expansion, when it is known due to the substitution of an out
parameter pack. This allows us to properly handle substitution into
pack expansions that involve multiple parameter packs at different
template parameter levels, even when this substitution happens one
level at a time (as with partial specializations of member class
templates and the signatures of member function templates).
Note that the diagnostic we provide when there is an arity mismatch
between an outer parameter pack and an inner parameter pack in this
case isn't as clear as the normal diagnostic for an arity
mismatch. However, this doesn't matter because these cases are very,
very rare and (even then) only typically occur in a SFINAE context.
The other kinds of pack expansions (expression, template, etc.) still
need to support optional tracking of the number of expansions, and we
need the moral equivalent of SubstTemplateTypeParmPackType for
substituted argument packs of template template and non-type template
parameters.
llvm-svn: 123448
initialize *all* of the bits to zero. Also, when the pattern of a
template argument pack expansion, make sure to set the ellipsis
location along all paths.
This should clear up the valgrind failure that popped up in Clang.
llvm-svn: 122931
expansions with something that is easier to use correctly: a new
template argment kind, rather than a bit on an existing kind. Update
all of the switch statements that deal with template arguments, fixing
a few latent bugs in the process. I"m happy with this representation,
now.
And, oh look! Template instantiation and deduction work for template
template argument pack expansions.
llvm-svn: 122896
for template template argument pack expansions. This allows fun such
as:
template<template<class> class ...> struct apply_impl { /*...*/ };
template<template<class> class ...Metafunctions> struct apply {
typedef typename apply_impl<Metafunctions...>::type type;
};
However, neither template argument deduction nor template
instantiation is implemented for template template argument packs, so
this functionality isn't useful yet.
I'll probably replace the encoding of template template
argument pack expansions in TemplateArgument so that it's harder to
accidentally forget about the expansion. However, this is a step in
the right general direction.
llvm-svn: 122890
template argument (described by an expression, of course). For
example:
template<int...> struct int_tuple { };
template<int ...Values>
struct square {
typedef int_tuple<(Values*Values)...> type;
};
It also lays the foundation for pack expansions in an initializer-list.
llvm-svn: 122751
pattern is a template argument, which involves repeatedly deducing
template arguments using the pattern of the pack expansion, then
bundling the resulting deductions into an argument pack.
We can now handle a variety of simple list-handling metaprograms using
variadic templates. See, e.g., the new "count" metaprogram.
llvm-svn: 122439
whose patterns are template arguments. We can now instantiate, e.g.,
typedef tuple<pair<OuterTypes, InnerTypes>...> type;
where OuterTypes and InnerTypes are template type parameter packs.
There is a horrible inefficiency in
TemplateArgumentLoc::getPackExpansionPattern(), where we need to
create copies of TypeLoc data because our interfaces traffic in
TypeSourceInfo pointers where they should traffic in TypeLocs
instead. I've isolated in efficiency in this one routine; once we
refactor our interfaces to traffic in TypeLocs, we can eliminate it.
llvm-svn: 122278
area of printing template arguments. The functionality changes here
are limited to cases of variadic templates that aren't yet enabled.
llvm-svn: 122250
whether the expression contains an unexpanded parameter pack, in the
same vein as the changes to the Type hierarchy. Compute this bit
within all of the Expr subclasses.
This change required a bunch of reshuffling of dependency
calculations, mainly to consolidate them inside the constructors and
to fuse multiple loops that iterate over arguments to determine type
dependence, value dependence, and (now) containment of unexpanded
parameter packs.
Again, testing is painfully sparse, because all of the diagnostics
will change and it is more important to test the to-be-written visitor
that collects unexpanded parameter packs.
llvm-svn: 121831
and TemplateArgument with an operation that determines whether there
are any unexpanded parameter packs within that construct. Use this
information to diagnose the appearance of the names of parameter packs
that have not been expanded (C++ [temp.variadic]p5). Since this
property is checked often (every declaration, ever expression
statement, etc.), we extend Type and Expr with a bit storing the
result of this computation, rather than walking the AST each time to
determine whether any unexpanded parameter packs occur.
This commit is deficient in several ways, which will be remedied with
future commits:
- Expr has a bit to store the presence of an unexpanded parameter
pack, but it is never set.
- The error messages don't point out where the unexpanded parameter
packs were named in the type/expression, but they should.
- We don't check for unexpanded parameter packs in all of the places
where we should.
- Testing is sparse, pending the resolution of the above three
issues.
llvm-svn: 121724
abstractions (e.g., TemplateArgumentListBuilder) that were designed to
support variadic templates. Only a few remnants of variadic templates
remain, in the parser (parsing template type parameter packs), AST
(template type parameter pack bits and TemplateArgument::Pack), and
Sema; these are expected to be used in a future implementation of
variadic templates.
But don't get too excited about that happening now.
llvm-svn: 118385
case of an elaborated-type-specifier like 'typename A<T>::foo', and
DependentTemplateSpecializationType represents the case of an
elaborated-type-specifier like 'typename A<T>::template B<T>'. The TypeLoc
representation of a DependentTST conveniently exactly matches that of an
ElaboratedType wrapping a TST.
Kill off the explicit rebuild methods for RebuildInCurrentInstantiation;
the standard implementations work fine because the nested name specifier
is computable in the newly-entered context.
llvm-svn: 105801
conflicting deduced template argument values, give a more specific
reason along with those values, e.g.,
test/SemaTemplate/overload-candidates.cpp:4:10: note: candidate template
ignored: deduced conflicting types for parameter 'T' ('int' vs. 'long')
const T& min(const T&, const T&);
^
llvm-svn: 103339
nested-name-specifiers so that they don't gobble the template name (or
operator-function-id) unless there is also a
template-argument-list. For example, given
T::template apply
we would previously consume both "template" and "apply" as part of
parsing the nested-name-specifier, then error when we see that there
is no "<" starting a template argument list. Now, we parse such
constructs tentatively, and back off if the "<" is not present. This
allows us to parse dependent template names as one would use them for,
e.g., template template parameters:
template<typename T, template<class> class X = T::template apply>
struct MetaSomething;
Also, test default arguments for template template parameters.
llvm-svn: 86841
parameters. Rather than storing them as either declarations (for the
non-dependent case) or expressions (for the dependent case), we now
(always) store them as TemplateNames.
The primary change here is to add a new kind of TemplateArgument,
which stores a TemplateName. However, making that change ripples to
every switch on a TemplateArgument's kind, also affecting
TemplateArgumentLocInfo/TemplateArgumentLoc, default template
arguments for template template parameters, type-checking of template
template arguments, etc.
This change is light on testing. It should fix several pre-existing
problems with template template parameters, such as:
- the inability to use dependent template names as template template
arguments
- template template parameter default arguments cannot be
instantiation
However, there are enough pieces missing that more implementation is
required before we can adequately test template template parameters.
llvm-svn: 86777
types. Preserve it through template instantiation. Preserve it through PCH,
although TSTs themselves aren't serializable, so that's pretty much meaningless.
llvm-svn: 85500
Douglas Gregor