<div dir="ltr">Sorry if this is expected behavior, but saw a regression that looks /plausibly/ correct & is rendered ambiguous by this change so I've gone ahead and reverted this patch in d8018233d1ea4234de68d5b4593abd773db79484<br><br>Comment from the original:<br><br> Regressed/causes this to error due to ambiguity:<br> <br> void f(const int * const &);<br> void f(int *);<br> int main() {<br> int * x;<br> f(x);<br> }<br> <br> (in case it's important - the original case where this turned up was a<br> member function overload in a class template with, essentially:<br> <br> f(const T1&)<br> f(T2*)<br> <br> (where T1 == X const *, T2 == X))<br></div><br><div class="gmail_quote"><div dir="ltr" class="gmail_attr">On Thu, Dec 19, 2019 at 6:56 PM Richard Smith via cfe-commits <<a href="mailto:cfe-commits@lists.llvm.org">cfe-commits@lists.llvm.org</a>> wrote:<br></div><blockquote class="gmail_quote" style="margin:0px 0px 0px 0.8ex;border-left:1px solid rgb(204,204,204);padding-left:1ex"><br>
Author: Richard Smith<br>
Date: 2019-12-19T18:37:55-08:00<br>
New Revision: de21704ba96fa80d3e9402f12c6505917a3885f4<br>
<br>
URL: <a href="https://github.com/llvm/llvm-project/commit/de21704ba96fa80d3e9402f12c6505917a3885f4" rel="noreferrer" target="_blank">https://github.com/llvm/llvm-project/commit/de21704ba96fa80d3e9402f12c6505917a3885f4</a><br>
DIFF: <a href="https://github.com/llvm/llvm-project/commit/de21704ba96fa80d3e9402f12c6505917a3885f4.diff" rel="noreferrer" target="_blank">https://github.com/llvm/llvm-project/commit/de21704ba96fa80d3e9402f12c6505917a3885f4.diff</a><br>
<br>
LOG: CWG2352: Allow qualification conversions during reference binding.<br>
<br>
The language wording change forgot to update overload resolution to rank<br>
implicit conversion sequences based on qualification conversions in<br>
reference bindings. The anticipated resolution for that oversight is<br>
implemented here -- we order candidates based on qualification<br>
conversion, not only on top-level cv-qualifiers.<br>
<br>
For OpenCL/C++, this allows reference binding between pointers with<br>
differing (nested) address spaces. This makes the behavior of reference<br>
binding consistent with that of implicit pointer conversions, as is the<br>
purpose of this change, but that pre-existing behavior for pointer<br>
conversions is itself probably not correct. In any case, it's now<br>
consistently the same behavior and implemented in only one place.<br>
<br>
Added: <br>
<br>
<br>
Modified: <br>
clang/include/clang/Basic/DiagnosticSemaKinds.td<br>
clang/lib/Sema/SemaExprCXX.cpp<br>
clang/lib/Sema/SemaInit.cpp<br>
clang/lib/Sema/SemaOverload.cpp<br>
clang/test/CXX/drs/dr23xx.cpp<br>
clang/test/CXX/drs/dr4xx.cpp<br>
clang/test/SemaObjCXX/<a href="http://arc-overloading.mm" rel="noreferrer" target="_blank">arc-overloading.mm</a><br>
clang/test/SemaOpenCL/<a href="http://address-spaces-conversions-cl2.0.cl" rel="noreferrer" target="_blank">address-spaces-conversions-cl2.0.cl</a><br>
clang/www/cxx_dr_status.html<br>
clang/www/make_cxx_dr_status<br>
<br>
Removed: <br>
<br>
<br>
<br>
################################################################################<br>
diff --git a/clang/include/clang/Basic/DiagnosticSemaKinds.td b/clang/include/clang/Basic/DiagnosticSemaKinds.td<br>
index c7b501b9bb2b..315e836cd397 100644<br>
--- a/clang/include/clang/Basic/DiagnosticSemaKinds.td<br>
+++ b/clang/include/clang/Basic/DiagnosticSemaKinds.td<br>
@@ -1927,7 +1927,8 @@ def err_lvalue_reference_bind_to_unrelated : Error<<br>
"cannot bind to a value of unrelated type}1,2">;<br>
def err_reference_bind_drops_quals : Error<<br>
"binding reference %<br>
diff {of type $ to value of type $|to value}0,1 "<br>
- "%select{drops %3 qualifier%plural{1:|2:|4:|:s}4|changes address space}2">;<br>
+ "%select{drops %3 qualifier%plural{1:|2:|4:|:s}4|changes address space|"<br>
+ "not permitted due to incompatible qualifiers}2">;<br>
def err_reference_bind_failed : Error<<br>
