[clang] d052a57 - [c++2a] Allow comparison functions to be explicitly defaulted.
Hubert Tong via cfe-commits
cfe-commits at lists.llvm.org
Sat Mar 7 08:04:55 PST 2020
Following this commit, the error recovery for invalid cases that explicitly
define (out-of-line) a member function template as deleted and attempts to
instantiate said function appears broken.
<stdin>:4:35: error: deleted definition must be first declaration
template <typename> void A::f() = delete;
^
<stdin>:2:35: note: previous declaration is here
template <typename> static void f();
^
clang:
/src_d052a578de58cbbb638cbe2dba05242d1ff443b9/clang/lib/Sema/SemaTemplateInstantiateDecl.cpp:4288:
void clang::Sema::InstantiateFunctionDefinition(clang::SourceLocation,
clang::FunctionDecl *, bool, bool, bool): Assertion `(Pattern ||
PatternDecl->isDefaulted() || PatternDecl->hasSkippedBody()) && "unexpected
kind of function template definition"' failed.
Stack dump:
0. Program arguments:
/build_d052a578de58cbbb638cbe2dba05242d1ff443b9/bin/clang -cc1 -std=c++11
-xc++ -
1. <stdin>:5:26: current parser token ';'
#0 0x00003fff7fe6a024 PrintStackTraceSignalHandler(void*)
(/build_d052a578de58cbbb638cbe2dba05242d1ff443b9/bin/../lib/libLLVMSupport.so.10svn+0x1ea024)
#1 0x00003fff7fe670c8 llvm::sys::RunSignalHandlers()
(/build_d052a578de58cbbb638cbe2dba05242d1ff443b9/bin/../lib/libLLVMSupport.so.10svn+0x1e70c8)
#2 0x00003fff7fe6a49c SignalHandler(int)
(/build_d052a578de58cbbb638cbe2dba05242d1ff443b9/bin/../lib/libLLVMSupport.so.10svn+0x1ea49c)
#3 0x00003fff82030478 0x478 abort
#4 0x00003fff82030478
#5 0x00003fff82030478 __assert_fail_base (+0x478)
#6 0x00003fff7e0a1f94 __assert_fail (/lib64/libc.so.6+0x41f94)
#7 0x00003fff7e0955d4
clang::Sema::InstantiateFunctionDefinition(clang::SourceLocation,
clang::FunctionDecl*, bool, bool, bool) (/lib64/libc.so.6+0x355d4)
#8 0x00003fff7e0956c4
clang::Sema::ActOnExplicitInstantiation(clang::Scope*,
clang::SourceLocation, clang::SourceLocation, clang::Declarator&)
(/lib64/libc.so.6+0x356c4)
#9 0x00003fff7c28d604
clang::Parser::ParseDeclarationAfterDeclaratorAndAttributes(clang::Declarator&,
clang::Parser::ParsedTemplateInfo const&, clang::Parser::ForRangeInit*)
(/build_d052a578de58cbbb638cbe2dba05242d1ff443b9/bin/../lib/../lib/libclangSema.so.10svn+0x8ad604)
#10 0x00003fff7c15c2b0
clang::Parser::ParseDeclarationAfterDeclarator(clang::Declarator&,
clang::Parser::ParsedTemplateInfo const&)
(/build_d052a578de58cbbb638cbe2dba05242d1ff443b9/bin/../lib/../lib/libclangSema.so.10svn+0x77c2b0)
#11 0x00003fff7c4cc8f8
clang::Parser::ParseSingleDeclarationAfterTemplate(clang::DeclaratorContext,
clang::Parser::ParsedTemplateInfo const&, clang::ParsingDeclRAIIObject&,
clang::SourceLocation&, clang::ParsedAttributes&, clang::AccessSpecifier)
(/build_d052a578de58cbbb638cbe2dba05242d1ff443b9/bin/../lib/../lib/libclangParse.so.10svn+0x4c8f8)
#12 0x00003fff7c4cdf48
clang::Parser::ParseExplicitInstantiation(clang::DeclaratorContext,
clang::SourceLocation, clang::SourceLocation, clang::SourceLocation&,
clang::ParsedAttributes&, clang::AccessSpecifier)
(/build_d052a578de58cbbb638cbe2dba05242d1ff443b9/bin/../lib/../lib/libclangParse.so.10svn+0x4df48)
#13 0x00003fff7c57c1f0
clang::Parser::ParseDeclarationStartingWithTemplate(clang::DeclaratorContext,
clang::SourceLocation&, clang::ParsedAttributes&, clang::AccessSpecifier)
(/build_d052a578de58cbbb638cbe2dba05242d1ff443b9/bin/../lib/../lib/libclangParse.so.10svn+0xfc1f0)
#14 0x00003fff7c57a6c0
clang::Parser::ParseDeclaration(clang::DeclaratorContext,
clang::SourceLocation&, clang::Parser::ParsedAttributesWithRange&,
clang::SourceLocation*)
(/build_d052a578de58cbbb638cbe2dba05242d1ff443b9/bin/../lib/../lib/libclangParse.so.10svn+0xfa6c0)
#15 0x00003fff7c57a4f8
clang::Parser::ParseExternalDeclaration(clang::Parser::ParsedAttributesWithRange&,
clang::ParsingDeclSpec*)
(/build_d052a578de58cbbb638cbe2dba05242d1ff443b9/bin/../lib/../lib/libclangParse.so.10svn+0xfa4f8)
#16 0x00003fff7c4c5db0
clang::Parser::ParseTopLevelDecl(clang::OpaquePtr<clang::DeclGroupRef>&,
bool)
(/build_d052a578de58cbbb638cbe2dba05242d1ff443b9/bin/../lib/../lib/libclangParse.so.10svn+0x45db0)
#17 0x00003fff7c58fffc clang::ParseAST(clang::Sema&, bool, bool)
(/build_d052a578de58cbbb638cbe2dba05242d1ff443b9/bin/../lib/../lib/libclangParse.so.10svn+0x10fffc)
#18 0x00003fff7c58def4 clang::ASTFrontendAction::ExecuteAction()
(/build_d052a578de58cbbb638cbe2dba05242d1ff443b9/bin/../lib/../lib/libclangParse.so.10svn+0x10def4)
#19 0x00003fff7c4b01e0 clang::FrontendAction::Execute()
(/build_d052a578de58cbbb638cbe2dba05242d1ff443b9/bin/../lib/../lib/libclangParse.so.10svn+0x301e0)
#20 0x00003fff7e93d57c
clang::CompilerInstance::ExecuteAction(clang::FrontendAction&)
(/build_d052a578de58cbbb638cbe2dba05242d1ff443b9/bin/../lib/libclangFrontend.so.10svn+0x10d57c)
#21 0x00003fff7e93cbf0
clang::ExecuteCompilerInvocation(clang::CompilerInstance*)
(/build_d052a578de58cbbb638cbe2dba05242d1ff443b9/bin/../lib/libclangFrontend.so.10svn+0x10cbf0)
#22 0x00003fff7e8d5bd4 cc1_main(llvm::ArrayRef<char const*>, char const*,
void*)
(/build_d052a578de58cbbb638cbe2dba05242d1ff443b9/bin/../lib/libclangFrontend.so.10svn+0xa5bd4)
#23 0x00003fff7e8042f0 main
(/build_d052a578de58cbbb638cbe2dba05242d1ff443b9/bin/../lib/libclangFrontendTool.so.10svn+0x42f0)
#24 0x0000000010012594 generic_start_main.isra.0
(/build_d052a578de58cbbb638cbe2dba05242d1ff443b9/bin/clang+0x10012594)
#25 0x000000001000f37c __libc_start_main
(/build_d052a578de58cbbb638cbe2dba05242d1ff443b9/bin/clang+0x1000f37c)
/build_d052a578de58cbbb638cbe2dba05242d1ff443b9/bin/../lib/libLLVMSupport.so.10svn(+0x1ea024)[0x3fff7fe6a024]
/build_d052a578de58cbbb638cbe2dba05242d1ff443b9/bin/../lib/libLLVMSupport.so.10svn(_ZN4llvm3sys17RunSignalHandlersEv+0xc8)[0x3fff7fe670c8]
