks building LLVM on mac when targeting macOS before 10.15, see
comments on https://reviews.llvm.org/D136533

Author: nico

clang/docs/ReleaseNotes.rst

@@ -255,9 +255,6 @@ Bug Fixes
 - Reject non-type template arguments formed by casting a non-zero integer
   to a pointer in pre-C++17 modes, instead of treating them as null
   pointers.
-- Fix missing diagnostics for uses of declarations when performing typename access,
-  such as when performing member access on a '[[deprecated]]' type alias.
-  `Issue 58547 <https://github.com/llvm/llvm-project/issues/58547>`
 
 Improvements to Clang's diagnostics
 ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^

clang/include/clang/Sema/Sema.h

@@ -2566,10 +2566,6 @@ class Sema final {
 
   bool isSimpleTypeSpecifier(tok::TokenKind Kind) const;
 
-  enum class DiagCtorKind { None, Implicit, Typename };
-  QualType getTypeDeclType(DeclContext *LookupCtx, DiagCtorKind DCK,
-                           TypeDecl *TD, SourceLocation NameLoc);
-
   ParsedType getTypeName(const IdentifierInfo &II, SourceLocation NameLoc,
                          Scope *S, CXXScopeSpec *SS = nullptr,
                          bool isClassName = false, bool HasTrailingDot = false,

clang/lib/Sema/SemaDecl.cpp

@@ -169,26 +169,6 @@ bool Sema::isSimpleTypeSpecifier(tok::TokenKind Kind) const {
   return false;
 }
 
-QualType Sema::getTypeDeclType(DeclContext *LookupCtx, DiagCtorKind DCK,
-                               TypeDecl *TD, SourceLocation NameLoc) {
-  auto *LookupRD = dyn_cast_or_null<CXXRecordDecl>(LookupCtx);
-  auto *FoundRD = dyn_cast<CXXRecordDecl>(TD);
-  if (DCK != DiagCtorKind::None && LookupRD && FoundRD &&
-      FoundRD->isInjectedClassName() &&
-      declaresSameEntity(LookupRD, cast<Decl>(FoundRD->getParent()))) {
-    Diag(NameLoc,
-         DCK == DiagCtorKind::Typename
-             ? diag::ext_out_of_line_qualified_id_type_names_constructor
-             : diag::err_out_of_line_qualified_id_type_names_constructor)
-        << TD->getIdentifier() << /*Type*/ 1
-        << 0 /*if any keyword was present, it was 'typename'*/;
-  }
-
-  DiagnoseUseOfDecl(TD, NameLoc);
-  MarkAnyDeclReferenced(TD->getLocation(), TD, /*OdrUse=*/false);
-  return Context.getTypeDeclType(TD);
-}
-
 namespace {
 enum class UnqualifiedTypeNameLookupResult {
   NotFound,
@@ -352,11 +332,10 @@ ParsedType Sema::getTypeName(const IdentifierInfo &II, SourceLocation NameLoc,
                              bool IsClassTemplateDeductionContext,
                              ImplicitTypenameContext AllowImplicitTypename,
                              IdentifierInfo **CorrectedII) {
-  bool IsImplicitTypename = !isClassName && !IsCtorOrDtorName;
   // FIXME: Consider allowing this outside C++1z mode as an extension.
   bool AllowDeducedTemplate = IsClassTemplateDeductionContext &&
-                              getLangOpts().CPlusPlus17 && IsImplicitTypename &&
-                              !HasTrailingDot;
+                              getLangOpts().CPlusPlus17 && !IsCtorOrDtorName &&
+                              !isClassName && !HasTrailingDot;
 
   // Determine where we will perform name lookup.
   DeclContext *LookupCtx = nullptr;
@@ -380,9 +359,11 @@ ParsedType Sema::getTypeName(const IdentifierInfo &II, SourceLocation NameLoc,
         // refer to a member of an unknown specialization.
         // In C++2a, in several contexts a 'typename' is not required. Also
         // allow this as an extension.
+        if (AllowImplicitTypename == ImplicitTypenameContext::No &&
+            !isClassName && !IsCtorOrDtorName)
+          return nullptr;
+        bool IsImplicitTypename = !isClassName && !IsCtorOrDtorName;
         if (IsImplicitTypename) {
-          if (AllowImplicitTypename == ImplicitTypenameContext::No)
-            return nullptr;
           SourceLocation QualifiedLoc = SS->getRange().getBegin();
           if (getLangOpts().CPlusPlus20)
             Diag(QualifiedLoc, diag::warn_cxx17_compat_implicit_typename);
@@ -556,10 +537,18 @@ ParsedType Sema::getTypeName(const IdentifierInfo &II, SourceLocation NameLoc,
     // C++ [class.qual]p2: A lookup that would find the injected-class-name
     // instead names the constructors of the class, except when naming a class.
     // This is ill-formed when we're not actually forming a ctor or dtor name.
-    T = getTypeDeclType(LookupCtx,
-                        IsImplicitTypename ? DiagCtorKind::Implicit
-                                           : DiagCtorKind::None,
-                        TD, NameLoc);
+    auto *LookupRD = dyn_cast_or_null<CXXRecordDecl>(LookupCtx);
+    auto *FoundRD = dyn_cast<CXXRecordDecl>(TD);
+    if (!isClassName && !IsCtorOrDtorName && LookupRD && FoundRD &&
+        FoundRD->isInjectedClassName() &&
+        declaresSameEntity(LookupRD, cast<Decl>(FoundRD->getParent())))
+      Diag(NameLoc, diag::err_out_of_line_qualified_id_type_names_constructor)
+          << &II << /*Type*/1;
+
+    DiagnoseUseOfDecl(IIDecl, NameLoc);
+
+    T = Context.getTypeDeclType(TD);
+    MarkAnyDeclReferenced(TD->getLocation(), TD, /*OdrUse=*/false);
   } else if (ObjCInterfaceDecl *IDecl = dyn_cast<ObjCInterfaceDecl>(IIDecl)) {
     (void)DiagnoseUseOfDecl(IDecl, NameLoc);
     if (!HasTrailingDot)