"reference %<br>
diff {to %select{type|incomplete type}1 $ could not bind to an "<br>
"%select{rvalue|lvalue}2 of type $|could not bind to %select{rvalue|lvalue}2 of "<br>
<br>
diff --git a/clang/lib/Sema/SemaExprCXX.cpp b/clang/lib/Sema/SemaExprCXX.cpp<br>
index cfb3a05e9c14..cd78f096bb22 100644<br>
--- a/clang/lib/Sema/SemaExprCXX.cpp<br>
+++ b/clang/lib/Sema/SemaExprCXX.cpp<br>
@@ -5864,6 +5864,8 @@ QualType Sema::CXXCheckConditionalOperands(ExprResult &Cond, ExprResult &LHS,<br>
// one of the operands is reference-compatible with the other, in order<br>
// to support conditionals between functions <br>
diff ering in noexcept. This<br>
// will similarly cover <br>
diff erence in array bounds after P0388R4.<br>
+ // FIXME: If LTy and RTy have a composite pointer type, should we convert to<br>
+ // that instead?<br>
ExprValueKind LVK = LHS.get()->getValueKind();<br>
ExprValueKind RVK = RHS.get()->getValueKind();<br>
if (!Context.hasSameType(LTy, RTy) &&<br>
<br>
diff --git a/clang/lib/Sema/SemaInit.cpp b/clang/lib/Sema/SemaInit.cpp<br>
index 94d524a63f5a..ef4fa827064e 100644<br>
--- a/clang/lib/Sema/SemaInit.cpp<br>
+++ b/clang/lib/Sema/SemaInit.cpp<br>
@@ -8919,11 +8919,17 @@ bool InitializationSequence::Diagnose(Sema &S,<br>
S.Diag(Kind.getLocation(), diag::err_reference_bind_drops_quals)<br>
<< NonRefType << SourceType << 1 /*addr space*/<br>
<< Args[0]->getSourceRange();<br>
- else<br>
+ else if (DroppedQualifiers.hasQualifiers())<br>
S.Diag(Kind.getLocation(), diag::err_reference_bind_drops_quals)<br>
<< NonRefType << SourceType << 0 /*cv quals*/<br>
<< Qualifiers::fromCVRMask(DroppedQualifiers.getCVRQualifiers())<br>
<< DroppedQualifiers.getCVRQualifiers() << Args[0]->getSourceRange();<br>
+ else<br>
+ // FIXME: Consider decomposing the type and explaining which qualifiers<br>
+ // were dropped where, or on which level a 'const' is missing, etc.<br>
+ S.Diag(Kind.getLocation(), diag::err_reference_bind_drops_quals)<br>
+ << NonRefType << SourceType << 2 /*incompatible quals*/<br>
+ << Args[0]->getSourceRange();<br>
break;<br>
}<br>
<br>
<br>
diff --git a/clang/lib/Sema/SemaOverload.cpp b/clang/lib/Sema/SemaOverload.cpp<br>
index 74a0bc7c78ff..92058c3aa5fd 100644<br>
--- a/clang/lib/Sema/SemaOverload.cpp<br>
+++ b/clang/lib/Sema/SemaOverload.cpp<br>
@@ -3153,6 +3153,70 @@ static bool isNonTrivialObjCLifetimeConversion(Qualifiers FromQuals,<br>
return true;<br>
}<br>
<br>
+/// Perform a single iteration of the loop for checking if a qualification<br>
+/// conversion is valid.<br>
+///<br>
+/// Specifically, check whether any change between the qualifiers of \p<br>
+/// FromType and \p ToType is permissible, given knowledge about whether every<br>
+/// outer layer is const-qualified.<br>
+static bool isQualificationConversionStep(QualType FromType, QualType ToType,<br>
+ bool CStyle,<br>
+ bool &PreviousToQualsIncludeConst,<br>
+ bool &ObjCLifetimeConversion) {<br>
+ Qualifiers FromQuals = FromType.getQualifiers();<br>
+ Qualifiers ToQuals = ToType.getQualifiers();<br>
+<br>
+ // Ignore __unaligned qualifier if this type is void.<br>
+ if (ToType.getUnqualifiedType()->isVoidType())<br>
+ FromQuals.removeUnaligned();<br>
+<br>
+ // Objective-C ARC:<br>
+ // Check Objective-C lifetime conversions.<br>
+ if (FromQuals.getObjCLifetime() != ToQuals.getObjCLifetime()) {<br>
+ if (ToQuals.compatiblyIncludesObjCLifetime(FromQuals)) {<br>
+ if (isNonTrivialObjCLifetimeConversion(FromQuals, ToQuals))<br>
+ ObjCLifetimeConversion = true;<br>
+ FromQuals.removeObjCLifetime();<br>
+ ToQuals.removeObjCLifetime();<br>
+ } else {<br>
+ // Qualification conversions cannot cast between <br>
diff erent<br>
+ // Objective-C lifetime qualifiers.<br>
+ return false;<br>
+ }<br>
+ }<br>
+<br>
+ // Allow addition/removal of GC attributes but not changing GC attributes.<br>
+ if (FromQuals.getObjCGCAttr() != ToQuals.getObjCGCAttr() &&<br>
+ (!FromQuals.hasObjCGCAttr() || !ToQuals.hasObjCGCAttr())) {<br>
+ FromQuals.removeObjCGCAttr();<br>