/build_d052a578de58cbbb638cbe2dba05242d1ff443b9/bin/../lib/libLLVMSupport.so.10svn(+0x1ea49c)[0x3fff7fe6a49c]
[0x3fff82030478]
/lib64/libc.so.6(abort+0x2b4)[0x3fff7e0a1f94]
/lib64/libc.so.6(+0x355d4)[0x3fff7e0955d4]
/lib64/libc.so.6(__assert_fail+0x64)[0x3fff7e0956c4]
/build_d052a578de58cbbb638cbe2dba05242d1ff443b9/bin/../lib/../lib/libclangSema.so.10svn(_ZN5clang4Sema29InstantiateFunctionDefinitionENS_14SourceLocationEPNS_12FunctionDeclEbbb+0x1244)[0x3fff7c28d604]
/build_d052a578de58cbbb638cbe2dba05242d1ff443b9/bin/../lib/../lib/libclangSema.so.10svn(_ZN5clang4Sema26ActOnExplicitInstantiationEPNS_5ScopeENS_14SourceLocationES3_RNS_10DeclaratorE+0x2290)[0x3fff7c15c2b0]
/build_d052a578de58cbbb638cbe2dba05242d1ff443b9/bin/../lib/../lib/libclangParse.so.10svn(_ZN5clang6Parser44ParseDeclarationAfterDeclaratorAndAttributesERNS_10DeclaratorERKNS0_18ParsedTemplateInfoEPNS0_12ForRangeInitE+0xf8)[0x3fff7c4cc8f8]
/build_d052a578de58cbbb638cbe2dba05242d1ff443b9/bin/../lib/../lib/libclangParse.so.10svn(_ZN5clang6Parser31ParseDeclarationAfterDeclaratorERNS_10DeclaratorERKNS0_18ParsedTemplateInfoE+0x98)[0x3fff7c4cdf48]
/build_d052a578de58cbbb638cbe2dba05242d1ff443b9/bin/../lib/../lib/libclangParse.so.10svn(_ZN5clang6Parser35ParseSingleDeclarationAfterTemplateENS_17DeclaratorContextERKNS0_18ParsedTemplateInfoERNS_21ParsingDeclRAIIObjectERNS_14SourceLocationERNS_16ParsedAttributesENS_15AccessSpecifierE+0x950)[0x3fff7c57c1f0]
/build_d052a578de58cbbb638cbe2dba05242d1ff443b9/bin/../lib/../lib/libclangParse.so.10svn(_ZN5clang6Parser26ParseExplicitInstantiationENS_17DeclaratorContextENS_14SourceLocationES2_RS2_RNS_16ParsedAttributesENS_15AccessSpecifierE+0x80)[0x3fff7c57a6c0]
/build_d052a578de58cbbb638cbe2dba05242d1ff443b9/bin/../lib/../lib/libclangParse.so.10svn(_ZN5clang6Parser36ParseDeclarationStartingWithTemplateENS_17DeclaratorContextERNS_14SourceLocationERNS_16ParsedAttributesENS_15AccessSpecifierE+0x158)[0x3fff7c57a4f8]
/build_d052a578de58cbbb638cbe2dba05242d1ff443b9/bin/../lib/../lib/libclangParse.so.10svn(_ZN5clang6Parser16ParseDeclarationENS_17DeclaratorContextERNS_14SourceLocationERNS0_25ParsedAttributesWithRangeEPS2_+0x350)[0x3fff7c4c5db0]
/build_d052a578de58cbbb638cbe2dba05242d1ff443b9/bin/../lib/../lib/libclangParse.so.10svn(_ZN5clang6Parser24ParseExternalDeclarationERNS0_25ParsedAttributesWithRangeEPNS_15ParsingDeclSpecE+0x2bc)[0x3fff7c58fffc]
/build_d052a578de58cbbb638cbe2dba05242d1ff443b9/bin/../lib/../lib/libclangParse.so.10svn(_ZN5clang6Parser17ParseTopLevelDeclERNS_9OpaquePtrINS_12DeclGroupRefEEEb+0x614)[0x3fff7c58def4]
/build_d052a578de58cbbb638cbe2dba05242d1ff443b9/bin/../lib/../lib/libclangParse.so.10svn(_ZN5clang8ParseASTERNS_4SemaEbb+0x2c0)[0x3fff7c4b01e0]
/build_d052a578de58cbbb638cbe2dba05242d1ff443b9/bin/../lib/libclangFrontend.so.10svn(_ZN5clang17ASTFrontendAction13ExecuteActionEv+0xdc)[0x3fff7e93d57c]
/build_d052a578de58cbbb638cbe2dba05242d1ff443b9/bin/../lib/libclangFrontend.so.10svn(_ZN5clang14FrontendAction7ExecuteEv+0x150)[0x3fff7e93cbf0]
/build_d052a578de58cbbb638cbe2dba05242d1ff443b9/bin/../lib/libclangFrontend.so.10svn(_ZN5clang16CompilerInstance13ExecuteActionERNS_14FrontendActionE+0x714)[0x3fff7e8d5bd4]
/build_d052a578de58cbbb638cbe2dba05242d1ff443b9/bin/../lib/libclangFrontendTool.so.10svn(_ZN5clang25ExecuteCompilerInvocationEPNS_16CompilerInstanceE+0x830)[0x3fff7e8042f0]
/build_d052a578de58cbbb638cbe2dba05242d1ff443b9/bin/clang(_Z8cc1_mainN4llvm8ArrayRefIPKcEES2_Pv+0x674)[0x10012594]
/build_d052a578de58cbbb638cbe2dba05242d1ff443b9/bin/clang(main+0x321c)[0x1000f37c]
/lib64/libc.so.6(+0x25100)[0x3fff7e085100]
/lib64/libc.so.6(__libc_start_main+0xc4)[0x3fff7e0852f4]
On Tue, Oct 22, 2019 at 9:18 PM Richard Smith via cfe-commits <
cfe-commits at lists.llvm.org> wrote:
>
> Author: Richard Smith
> Date: 2019-10-22T18:16:17-07:00
> New Revision: d052a578de58cbbb638cbe2dba05242d1ff443b9
>
> URL:
> https://github.com/llvm/llvm-project/commit/d052a578de58cbbb638cbe2dba05242d1ff443b9
> DIFF:
> https://github.com/llvm/llvm-project/commit/d052a578de58cbbb638cbe2dba05242d1ff443b9.diff
>
> LOG: [c++2a] Allow comparison functions to be explicitly defaulted.
>
> This adds some initial syntactic checking that only the appropriate
> function signatures can be defaulted. No implicit definitions are
> generated yet.
>
> Added:
> clang/test/CXX/class/class.compare/class.compare.default/p1.cpp
> clang/test/CXX/class/class.compare/class.eq/p1.cpp
> clang/test/CXX/class/class.compare/class.rel/p1.cpp
>
> Modified:
> clang/include/clang/AST/Decl.h
> clang/include/clang/Basic/DiagnosticCommonKinds.td
> clang/include/clang/Basic/DiagnosticSemaKinds.td
> clang/include/clang/Sema/Sema.h
> clang/lib/AST/Decl.cpp
> clang/lib/Parse/ParseDecl.cpp
> clang/lib/Parse/ParseDeclCXX.cpp
> clang/lib/Sema/SemaDecl.cpp
> clang/lib/Sema/SemaDeclCXX.cpp
> clang/lib/Sema/SemaTemplateInstantiateDecl.cpp
> clang/test/CXX/dcl.decl/dcl.fct.def/dcl.fct.def.default/p1.cpp
> clang/test/Parser/cxx0x-decl.cpp
> clang/test/SemaCXX/cxx0x-defaulted-functions.cpp
> clang/test/SemaCXX/cxx17-compat.cpp
>
> Removed:
>
>
>
>
> ################################################################################
> diff --git a/clang/include/clang/AST/Decl.h
> b/clang/include/clang/AST/Decl.h
> index ce674e09c44d..b3e7a570fd6d 100644
> --- a/clang/include/clang/AST/Decl.h
> +++ b/clang/include/clang/AST/Decl.h
> @@ -59,6 +59,7 @@ class EnumDecl;
> class Expr;
> class FunctionTemplateDecl;
> class FunctionTemplateSpecializationInfo;
> +class FunctionTypeLoc;
> class LabelStmt;
> class MemberSpecializationInfo;
> class Module;
> @@ -2362,6 +2363,12 @@ class FunctionDecl : public DeclaratorDecl,
> /// parameters have default arguments (in C++).
