This is not required by the standard (yet), but there seems to be reasonable
support for this being a defect according to CWG discussion, and libstdc++ 7.1
relies on it working.
llvm-svn: 304946
such guides below explicit ones, and ensure that references to the class's
template parameters are not treated as forwarding references.
We make a few tweaks to the wording in the current standard:
1) The constructor parameter list is copied faithfully to the deduction guide,
without losing default arguments or a varargs ellipsis (which the standard
wording loses by omission).
2) If the class template declares no constructors, we add a T() -> T<...> guide
(which will only ever work if T has default arguments for all non-pack
template parameters).
3) If the class template declares nothing that looks like a copy or move
constructor, we add a T(T<...>) -> T<...> guide.
#2 and #3 follow from the "pretend we had a class type with these constructors"
philosophy for deduction guides.
llvm-svn: 295007
This issue clarifies how deduction proceeds past a non-trailing function
parameter pack. Essentially, the pack itself is skipped and consumes no
arguments (except for those implied by an explicitly-specified template
arguments), and nothing is deduced from it. As a small fix to the standard's
rule, we do not allow subsequent deduction to change the length of the function
parameter pack (by preventing extension of the explicitly-specified pack if
present, and otherwise deducing all contained packs to empty packs).
llvm-svn: 291425
to make reference to template parameters. This is only a partial
implementation; we retain the restriction that the argument must not be
type-dependent, since it's unclear how that would work given the existence of
other language rules requiring an exact type match in this context, even for
type-dependent cases (a question has been raised on the core reflector).
llvm-svn: 290647
fail the merge if the arguments have different types (except if one of them was
deduced from an array bound, in which case take the type from the other).
This is correct because (except in the array bound case) the type of the
template argument in each deduction must match the type of the parameter, so at
least one of the two deduced arguments must have a mismatched type.
This is necessary because we would otherwise lose the type information for the
discarded template argument in the merge, and fail to diagnose the mismatch.
In order to power this, we now properly retain the type of a deduced non-type
template argument deduced from a declaration, rather than giving it the type of
the template parameter; we'll convert it to the template parameter type when
checking the deduced arguments.
llvm-svn: 290399
mismatched dynamic exception specifications in expressions from an error to a
warning, since this is no longer ill-formed in C++1z.
Allow reference binding of a reference-to-non-noexcept function to a noexcept
function lvalue. As defect resolutions, also allow a conditional between
noexcept and non-noexcept function lvalues to produce a non-noexcept function
lvalue (rather than decaying to a function pointer), and allow function
template argument deduction to deduce a reference to non-noexcept function when
binding to a noexcept function type.
llvm-svn: 284905
by overload resolution because deduction succeeds, but the substituted
parameter type for some parameter (with deduced type) doesn't exactly match the
corresponding adjusted argument type.
llvm-svn: 256657
have a direct mismatch between some component of the template and some
component of the argument. The diagnostic now says what the mismatch was, but
doesn't yet say which part of the template doesn't match.
llvm-svn: 174039
partially-substituted parameter pack in a template, forget about the
partially-substituted parameter pack: it is now completed. Fixes
<rdar://problem/12176336>.
llvm-svn: 172859
Don't require that, during template deduction, a template specialization type
as a function parameter has at least as many template arguments as one used in
a function argument (not even if the argument has been resolved to an exact
type); the additional parameters might be provided by default template
arguments in the template. We don't need this check, since we now implement
[temp.deduct.call]p4 with an additional check after deduction.
llvm-svn: 169475
functions that includes an explicit template argument list, perform
an inner deduction against each of the function templates in that list
and, if successful, use the result of that deduction for the outer
template argument deduction. Fixes PR11713.
llvm-svn: 152575
structural comparison of non-dependent types. Otherwise, we end up
rejecting cases where the non-dependent types don't match due to
qualifiers in, e.g., a pointee type. Fixes PR12132.
llvm-svn: 152529
and DefaultFunctionArrayLvalueConversion. To prevent
significant regression for should-this-be-a-call fixits,
and to repair some such regression from the introduction of
bound member placeholders, make those placeholder checks
try to build calls appropriately. Harden the build-a-call
logic while we're at it.
llvm-svn: 141738
deducing template parameter types. Recently Clang began enforcing the
more strict checking that the argument type and the deduced function
parameter type (after substitution) match, but that only consideres
qualification conversions.
One problem with this patch is that we check noreturn conversions and
qualification conversions independently. If a valid conversion would
require *both*, perhaps interleaved with each other, it will be
rejected. If this actually occurs (I'm not yet sure it does) and is in
fact a problem (I'm not yet sure it is), there is a FIXME to implement
more intelligent conversion checking.
