[clang] 3d20806 - [clang][DR2621] using enum NAME lookup fix
Nathan Sidwell via cfe-commits
cfe-commits at lists.llvm.org
Wed Sep 28 08:50:40 PDT 2022
Author: Nathan Sidwell
Date: 2022-09-28T08:50:27-07:00
New Revision: 3d2080683f1dc37010fb56cf7d0e1632cda00f15
URL: https://github.com/llvm/llvm-project/commit/3d2080683f1dc37010fb56cf7d0e1632cda00f15
DIFF: https://github.com/llvm/llvm-project/commit/3d2080683f1dc37010fb56cf7d0e1632cda00f15.diff
LOG: [clang][DR2621] using enum NAME lookup fix
Although using-enum's grammar is 'using elaborated-enum-specifier',
the lookup for the enum is ordinary lookup (and not the tagged-type
lookup that normally occurs wth an tagged-type specifier). Thus (a)
we can find typedefs and (b) do not find enum tags hidden by a non-tag
name (the struct stat thing).
This reimplements that part of using-enum handling, to address DR2621,
where clang's behaviour does not match std intent (and other
compilers).
Reviewed By: aaron.ballman
Differential Revision: https://reviews.llvm.org/D134283
Added:
Modified:
clang/docs/ReleaseNotes.rst
clang/include/clang/Basic/DiagnosticParseKinds.td
clang/include/clang/Basic/DiagnosticSemaKinds.td
clang/include/clang/Sema/Sema.h
clang/lib/Parse/ParseDeclCXX.cpp
clang/lib/Sema/SemaDeclCXX.cpp
clang/test/CXX/drs/dr26xx.cpp
clang/test/CodeCompletion/using-enum.cpp
clang/test/Parser/cxx20-using-enum.cpp
clang/test/SemaCXX/cxx20-using-enum.cpp
Removed:
################################################################################
diff --git a/clang/docs/ReleaseNotes.rst b/clang/docs/ReleaseNotes.rst
index 0dd3b54aa4753..0bae33cdf4234 100644
--- a/clang/docs/ReleaseNotes.rst
+++ b/clang/docs/ReleaseNotes.rst
@@ -356,6 +356,8 @@ C++20 Feature Support
the time of checking, which should now allow the libstdc++ ranges implementation
to work for at least trivial examples. This fixes
`Issue 44178 <https://github.com/llvm/llvm-project/issues/44178>`_.
+- Clang implements DR2621, correcting a defect in ``using enum`` handling. The
+ name is found via ordinary lookup so typedefs are found.
C++2b Feature Support
^^^^^^^^^^^^^^^^^^^^^
diff --git a/clang/include/clang/Basic/DiagnosticParseKinds.td b/clang/include/clang/Basic/DiagnosticParseKinds.td
index 2abb5f09292ec..ee401200ddfa5 100644
--- a/clang/include/clang/Basic/DiagnosticParseKinds.td
+++ b/clang/include/clang/Basic/DiagnosticParseKinds.td
@@ -607,6 +607,9 @@ def warn_cxx17_compat_using_enum_declaration : Warning<
def ext_using_enum_declaration : ExtWarn<
"using enum declaration is a C++20 extension">,
InGroup<CXX20>;
+def err_using_enum_expect_identifier : Error<