> unsigned getMinRequiredArguments() const;
>
> + /// Find the source location information for how the type of this
> function
> + /// was written. May be absent (for example if the function was
> declared via
> + /// a typedef) and may contain a
> diff erent type from that of the function
> + /// (for example if the function type was adjusted by an attribute).
> + FunctionTypeLoc getFunctionTypeLoc() const;
> +
> QualType getReturnType() const {
> return getType()->castAs<FunctionType>()->getReturnType();
> }
>
> diff --git a/clang/include/clang/Basic/DiagnosticCommonKinds.td
> b/clang/include/clang/Basic/DiagnosticCommonKinds.td
> index 6018c1417789..7a416c282e3d 100644
> --- a/clang/include/clang/Basic/DiagnosticCommonKinds.td
> +++ b/clang/include/clang/Basic/DiagnosticCommonKinds.td
> @@ -87,7 +87,8 @@ def warn_cxx98_compat_variadic_templates :
> Warning<"variadic templates are incompatible with C++98">,
> InGroup<CXX98Compat>, DefaultIgnore;
> def err_default_special_members : Error<
> - "only special member functions may be defaulted">;
> + "only special member functions %select{|and comparison operators }0"
> + "may be defaulted">;
> def err_deleted_non_function : Error<
> "only functions can have deleted definitions">;
> def err_module_not_found : Error<"module '%0' not found">, DefaultFatal;
>
> diff --git a/clang/include/clang/Basic/DiagnosticSemaKinds.td
> b/clang/include/clang/Basic/DiagnosticSemaKinds.td
> index d802a92c42c0..f7b98bb9ea86 100644
> --- a/clang/include/clang/Basic/DiagnosticSemaKinds.td
> +++ b/clang/include/clang/Basic/DiagnosticSemaKinds.td
> @@ -8099,6 +8099,31 @@ def note_vbase_moved_here : Note<
> "%select{%1 is a virtual base class of base class %2 declared here|"
> "virtual base class %1 declared here}0">;
>
> +// C++20 defaulted comparisons
> +// This corresponds to values of Sema::DefaultedComparisonKind.
> +def select_defaulted_comparison_kind : TextSubstitution<
> + "%select{<ERROR>|equality|three-way|equality|relational}0 comparison "
> + "operator">;
> +def ext_defaulted_comparison : ExtWarn<
> + "defaulted comparison operators are a C++20 extension">, InGroup<CXX2a>;
> +def warn_cxx17_compat_defaulted_comparison : Warning<
> + "defaulted comparison operators are incompatible with C++ standards "
> + "before C++20">, InGroup<CXXPre2aCompat>, DefaultIgnore;
> +def err_defaulted_comparison_template : Error<
> + "comparison operator template cannot be defaulted">;
> +def err_defaulted_comparison_out_of_class : Error<
> + "%sub{select_defaulted_comparison_kind}0 can only be defaulted in a
> class "
> + "definition">;
> +def err_defaulted_comparison_param : Error<
> + "invalid parameter type for defaulted
> %sub{select_defaulted_comparison_kind}0"
> + "%
> diff {; found $, expected $|}1,2">;
> +def err_defaulted_comparison_non_const : Error<
> + "defaulted member %sub{select_defaulted_comparison_kind}0 must be "
> + "const-qualified">;
> +def err_defaulted_comparison_return_type_not_bool : Error<
> + "return type for defaulted %sub{select_defaulted_comparison_kind}0 "
> + "must be 'bool', not %1">;
> +
> def ext_implicit_exception_spec_mismatch : ExtWarn<
> "function previously declared with an %select{explicit|implicit}0
> exception "
> "specification redeclared with an %select{implicit|explicit}0 exception
> "
>
> diff --git a/clang/include/clang/Sema/Sema.h
> b/clang/include/clang/Sema/Sema.h
> index a911c61a07f8..3058f862c6ec 100644
> --- a/clang/include/clang/Sema/Sema.h
> +++ b/clang/include/clang/Sema/Sema.h
> @@ -1237,6 +1237,24 @@ class Sema {
> /// same special member, we should act as if it is not yet declared.
> llvm::SmallPtrSet<SpecialMemberDecl, 4> SpecialMembersBeingDeclared;
>
> + /// Kinds of defaulted comparison operator functions.
> + enum class DefaultedComparisonKind {
> + /// This is not a defaultable comparison operator.
> + None,
> + /// This is an operator== that should be implemented as a series of
> + /// subobject comparisons.
> + Equal,
> + /// This is an operator<=> that should be implemented as a series of
> + /// subobject comparisons.
> + ThreeWay,
> + /// This is an operator!= that should be implemented as a rewrite in
> terms
> + /// of a == comparison.
> + NotEqual,
> + /// This is an <, <=, >, or >= that should be implemented as a
> rewrite in
> + /// terms of a <=> comparison.
> + Relational,
> + };
> +
> /// The function definitions which were renamed as part of
> typo-correction
> /// to match their respective declarations. We want to keep track of
> them
> /// to ensure that we don't emit a "redefinition" error if we encounter
> a
> @@ -2541,7 +2559,52 @@ class Sema {
> bool SpecialMemberIsTrivial(CXXMethodDecl *MD, CXXSpecialMember CSM,
> TrivialABIHandling TAH =
> TAH_IgnoreTrivialABI,
> bool Diagnose = false);
> - CXXSpecialMember getSpecialMember(const CXXMethodDecl *MD);
> +
> + /// For a defaulted function, the kind of defaulted function that it is.
> + class DefaultedFunctionKind {
> + CXXSpecialMember SpecialMember : 8;
> + DefaultedComparisonKind Comparison : 8;
> +
> + public:
> + DefaultedFunctionKind()
> + : SpecialMember(CXXInvalid),
> Comparison(DefaultedComparisonKind::None) {
> + }
> + DefaultedFunctionKind(CXXSpecialMember CSM)
> + : SpecialMember(CSM), Comparison(DefaultedComparisonKind::None) {}
> + DefaultedFunctionKind(DefaultedComparisonKind Comp)
> + : SpecialMember(CXXInvalid), Comparison(Comp) {}
> +
> + bool isSpecialMember() const { return SpecialMember != CXXInvalid; }
> + bool isComparison() const {
> + return Comparison != DefaultedComparisonKind::None;
> + }
> +
> + explicit operator bool() const {
> + return isSpecialMember() || isComparison();
> + }
> +
> + CXXSpecialMember asSpecialMember() const { return SpecialMember; }
> + DefaultedComparisonKind asComparison() const { return Comparison; }
> +
> + /// Get the index of this function kind for use in diagnostics.
