Rakete1111 updated this revision to Diff 159160.
Rakete1111 added a comment.
Add missing test cases. :)
Repository:
rC Clang
https://reviews.llvm.org/D50291
Files:
include/clang/Sema/Sema.h
lib/Sema/SemaDeclCXX.cpp
test/CXX/special/class.copy/p10.cpp
Index: test/CXX/special/class.copy/p10.cpp
===================================================================
--- /dev/null
+++ test/CXX/special/class.copy/p10.cpp
@@ -0,0 +1,25 @@
+// RUN: %clang_cc1 -std=c++14 -fsyntax-only -verify %s
+// expected-no-diagnostics
+
+// The implicitly-defined copy/move assignment operator is constexpr if
+// - X is a literal type, and
+// - [...]
+//
+// PR38143: Order of defaulted special members matters.
+struct X {
+ constexpr X() = default;
+ constexpr X(const X &) = default;
+ constexpr X &operator=(const X &) = default;
+ ~X() = default;
+ constexpr X(X &&) = default;
+ constexpr X &operator=(X &&) = default;
+};
+
+struct Y {
+ constexpr Y &operator=(const Y &) = default;
+ constexpr Y &operator=(Y &&) = default;
+ constexpr Y() = default;
+ constexpr Y(const Y &) = default;
+ ~Y() = default;
+ constexpr Y(Y &&) = default;
+};
Index: lib/Sema/SemaDeclCXX.cpp
===================================================================
--- lib/Sema/SemaDeclCXX.cpp
+++ lib/Sema/SemaDeclCXX.cpp
@@ -6020,6 +6020,7 @@
bool HasMethodWithOverrideControl = false,
HasOverridingMethodWithoutOverrideControl = false;
+ CXXMethodDecl *CopyAssignment = nullptr, *MoveAssignment = nullptr;
if (!Record->isDependentType()) {
for (auto *M : Record->methods()) {
// See if a method overloads virtual methods in a base
@@ -6049,6 +6050,11 @@
}
}
+ if (CSM == CXXCopyAssignment)
+ CopyAssignment = M;
+ else if (CSM == CXXMoveAssignment)
+ MoveAssignment = M;
+
// Set triviality for the purpose of calls if this is a user-provided
// copy/move constructor or destructor.
if ((CSM == CXXCopyConstructor || CSM == CXXMoveConstructor ||
@@ -6071,6 +6077,22 @@
}
}
}
+
+ // Now we can decide whether the special members are constexpr.
+ auto ActOnSpecialMember = [this, &Record](CXXMethodDecl *MD) {
+ if (!MD->isInvalidDecl() && MD->isExplicitlyDefaulted()) {
+ CheckExplicitlyDefaultedSpecialMemberConstexpr(MD);
+ Record->finishedDefaultedOrDeletedMember(MD);
+ }
+ };
+ for (auto *M : Record->ctors())
+ ActOnSpecialMember(M);
+ if (CopyAssignment)
+ ActOnSpecialMember(CopyAssignment);
+ if (MoveAssignment)
+ ActOnSpecialMember(MoveAssignment);
+ if (CXXDestructorDecl *CD = Record->getDestructor())
+ ActOnSpecialMember(CD);
}
if (HasMethodWithOverrideControl &&
@@ -6532,20 +6554,8 @@
// C++11 [dcl.fct.def.default]p2:
// An explicitly-defaulted function may be declared constexpr only if it
// would have been implicitly declared as constexpr,
- // Do not apply this rule to members of class templates, since core issue 1358
- // makes such functions always instantiate to constexpr functions. For
- // functions which cannot be constexpr (for non-constructors in C++11 and for
- // destructors in C++1y), this is checked elsewhere.