+ "using enum %select{requires an enum or typedef name|"
+ "does not permit an elaborated enum specifier}0">;
def err_constructor_bad_name : Error<
"missing return type for function %0; did you mean the constructor name %1?">;
def err_destructor_tilde_identifier : Error<
diff --git a/clang/include/clang/Basic/DiagnosticSemaKinds.td b/clang/include/clang/Basic/DiagnosticSemaKinds.td
index 93c598b2eba48..2b544928ab763 100644
--- a/clang/include/clang/Basic/DiagnosticSemaKinds.td
+++ b/clang/include/clang/Basic/DiagnosticSemaKinds.td
@@ -562,6 +562,8 @@ def warn_cxx17_compat_using_decl_class_member_enumerator : Warning<
"with C++ standards before C++20">, InGroup<CXXPre20Compat>, DefaultIgnore;
def err_using_enum_is_dependent : Error<
"using-enum cannot name a dependent type">;
+def err_using_enum_not_enum : Error<
+ "%0 is not an enumerated type">;
def err_ambiguous_inherited_constructor : Error<
"constructor of %0 inherited from multiple base class subobjects">;
def note_ambiguous_inherited_constructor_using : Note<
diff --git a/clang/include/clang/Sema/Sema.h b/clang/include/clang/Sema/Sema.h
index b6fd8174e1d87..72995befeadf2 100644
--- a/clang/include/clang/Sema/Sema.h
+++ b/clang/include/clang/Sema/Sema.h
@@ -6125,7 +6125,9 @@ class Sema final {
const ParsedAttributesView &AttrList);
Decl *ActOnUsingEnumDeclaration(Scope *CurScope, AccessSpecifier AS,
SourceLocation UsingLoc,
- SourceLocation EnumLoc, const DeclSpec &);
+ SourceLocation EnumLoc,
+ SourceLocation IdentLoc, IdentifierInfo &II,
+ CXXScopeSpec *SS = nullptr);
Decl *ActOnAliasDeclaration(Scope *CurScope, AccessSpecifier AS,
MultiTemplateParamsArg TemplateParams,
SourceLocation UsingLoc, UnqualifiedId &Name,
diff --git a/clang/lib/Parse/ParseDeclCXX.cpp b/clang/lib/Parse/ParseDeclCXX.cpp
index d0bf89799c258..52e627a375442 100644
--- a/clang/lib/Parse/ParseDeclCXX.cpp
+++ b/clang/lib/Parse/ParseDeclCXX.cpp
@@ -678,6 +678,8 @@ bool Parser::ParseUsingDeclarator(DeclaratorContext Context,
///
/// using-enum-declaration: [C++20, dcl.enum]
/// 'using' elaborated-enum-specifier ;
+/// The terminal name of the elaborated-enum-specifier undergoes
+/// ordinary lookup
///
/// elaborated-enum-specifier:
/// 'enum' nested-name-specifier[opt] identifier
@@ -697,21 +699,47 @@ Parser::DeclGroupPtrTy Parser::ParseUsingDeclaration(
DiagnoseCXX11AttributeExtension(PrefixAttrs);
- DeclSpec DS(AttrFactory);
- ParseEnumSpecifier(UELoc, DS, TemplateInfo, AS,
- // DSC_trailing has the semantics we desire
- DeclSpecContext::DSC_trailing);
-
if (TemplateInfo.Kind) {
SourceRange R = TemplateInfo.getSourceRange();
Diag(UsingLoc, diag::err_templated_using_directive_declaration)