> + unsigned getDiagnosticIndex() const {
> + static_assert(CXXInvalid > CXXDestructor,
> + "invalid should have highest index");
> + static_assert((unsigned)DefaultedComparisonKind::None == 0,
> + "none should be equal to zero");
> + return SpecialMember + (unsigned)Comparison;
> + }
> + };
> +
> + DefaultedFunctionKind getDefaultedFunctionKind(const FunctionDecl *FD);
> +
> + CXXSpecialMember getSpecialMember(const CXXMethodDecl *MD) {
> + return getDefaultedFunctionKind(MD).asSpecialMember();
> + }
> + DefaultedComparisonKind getDefaultedComparisonKind(const FunctionDecl
> *FD) {
> + return getDefaultedFunctionKind(FD).asComparison();
> + }
> +
> void ActOnLastBitfield(SourceLocation DeclStart,
> SmallVectorImpl<Decl *> &AllIvarDecls);
> Decl *ActOnIvar(Scope *S, SourceLocation DeclStart,
> @@ -6361,9 +6424,15 @@ class Sema {
> StorageClass &SC);
> void CheckDeductionGuideTemplate(FunctionTemplateDecl *TD);
>
> - void CheckExplicitlyDefaultedSpecialMember(CXXMethodDecl *MD);
> + void CheckExplicitlyDefaultedFunction(FunctionDecl *MD);
> +
> + bool CheckExplicitlyDefaultedSpecialMember(CXXMethodDecl *MD,
> + CXXSpecialMember CSM);
> void CheckDelayedMemberExceptionSpecs();
>
> + bool CheckExplicitlyDefaultedComparison(FunctionDecl *MD,
> + DefaultedComparisonKind DCK);
> +
>
> //===--------------------------------------------------------------------===//
> // C++ Derived Classes
> //
>
> diff --git a/clang/lib/AST/Decl.cpp b/clang/lib/AST/Decl.cpp
> index 80235d8496d2..dae4af8bb249 100644
> --- a/clang/lib/AST/Decl.cpp
> +++ b/clang/lib/AST/Decl.cpp
> @@ -3322,12 +3322,14 @@ bool
> FunctionDecl::doesDeclarationForceExternallyVisibleDefinition() const {
> return FoundBody;
> }
>
> -SourceRange FunctionDecl::getReturnTypeSourceRange() const {
> +FunctionTypeLoc FunctionDecl::getFunctionTypeLoc() const {
> const TypeSourceInfo *TSI = getTypeSourceInfo();
> - if (!TSI)
> - return SourceRange();
> - FunctionTypeLoc FTL =
> - TSI->getTypeLoc().IgnoreParens().getAs<FunctionTypeLoc>();
> + return TSI ? TSI->getTypeLoc().IgnoreParens().getAs<FunctionTypeLoc>()
> + : FunctionTypeLoc();
> +}
> +
> +SourceRange FunctionDecl::getReturnTypeSourceRange() const {
> + FunctionTypeLoc FTL = getFunctionTypeLoc();
> if (!FTL)
> return SourceRange();
>
> @@ -3343,15 +3345,8 @@ SourceRange
> FunctionDecl::getReturnTypeSourceRange() const {
> }
>
> SourceRange FunctionDecl::getExceptionSpecSourceRange() const {
> - const TypeSourceInfo *TSI = getTypeSourceInfo();
> - if (!TSI)
> - return SourceRange();
> - FunctionTypeLoc FTL =
> - TSI->getTypeLoc().IgnoreParens().getAs<FunctionTypeLoc>();
> - if (!FTL)
> - return SourceRange();
> -
> - return FTL.getExceptionSpecRange();
> + FunctionTypeLoc FTL = getFunctionTypeLoc();
> + return FTL ? FTL.getExceptionSpecRange() : SourceRange();
> }
>
> /// For an inline function definition in C, or for a gnu_inline function
>
> diff --git a/clang/lib/Parse/ParseDecl.cpp b/clang/lib/Parse/ParseDecl.cpp
> index b248d7582d84..c41eb74a9cf3 100644
> --- a/clang/lib/Parse/ParseDecl.cpp
> +++ b/clang/lib/Parse/ParseDecl.cpp
> @@ -2349,7 +2349,8 @@ Decl
> *Parser::ParseDeclarationAfterDeclaratorAndAttributes(
> Diag(ConsumeToken(),
> diag::err_default_delete_in_multiple_declaration)
> << 0 /* default */;
> else
> - Diag(ConsumeToken(), diag::err_default_special_members);
> + Diag(ConsumeToken(), diag::err_default_special_members)
> + << getLangOpts().CPlusPlus2a;
> } else {
> InitializerScopeRAII InitScope(*this, D, ThisDecl);
>
>
> diff --git a/clang/lib/Parse/ParseDeclCXX.cpp
> b/clang/lib/Parse/ParseDeclCXX.cpp
> index b98ce3e66292..6d4a1a4a4e87 100644
> --- a/clang/lib/Parse/ParseDeclCXX.cpp
> +++ b/clang/lib/Parse/ParseDeclCXX.cpp
> @@ -2978,7 +2978,8 @@ ExprResult Parser::ParseCXXMemberInitializer(Decl
> *D, bool IsFunction,
> Diag(Tok, diag::err_default_delete_in_multiple_declaration)
> << 0 /* default */;
> else
> - Diag(ConsumeToken(), diag::err_default_special_members);
> + Diag(ConsumeToken(), diag::err_default_special_members)
> + << getLangOpts().CPlusPlus2a;
> return ExprError();
> }
> }
>
> diff --git a/clang/lib/Sema/SemaDecl.cpp b/clang/lib/Sema/SemaDecl.cpp
> index 62ec83967bff..6202391ee0b8 100644
> --- a/clang/lib/Sema/SemaDecl.cpp
> +++ b/clang/lib/Sema/SemaDecl.cpp
> @@ -2993,28 +2993,6 @@ struct GNUCompatibleParamWarning {
>
> } // end anonymous namespace
>
> -/// getSpecialMember - get the special member enum for a method.
> -Sema::CXXSpecialMember Sema::getSpecialMember(const CXXMethodDecl *MD) {
> - if (const CXXConstructorDecl *Ctor = dyn_cast<CXXConstructorDecl>(MD)) {
> - if (Ctor->isDefaultConstructor())
> - return Sema::CXXDefaultConstructor;
> -
> - if (Ctor->isCopyConstructor())
> - return Sema::CXXCopyConstructor;
> -
> - if (Ctor->isMoveConstructor())
> - return Sema::CXXMoveConstructor;
> - } else if (isa<CXXDestructorDecl>(MD)) {
> - return Sema::CXXDestructor;
> - } else if (MD->isCopyAssignmentOperator()) {
> - return Sema::CXXCopyAssignment;
> - } else if (MD->isMoveAssignmentOperator()) {
> - return Sema::CXXMoveAssignment;
> - }
> -
> - return Sema::CXXInvalid;
> -}
> -
> // Determine whether the previous declaration was a definition, implicit
> // declaration, or a declaration.
> template <typename T>
>
> diff --git a/clang/lib/Sema/SemaDeclCXX.cpp
> b/clang/lib/Sema/SemaDeclCXX.cpp
> index ff90b9548e29..0201d014e6f2 100644
> --- a/clang/lib/Sema/SemaDeclCXX.cpp
> +++ b/clang/lib/Sema/SemaDeclCXX.cpp
> @@ -6084,6 +6084,67 @@ void Sema::propagateDLLAttrToBaseClassTemplate(
> }
> }
>
> +/// Determine the kind of defaulting that would be done for a given
> function.
> +///
> +/// If the function is both a default constructor and a copy / move
> constructor
> +/// (due to having a default argument for the first parameter), this picks
> +/// CXXDefaultConstructor.
> +///
> +/// FIXME: Check that case is properly handled by all callers.
