Author: rsmith
Date: Mon Sep 24 16:17:44 2018
New Revision: 342925
URL: http://llvm.org/viewvc/llvm-project?rev=342925&view=rev
Log:
P0962R1: only use the member form of 'begin' and 'end' in a range-based
for loop if both members exist.
This resolves a DR whereby an errant 'begin' or 'end' member in a base
class could result in a derived class not being usable as a range with
non-member 'begin' and 'end'.
Modified:
cfe/trunk/include/clang/Basic/DiagnosticSemaKinds.td
cfe/trunk/lib/Sema/SemaStmt.cpp
cfe/trunk/test/CXX/stmt.stmt/stmt.iter/stmt.ranged/p1.cpp
cfe/trunk/test/SemaCXX/for-range-dereference.cpp
Modified: cfe/trunk/include/clang/Basic/DiagnosticSemaKinds.td
URL:
http://llvm.org/viewvc/llvm-project/cfe/trunk/include/clang/Basic/DiagnosticSemaKinds.td?rev=342925&r1=342924&r2=342925&view=diff
==============================================================================
--- cfe/trunk/include/clang/Basic/DiagnosticSemaKinds.td (original)
+++ cfe/trunk/include/clang/Basic/DiagnosticSemaKinds.td Mon Sep 24 16:17:44
2018
@@ -2254,8 +2254,6 @@ def err_for_range_incomplete_type : Erro
"cannot use incomplete type %0 as a range">;
def err_for_range_iter_deduction_failure : Error<
"cannot use type %0 as an iterator">;
-def err_for_range_member_begin_end_mismatch : Error<
- "range type %0 has '%select{begin|end}1' member but no '%select{end|begin}1'
member">;
def ext_for_range_begin_end_types_differ : ExtWarn<
"'begin' and 'end' returning different types (%0 and %1) is a C++17
extension">,
InGroup<CXX17>;
@@ -2268,6 +2266,8 @@ def note_in_for_range: Note<
def err_for_range_invalid: Error<
"invalid range expression of type %0; no viable '%select{begin|end}1' "
"function available">;
+def note_for_range_member_begin_end_ignored : Note<
+ "member is not a candidate because range type %0 has no
'%select{end|begin}1' member">;
def err_range_on_array_parameter : Error<
"cannot build range expression with array function parameter %0 since "
"parameter with array type %1 is treated as pointer type %2">;
Modified: cfe/trunk/lib/Sema/SemaStmt.cpp
URL:
http://llvm.org/viewvc/llvm-project/cfe/trunk/lib/Sema/SemaStmt.cpp?rev=342925&r1=342924&r2=342925&view=diff
==============================================================================
--- cfe/trunk/lib/Sema/SemaStmt.cpp (original)
+++ cfe/trunk/lib/Sema/SemaStmt.cpp Mon Sep 24 16:17:44 2018
@@ -2149,6 +2149,56 @@ BuildNonArrayForRange(Sema &SemaRef, Exp
Sema::LookupMemberName);
LookupResult EndMemberLookup(SemaRef, EndNameInfo, Sema::LookupMemberName);
+ auto BuildBegin = [&] {
+ *BEF = BEF_begin;
+ Sema::ForRangeStatus RangeStatus =
+ SemaRef.BuildForRangeBeginEndCall(ColonLoc, ColonLoc, BeginNameInfo,
+ BeginMemberLookup, CandidateSet,
+ BeginRange, BeginExpr);
+
+ if (RangeStatus != Sema::FRS_Success) {
+ if (RangeStatus == Sema::FRS_DiagnosticIssued)
+ SemaRef.Diag(BeginRange->getBeginLoc(), diag::note_in_for_range)
+ << ColonLoc << BEF_begin << BeginRange->getType();
+ return RangeStatus;
+ }
+ if (!CoawaitLoc.isInvalid()) {
+ // FIXME: getCurScope() should not be used during template instantiation.
+ // We should pick up the set of unqualified lookup results for operator
+ // co_await during the initial parse.