<< 1 /* declaration */ << R << FixItHint::CreateRemoval(R);
+ SkipUntil(tok::semi);
+ return nullptr;
+ }
+ CXXScopeSpec SS;
+ if (ParseOptionalCXXScopeSpecifier(SS, /*ParsedType=*/nullptr,
+ /*ObectHasErrors=*/false,
+ /*EnteringConttext=*/false,
+ /*MayBePseudoDestructor=*/nullptr,
+ /*IsTypename=*/false,
+ /*IdentifierInfo=*/nullptr,
+ /*OnlyNamespace=*/false,
+ /*InUsingDeclaration=*/true)) {
+ SkipUntil(tok::semi);
+ return nullptr;
+ }
+ if (Tok.is(tok::code_completion)) {
+ cutOffParsing();
+ Actions.CodeCompleteUsing(getCurScope());
+ return nullptr;
+ }
+
+ if (!Tok.is(tok::identifier)) {
+ Diag(Tok.getLocation(), diag::err_using_enum_expect_identifier)
+ << Tok.is(tok::kw_enum);
+ SkipUntil(tok::semi);
+ return nullptr;
+ }
+ IdentifierInfo *IdentInfo = Tok.getIdentifierInfo();
+ SourceLocation IdentLoc = ConsumeToken();
+ Decl *UED = Actions.ActOnUsingEnumDeclaration(
+ getCurScope(), AS, UsingLoc, UELoc, IdentLoc, *IdentInfo, &SS);
+ if (!UED) {
+ SkipUntil(tok::semi);
return nullptr;
}
- Decl *UED = Actions.ActOnUsingEnumDeclaration(getCurScope(), AS, UsingLoc,
- UELoc, DS);
DeclEnd = Tok.getLocation();
if (ExpectAndConsume(tok::semi, diag::err_expected_after,
"using-enum declaration"))
diff --git a/clang/lib/Sema/SemaDeclCXX.cpp b/clang/lib/Sema/SemaDeclCXX.cpp
index 2516d18b31c25..b72bded8397ad 100644
--- a/clang/lib/Sema/SemaDeclCXX.cpp
+++ b/clang/lib/Sema/SemaDeclCXX.cpp
@@ -11851,30 +11851,30 @@ Decl *Sema::ActOnUsingDeclaration(Scope *S, AccessSpecifier AS,
Decl *Sema::ActOnUsingEnumDeclaration(Scope *S, AccessSpecifier AS,
SourceLocation UsingLoc,
SourceLocation EnumLoc,
- const DeclSpec &DS) {
- switch (DS.getTypeSpecType()) {
- case DeclSpec::TST_error:
- // This will already have been diagnosed
+ SourceLocation IdentLoc,
+ IdentifierInfo &II, CXXScopeSpec *SS) {
+ assert(!SS->isInvalid() && "ScopeSpec is invalid");
+ ParsedType TypeRep = getTypeName(II, IdentLoc, S, SS);
+ if (!TypeRep) {
+ Diag(IdentLoc, SS && isDependentScopeSpecifier(*SS)
+ ? diag::err_using_enum_is_dependent
+ : diag::err_unknown_typename)
+ << II.getName()
+ << SourceRange(SS ? SS->getBeginLoc() : IdentLoc, IdentLoc);
return nullptr;
+ }
- case DeclSpec::TST_enum:
- break;
-
- case DeclSpec::TST_typename:
- Diag(DS.getTypeSpecTypeLoc(), diag::err_using_enum_is_dependent);
+ auto *Enum = dyn_cast_if_present<EnumDecl>(TypeRep.get()->getAsTagDecl());
+ if (!Enum) {
+ Diag(IdentLoc, diag::err_using_enum_not_enum) << TypeRep.get();
return nullptr;
-
- default:
- llvm_unreachable("unexpected DeclSpec type");
}
- // As with enum-decls, we ignore attributes for now.