> +Sema::DefaultedFunctionKind
> +Sema::getDefaultedFunctionKind(const FunctionDecl *FD) {
> + if (auto *MD = dyn_cast<CXXMethodDecl>(FD)) {
> + if (const CXXConstructorDecl *Ctor =
> dyn_cast<CXXConstructorDecl>(FD)) {
> + if (Ctor->isDefaultConstructor())
> + return Sema::CXXDefaultConstructor;
> +
> + if (Ctor->isCopyConstructor())
> + return Sema::CXXCopyConstructor;
> +
> + if (Ctor->isMoveConstructor())
> + return Sema::CXXMoveConstructor;
> + }
> +
> + if (MD->isCopyAssignmentOperator())
> + return Sema::CXXCopyAssignment;
> +
> + if (MD->isMoveAssignmentOperator())
> + return Sema::CXXMoveAssignment;
> +
> + if (isa<CXXDestructorDecl>(FD))
> + return Sema::CXXDestructor;
> + }
> +
> + switch (FD->getDeclName().getCXXOverloadedOperator()) {
> + case OO_EqualEqual:
> + return DefaultedComparisonKind::Equal;
> +
> + case OO_ExclaimEqual:
> + return DefaultedComparisonKind::NotEqual;
> +
> + case OO_Spaceship:
> + // No point allowing this if <=> doesn't exist in the current
> language mode.
> + if (!getLangOpts().CPlusPlus2a)
> + break;
> + return DefaultedComparisonKind::ThreeWay;
> +
> + case OO_Less:
> + case OO_LessEqual:
> + case OO_Greater:
> + case OO_GreaterEqual:
> + // No point allowing this if <=> doesn't exist in the current
> language mode.
> + if (!getLangOpts().CPlusPlus2a)
> + break;
> + return DefaultedComparisonKind::Relational;
> +
> + default:
> + break;
> + }
> +
> + // Not defaultable.
> + return DefaultedFunctionKind();
> +}
> +
> static void DefineImplicitSpecialMember(Sema &S, CXXMethodDecl *MD,
> SourceLocation DefaultLoc) {
> switch (S.getSpecialMember(MD)) {
> @@ -6331,9 +6392,9 @@ void Sema::CheckCompletedCXXClass(CXXRecordDecl
> *Record) {
> Record->setHasTrivialSpecialMemberForCall();
>
> auto CompleteMemberFunction = [&](CXXMethodDecl *M) {
> - // Check whether the explicitly-defaulted special members are valid.
> + // Check whether the explicitly-defaulted members are valid.
> if (!M->isInvalidDecl() && M->isExplicitlyDefaulted())
> - CheckExplicitlyDefaultedSpecialMember(M);
> + CheckExplicitlyDefaultedFunction(M);
>
> // For an explicitly defaulted or deleted special member, we defer
> // determining triviality until the class is complete. That time is
> now!
> @@ -6413,6 +6474,15 @@ void Sema::CheckCompletedCXXClass(CXXRecordDecl
> *Record) {
> DiagnoseAbsenceOfOverrideControl(M);
> }
>
> + // Process any defaulted friends in the member-specification.
> + if (!Record->isDependentType()) {
> + for (FriendDecl *D : Record->friends()) {
> + auto *FD = dyn_cast_or_null<FunctionDecl>(D->getFriendDecl());
> + if (FD && !FD->isInvalidDecl() && FD->isExplicitlyDefaulted())
> + CheckExplicitlyDefaultedFunction(FD);
> + }
> + }
> +
> // ms_struct is a request to use the same ABI rules as MSVC. Check
> // whether this class uses any C++ features that are implemented
> // completely
> diff erently in MSVC, and if so, emit a diagnostic.
> @@ -6766,9 +6836,22 @@ void
> Sema::EvaluateImplicitExceptionSpec(SourceLocation Loc, CXXMethodDecl *MD)
> UpdateExceptionSpec(MD->getCanonicalDecl(), ESI);
> }
>
> -void Sema::CheckExplicitlyDefaultedSpecialMember(CXXMethodDecl *MD) {
> +void Sema::CheckExplicitlyDefaultedFunction(FunctionDecl *FD) {
> + assert(FD->isExplicitlyDefaulted() && "not explicitly-defaulted");
> +
> + DefaultedFunctionKind DefKind = getDefaultedFunctionKind(FD);
> + assert(DefKind && "not a defaultable function");
> +
> + if (DefKind.isSpecialMember()
> + ? CheckExplicitlyDefaultedSpecialMember(cast<CXXMethodDecl>(FD),
> +
> DefKind.asSpecialMember())
> + : CheckExplicitlyDefaultedComparison(FD,
> DefKind.asComparison()))
> + FD->setInvalidDecl();
> +}
> +
> +bool Sema::CheckExplicitlyDefaultedSpecialMember(CXXMethodDecl *MD,
> + CXXSpecialMember CSM) {
> CXXRecordDecl *RD = MD->getParent();
> - CXXSpecialMember CSM = getSpecialMember(MD);
>
> assert(MD->isExplicitlyDefaulted() && CSM != CXXInvalid &&
> "not an explicitly-defaulted special member");
> @@ -6781,7 +6864,7 @@ void
> Sema::CheckExplicitlyDefaultedSpecialMember(CXXMethodDecl *MD) {
>
> // C++11 [dcl.fct.def.default]p1:
> // A function that is explicitly defaulted shall
> - // -- be a special member function (checked elsewhere),
> + // -- be a special member function [...] (checked elsewhere),
> // -- have the same type (except for ref-qualifiers, and except
> that a
> // copy operation can take a non-const reference) as an implicit
> // declaration, and
> @@ -6960,8 +7043,87 @@ void
> Sema::CheckExplicitlyDefaultedSpecialMember(CXXMethodDecl *MD) {
> }
> }
>
> - if (HadError)
> - MD->setInvalidDecl();
> + return HadError;
> +}
> +
> +bool Sema::CheckExplicitlyDefaultedComparison(FunctionDecl *FD,
> + DefaultedComparisonKind
> DCK) {
> + assert(DCK != DefaultedComparisonKind::None && "not a defaulted
> comparison");
> +
> + // C++2a [class.compare.default]p1:
> + // A defaulted comparison operator function for some class C shall be
> a
> + // non-template function declared in the member-specification of C
> that is
> + // -- a non-static const member of C having one parameter of type
> + // const C&, or
> + // -- a friend of C having two parameters of type const C&.
> + CXXRecordDecl *RD =
> dyn_cast<CXXRecordDecl>(FD->getLexicalDeclContext());
> + assert(RD && "defaulted comparison is not defaulted in a class");
> +
> + QualType ExpectedParmType =
> +
> Context.getLValueReferenceType(Context.getRecordType(RD).withConst());
> + for (const ParmVarDecl *Param : FD->parameters()) {
> + if (!Context.hasSameType(Param->getType(), ExpectedParmType)) {
> + Diag(FD->getLocation(), diag::err_defaulted_comparison_param)
> + << (int)DCK << Param->getType() << ExpectedParmType
> + << Param->getSourceRange();
> + return true;
> + }
> + }
> +
> + // ... non-static const member ...
> + if (auto *MD = dyn_cast<CXXMethodDecl>(FD)) {
> + assert(!MD->isStatic() && "comparison function cannot be a static
> member");
> + if (!MD->isConst()) {
> + SourceLocation InsertLoc;
> + if (FunctionTypeLoc Loc = MD->getFunctionTypeLoc())
> + InsertLoc = getLocForEndOfToken(Loc.getRParenLoc());
> + Diag(MD->getLocation(), diag::err_defaulted_comparison_non_const)
> + << (int)DCK << FixItHint::CreateInsertion(InsertLoc, " const");
> +
> + // Add the 'const' to the type to recover.
> + const auto *FPT = MD->getType()->castAs<FunctionProtoType>();
> + FunctionProtoType::ExtProtoInfo EPI = FPT->getExtProtoInfo();
> + EPI.TypeQuals.addConst();
> + MD->setType(Context.getFunctionType(FPT->getReturnType(),
> + FPT->getParamTypes(), EPI));
> + }
> + } else {
> + // A non-member function declared in a class must be a friend.