+ ToQuals.removeObjCGCAttr();<br>
+ }<br>
+<br>
+ // -- for every j > 0, if const is in cv 1,j then const is in cv<br>
+ // 2,j, and similarly for volatile.<br>
+ if (!CStyle && !ToQuals.compatiblyIncludes(FromQuals))<br>
+ return false;<br>
+<br>
+ // For a C-style cast, just require the address spaces to overlap.<br>
+ // FIXME: Does "superset" also imply the representation of a pointer is the<br>
+ // same? We're assuming that it does here and in compatiblyIncludes.<br>
+ if (CStyle && !ToQuals.isAddressSpaceSupersetOf(FromQuals) &&<br>
+ !FromQuals.isAddressSpaceSupersetOf(ToQuals))<br>
+ return false;<br>
+<br>
+ // -- if the cv 1,j and cv 2,j are <br>
diff erent, then const is in<br>
+ // every cv for 0 < k < j.<br>
+ if (!CStyle && FromQuals.getCVRQualifiers() != ToQuals.getCVRQualifiers() &&<br>
+ !PreviousToQualsIncludeConst)<br>
+ return false;<br>
+<br>
+ // Keep track of whether all prior cv-qualifiers in the "to" type<br>
+ // include const.<br>
+ PreviousToQualsIncludeConst =<br>
+ PreviousToQualsIncludeConst && ToQuals.hasConst();<br>
+ return true;<br>
+}<br>
+<br>
/// IsQualificationConversion - Determines whether the conversion from<br>
/// an rvalue of type FromType to ToType is a qualification conversion<br>
/// (C++ 4.4).<br>
@@ -3178,73 +3242,16 @@ Sema::IsQualificationConversion(QualType FromType, QualType ToType,<br>
bool PreviousToQualsIncludeConst = true;<br>
bool UnwrappedAnyPointer = false;<br>
while (Context.UnwrapSimilarTypes(FromType, ToType)) {<br>
- // Within each iteration of the loop, we check the qualifiers to<br>
- // determine if this still looks like a qualification<br>
- // conversion. Then, if all is well, we unwrap one more level of<br>
- // pointers or pointers-to-members and do it all again<br>
- // until there are no more pointers or pointers-to-members left to<br>
- // unwrap.<br>
- UnwrappedAnyPointer = true;<br>
-<br>
- Qualifiers FromQuals = FromType.getQualifiers();<br>
- Qualifiers ToQuals = ToType.getQualifiers();<br>
-<br>
- // Ignore __unaligned qualifier if this type is void.<br>
- if (ToType.getUnqualifiedType()->isVoidType())<br>
- FromQuals.removeUnaligned();<br>
-<br>
- // Objective-C ARC:<br>
- // Check Objective-C lifetime conversions.<br>
- if (FromQuals.getObjCLifetime() != ToQuals.getObjCLifetime() &&<br>
- UnwrappedAnyPointer) {<br>
- if (ToQuals.compatiblyIncludesObjCLifetime(FromQuals)) {<br>
- if (isNonTrivialObjCLifetimeConversion(FromQuals, ToQuals))<br>
- ObjCLifetimeConversion = true;<br>
- FromQuals.removeObjCLifetime();<br>
- ToQuals.removeObjCLifetime();<br>
- } else {<br>
- // Qualification conversions cannot cast between <br>
diff erent<br>
- // Objective-C lifetime qualifiers.<br>
- return false;<br>
- }<br>
- }<br>
-<br>
- // Allow addition/removal of GC attributes but not changing GC attributes.<br>
- if (FromQuals.getObjCGCAttr() != ToQuals.getObjCGCAttr() &&<br>
- (!FromQuals.hasObjCGCAttr() || !ToQuals.hasObjCGCAttr())) {<br>
- FromQuals.removeObjCGCAttr();<br>
- ToQuals.removeObjCGCAttr();<br>
- }<br>
-<br>
- // -- for every j > 0, if const is in cv 1,j then const is in cv<br>
- // 2,j, and similarly for volatile.<br>
- if (!CStyle && !ToQuals.compatiblyIncludes(FromQuals))<br>
- return false;<br>
-<br>
- // -- if the cv 1,j and cv 2,j are <br>
diff erent, then const is in<br>
- // every cv for 0 < k < j.<br>
- if (!CStyle && FromQuals.getCVRQualifiers() != ToQuals.getCVRQualifiers()<br>
- && !PreviousToQualsIncludeConst)<br>
+ if (!isQualificationConversionStep(FromType, ToType, CStyle,<br>
+ PreviousToQualsIncludeConst,<br>
+ ObjCLifetimeConversion))<br>
return false;<br>
-<br>
- // Keep track of whether all prior cv-qualifiers in the "to" type<br>
- // include const.<br>
- PreviousToQualsIncludeConst<br>
- = PreviousToQualsIncludeConst && ToQuals.hasConst();<br>
- }<br>
-<br>
- // Allows address space promotion by language rules implemented in<br>
- // Type::Qualifiers::isAddressSpaceSupersetOf.<br>
