This patch reverts the changes to tuple which fixed construction from
types derived from tuple. It breaks the code mentioned in llvm.org/PR31384.
I'll follow this commit up with a test case.
llvm-svn: 289773
Summary:
The standard requires tuple have the following constructors:
```
tuple(tuple<OtherTypes...> const&);
tuple(tuple<OtherTypes...> &&);
tuple(pair<T1, T2> const&);
tuple(pair<T1, T2> &&);
tuple(array<T, N> const&);
tuple(array<T, N> &&);
```
However libc++ implements these as a single constructor with the signature:
```
template <class TupleLike, enable_if_t<__is_tuple_like<TupleLike>::value>>
tuple(TupleLike&&);
```
This causes the constructor to reject types derived from tuple-like types; Unlike if we had all of the concrete overloads, because they cause the derived->base conversion in the signature.
This patch fixes this issue by detecting derived types and the tuple-like base they are derived from. It does this by creating an overloaded function with signatures for each of tuple/pair/array and checking if the possibly derived type can convert to any of them.
This patch fixes [PR17550]( https://llvm.org/bugs/show_bug.cgi?id=17550)
This patch
Reviewers: mclow.lists, K-ballo, mpark, EricWF
Subscribers: cfe-commits
Differential Revision: https://reviews.llvm.org/D27606
llvm-svn: 289727
This patch removes libc++'s tuple extension which allowed it to be
constructed from fewer initializers than elements; with the remaining
elements being default constructed. However the implicit version of
this extension breaks conforming code. For example:
int fun(std::string);
int fun(std::tuple<std::string, int>);
int x = fun("hello"); // ambigious
Because existing code may already depend on this extension it can be re-enabled
by defining _LIBCPP_ENABLE_TUPLE_IMPLICIT_REDUCED_ARITY_EXTENSION.
Note that the explicit version of this extension is still supported,
although it's somewhat less useful than the implicit one.
llvm-svn: 289158
Instead of storing double in double and then truncating to int, store int in long
and then widen to long long. This preserves test coverage (as these tests are
interested in various tuple conversions) while avoiding truncation warnings.
test/std/utilities/tuple/tuple.tuple/tuple.cnstr/const_pair.pass.cpp
Since we aren't physically truncating anymore, t1 is equal to p0.
test/std/utilities/tuple/tuple.tuple/tuple.cnstr/convert_copy.pass.cpp
One edit is different from the usual pattern. Previously, we were storing
double in double and then converting to A, which has an implicitly converting
constructor from int. Now, we're storing int in int and then converting to A,
avoiding the truncation.
Fixes D27542.
llvm-svn: 289109
This replaces every occurrence of _LIBCPP_STD_VER in the tests with
TEST_STD_VER. Additionally, for every affected
file, #include "test_macros.h" is being added explicitly if it wasn't
already there.
https://reviews.llvm.org/D26294
llvm-svn: 286007
Libc++ has to deduce the 'allocator_arg_t' parameter as 'AllocArgT' for the
following constructor:
template <class Alloc> tuple(allocator_arg_t, Alloc const&)
Previously libc++ has tried to support tags derived from 'allocator_arg_t' by
using 'is_base_of<AllocArgT, allocator_arg_t>'. However this breaks whenever a
2-tuple contains a reference to an incomplete type as its first parameter.
See https://llvm.org/bugs/show_bug.cgi?id=27684
llvm-svn: 273334
There are two main fixes in this patch.
First the constructor SFINAE was changed so that it's evaluated in two stages
where the first stage evaluates the "safe" SFINAE conditions and the second
evaluates the "dangerous" ones. The key is that the second stage is lazily
evaluated only if the first stage passes. This helps fix PR23256
(https://llvm.org/bugs/show_bug.cgi?id=23256).
The second fix is for PR22806 and LWG issue 2549. This fix applies
the suggested resolution to the LWG issue in order to prevent the construction
of dangling references. The SFINAE for this check is contained within
the _PreferTupleLikeConstructor alias template. The tuple-like constructors
are disabled whenever that trait returns false.
(https://llvm.org/bugs/show_bug.cgi?id=22806)
(http://cplusplus.github.io/LWG/lwg-active.html#2549)
llvm-svn: 266461
Summary:
A default uses-allocator constructor has been added since that overload was previously provided by the extended constructor.
Since Clang does implicit conversion checking after substitution this constructor has to deduce the allocator_arg_t parameter so that it can prevent the evaluation of "is_default_constructible" if the first argument doesn't match. See http://www.open-std.org/jtc1/sc22/wg21/docs/cwg_defects.html#1391 for more information.
This patch fixes PR24779 (https://llvm.org/bugs/show_bug.cgi?id=24779)
Subscribers: cfe-commits
Differential Revision: http://reviews.llvm.org/D19006
llvm-svn: 266409
Summary:
Currently parts of the SFINAE on tuples default constructor always gets evaluated even when the default constructor is never called or instantiated. This can cause a hard compile error when a tuple is created with types that do not have a default constructor. Below is a self contained example using a pair like class. This code will not compile but probably should.
```
#include <type_traits>
template <class T>
struct IllFormedDefaultImp {
IllFormedDefaultImp(T x) : value(x) {}
constexpr IllFormedDefaultImp() {}
T value;
};
typedef IllFormedDefaultImp<int &> IllFormedDefault;
template <class T, class U>
struct pair
{
template <bool Dummy = true,
class = typename std::enable_if<
std::is_default_constructible<T>::value
&& std::is_default_constructible<U>::value
&& Dummy>::type
>
constexpr pair() : first(), second() {}
pair(T const & t, U const & u) : first(t), second(u) {}
T first;
U second;
};
int main()
{
int x = 1;
IllFormedDefault v(x);
pair<IllFormedDefault, IllFormedDefault> p(v, v);
}
```
One way to fix this is to use `Dummy` in a more involved way in the constructor SFINAE. The following patch fixes these sorts of hard compile errors for tuple.
Reviewers: mclow.lists, rsmith, K-ballo, EricWF
Reviewed By: EricWF
Subscribers: ldionne, cfe-commits
Differential Revision: http://reviews.llvm.org/D7569
llvm-svn: 230120
Summary: No declaration for the type `tuple` is given in c++03 or c++98 modes. Mark all tests that use the actual `tuple` type as UNSUPPORTED.
Reviewers: jroelofs, mclow.lists, danalbert
Reviewed By: danalbert
Subscribers: cfe-commits
Differential Revision: http://reviews.llvm.org/D5956
llvm-svn: 229808