> + assert(FD->getFriendObjectKind() && "expected a friend declaration");
> + }
> +
> + // C++2a [class.compare.default]p2:
> + // A defaulted comparison operator function for class C is defined as
> + // deleted if any non-static data member of C is of reference type or
> C is
> + // a union-like class.
> + // FIXME: Applying this to cases other than == and <=> is unreasonable.
> + // FIXME: Implement.
> +
> + // C++2a [class.eq]p1, [class.rel]p1:
> + // A [defaulted comparison other than <=>] shall have a declared
> return
> + // type bool.
> + if (DCK != DefaultedComparisonKind::ThreeWay &&
> + !Context.hasSameType(FD->getDeclaredReturnType(), Context.BoolTy)) {
> + Diag(FD->getLocation(),
> diag::err_defaulted_comparison_return_type_not_bool)
> + << (int)DCK << FD->getDeclaredReturnType() << Context.BoolTy
> + << FD->getReturnTypeSourceRange();
> + return true;
> + }
> +
> + // FIXME: Determine whether the function should be defined as deleted.
> +
> + // C++2a [dcl.fct.def.default]p3:
> + // An explicitly-defaulted function [..] may be declared constexpr or
> + // consteval only if it would have been implicitly declared constexpr.
> + // FIXME: There are no rules governing when these should be constexpr,
> + // except for the special case of the injected operator==, for which
> + // C++2a [class.compare.default]p3 says:
> + // The operator is a constexpr function if its definition would
> satisfy
> + // the requirements for a constexpr function.
> + // FIXME: Apply this rule to all defaulted comparisons. The only way
> this
> + // can fail is if the return type of a defaulted operator<=> is not a
> literal
> + // type.
> + return false;
> }
>
> void Sema::CheckDelayedMemberExceptionSpecs() {
> @@ -15006,51 +15168,88 @@ void Sema::SetDeclDeleted(Decl *Dcl,
> SourceLocation DelLoc) {
> }
>
> void Sema::SetDeclDefaulted(Decl *Dcl, SourceLocation DefaultLoc) {
> - CXXMethodDecl *MD = dyn_cast_or_null<CXXMethodDecl>(Dcl);
> + if (!Dcl || Dcl->isInvalidDecl())
> + return;
>
> - if (MD) {
> - if (MD->getParent()->isDependentType()) {
> - MD->setDefaulted();
> - MD->setExplicitlyDefaulted();
> - return;
> + auto *FD = dyn_cast<FunctionDecl>(Dcl);
> + if (!FD) {
> + if (auto *FTD = dyn_cast<FunctionTemplateDecl>(Dcl)) {
> + if
> (getDefaultedFunctionKind(FTD->getTemplatedDecl()).isComparison()) {
> + Diag(DefaultLoc, diag::err_defaulted_comparison_template);
> + return;
> + }
> }
>
> - CXXSpecialMember Member = getSpecialMember(MD);
> - if (Member == CXXInvalid) {
> - if (!MD->isInvalidDecl())
> - Diag(DefaultLoc, diag::err_default_special_members);
> - return;
> - }
> + Diag(DefaultLoc, diag::err_default_special_members)
> + << getLangOpts().CPlusPlus2a;
> + return;
> + }
>
> - MD->setDefaulted();
> - MD->setExplicitlyDefaulted();
> + // Reject if this can't possibly be a defaultable function.
> + DefaultedFunctionKind DefKind = getDefaultedFunctionKind(FD);
> + if (!DefKind &&
> + // A dependent function that doesn't locally look defaultable can
> + // still instantiate to a defaultable function if it's a constructor
> + // or assignment operator.
> + (!FD->isDependentContext() ||
> + (!isa<CXXConstructorDecl>(FD) &&
> + FD->getDeclName().getCXXOverloadedOperator() != OO_Equal))) {
> + Diag(DefaultLoc, diag::err_default_special_members)
> + << getLangOpts().CPlusPlus2a;
> + return;
> + }
>
> - // Unset that we will have a body for this function. We might not,
> - // if it turns out to be trivial, and we don't need this marking now
> - // that we've marked it as defaulted.
> - MD->setWillHaveBody(false);
> + if (DefKind.isComparison() &&
> + !isa<CXXRecordDecl>(FD->getLexicalDeclContext())) {
> + Diag(FD->getLocation(), diag::err_defaulted_comparison_out_of_class)
> + << (int)DefKind.asComparison();
> + return;
> + }
>
> - // If this definition appears within the record, do the checking when
> - // the record is complete.
> - const FunctionDecl *Primary = MD;
> - if (const FunctionDecl *Pattern =
> MD->getTemplateInstantiationPattern())
> - // Ask the template instantiation pattern that actually had the
> - // '= default' on it.
> - Primary = Pattern;
> + // Issue compatibility warning. We already warned if the operator is
> + // 'operator<=>' when parsing the '<=>' token.
> + if (DefKind.isComparison() &&
> + DefKind.asComparison() != DefaultedComparisonKind::ThreeWay) {
> + Diag(DefaultLoc, getLangOpts().CPlusPlus2a
> + ? diag::warn_cxx17_compat_defaulted_comparison
> + : diag::ext_defaulted_comparison);
> + }
>
> - // If the method was defaulted on its first declaration, we will have
> - // already performed the checking in CheckCompletedCXXClass. Such a
> - // declaration doesn't trigger an implicit definition.
> - if (Primary->getCanonicalDecl()->isDefaulted())
> - return;
> + FD->setDefaulted();
> + FD->setExplicitlyDefaulted();
>
> - CheckExplicitlyDefaultedSpecialMember(MD);
> + // Defer checking functions that are defaulted in a dependent context.
> + if (FD->isDependentContext())
> + return;
>
> - if (!MD->isInvalidDecl())
> - DefineImplicitSpecialMember(*this, MD, DefaultLoc);
> - } else {
> - Diag(DefaultLoc, diag::err_default_special_members);
> - }
> + // Unset that we will have a body for this function. We might not,
> + // if it turns out to be trivial, and we don't need this marking now
> + // that we've marked it as defaulted.
> + FD->setWillHaveBody(false);
> +
> + // If this definition appears within the record, do the checking when
> + // the record is complete. This is always the case for a defaulted
> + // comparison.
> + if (DefKind.isComparison())
> + return;
> + auto *MD = cast<CXXMethodDecl>(FD);
> +
> + const FunctionDecl *Primary = FD;
> + if (const FunctionDecl *Pattern = FD->getTemplateInstantiationPattern())
> + // Ask the template instantiation pattern that actually had the
> + // '= default' on it.
> + Primary = Pattern;
> +
> + // If the method was defaulted on its first declaration, we will have
> + // already performed the checking in CheckCompletedCXXClass. Such a
> + // declaration doesn't trigger an implicit definition.
> + if (Primary->getCanonicalDecl()->isDefaulted())
> + return;
> +
> + if (CheckExplicitlyDefaultedSpecialMember(MD,
> DefKind.asSpecialMember()))
> + MD->setInvalidDecl();
> + else
> + DefineImplicitSpecialMember(*this, MD, DefaultLoc);
> }
>
> static void SearchForReturnInStmt(Sema &Self, Stmt *S) {
>
> diff --git a/clang/lib/Sema/SemaTemplateInstantiateDecl.cpp
> b/clang/lib/Sema/SemaTemplateInstantiateDecl.cpp
> index d1ad304e62e4..31a4302ba826 100644
> --- a/clang/lib/Sema/SemaTemplateInstantiateDecl.cpp
> +++ b/clang/lib/Sema/SemaTemplateInstantiateDecl.cpp
> @@ -2049,6 +2049,11 @@ Decl
> *TemplateDeclInstantiator::VisitFunctionDecl(FunctionDecl *D,
> }
> }
>
> + if (D->isExplicitlyDefaulted())
> + SemaRef.SetDeclDefaulted(Function, D->getLocation());
> + if (D->isDeleted())
> + SemaRef.SetDeclDeleted(Function, D->getLocation());
> +
> if (Function->isLocalExternDecl() && !Function->getPreviousDecl())
> DC->makeDeclVisibleInContext(PrincipalDecl);
>
> @@ -2056,7 +2061,6 @@ Decl
> *TemplateDeclInstantiator::VisitFunctionDecl(FunctionDecl *D,
> PrincipalDecl->isInIdentifierNamespace(Decl::IDNS_Ordinary))
> PrincipalDecl->setNonMemberOperator();
>
> - assert(!D->isDefaulted() && "only methods should be defaulted");
> return Function;
> }
>
> @@ -4016,9 +4020,6 @@ void Sema::InstantiateExceptionSpec(SourceLocation
> PointOfInstantiation,
> bool
> TemplateDeclInstantiator::InitFunctionInstantiation(FunctionDecl *New,
> FunctionDecl *Tmpl) {
> - if (Tmpl->isDeleted())
> - New->setDeletedAsWritten();
> -
> New->setImplicit(Tmpl->isImplicit());
>
> // Forward the mangling number from the template to the instantiated
> decl.