- Qualifiers FromQuals = FromType.getQualifiers();<br>
- Qualifiers ToQuals = ToType.getQualifiers();<br>
- if (!ToQuals.isAddressSpaceSupersetOf(FromQuals) &&<br>
- !FromQuals.isAddressSpaceSupersetOf(ToQuals)) {<br>
- return false;<br>
+ UnwrappedAnyPointer = true;<br>
}<br>
<br>
// We are left with FromType and ToType being the pointee types<br>
// after unwrapping the original FromType and ToType the same number<br>
- // of types. If we unwrapped any pointers, and if FromType and<br>
+ // of times. If we unwrapped any pointers, and if FromType and<br>
// ToType have the same unqualified type (since we checked<br>
// qualifiers above), then this is a qualification conversion.<br>
return UnwrappedAnyPointer && Context.hasSameUnqualifiedType(FromType,ToType);<br>
@@ -3990,32 +3997,41 @@ CompareStandardConversionSequences(Sema &S, SourceLocation Loc,<br>
// top-level cv-qualifiers, and the type to which the reference<br>
// initialized by S2 refers is more cv-qualified than the type<br>
// to which the reference initialized by S1 refers.<br>
+ // FIXME: This should have been updated by DR2352, but was overlooked. The<br>
+ // corrected rule is:<br>
+ // -- S1 and S2 include reference bindings, and references refer to types<br>
+ // T1 and T2, respectively, where T2 is reference-compatible with T1.<br>
QualType T1 = SCS1.getToType(2);<br>
QualType T2 = SCS2.getToType(2);<br>
- T1 = S.Context.getCanonicalType(T1);<br>
- T2 = S.Context.getCanonicalType(T2);<br>
- Qualifiers T1Quals, T2Quals;<br>
- QualType UnqualT1 = S.Context.getUnqualifiedArrayType(T1, T1Quals);<br>
- QualType UnqualT2 = S.Context.getUnqualifiedArrayType(T2, T2Quals);<br>
- if (UnqualT1 == UnqualT2) {<br>
- // Objective-C++ ARC: If the references refer to objects with <br>
diff erent<br>
- // lifetimes, prefer bindings that don't change lifetime.<br>
- if (SCS1.ObjCLifetimeConversionBinding !=<br>
- SCS2.ObjCLifetimeConversionBinding) {<br>
- return SCS1.ObjCLifetimeConversionBinding<br>
- ? ImplicitConversionSequence::Worse<br>
- : ImplicitConversionSequence::Better;<br>
- }<br>
<br>
- // If the type is an array type, promote the element qualifiers to the<br>
- // type for comparison.<br>
- if (isa<ArrayType>(T1) && T1Quals)<br>
- T1 = S.Context.getQualifiedType(UnqualT1, T1Quals);<br>
- if (isa<ArrayType>(T2) && T2Quals)<br>
- T2 = S.Context.getQualifiedType(UnqualT2, T2Quals);<br>
- if (T2.isMoreQualifiedThan(T1))<br>
+ // Objective-C++ ARC: If the references refer to objects with <br>
diff erent<br>
+ // lifetimes, prefer bindings that don't change lifetime.<br>
+ //<br>
+ // FIXME: Should this really override ordering based on qualification<br>
+ // conversions? In the correspnding check for pointers, we treat a case<br>
+ // where one candidate has worse qualifications and the other has a<br>
+ // lifetime conversion as ambiguous.<br>
+ if (SCS1.ObjCLifetimeConversionBinding !=<br>
+ SCS2.ObjCLifetimeConversionBinding &&<br>
+ S.Context.hasSameUnqualifiedType(T1, T2)) {<br>
+ return SCS1.ObjCLifetimeConversionBinding<br>
+ ? ImplicitConversionSequence::Worse<br>
+ : ImplicitConversionSequence::Better;<br>
+ }<br>
+<br>
+ if (!S.Context.hasSameType(T1, T2)) {<br>
+ // FIXME: Unfortunately, there are pairs of types that admit reference<br>
+ // bindings in both directions, so we can't shortcut the second check<br>
+ // here.<br>
+ bool Better =<br>
+ S.CompareReferenceRelationship(Loc, T2, T1) == Sema::Ref_Compatible;<br>
+ bool Worse =<br>
+ S.CompareReferenceRelationship(Loc, T1, T2) == Sema::Ref_Compatible;<br>
+ if (Better && Worse)<br>
+ return ImplicitConversionSequence::Indistinguishable;<br>
+ if (Better)<br>
return ImplicitConversionSequence::Better;<br>
- else if (T1.isMoreQualifiedThan(T2))<br>
+ if (Worse)<br>
return ImplicitConversionSequence::Worse;<br>
}<br>
}<br>
@@ -4402,10 +4418,19 @@ static bool isTypeValid(QualType T) {<br>
return true;<br>
}<br>
<br>
+static QualType withoutUnaligned(ASTContext &Ctx, QualType T) {<br>