+ *BeginExpr = SemaRef.ActOnCoawaitExpr(SemaRef.getCurScope(), ColonLoc,
+ BeginExpr->get());
+ if (BeginExpr->isInvalid())
+ return Sema::FRS_DiagnosticIssued;
+ }
+ if (FinishForRangeVarDecl(SemaRef, BeginVar, BeginExpr->get(), ColonLoc,
+ diag::err_for_range_iter_deduction_failure)) {
+ NoteForRangeBeginEndFunction(SemaRef, BeginExpr->get(), *BEF);
+ return Sema::FRS_DiagnosticIssued;
+ }
+ return Sema::FRS_Success;
+ };
+
+ auto BuildEnd = [&] {
+ *BEF = BEF_end;
+ Sema::ForRangeStatus RangeStatus =
+ SemaRef.BuildForRangeBeginEndCall(ColonLoc, ColonLoc, EndNameInfo,
+ EndMemberLookup, CandidateSet,
+ EndRange, EndExpr);
+ if (RangeStatus != Sema::FRS_Success) {
+ if (RangeStatus == Sema::FRS_DiagnosticIssued)
+ SemaRef.Diag(EndRange->getBeginLoc(), diag::note_in_for_range)
+ << ColonLoc << BEF_end << EndRange->getType();
+ return RangeStatus;
+ }
+ if (FinishForRangeVarDecl(SemaRef, EndVar, EndExpr->get(), ColonLoc,
+ diag::err_for_range_iter_deduction_failure)) {
+ NoteForRangeBeginEndFunction(SemaRef, EndExpr->get(), *BEF);
+ return Sema::FRS_DiagnosticIssued;
+ }
+ return Sema::FRS_Success;
+ };
+
if (CXXRecordDecl *D = RangeType->getAsCXXRecordDecl()) {
// - if _RangeT is a class type, the unqualified-ids begin and end are
// looked up in the scope of class _RangeT as if by class member access
@@ -2156,68 +2206,62 @@ BuildNonArrayForRange(Sema &SemaRef, Exp
// declaration, begin-expr and end-expr are __range.begin() and
// __range.end(), respectively;
SemaRef.LookupQualifiedName(BeginMemberLookup, D);
+ if (BeginMemberLookup.isAmbiguous())
+ return Sema::FRS_DiagnosticIssued;
+
SemaRef.LookupQualifiedName(EndMemberLookup, D);
+ if (EndMemberLookup.isAmbiguous())
+ return Sema::FRS_DiagnosticIssued;
if (BeginMemberLookup.empty() != EndMemberLookup.empty()) {
- SourceLocation RangeLoc = BeginVar->getLocation();
- *BEF = BeginMemberLookup.empty() ? BEF_end : BEF_begin;
-
- SemaRef.Diag(RangeLoc, diag::err_for_range_member_begin_end_mismatch)
- << RangeLoc << BeginRange->getType() << *BEF;
- return Sema::FRS_DiagnosticIssued;
+ // Look up the non-member form of the member we didn't find, first.
+ // This way we prefer a "no viable 'end'" diagnostic over a "i found
+ // a 'begin' but ignored it because there was no member 'end'"
+ // diagnostic.
+ auto BuildNonmember = [&](
+ BeginEndFunction BEFFound, LookupResult &Found,
+ llvm::function_ref<Sema::ForRangeStatus()> BuildFound,
+ llvm::function_ref<Sema::ForRangeStatus()> BuildNotFound) {
+ LookupResult OldFound = std::move(Found);
+ Found.clear();
+
+ if (Sema::ForRangeStatus Result = BuildNotFound())
+ return Result;
+
+ switch (BuildFound()) {
+ case Sema::FRS_Success:
+ return Sema::FRS_Success;
+
+ case Sema::FRS_NoViableFunction:
+ SemaRef.Diag(BeginRange->getBeginLoc(), diag::err_for_range_invalid)
+ << BeginRange->getType() << BEFFound;
+ CandidateSet->NoteCandidates(SemaRef, OCD_AllCandidates, BeginRange);
+ LLVM_FALLTHROUGH;
+
+ case Sema::FRS_DiagnosticIssued:
+ for (NamedDecl *D : OldFound) {
+ SemaRef.Diag(D->getLocation(),
+ diag::note_for_range_member_begin_end_ignored)
+ << BeginRange->getType() << BEFFound;
+ }
+ return Sema::FRS_DiagnosticIssued;
+ }
+ llvm_unreachable("unexpected ForRangeStatus");
+ };
+ if (BeginMemberLookup.empty())
+ return BuildNonmember(BEF_end, EndMemberLookup, BuildEnd, BuildBegin);
+ return BuildNonmember(BEF_begin, BeginMemberLookup, BuildBegin,
BuildEnd);
}
} else {
// - otherwise, begin-expr and end-expr are begin(__range) and
// end(__range), respectively, where begin and end are looked up with
// argument-dependent lookup (3.4.2). For the purposes of this name
// lookup, namespace std is an associated namespace.
