erik.pilkington created this revision.
erik.pilkington added a reviewer: rsmith.
erik.pilkington added a subscriber: cfe-commits.
Previously, when the 2 expressions passed to a ternary operator were xvalues
and one inherits from the other, the resulting expression had type 'T', not
'T&&' as 5.16p3 dictates. For example:
`
Base b; Derived d;
typedef decltype(true ? static_cast<Base&&>(b) : static_cast<Derived&&>(d)) x;
// x has type Base, not Base&&`
PR: https://llvm.org/bugs/show_bug.cgi?id=26448
http://reviews.llvm.org/D17451
Files:
lib/Sema/SemaExprCXX.cpp
test/SemaCXX/conditional-expr.cpp
Index: test/SemaCXX/conditional-expr.cpp
===================================================================
--- test/SemaCXX/conditional-expr.cpp
+++ test/SemaCXX/conditional-expr.cpp
@@ -384,3 +384,12 @@
int &test() { return b_ ? i_ : throw 1; }
};
}
+
+namespace PR26448 {
+struct Base {};
+struct Derived : Base {};
+Base b;
+Derived d;
+typedef decltype(true ? static_cast<Base&&>(b) : static_cast<Derived&&>(d)) x;
+typedef Base &&x;
+}
Index: lib/Sema/SemaExprCXX.cpp
===================================================================
--- lib/Sema/SemaExprCXX.cpp
+++ lib/Sema/SemaExprCXX.cpp
@@ -4671,7 +4671,7 @@
return Result;
}
-/// \brief Try to convert a type to another according to C++0x 5.16p3.
+/// \brief Try to convert a type to another according to C++11 5.16p3.
///
/// This is part of the parameter validation for the ? operator. If either
/// value operand is a class type, the two operands are attempted to be
@@ -4687,17 +4687,21 @@
InitializationKind Kind = InitializationKind::CreateCopy(To->getLocStart(),
SourceLocation());
- // C++0x 5.16p3
+ // C++11 5.16p3
// The process for determining whether an operand expression E1 of type T1
// can be converted to match an operand expression E2 of type T2 is defined
// as follows:
- // -- If E2 is an lvalue:
- bool ToIsLvalue = To->isLValue();
- if (ToIsLvalue) {
- // E1 can be converted to match E2 if E1 can be implicitly converted to
- // type "lvalue reference to T2", subject to the constraint that in the
- // conversion the reference must bind directly to E1.
- QualType T = Self.Context.getLValueReferenceType(ToType);
+ // -- If E2 is an lvalue: E1 can be converted to match E2 if E1 can be
+ // implicitly converted to type "lvalue reference to T2", subject to the
+ // constraint that in the conversion the reference must bind directly to
+ // E1.
+ // -- If E2 is an xvalue: E1 can be converted to match E2 if E1 can be
+ // implicitly conveted to the type "rvalue reference to R2", subject to
+ // the constraint that the reference must bind directly.
+ if (To->isLValue() || To->isXValue()) {
+ QualType T = To->isLValue() ? Self.Context.getLValueReferenceType(ToType)
+ : Self.Context.getRValueReferenceType(ToType);
+
InitializedEntity Entity = InitializedEntity::InitializeTemporary(T);
InitializationSequence InitSeq(Self, Entity, Kind, From);
Index: test/SemaCXX/conditional-expr.cpp
===================================================================
--- test/SemaCXX/conditional-expr.cpp
+++ test/SemaCXX/conditional-expr.cpp
@@ -384,3 +384,12 @@
int &test() { return b_ ? i_ : throw 1; }
};
}
+
+namespace PR26448 {
+struct Base {};
+struct Derived : Base {};
+Base b;
+Derived d;
+typedef decltype(true ? static_cast<Base&&>(b) : static_cast<Derived&&>(d)) x;
+typedef Base &&x;
+}
Index: lib/Sema/SemaExprCXX.cpp
===================================================================
--- lib/Sema/SemaExprCXX.cpp
+++ lib/Sema/SemaExprCXX.cpp
@@ -4671,7 +4671,7 @@
return Result;
}
-/// \brief Try to convert a type to another according to C++0x 5.16p3.
+/// \brief Try to convert a type to another according to C++11 5.16p3.
///
/// This is part of the parameter validation for the ? operator. If either
/// value operand is a class type, the two operands are attempted to be
@@ -4687,17 +4687,21 @@
InitializationKind Kind = InitializationKind::CreateCopy(To->getLocStart(),
SourceLocation());
- // C++0x 5.16p3
+ // C++11 5.16p3
// The process for determining whether an operand expression E1 of type T1
// can be converted to match an operand expression E2 of type T2 is defined
// as follows:
- // -- If E2 is an lvalue:
- bool ToIsLvalue = To->isLValue();
- if (ToIsLvalue) {
- // E1 can be converted to match E2 if E1 can be implicitly converted to
- // type "lvalue reference to T2", subject to the constraint that in the
- // conversion the reference must bind directly to E1.
- QualType T = Self.Context.getLValueReferenceType(ToType);
+ // -- If E2 is an lvalue: E1 can be converted to match E2 if E1 can be
+ // implicitly converted to type "lvalue reference to T2", subject to the
+ // constraint that in the conversion the reference must bind directly to
+ // E1.
+ // -- If E2 is an xvalue: E1 can be converted to match E2 if E1 can be
+ // implicitly conveted to the type "rvalue reference to R2", subject to
+ // the constraint that the reference must bind directly.
+ if (To->isLValue() || To->isXValue()) {
+ QualType T = To->isLValue() ? Self.Context.getLValueReferenceType(ToType)
+ : Self.Context.getRValueReferenceType(ToType);
+
InitializedEntity Entity = InitializedEntity::InitializeTemporary(T);
InitializationSequence InitSeq(Self, Entity, Kind, From);
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