+ if (!T.getQualifiers().hasUnaligned())<br>
+ return T;<br>
+<br>
+ Qualifiers Q;<br>
+ T = Ctx.getUnqualifiedArrayType(T, Q);<br>
+ Q.removeUnaligned();<br>
+ return Ctx.getQualifiedType(T, Q);<br>
+}<br>
+<br>
/// CompareReferenceRelationship - Compare the two types T1 and T2 to<br>
-/// determine whether they are reference-related,<br>
-/// reference-compatible, reference-compatible with added<br>
-/// qualification, or incompatible, for use in C++ initialization by<br>
+/// determine whether they are reference-compatible,<br>
+/// reference-related, or incompatible, for use in C++ initialization by<br>
/// reference (C++ [dcl.ref.init]p4). Neither type can be a reference<br>
/// type, and the first type (T1) is the pointee type of the reference<br>
/// type being initialized.<br>
@@ -4427,10 +4452,17 @@ Sema::CompareReferenceRelationship(SourceLocation Loc,<br>
ReferenceConversions &Conv = ConvOut ? *ConvOut : ConvTmp;<br>
Conv = ReferenceConversions();<br>
<br>
- // C++ [dcl.init.ref]p4:<br>
+ // C++2a [dcl.init.ref]p4:<br>
// Given types "cv1 T1" and "cv2 T2," "cv1 T1" is<br>
- // reference-related to "cv2 T2" if T1 is the same type as T2, or<br>
+ // reference-related to "cv2 T2" if T1 is similar to T2, or<br>
// T1 is a base class of T2.<br>
+ // "cv1 T1" is reference-compatible with "cv2 T2" if<br>
+ // a prvalue of type "pointer to cv2 T2" can be converted to the type<br>
+ // "pointer to cv1 T1" via a standard conversion sequence.<br>
+<br>
+ // Check for standard conversions we can apply to pointers: derived-to-base<br>
+ // conversions, ObjC pointer conversions, and function pointer conversions.<br>
+ // (Qualification conversions are checked last.)<br>
QualType ConvertedT2;<br>
if (UnqualT1 == UnqualT2) {<br>
// Nothing to do.<br>
@@ -4444,59 +4476,47 @@ Sema::CompareReferenceRelationship(SourceLocation Loc,<br>
Conv |= ReferenceConversions::ObjC;<br>
else if (UnqualT2->isFunctionType() &&<br>
IsFunctionConversion(UnqualT2, UnqualT1, ConvertedT2)) {<br>
- // C++1z [dcl.init.ref]p4:<br>
- // cv1 T1" is reference-compatible with "cv2 T2" if [...] T2 is "noexcept<br>
- // function" and T1 is "function"<br>
- //<br>
- // We extend this to also apply to 'noreturn', so allow any function<br>
- // conversion between function types.<br>
Conv |= ReferenceConversions::Function;<br>
+ // No need to check qualifiers; function types don't have them.<br>
return Ref_Compatible;<br>
- } else<br>
- return Ref_Incompatible;<br>
-<br>
- // At this point, we know that T1 and T2 are reference-related (at<br>
- // least).<br>
-<br>
- // If the type is an array type, promote the element qualifiers to the type<br>
- // for comparison.<br>
- if (isa<ArrayType>(T1) && T1Quals)<br>
- T1 = Context.getQualifiedType(UnqualT1, T1Quals);<br>
- if (isa<ArrayType>(T2) && T2Quals)<br>
- T2 = Context.getQualifiedType(UnqualT2, T2Quals);<br>
-<br>
- // C++ [dcl.init.ref]p4:<br>
- // "cv1 T1" is reference-compatible with "cv2 T2" if T1 is<br>
- // reference-related to T2 and cv1 is the same cv-qualification<br>
- // as, or greater cv-qualification than, cv2. For purposes of<br>
- // overload resolution, cases for which cv1 is greater<br>
- // cv-qualification than cv2 are identified as<br>
- // reference-compatible with added qualification (see 13.3.3.2).<br>
- //<br>
- // Note that we also require equivalence of Objective-C GC and address-space<br>
- // qualifiers when performing these computations, so that e.g., an int in<br>
- // address space 1 is not reference-compatible with an int in address<br>
- // space 2.<br>
- if (T1Quals.getObjCLifetime() != T2Quals.getObjCLifetime() &&<br>
- T1Quals.compatiblyIncludesObjCLifetime(T2Quals)) {<br>
- if (isNonTrivialObjCLifetimeConversion(T2Quals, T1Quals))<br>
- Conv |= ReferenceConversions::ObjCLifetime;<br>
-<br>
- T1Quals.removeObjCLifetime();<br>
- T2Quals.removeObjCLifetime();<br>
}<br>
+ bool ConvertedReferent = Conv != 0;<br>
<br>
- // MS compiler ignores __unaligned qualifier for references; do the same.<br>