-
}
- *BEF = BEF_begin;
- Sema::ForRangeStatus RangeStatus =
- SemaRef.BuildForRangeBeginEndCall(ColonLoc, ColonLoc, BeginNameInfo,
- BeginMemberLookup, CandidateSet,
- BeginRange, BeginExpr);
-
- if (RangeStatus != Sema::FRS_Success) {
- if (RangeStatus == Sema::FRS_DiagnosticIssued)
- SemaRef.Diag(BeginRange->getBeginLoc(), diag::note_in_for_range)
- << ColonLoc << BEF_begin << BeginRange->getType();
- return RangeStatus;
- }
- if (!CoawaitLoc.isInvalid()) {
- // FIXME: getCurScope() should not be used during template instantiation.
- // We should pick up the set of unqualified lookup results for operator
- // co_await during the initial parse.
- *BeginExpr = SemaRef.ActOnCoawaitExpr(SemaRef.getCurScope(), ColonLoc,
- BeginExpr->get());
- if (BeginExpr->isInvalid())
- return Sema::FRS_DiagnosticIssued;
- }
- if (FinishForRangeVarDecl(SemaRef, BeginVar, BeginExpr->get(), ColonLoc,
- diag::err_for_range_iter_deduction_failure)) {
- NoteForRangeBeginEndFunction(SemaRef, BeginExpr->get(), *BEF);
- return Sema::FRS_DiagnosticIssued;
- }
-
- *BEF = BEF_end;
- RangeStatus =
- SemaRef.BuildForRangeBeginEndCall(ColonLoc, ColonLoc, EndNameInfo,
- EndMemberLookup, CandidateSet,
- EndRange, EndExpr);
- if (RangeStatus != Sema::FRS_Success) {
- if (RangeStatus == Sema::FRS_DiagnosticIssued)
- SemaRef.Diag(EndRange->getBeginLoc(), diag::note_in_for_range)
- << ColonLoc << BEF_end << EndRange->getType();
- return RangeStatus;
- }
- if (FinishForRangeVarDecl(SemaRef, EndVar, EndExpr->get(), ColonLoc,
- diag::err_for_range_iter_deduction_failure)) {
- NoteForRangeBeginEndFunction(SemaRef, EndExpr->get(), *BEF);
- return Sema::FRS_DiagnosticIssued;
- }
- return Sema::FRS_Success;
+ if (Sema::ForRangeStatus Result = BuildBegin())
+ return Result;
+ return BuildEnd();
}
/// Speculatively attempt to dereference an invalid range expression.