>
> diff --git
> a/clang/test/CXX/class/class.compare/class.compare.default/p1.cpp
> b/clang/test/CXX/class/class.compare/class.compare.default/p1.cpp
> new file mode 100644
> index 000000000000..1f8d6a2a7cff
> --- /dev/null
> +++ b/clang/test/CXX/class/class.compare/class.compare.default/p1.cpp
> @@ -0,0 +1,46 @@
> +// RUN: %clang_cc1 -std=c++2a -verify %s
> +
> +struct B {};
> +bool operator==(const B&, const B&) = default; // expected-error
> {{equality comparison operator can only be defaulted in a class definition}}
> +bool operator<=>(const B&, const B&) = default; // expected-error
> {{three-way comparison operator can only be defaulted in a class
> definition}}
> +
> +template<typename T = void>
> + bool operator<(const B&, const B&) = default; // expected-error
> {{comparison operator template cannot be defaulted}}
> +
> +struct A {
> + friend bool operator==(const A&, const A&) = default;
> + friend bool operator!=(const A&, const B&) = default; // expected-error
> {{invalid parameter type for defaulted equality comparison}}
> + friend bool operator!=(const B&, const B&) = default; // expected-error
> {{invalid parameter type for defaulted equality comparison}}
> + friend bool operator<(const A&, const A&);
> + friend bool operator<(const B&, const B&) = default; // expected-error
> {{invalid parameter type for defaulted relational comparison}}
> + friend bool operator>(A, A) = default; // expected-error {{invalid
> parameter type for defaulted relational comparison}}
> +
> + bool operator<(const A&) const;
> + bool operator<=(const A&) const = default;
> + bool operator==(const A&) const volatile && = default; // surprisingly,
> OK
> + bool operator<=>(const A&) = default; // expected-error {{defaulted
> member three-way comparison operator must be const-qualified}}
> + bool operator>=(const B&) const = default; // expected-error {{invalid
> parameter type for defaulted relational comparison}}
> + static bool operator>(const B&) = default; // expected-error
> {{overloaded 'operator>' cannot be a static member function}}
> +
> + template<typename T = void>
> + friend bool operator==(const A&, const A&) = default; //
> expected-error {{comparison operator template cannot be defaulted}}
> + template<typename T = void>
> + bool operator==(const A&) const = default; // expected-error
> {{comparison operator template cannot be defaulted}}
> +};
> +
> +// FIXME: The wording is not clear as to whether these are valid, but the
> +// intention is that they are not.
> +bool operator<(const A&, const A&) = default; // expected-error
> {{relational comparison operator can only be defaulted in a class
> definition}}
> +bool A::operator<(const A&) const = default; // expected-error {{can only
> be defaulted in a class definition}}
> +
> +template<typename T> struct Dependent {
> + using U = typename T::type;
> + bool operator==(U) const = default; // expected-error {{found
> 'Dependent<Bad>::U'}}
> + friend bool operator==(U, U) = default; // expected-error {{found
> 'Dependent<Bad>::U'}}
> +};
> +
> +struct Good { using type = const Dependent<Good>&; };
> +template struct Dependent<Good>;
> +
> +struct Bad { using type = Dependent<Bad>&; };
> +template struct Dependent<Bad>; // expected-note {{in instantiation of}}
>
> diff --git a/clang/test/CXX/class/class.compare/class.eq/p1.cpp
> b/clang/test/CXX/class/class.compare/class.eq/p1.cpp
> new file mode 100644
> index 000000000000..622f66cf9281
> --- /dev/null
> +++ b/clang/test/CXX/class/class.compare/class.eq/p1.cpp
> @@ -0,0 +1,25 @@
> +// RUN: %clang_cc1 -std=c++2a -verify %s
> +
> +struct Good {
> + bool operator==(const Good&) const = default;
> + bool operator!=(const Good&) const = default;
> + friend bool operator==(const Good&, const Good&) = default;
> + friend bool operator!=(const Good&, const Good&) = default;
> +};
> +
> +enum Bool : bool {};
> +struct Bad {
> + bool &operator==(const Bad&) const = default; // expected-error
> {{return type for defaulted equality comparison operator must be 'bool',
> not 'bool &'}}
> + const bool operator!=(const Bad&) const = default; // expected-error
> {{return type for defaulted equality comparison operator must be 'bool',
> not 'const bool'}}
> + friend Bool operator==(const Bad&, const Bad&) = default; //
> expected-error {{return type for defaulted equality comparison operator
> must be 'bool', not 'Bool'}}
> + friend int operator!=(const Bad&, const Bad&) = default; //
> expected-error {{return type for defaulted equality comparison operator
> must be 'bool', not 'int'}}
> +};
> +
> +template<typename T> struct Ugly {
> + T operator==(const Ugly&) const = default; // expected-error {{return
> type}}
> + T operator!=(const Ugly&) const = default; // expected-error {{return
> type}}
> + friend T operator==(const Ugly&, const Ugly&) = default; //
> expected-error {{return type}}
> + friend T operator!=(const Ugly&, const Ugly&) = default; //
> expected-error {{return type}}
> +};
> +template struct Ugly<bool>;
> +template struct Ugly<int>; // expected-note {{in instantiation of}}
>
> diff --git a/clang/test/CXX/class/class.compare/class.rel/p1.cpp
> b/clang/test/CXX/class/class.compare/class.rel/p1.cpp
> new file mode 100644
> index 000000000000..3797d5f81f56
> --- /dev/null
> +++ b/clang/test/CXX/class/class.compare/class.rel/p1.cpp
> @@ -0,0 +1,25 @@
> +// RUN: %clang_cc1 -std=c++2a -verify %s
> +
> +struct Good {
> + bool operator<(const Good&) const = default;
> + bool operator>(const Good&) const = default;
> + friend bool operator<=(const Good&, const Good&) = default;
> + friend bool operator>=(const Good&, const Good&) = default;
> +};
> +
> +enum Bool : bool {};
> +struct Bad {
> + bool &operator<(const Bad&) const = default; // expected-error {{return
> type for defaulted relational comparison operator must be 'bool', not 'bool
> &'}}
> + const bool operator>(const Bad&) const = default; // expected-error
> {{return type for defaulted relational comparison operator must be 'bool',
> not 'const bool'}}
> + friend Bool operator<=(const Bad&, const Bad&) = default; //
> expected-error {{return type for defaulted relational comparison operator
> must be 'bool', not 'Bool'}}
> + friend int operator>=(const Bad&, const Bad&) = default; //
> expected-error {{return type for defaulted relational comparison operator
> must be 'bool', not 'int'}}
> +};
> +
> +template<typename T> struct Ugly {
> + T operator<(const Ugly&) const = default; // expected-error {{return
> type}}
> + T operator>(const Ugly&) const = default; // expected-error {{return
> type}}
> + friend T operator<=(const Ugly&, const Ugly&) = default; //
> expected-error {{return type}}
> + friend T operator>=(const Ugly&, const Ugly&) = default; //
> expected-error {{return type}}
> +};
> +template struct Ugly<bool>;
> +template struct Ugly<int>; // expected-note {{in instantiation of}}
>
> diff --git
> a/clang/test/CXX/dcl.decl/dcl.fct.def/dcl.fct.def.default/p1.cpp
> b/clang/test/CXX/dcl.decl/dcl.fct.def/dcl.fct.def.default/p1.cpp