- T1Quals.removeUnaligned();<br>
- T2Quals.removeUnaligned();<br>
+ // We can have a qualification conversion. Compute whether the types are<br>
+ // similar at the same time.<br>
+ bool PreviousToQualsIncludeConst = true;<br>
+ do {<br>
+ if (T1 == T2)<br>
+ break;<br>
<br>
- if (T1Quals != T2Quals)<br>
+ // We will need a qualification conversion.<br>
Conv |= ReferenceConversions::Qualification;<br>
<br>
- if (T1Quals.compatiblyIncludes(T2Quals))<br>
- return Ref_Compatible;<br>
- else<br>
- return Ref_Related;<br>
+ // MS compiler ignores __unaligned qualifier for references; do the same.<br>
+ T1 = withoutUnaligned(Context, T1);<br>
+ T2 = withoutUnaligned(Context, T2);<br>
+<br>
+ // If we find a qualifier mismatch, the types are not reference-compatible,<br>
+ // but are still be reference-related if they're similar.<br>
+ bool ObjCLifetimeConversion = false;<br>
+ if (!isQualificationConversionStep(T2, T1, /*CStyle=*/false,<br>
+ PreviousToQualsIncludeConst,<br>
+ ObjCLifetimeConversion))<br>
+ return (ConvertedReferent || Context.hasSimilarType(T1, T2))<br>
+ ? Ref_Related<br>
+ : Ref_Incompatible;<br>
+<br>
+ // FIXME: Should we track this for any level other than the first?<br>
+ if (ObjCLifetimeConversion)<br>
+ Conv |= ReferenceConversions::ObjCLifetime;<br>
+ } while (Context.UnwrapSimilarTypes(T1, T2));<br>
+<br>
+ // At this point, if the types are reference-related, we must either have the<br>
+ // same inner type (ignoring qualifiers), or must have already worked out how<br>
+ // to convert the referent.<br>
+ return (ConvertedReferent || Context.hasSameUnqualifiedType(T1, T2))<br>
+ ? Ref_Compatible<br>
+ : Ref_Incompatible;<br>
}<br>
<br>
/// Look for a user-defined conversion to a value reference-compatible<br>
<br>
diff --git a/clang/test/CXX/drs/dr23xx.cpp b/clang/test/CXX/drs/dr23xx.cpp<br>
index 763abd5368ef..caf3be114547 100644<br>
--- a/clang/test/CXX/drs/dr23xx.cpp<br>
+++ b/clang/test/CXX/drs/dr23xx.cpp<br>
@@ -4,9 +4,38 @@<br>
// RUN: %clang_cc1 -std=c++17 %s -verify -fexceptions -fcxx-exceptions -pedantic-errors 2>&1 | FileCheck %s<br>
// RUN: %clang_cc1 -std=c++2a %s -verify -fexceptions -fcxx-exceptions -pedantic-errors 2>&1 | FileCheck %s<br>
<br>
-#if __cplusplus <= 201103L<br>
-// expected-no-diagnostics<br>
+namespace dr2352 { // dr2352: 10<br>
+ int **p;<br>
+ const int *const *const &f1() { return p; }<br>
+ int *const *const &f2() { return p; }<br>
+ int **const &f3() { return p; }<br>
+<br>
+ const int **const &f4() { return p; } // expected-error {{reference to type 'const int **const' could not bind to an lvalue of type 'int **'}}<br>
+ const int *const *&f5() { return p; } // expected-error {{binding reference of type 'const int *const *' to value of type 'int **' not permitted due to incompatible qualifiers}}<br>
+<br>
+ // FIXME: We permit this as a speculative defect resolution, allowing<br>
+ // qualification conversions when forming a glvalue conditional expression.<br>
+ const int * const * const q = 0;<br>
+ __typeof(&(true ? p : q)) x = &(true ? p : q);<br>
+<br>
+ // FIXME: Should we compute the composite pointer type here and produce an<br>
+ // lvalue of type 'const int *const * const'?<br>
+ const int * const * r;<br>
+ void *y = &(true ? p : r); // expected-error {{rvalue of type 'const int *const *'}}<br>
+<br>
+ // FIXME: We order these as a speculative defect resolution.<br>
+ void f(const int * const * const &r);<br>
+#if __cplusplus >= 201103L<br>
+ constexpr<br>
#endif<br>
+ int *const *const &f(int * const * const &r) { return r; }<br>
+<br>
+ // No temporary is created here.<br>
+ int *const *const &check_f = f(p);<br>
+#if __cplusplus >= 201103L<br>
+ static_assert(&p == &check_f, "");<br>
+#endif<br>
+}<br>
<br>
namespace dr2353 { // dr2353: 9<br>
struct X {<br>
<br>
diff --git a/clang/test/CXX/drs/dr4xx.cpp b/clang/test/CXX/drs/dr4xx.cpp<br>
index 8eeb7715cadf..d37ece6cb882 100644<br>
--- a/clang/test/CXX/drs/dr4xx.cpp<br>