- bool Constexpr = defaultedSpecialMemberIsConstexpr(*this, RD, CSM,
- HasConstParam);
- if ((getLangOpts().CPlusPlus14 ? !isa<CXXDestructorDecl>(MD)
- : isa<CXXConstructorDecl>(MD)) &&
- MD->isConstexpr() && !Constexpr &&
- MD->getTemplatedKind() == FunctionDecl::TK_NonTemplate) {
- Diag(MD->getLocStart(), diag::err_incorrect_defaulted_constexpr) << CSM;
- // FIXME: Explain why the special member can't be constexpr.
- HadError = true;
- }
+ // We need to delay this, because at this point we may not have enough
+ // information to determine if MD is really constexpr or not.
// and may have an explicit exception-specification only if it is compatible
// with the exception-specification on the implicit declaration.
@@ -6568,8 +6578,6 @@
if (First) {
// -- it is implicitly considered to be constexpr if the implicit
// definition would be,
- MD->setConstexpr(Constexpr);
-
// -- it is implicitly considered to have the same exception-specification
// as if it had been implicitly declared,
FunctionProtoType::ExtProtoInfo EPI = Type->getExtProtoInfo();
@@ -6598,6 +6606,39 @@
MD->setInvalidDecl();
}
+void Sema::CheckExplicitlyDefaultedSpecialMemberConstexpr(CXXMethodDecl *MD) {
+ CXXSpecialMember CSM = getSpecialMember(MD);
+ assert(MD && MD->isExplicitlyDefaulted() && CSM != CXXInvalid &&
+ "not an explicitly-defaulted special member");
+
+ const FunctionProtoType *Type = MD->getType()->getAs<FunctionProtoType>();
+
+ unsigned ExpectedParams =
+ CSM != CXXDefaultConstructor && CSM != CXXDestructor;
+ QualType ArgType = ExpectedParams ? Type->getParamType(0) : QualType();
+
+ bool HasConstParam = ExpectedParams && ArgType->isReferenceType() &&
+ ArgType->getPointeeType().isConstQualified();
+
+ // Do not apply this rule to members of class templates, since core issue 1358
+ // makes such functions always instantiate to constexpr functions. For
+ // functions which cannot be constexpr (for non-constructors in C++11 and for
+ // destructors in C++1y), this is checked elsewhere.
+ bool Constexpr = defaultedSpecialMemberIsConstexpr(*this, MD->getParent(),
+ CSM, HasConstParam);
+ if ((getLangOpts().CPlusPlus14 ? !isa<CXXDestructorDecl>(MD)
+ : isa<CXXConstructorDecl>(MD)) &&
+ MD->isConstexpr() && !Constexpr &&
+ MD->getTemplatedKind() == FunctionDecl::TK_NonTemplate) {
+ Diag(MD->getLocStart(), diag::err_incorrect_defaulted_constexpr) << CSM;
+ // FIXME: Explain why the special member can't be constexpr.
+ MD->setInvalidDecl();
+ }
+
+ if (MD == MD->getCanonicalDecl())
+ MD->setConstexpr(Constexpr);
+}
+
/// Check whether the exception specification provided for an
/// explicitly-defaulted special member matches the exception specification
/// that would have been generated for an implicit special member, per
@@ -14519,6 +14560,7 @@
return;
CheckExplicitlyDefaultedSpecialMember(MD);
+ CheckExplicitlyDefaultedSpecialMemberConstexpr(MD);
if (!MD->isInvalidDecl())
DefineImplicitSpecialMember(*this, MD, DefaultLoc);
Index: include/clang/Sema/Sema.h
===================================================================
--- include/clang/Sema/Sema.h
+++ include/clang/Sema/Sema.h
@@ -5924,6 +5924,7 @@
void CheckDeductionGuideTemplate(FunctionTemplateDecl *TD);
void CheckExplicitlyDefaultedSpecialMember(CXXMethodDecl *MD);
+ void CheckExplicitlyDefaultedSpecialMemberConstexpr(CXXMethodDecl *MD);
void CheckExplicitlyDefaultedMemberExceptionSpec(CXXMethodDecl *MD,
const FunctionProtoType *T);
void CheckDelayedMemberExceptionSpecs();
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