> index 3f2bc569edf6..6e9b45903d39 100644
> --- a/clang/test/CXX/dcl.decl/dcl.fct.def/dcl.fct.def.default/p1.cpp
> +++ b/clang/test/CXX/dcl.decl/dcl.fct.def/dcl.fct.def.default/p1.cpp
> @@ -1,12 +1,28 @@
> -// RUN: %clang_cc1 -verify %s -std=c++11
> -// RUN: %clang_cc1 -verify %s -std=c++17
> -// RUN: %clang_cc1 -verify %s -std=c++2a
> +// RUN: %clang_cc1 -verify=expected,pre2a %s -std=c++11
> +// RUN: %clang_cc1 -verify=expected,pre2a %s -std=c++17
> +// RUN: %clang_cc1 -verify=expected %s -std=c++2a
>
> // A function that is explicitly defaulted shall
> struct A {
> - // -- be a special member function,
> - A(int) = default; // expected-error {{only special member functions may
> be defaulted}}
> + // -- be a special member function [C++2a: or a comparison operator
> function],
> + A(int) = default;
> +#if __cplusplus <= 201703L
> + // expected-error at -2 {{only special member functions may be defaulted}}
> +#else
> + // expected-error at -4 {{only special member functions and comparison
> operators may be defaulted}}
> +#endif
> A(A) = default; // expected-error {{must pass its first argument by
> reference}}
> + void f(A) = default; // expected-error-re {{only special member
> functions{{( and comparison operators)?}} may be defaulted}}
> +
> + bool operator==(const A&) const = default; // pre2a-warning {{defaulted
> comparison operators are a C++20 extension}}
> + bool operator!=(const A&) const = default; // pre2a-warning {{defaulted
> comparison operators are a C++20 extension}}
> + bool operator<(const A&) const = default; // pre2a-error {{only special
> member functions may be defaulted}}
> + bool operator>(const A&) const = default; // pre2a-error {{only special
> member functions may be defaulted}}
> + bool operator<=(const A&) const = default; // pre2a-error {{only
> special member functions may be defaulted}}
> + bool operator>=(const A&) const = default; // pre2a-error {{only
> special member functions may be defaulted}}
> + bool operator<=>(const A&) const = default; // pre2a-error 1+{{}}
> pre2a-warning {{'<=>' is a single token in C++2a}}
> +
> + A operator+(const A&) const = default; // expected-error-re {{only
> special member functions{{( and comparison operators)?}} may be defaulted}}
>
> // -- have the same declared function type as if it had been implicitly
> // declared
>
> diff --git a/clang/test/Parser/cxx0x-decl.cpp
> b/clang/test/Parser/cxx0x-decl.cpp
> index 2f219ac87fb8..3c1c3602691b 100644
> --- a/clang/test/Parser/cxx0x-decl.cpp
> +++ b/clang/test/Parser/cxx0x-decl.cpp
> @@ -39,7 +39,7 @@ static_assert(something, ""); // expected-error
> {{undeclared identifier}}
>
> // PR9903
> struct SS {
> - typedef void d() = default; // expected-error {{function definition
> declared 'typedef'}} expected-error {{only special member functions may be
> defaulted}}
> + typedef void d() = default; // expected-error {{function definition
> declared 'typedef'}} expected-error {{only special member functions and
> comparison operators may be defaulted}}
> };
>
> using PR14855 = int S::; // expected-error {{expected ';' after alias
> declaration}}
>
> diff --git a/clang/test/SemaCXX/cxx0x-defaulted-functions.cpp
> b/clang/test/SemaCXX/cxx0x-defaulted-functions.cpp
> index 45a65440d599..c68b7d67932e 100644
> --- a/clang/test/SemaCXX/cxx0x-defaulted-functions.cpp
> +++ b/clang/test/SemaCXX/cxx0x-defaulted-functions.cpp
> @@ -175,7 +175,7 @@ namespace PR14577 {
> Outer<T>::Inner1<T>::~Inner1() = delete; // expected-error {{nested
> name specifier 'Outer<T>::Inner1<T>::' for declaration does not refer into
> a class, class template or class template partial specialization}}
> expected-error {{only functions can have deleted definitions}}
>
> template<typename T>
> - Outer<T>::Inner2<T>::~Inner2() = default; // expected-error {{nested
> name specifier 'Outer<T>::Inner2<T>::' for declaration does not refer into
> a class, class template or class template partial specialization}}
> expected-error {{only special member functions may be defaulted}}
> + Outer<T>::Inner2<T>::~Inner2() = default; // expected-error {{nested
> name specifier 'Outer<T>::Inner2<T>::' for declaration does not refer into
> a class, class template or class template partial specialization}}
> }
>
> extern "C" { // expected-note {{extern "C" language linkage specification
> begins here}}
>
> diff --git a/clang/test/SemaCXX/cxx17-compat.cpp
> b/clang/test/SemaCXX/cxx17-compat.cpp
> index 3d5420fa0637..e063b1fc1807 100644
> --- a/clang/test/SemaCXX/cxx17-compat.cpp
> +++ b/clang/test/SemaCXX/cxx17-compat.cpp
> @@ -88,3 +88,36 @@ void f() {
> // expected-warning at -4 {{decomposition declaration declared with
> 'static thread_local' specifiers is incompatible with C++ standards before
> C++2a}}
> #endif
> }
> +
> +struct DefaultedComparisons {
> + bool operator==(const DefaultedComparisons&) const = default;
> + bool operator!=(const DefaultedComparisons&) const = default;
> +#if __cplusplus <= 201703L
> + // expected-warning at -3 {{defaulted comparison operators are a C++20
> extension}}
> + // expected-warning at -3 {{defaulted comparison operators are a C++20
> extension}}
> +#else
> + // expected-warning at -6 {{defaulted comparison operators are
> incompatible with C++ standards before C++20}}
> + // expected-warning at -6 {{defaulted comparison operators are
> incompatible with C++ standards before C++20}}
> +#endif
> + bool operator<=>(const DefaultedComparisons&) const = default;
> +#if __cplusplus <= 201703L
> + // expected-error at -2 {{'operator<=' cannot be the name of a variable
> or data member}} expected-error at -2 0+{{}} expected-warning at -2 {{}}
> +#else
> + // expected-warning at -4 {{'<=>' operator is incompatible with C++
> standards before C++2a}}
> +#endif
> + bool operator<(const DefaultedComparisons&) const = default;
> + bool operator<=(const DefaultedComparisons&) const = default;
> + bool operator>(const DefaultedComparisons&) const = default;
> + bool operator>=(const DefaultedComparisons&) const = default;
> +#if __cplusplus <= 201703L
> + // expected-error at -5 {{only special member functions}}
> + // expected-error at -5 {{only special member functions}}
> + // expected-error at -5 {{only special member functions}}
> + // expected-error at -5 {{only special member functions}}
> +#else
> + // expected-warning at -10 {{defaulted comparison operators are
> incompatible with C++ standards before C++20}}
> + // expected-warning at -10 {{defaulted comparison operators are
> incompatible with C++ standards before C++20}}
> + // expected-warning at -10 {{defaulted comparison operators are
> incompatible with C++ standards before C++20}}
> + // expected-warning at -10 {{defaulted comparison operators are
> incompatible with C++ standards before C++20}}
> +#endif
> +};
>
>
>
> _______________________________________________
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> cfe-commits at lists.llvm.org
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