+++ b/clang/test/CXX/drs/dr4xx.cpp<br>
@@ -486,14 +486,21 @@ namespace dr433 { // dr433: yes<br>
S<int> s;<br>
}<br>
<br>
-namespace dr434 { // dr434: yes<br>
+namespace dr434 { // dr434: sup 2352<br>
void f() {<br>
const int ci = 0;<br>
int *pi = 0;<br>
- const int *&rpci = pi; // expected-error {{cannot bind}}<br>
+ const int *&rpci = pi; // expected-error {{incompatible qualifiers}}<br>
+ const int * const &rcpci = pi; // OK<br>
rpci = &ci;<br>
*pi = 1;<br>
}<br>
+<br>
+#if __cplusplus >= 201103L<br>
+ int *pi = 0;<br>
+ const int * const &rcpci = pi;<br>
+ static_assert(&rcpci == &pi, "");<br>
+#endif<br>
}<br>
<br>
// dr435: na<br>
<br>
diff --git a/clang/test/SemaObjCXX/<a href="http://arc-overloading.mm" rel="noreferrer" target="_blank">arc-overloading.mm</a> b/clang/test/SemaObjCXX/<a href="http://arc-overloading.mm" rel="noreferrer" target="_blank">arc-overloading.mm</a><br>
index 3ac9c51293b7..910b5c7be978 100644<br>
--- a/clang/test/SemaObjCXX/<a href="http://arc-overloading.mm" rel="noreferrer" target="_blank">arc-overloading.mm</a><br>
+++ b/clang/test/SemaObjCXX/<a href="http://arc-overloading.mm" rel="noreferrer" target="_blank">arc-overloading.mm</a><br>
@@ -174,6 +174,36 @@ void test_f9() {<br>
const __autoreleasing id& ar4 = weak_a;<br>
}<br>
<br>
+int &f10(__strong id *&); // expected-note 2{{not viable: no known conversion}}<br>
+float &f10(__autoreleasing id *&); // expected-note 2{{not viable: no known conversion}}<br>
+<br>
+void test_f10() {<br>
+ __strong id *strong_id;<br>
+ __weak id *weak_id;<br>
+ __autoreleasing id *autoreleasing_id;<br>
+ __unsafe_unretained id *unsafe_id;<br>
+<br>
+ int &ir1 = f10(strong_id);<br>
+ float &fr1 = f10(autoreleasing_id);<br>
+ float &fr2 = f10(unsafe_id); // expected-error {{no match}}<br>
+ float &fr2a = f10(weak_id); // expected-error {{no match}}<br>
+}<br>
+<br>
+int &f11(__strong id *const &); // expected-note {{not viable: 1st argument ('__weak id *') has __weak ownership, but parameter has __strong ownership}}<br>
+float &f11(const __autoreleasing id *const &); // expected-note {{not viable: 1st argument ('__weak id *') has __weak ownership, but parameter has __autoreleasing ownership}}<br>
+<br>
+void test_f11() {<br>
+ __strong id *strong_id;<br>
+ __weak id *weak_id;<br>
+ __autoreleasing id *autoreleasing_id;<br>
+ __unsafe_unretained id *unsafe_id;<br>
+<br>
+ int &ir1 = f11(strong_id);<br>
+ float &fr1 = f11(autoreleasing_id);<br>
+ float &fr2 = f11(unsafe_id);<br>
+ float &fr2a = f11(weak_id); // expected-error {{no match}}<br>
+}<br>
+<br>
// rdar://9790531<br>
void f9790531(void *inClientData); // expected-note {{candidate function not viable: cannot implicitly convert argument of type 'MixerEQGraphTestDelegate *const __strong' to 'void *' for 1st argument under ARC}}<br>
void f9790531_1(struct S*inClientData); // expected-note {{candidate function not viable}}<br>
<br>
diff --git a/clang/test/SemaOpenCL/<a href="http://address-spaces-conversions-cl2.0.cl" rel="noreferrer" target="_blank">address-spaces-conversions-cl2.0.cl</a> b/clang/test/SemaOpenCL/<a href="http://address-spaces-conversions-cl2.0.cl" rel="noreferrer" target="_blank">address-spaces-conversions-cl2.0.cl</a><br>
index a97565f3a2e5..0209e1ea24de 100644<br>
--- a/clang/test/SemaOpenCL/<a href="http://address-spaces-conversions-cl2.0.cl" rel="noreferrer" target="_blank">address-spaces-conversions-cl2.0.cl</a><br>
+++ b/clang/test/SemaOpenCL/<a href="http://address-spaces-conversions-cl2.0.cl" rel="noreferrer" target="_blank">address-spaces-conversions-cl2.0.cl</a><br>
@@ -501,12 +501,9 @@ void test_pointer_chains() {<br>
// Case 1:<br>
// * address spaces of corresponded most outer pointees overlaps, their canonical types are equal<br>
// * CVR, address spaces and canonical types of the rest of pointees are equivalent.<br>
+ var_as_as_int = var_asc_as_int;<br>
var_as_as_int = 0 ? var_as_as_int : var_asc_as_int;<br>
-#if __OPENCL_CPP_VERSION__<br>