Modified: cfe/trunk/test/CXX/stmt.stmt/stmt.iter/stmt.ranged/p1.cpp
URL:
http://llvm.org/viewvc/llvm-project/cfe/trunk/test/CXX/stmt.stmt/stmt.iter/stmt.ranged/p1.cpp?rev=342925&r1=342924&r2=342925&view=diff
==============================================================================
--- cfe/trunk/test/CXX/stmt.stmt/stmt.iter/stmt.ranged/p1.cpp (original)
+++ cfe/trunk/test/CXX/stmt.stmt/stmt.iter/stmt.ranged/p1.cpp Mon Sep 24
16:17:44 2018
@@ -150,9 +150,9 @@ void g() {
struct NoEnd {
null_t begin();
};
- for (auto u : NoBegin()) { // expected-error {{range type 'NoBegin' has
'end' member but no 'begin' member}}
+ for (auto u : NoBegin()) { // expected-error {{no viable 'begin' function
available}}
}
- for (auto u : NoEnd()) { // expected-error {{range type 'NoEnd' has 'begin'
member but no 'end' member}}
+ for (auto u : NoEnd()) { // expected-error {{no viable 'end' function
available}}
}
struct NoIncr {
@@ -271,3 +271,58 @@ namespace rdar13712739 {
template void foo(const int&); // expected-note{{in instantiation of
function template specialization}}
}
+
+namespace p0962r1 {
+ namespace NA {
+ struct A {
+ void begin();
+ };
+ int *begin(A);
+ int *end(A);
+ }
+
+ namespace NB {
+ struct B {
+ void end();
+ };
+ int *begin(B);
+ int *end(B);
+ }
+
+ namespace NC {
+ struct C {
+ void begin();
+ };
+ int *begin(C);
+ }
+
+ namespace ND {
+ struct D {
+ void end();
+ };
+ int *end(D);
+ }
+
+ namespace NE {
+ struct E {
+ void begin(); // expected-note {{member is not a candidate because range
type 'p0962r1::NE::E' has no 'end' member}}
+ };
+ int *end(E);
+ }
+
+ namespace NF {
+ struct F {
+ void end(); // expected-note {{member is not a candidate because range
type 'p0962r1::NF::F' has no 'begin' member}}
+ };
+ int *begin(F);
+ }
+
+ void use(NA::A a, NB::B b, NC::C c, ND::D d, NE::E e, NF::F f) {
+ for (auto x : a) {}
+ for (auto x : b) {}
+ for (auto x : c) {} // expected-error {{no viable 'end' function}}
+ for (auto x : d) {} // expected-error {{no viable 'begin' function}}
+ for (auto x : e) {} // expected-error {{no viable 'begin' function}}
+ for (auto x : f) {} // expected-error {{no viable 'end' function}}
+ }
+}
Modified: cfe/trunk/test/SemaCXX/for-range-dereference.cpp
URL:
http://llvm.org/viewvc/llvm-project/cfe/trunk/test/SemaCXX/for-range-dereference.cpp?rev=342925&r1=342924&r2=342925&view=diff
==============================================================================
--- cfe/trunk/test/SemaCXX/for-range-dereference.cpp (original)
+++ cfe/trunk/test/SemaCXX/for-range-dereference.cpp Mon Sep 24 16:17:44 2018
@@ -17,7 +17,7 @@ struct DeletedEnd : public T {
struct DeletedADLBegin { };
int* begin(DeletedADLBegin) = delete; //expected-note {{candidate function has
been explicitly deleted}} \
- expected-note 5 {{candidate function not viable: no known conversion}}
+ expected-note 6 {{candidate function not viable: no known conversion}}
struct PrivateEnd {
Data *begin();
@@ -27,7 +27,7 @@ struct PrivateEnd {
};
struct ADLNoEnd { };
-Data * begin(ADLNoEnd); // expected-note 6 {{candidate function not viable: no
known conversion}}
+Data * begin(ADLNoEnd); // expected-note 7 {{candidate function not viable: no
known conversion}}
struct OverloadedStar {
T operator*();
@@ -45,7 +45,7 @@ void f() {
for (auto i : parr) { }// expected-error{{invalid range expression of type
'int (*)[10]'; did you mean to dereference it with '*'?}}
NoBegin NB;
- for (auto i : NB) { }// expected-error{{range type 'NoBegin' has 'end'
member but no 'begin' member}}
+ for (auto i : NB) { }// expected-error{{invalid range expression of type
'NoBegin'; no viable 'begin' function available}}
NoBegin *pNB;
for (auto i : pNB) { }// expected-error{{invalid range expression of type
'NoBegin *'; no viable 'begin' function available}}
NoBegin **ppNB;
_______________________________________________
cfe-commits mailing list
cfe-commits@lists.llvm.org
http://lists.llvm.org/cgi-bin/mailman/listinfo/cfe-commits
