Summary:
This is a side-effect brought in by p0620r0, which allows other placeholder types (derived from `auto` and `decltype(auto)`) to be usable in a `new` expression with a single-clause //braced-init-list// as its initializer (8.3.4 [expr.new]/2). N3922 defined its semantics.
References:
http://wg21.link/p0620r0http://wg21.link/n3922
Reviewers: rsmith, aaron.ballman
Reviewed By: rsmith
Subscribers: cfe-commits
Differential Revision: https://reviews.llvm.org/D39451
llvm-svn: 320401
Previously, if an overloaded function in a braced-init-list was encountered in
template argument deduction, and the overload set couldn't be resolved to a
particular function, we'd immediately produce a deduction failure. That's not
correct; this situation is supposed to result in that particular P/A pair being
treated as a non-deduced context, and deduction can still succeed if the type
can be deduced from elsewhere.
llvm-svn: 291014
Previously, if the arguments for a parameter pack contained a braced-init-list,
we would abort deduction (keeping the pack deductions from prior arguments) at
the point when we reached the braced-init-list, resulting in wrong deductions
and rejects-valids. We now just leave a "hole" in the pack for such an argument,
which needs to be filled by another deduction of the same pack.
llvm-svn: 290933
std::initializer_list<T> type. Instead, the list must contain a single element
and the type is deduced from that.
In Clang 3.7, we warned by default on all the cases that would change meaning
due to this change. In Clang 3.8, we will support only the new rules -- per
the request in N3922, this change is applied as a Defect Report against earlier
versions of the C++ standard.
This change is not entirely trivial, because for lambda init-captures we
previously did not track the difference between direct-list-initialization and
copy-list-initialization. The difference was not previously observable, because
the two forms of initialization always did the same thing (the elements of the
initializer list were always copy-initialized regardless of the initialization
style used for the init-capture).
llvm-svn: 252688
Summary:
This patch reduces duplication in the template argument deduction code
for handling deduction from initializer lists in a function call. This
extends the fix for PR12119 to also apply to the case where the
corresponding parameter is a trailing parameter pack.
Test Plan:
A test for deduction from nested initializer lists where the
corresponding parameter is a trailing parameter pack is added in
`clang/test/SemaCXX/cxx0x-initializer-stdinitializerlist.cpp`.
Reviewers: fraggamuffin, rsmith
Reviewed By: rsmith
Subscribers: cfe-commits
Differential Revision: http://reviews.llvm.org/D10681
llvm-svn: 240612
(or of a lambda init-capture, which is sort-of such a variable). The semantics
of such constructs will change when we implement N3922, so we intend to warn on
this in Clang 3.6 then change the semantics in Clang 3.7.
llvm-svn: 228792
list-initialization that gets converted to some form other than an
InitListExpr. CXXTemporaryObjectExpr is a special case here, because it
represents a fused CXXFunctionalCastExpr + CXXConstructExpr. That, in
itself, is probably a design error...
llvm-svn: 227377
-- a constructor list initialization that unpacked an initializer list into
constructor arguments and
-- a list initialization that created as std::initializer_list and passed it
as the first argument to a constructor
in the AST. Use this flag while instantiating templates to provide the right
semantics for the resulting initialization.
llvm-svn: 213224
constructor (and pass it an implicitly-generated std::initializer_list object),
be sure to mark the resulting construction as list-initialization. This fixes
an assert in template instantiation where we previously thought we'd got direct
non-list initialization without any parentheses.
llvm-svn: 213201
elements from {}, rather than value-initializing them. This permits calling an
initializer-list constructor or constructing a std::initializer_list object.
(It would also permit initializing a const reference or rvalue reference if
that weren't explicitly prohibited by other rules.)
llvm-svn: 210091
initializer list containing a single element of type T, be sure to mark the
sequence as a list conversion sequence so that it is known to be worse than an
implicit conversion sequence that initializes a std::initializer_list object.
llvm-svn: 190115
Introduce CXXStdInitializerListExpr node, representing the implicit
construction of a std::initializer_list<T> object from its underlying array.
The AST representation of such an expression goes from an InitListExpr with a
flag set, to a CXXStdInitializerListExpr containing a MaterializeTemporaryExpr
containing an InitListExpr (possibly wrapped in a CXXBindTemporaryExpr).
This more detailed representation has several advantages, the most important of
which is that the new MaterializeTemporaryExpr allows us to directly model
lifetime extension of the underlying temporary array. Using that, this patch
*drastically* simplifies the IR generation of this construct, provides IR
generation support for nested global initializer_list objects, fixes several
bugs where the destructors for the underlying array would accidentally not get
invoked, and provides constant expression evaluation support for
std::initializer_list objects.
llvm-svn: 183872
array from a braced-init-list. There seems to be a core wording wart
here (it suggests we should be testing whether the elements of the init
list are implicitly convertible to the array element type, not whether
there is an implicit conversion sequence) but our prior behavior appears
to be a bug, not a deliberate effort to implement the standard as written.
llvm-svn: 169690
be sure to perform the argument type adjustments in
[temp.deduct.call]p2, e.g., array decay.
And, when performing these deductions in the context of 'auto', make
sure that we're deducing the P' in std::initializer_list<P'> rather
than the whole initializer list.
Together, this makes code like
for( auto s : {"Deferred", "New", "Open", "Review"}) { }
work properly.
llvm-svn: 153998
Fix some review comments.
Add a test for deduction when std::initializer_list isn't available yet.
Fix redundant error messages. This fixes and outstanding FIXME too.
llvm-svn: 148735
Zhihao Yuan