clang/lib/Sema/SemaTemplate.cpp

@@ -10963,14 +10963,20 @@ Sema::CheckTypenameType(ElaboratedTypeKeyword Keyword,
       //
       // FIXME: That's not strictly true: mem-initializer-id lookup does not
       // ignore functions, but that appears to be an oversight.
-      QualType T = getTypeDeclType(
-          Ctx,
-          Keyword == ETK_Typename ? DiagCtorKind::Typename : DiagCtorKind::None,
-          Type, IILoc);
+      auto *LookupRD = dyn_cast_or_null<CXXRecordDecl>(Ctx);
+      auto *FoundRD = dyn_cast<CXXRecordDecl>(Type);
+      if (Keyword == ETK_Typename && LookupRD && FoundRD &&
+          FoundRD->isInjectedClassName() &&
+          declaresSameEntity(LookupRD, cast<Decl>(FoundRD->getParent())))
+        Diag(IILoc, diag::ext_out_of_line_qualified_id_type_names_constructor)
+            << &II << 1 << 0 /*'typename' keyword used*/;
+
       // We found a type. Build an ElaboratedType, since the
       // typename-specifier was just sugar.
-      return Context.getElaboratedType(
-          Keyword, QualifierLoc.getNestedNameSpecifier(), T);
+      MarkAnyDeclReferenced(Type->getLocation(), Type, /*OdrUse=*/false);
+      return Context.getElaboratedType(Keyword,
+                                       QualifierLoc.getNestedNameSpecifier(),
+                                       Context.getTypeDeclType(Type));
     }
 
     // C++ [dcl.type.simple]p2:

clang/test/CXX/dcl.dcl/dcl.attr/dcl.attr.deprecated/p1.cpp

@@ -58,17 +58,3 @@ template <typename T>
   FunS2 f;// No warning, entire function is deprecated, so usage here should be fine.
 
 }
-
-namespace GH58547 {
-struct A {
-  using ta [[deprecated]] = int; // expected-note 2{{marked deprecated here}}
-};
-
-using t1 = typename A::ta; // expected-warning {{'ta' is deprecated}}
-
-template <class B1> struct B {
-  using tb = typename B1::ta; // expected-warning {{'ta' is deprecated}}
-};
-
-template struct B<A>; // expected-note {{requested here}}
-} // namespace GH58547

libcxx/test/libcxx/depr/depr.default.allocator/allocator.members/allocate.depr_in_cxx17.verify.cpp

@@ -13,8 +13,7 @@
 
 // Deprecated in C++17
 
-// FIXME: Remove 'clang-16' from UNSUPPORTED by 2022-11-05 (bugfix D136533).
-// UNSUPPORTED: c++03, c++11, c++14, clang-16
+// UNSUPPORTED: c++03, c++11, c++14
 
 // ADDITIONAL_COMPILE_FLAGS: -D_LIBCPP_ENABLE_CXX20_REMOVED_ALLOCATOR_MEMBERS
 
@@ -24,11 +23,7 @@
 int main(int, char**)
 {
     std::allocator<int> a;
-    TEST_IGNORE_NODISCARD a.allocate(3, nullptr);
-    // expected-warning@-1 {{'allocate' is deprecated}}
-#if defined(TEST_CLANG_VER) && TEST_CLANG_VER >= 1600
-    // expected-warning@*:* {{'pointer' is deprecated}}
-    // expected-warning@*:* {{'const_pointer' is deprecated}}
-#endif
+    TEST_IGNORE_NODISCARD a.allocate(3, nullptr); // expected-warning {{'allocate' is deprecated}}
+
     return 0;
 }