-#ifdef GENERIC<br>
-// expected-error@-3{{incompatible operand types ('__generic int *__generic *' and '__generic int *__local *')}}<br>
-#endif<br>
-#endif<br>
+<br>
// Case 2: Corresponded inner pointees has non-overlapping address spaces.<br>
var_as_as_int = 0 ? var_as_as_int : var_asc_asn_int;<br>
#if !__OPENCL_CPP_VERSION__<br>
@@ -516,12 +513,17 @@ void test_pointer_chains() {<br>
#endif<br>
<br>
// Case 3: Corresponded inner pointees has overlapping but not equivalent address spaces.<br>
+ // FIXME: Should this really be allowed in C++ mode?<br>
+ var_as_as_int = var_asc_asc_int;<br>
+#if !__OPENCL_CPP_VERSION__<br>
#ifdef GENERIC<br>
+// expected-error@-3 {{assigning '__local int *__local *' to '__generic int *__generic *' changes address space of nested pointer}}<br>
+#endif<br>
+#endif<br>
var_as_as_int = 0 ? var_as_as_int : var_asc_asc_int;<br>
#if !__OPENCL_CPP_VERSION__<br>
-// expected-warning-re@-2{{pointer type mismatch ('__{{(generic|global|constant)}} int *__{{(generic|global|constant)}} *' and '__{{(local|global|constant)}} int *__{{(local|global|constant)}} *')}}<br>
-#else<br>
-// expected-error-re@-4{{incompatible operand types ('__{{generic|global|constant}} int *__{{generic|global|constant}} *' and '__{{local|global|constant}} int *__{{local|global|constant}} *')}}<br>
+#ifdef GENERIC<br>
+// expected-warning@-3{{pointer type mismatch ('__generic int *__generic *' and '__local int *__local *')}}<br>
#endif<br>
#endif<br>
}<br>
<br>
diff --git a/clang/www/cxx_dr_status.html b/clang/www/cxx_dr_status.html<br>
index 23a7218e897a..c4ec45736524 100755<br>
--- a/clang/www/cxx_dr_status.html<br>
+++ b/clang/www/cxx_dr_status.html<br>
@@ -2645,7 +2645,7 @@ <h2 id="cxxdr">C++ defect report implementation status</h2><br>
<td><a href="<a href="https://wg21.link/cwg434" rel="noreferrer" target="_blank">https://wg21.link/cwg434</a>">434</a></td><br>
<td>NAD</td><br>
<td>Unclear suppression of standard conversions while binding reference to lvalue</td><br>
- <td class="full" align="center">Yes</td><br>
+ <td class="svn" align="center">Superseded by <a href="#2352">2352</a></td><br>
</tr><br>
<tr id="435"><br>
<td><a href="<a href="https://wg21.link/cwg435" rel="noreferrer" target="_blank">https://wg21.link/cwg435</a>">435</a></td><br>
@@ -13927,7 +13927,7 @@ <h2 id="cxxdr">C++ defect report implementation status</h2><br>
<td><a href="<a href="https://wg21.link/cwg2352" rel="noreferrer" target="_blank">https://wg21.link/cwg2352</a>">2352</a></td><br>
<td>DR</td><br>
<td>Similar types and reference binding</td><br>
- <td class="none" align="center">Unknown</td><br>
+ <td class="svn" align="center">SVN</td><br>
</tr><br>
<tr id="2353"><br>
<td><a href="<a href="https://wg21.link/cwg2353" rel="noreferrer" target="_blank">https://wg21.link/cwg2353</a>">2353</a></td><br>
<br>
diff --git a/clang/www/make_cxx_dr_status b/clang/www/make_cxx_dr_status<br>
index 4351d659e41a..fd5eb7fbabb4 100755<br>
--- a/clang/www/make_cxx_dr_status<br>
+++ b/clang/www/make_cxx_dr_status<br>
@@ -28,7 +28,7 @@ def parse(dr):<br>
_, url, issue = issue_link.split('"', 2)<br>
url = url.strip()<br>
issue = int(issue.split('>', 1)[1].split('<', 1)[0])<br>
- title = title.replace('<issue_title>', '').replace('</issue_title>', '').strip()<br>
+ title = title.replace('<issue_title>', '').replace('</issue_title>', '').replace('\r\n', '\n').strip()<br>
return DR(section, issue, url, status, title)<br>
<br>
status_re = re.compile(r'\bdr([0-9]+): (.*)')<br>
@@ -171,7 +171,7 @@ for dr in drs:<br>
<br>
print >> out_file, '''\<br>
<tr%s id="%s"><br>
- <td><a href="<a href="http://wg21.link/cwg%s" rel="noreferrer" target="_blank">http://wg21.link/cwg%s</a>">%s</a></td><br>
+ <td><a href="<a href="https://wg21.link/cwg%s" rel="noreferrer" target="_blank">https://wg21.link/cwg%s</a>">%s</a></td><br>
<td>%s</td><br>
<td>%s</td><br>
<td%s align="center">%s</td><br>
<br>
<br>
<br>
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</blockquote></div>