However, this step at least allows Clang to resume accepting valid code
we're seeing in the wild.
llvm-svn: 133327
checks that the deduced argument type for a function call matches the
actual argument type provided. The only place we've found where the
consistency checking should actually cause template argument deduction
failure is due to qualifier differences that don't fall into the realm
of qualification conversions (which are *not* checked when we
initially perform deduction). However, we're performing the full
checking as specified in the standard to ensure that no other cases
exist.
Fixes PR9233 / <rdar://problem/9039590>.
llvm-svn: 133163
overload, so that we actually do the resolution for full expressions
and emit more consistent, useful diagnostics. Also fixes an IRGen
crasher, where Sema wouldn't diagnose a resolvable bound member
function template-id used in a full-expression (<rdar://problem/9108698>).
llvm-svn: 127747
parameter type to see what's behind it, so that we don't end up
printing silly things like "float const *" when "const float *" would
make more sense. Also, replace the pile of "isa" tests with a simple
switch enumerating all of the cases, making a few more obvious cases
use prefix qualifiers.
llvm-svn: 125729
T) when taking the address of an overloaded function or matching a
specialization to a template (C++0x [temp.deduct.type]p10). Fixes
PR9044.
llvm-svn: 124197
call (C++0x [temp.deduct.call]p3).
As part of this, start improving the reference-binding implementation
used in the computation of implicit conversion sequences (for overload
resolution) to reflect C++0x semantics. It still needs more work and
testing, of course.
llvm-svn: 123966
and function templates that contain variadic templates. This involves
three small-ish changes:
(1) When transforming a pack expansion, if the transformed argument
still contains unexpanded parameter packs, build a pack
expansion. This can happen during the substitution that occurs into
class template partial specialiation template arguments during
partial ordering.
(2) When performing template argument deduction where the argument
is a pack expansion, match against the pattern of that pack
expansion.
(3) When performing template argument deduction against a non-pack
parameter, or a non-expansion template argument, deduction fails if
the argument itself is a pack expansion (C++0x
[temp.deduct.type]p22).
llvm-svn: 123279
number of explicit call arguments. This actually fixes an erroneous
test for [temp.deduct.partial]p11, where we were considering
parameters corresponding to arguments beyond those that were
explicitly provided.
llvm-svn: 123244
parameters it expanded to, map exactly the number of function
parameters that were expanded rather than just running to the end of
the instantiated parameter list. This finishes the implementation of
the last sentence of C++0x [temp.deduct.call]p1.
llvm-svn: 123213
sentence of [temp.deduct.call]p1, both of which concern the
non-deducibility of parameter packs not at the end of a
parameter-type-list. The latter isn't fully implemented yet; see the
new FIXME.
llvm-svn: 123210
pack expansions in template argument lists and function parameter
lists. The implementation of this paragraph should be complete
*except* for cases where we're substituting into one of the unexpanded
packs in a pack expansion; that's a general issue I haven't solved yet.
llvm-svn: 123188
allows an argument pack determines via explicit specification of
function template arguments to be extended by further, deduced
arguments. For example:
template<class ... Types> void f(Types ... values);
void g() {
f<int*, float*>(0, 0, 0); // Types is deduced to the sequence int*, float*, int
}
There are a number of FIXMEs in here that indicate places where we
need to implement + test retained expansions, plus a number of other
places in deduction where we need to correctly cope with the
explicitly-specified arguments when deducing an argument
pack. Furthermore, it appears that the RecursiveASTVisitor needs to be
auditied; it's missing some traversals (especially w.r.t. template
arguments) that cause it not to find unexpanded parameter packs when
it should.
The good news, however, is that the tr1::tuple implementation now
works fully, and the tr1::bind example (both from N2080) is actually
working now.
llvm-svn: 123163
parameters into parameter types, so that substitution of
explicitly-specified function template arguments uses the same
path. This enables the use of explicitly-specified function template
arguments with variadic templates.
llvm-svn: 122986
template whose last parameter is a parameter pack. This allows us to
form a call to, e.g.,
template<typename ...Args1, typename ...Args2>
void f(std::pair<Args1, Args2> ...pairs);
given zero or more instances of "pair".
llvm-svn: 122973
caused an assertion when dealing with non-type template parameter
packs. Add some tests for deduction and instantiation of non-type
template parameter packs.
llvm-svn: 122534
parameter packs. In particular, a parameter pack not otherwise deduced
is deduced to an empty parameter pack.
The C++0x wording here is a bit unfortunate; this should really only
apply to function templates, and it mentions "trailing" parameter
packs, which doesn't really make sense in the context of function
templates. Will file a core issue separately.
llvm-svn: 122463
the presence of a pack expansion anywhere except at the end of a
template-argument-list causes the entire template-argument-list to be
a non-deduced context.
llvm-svn: 122461
Richard Smith