- auto *Enum = cast<EnumDecl>(DS.getRepAsDecl());
if (auto *Def = Enum->getDefinition())
Enum = Def;
- auto *UD = BuildUsingEnumDeclaration(S, AS, UsingLoc, EnumLoc,
- DS.getTypeSpecTypeNameLoc(), Enum);
+ auto *UD =
+ BuildUsingEnumDeclaration(S, AS, UsingLoc, EnumLoc, IdentLoc, Enum);
if (UD)
PushOnScopeChains(UD, S, /*AddToContext*/ false);
diff --git a/clang/test/CXX/drs/dr26xx.cpp b/clang/test/CXX/drs/dr26xx.cpp
index 1178cefa5bcdf..37d971a3ae1f2 100644
--- a/clang/test/CXX/drs/dr26xx.cpp
+++ b/clang/test/CXX/drs/dr26xx.cpp
@@ -1,5 +1,19 @@
// RUN: %clang_cc1 -std=c++20 -triple x86_64-unknown-unknown %s -verify
+namespace dr2621 { // dr2621: yes
+enum class E { a };
+namespace One {
+using E_t = E;
+using enum E_t; // typedef ok
+auto v = a;
+}
+namespace Two {
+using dr2621::E;
+int E; // we see this
+using enum E; // expected-error {{unknown type name E}}
+}
+}
+
namespace dr2628 { // dr2628: yes
template <bool A = false, bool B = false>
diff --git a/clang/test/CodeCompletion/using-enum.cpp b/clang/test/CodeCompletion/using-enum.cpp
index 1619e36c18f61..dfe297a2c0681 100644
--- a/clang/test/CodeCompletion/using-enum.cpp
+++ b/clang/test/CodeCompletion/using-enum.cpp
@@ -2,6 +2,6 @@ enum class AAA { X, Y, Z };
namespace N2 {
using enum AAA;
- // RUN: %clang_cc1 -fsyntax-only -code-completion-at=%s:4:14 %s | FileCheck -check-prefix=CHECK-CC1 %s
+ // RUN: %clang_cc1 -std=c++20 -fsyntax-only -code-completion-at=%s:4:14 %s | FileCheck -check-prefix=CHECK-CC1 %s
// CHECK-CC1: COMPLETION: AAA
};
diff --git a/clang/test/Parser/cxx20-using-enum.cpp b/clang/test/Parser/cxx20-using-enum.cpp
index d6744d3a91290..78b9d00848c78 100644
--- a/clang/test/Parser/cxx20-using-enum.cpp
+++ b/clang/test/Parser/cxx20-using-enum.cpp
@@ -4,9 +4,9 @@ namespace GH57347 {
namespace A {}
void f() {
- using enum A::+; // expected-error {{expected identifier}}
- using enum; // expected-error {{expected identifier or '{'}}
- using enum class; // expected-error {{expected identifier or '{'}}
- using enum : blah; // expected-error {{unknown type name 'blah'}} expected-error {{unnamed enumeration must be a definition}}
+ using enum A::+; // expected-error {{using enum requires an enum or typedef name}}
+ using enum; // expected-error {{using enum requires an enum or typedef name}}
+ using enum class; // expected-error {{using enum requires an enum or typedef name}}
+ using enum enum q; // expected-error {{using enum does not permit an elaborated enum specifier}}
}
}
diff --git a/clang/test/SemaCXX/cxx20-using-enum.cpp b/clang/test/SemaCXX/cxx20-using-enum.cpp
index daf35ebfefbbc..91dd0bac992f8 100644
--- a/clang/test/SemaCXX/cxx20-using-enum.cpp
+++ b/clang/test/SemaCXX/cxx20-using-enum.cpp
@@ -8,7 +8,7 @@ namespace Bob {
enum A { a, // expected-note{{declared here}}
b,
c };
-class C; // expected-note{{previous use}}
+class C;
enum class D : int;
enum class D { d,
e,
@@ -20,11 +20,11 @@ using enum Bob::A;
#if __cplusplus < 202002
// expected-warning at -2{{is a C++20 extension}}
#endif
-using enum Bob::B; // expected-error{{no enum named 'B'}}
+using enum Bob::B; // expected-error{{unknown type name B}}
#if __cplusplus < 202002
// expected-warning at -2{{is a C++20 extension}}
#endif
-using enum Bob::C; // expected-error{{tag type that does not match}}
+using enum Bob::C; // expected-error{{'Bob::C' is not an enumerated type}}
#if __cplusplus < 202002
// expected-warning at -2{{is a C++20 extension}}
#endif
@@ -38,6 +38,16 @@ using enum Bob::D;
#if __cplusplus < 202002
// expected-warning at -2{{is a C++20 extension}}
#endif
+
+void DR2621() {
+ using A_t = Bob::A;
+ using enum A_t;
+#if __cplusplus < 202002
+// expected-warning at -2{{is a C++20 extension}}
+#endif
+ A_t x = a;
+}
+
} // namespace One
namespace Two {
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