inferring based on the current module at the point of creation.
This should result in no functional change except when building a preprocessed
module (or more generally when using #pragma clang module begin/end to switch
module in the middle of a file), in which case it allows us to correctly track
the owning module for declarations. We can't map from FileID to module in the
preprocessed module case, since all modules would have the same FileID.
There are still a couple of remaining places that try to infer a module from a
source location; I'll clean those up in follow-up changes.
llvm-svn: 303322
When we parse a redefinition of an entity for which we have a hidden existing
declaration, make it visible in the current module instead of mapping the
current source location to its containing module.
llvm-svn: 302842
When an undeclared identifier in a context that requires a type is followed by
'<', only look for type templates when typo-correcting, tweak the diagnostic
text to say that a template name (not a type name) was undeclared, and parse
the template arguments when recovering from the error.
llvm-svn: 302732
The heuristic that we use here is:
* the left-hand side must be a simple identifier or a class member access
* the right-hand side must be '<' followed by either a '>' or by a type-id that
cannot be an expression (in particular, not followed by '(' or '{')
* there is a '>' token matching the '<' token
The second condition guarantees the expression would otherwise be ill-formed.
If we're confident that the user intended the name before the '<' to be
interpreted as a template, diagnose the fact that we didn't interpret it
that way, rather than diagnosing that the template arguments are not valid
expressions.
llvm-svn: 302615
This improves our behavior in a few ways:
* We now guarantee that if a member is marked as being a member
specialization, there will actually be a member specialization declaration
somewhere on its redeclaration chain. This fixes a crash in modules builds
where we would try to check that there was a visible declaration of the
member specialization and be surprised to not find any declaration of it at
all.
* We don't set the source location of the in-class declaration of the member
specialization to the out-of-line declaration's location until we have
actually finished merging them. This fixes some very silly looking
diagnostics, where we'd point a "previous declaration is here" note at the
same declaration we're complaining about. Ideally we wouldn't mess with the
prior declaration's location at all, but too much code assumes that the
first declaration of an entity is a reasonable thing to use as an indication
of where it was declared, and that's not really true for a member
specialization unless we fake it like this.
llvm-svn: 302596
This reverts an attempt to check that types match when matching a
dependently-typed non-type template parameter. (This comes up when matching the
parameters of a template template parameter against the parameters of a
template template argument.)
The matching rules here are murky at best. Our behavior after this revert is
definitely wrong for certain C++17 features (for 'auto' template parameter
types within the parameter list of a template template argument in particular),
but our behavior before this revert is wrong for some pre-existing testcases,
so reverting to our prior behavior seems like our best option.
llvm-svn: 300262
- also replace direct equality checks against the ConstantEvaluated enumerator with isConstantEvaluted(), in anticipation of adding finer granularity to the various ConstantEvaluated contexts and reinstating certain restrictions on where lambda expressions can occur in C++17.
- update the clang tablegen backend that uses these Enumerators, and add the relevant scope where needed.
llvm-svn: 299316
Correct class-template deprecation behavior
Based on the comment in the test, and my reading of the standard, a deprecated warning should be issued in the following case:
template<typename T> [[deprecated]] class Foo{}; Foo<int> f;
This was not the case, because the ClassTemplateSpecializationDecl creation did not also copy the deprecated attribute.
Note: I did NOT audit the complete set of attributes to see WHICH ones should be copied, so instead I simply copy ONLY the deprecated attribute.
Previous DiffRev: https://reviews.llvm.org/D27486, was reverted.
This patch fixes the issues brought up here by the reverter: https://reviews.llvm.org/rL298410
Differential Revision: https://reviews.llvm.org/D31245
llvm-svn: 298634
Based on the comment in the test, and my reading of the standard, a deprecated warning should be issued in the following case:
template<typename T> [[deprecated]] class Foo{}; Foo<int> f;
This was not the case, because the ClassTemplateSpecializationDecl creation did not also copy the deprecated attribute.
Note: I did NOT audit the complete set of attributes to see WHICH ones should be copied, so instead I simply copy ONLY the deprecated attribute.
Differential Revision: https://reviews.llvm.org/D27486
llvm-svn: 298410
A 'decltype(auto)' parameter can match any other kind of non-type template
parameter, so should be usable in place of any other parameter in a template
template argument. The standard is sadly extremely unclear on how this is
supposed to work, but this seems like the obviously-correct result.
It's less clear whether an 'auto' parameter should be able to match
'decltype(auto)', since the former cannot be used if the latter turns out to be
used for a reference type, but if we disallow that then consistency suggests we
should also disallow 'auto' matching 'T' for the same reason, defeating
intended use cases of the feature.
llvm-svn: 295866
template deduction guides for class template argument deduction.
Ensure that we have a local instantiation scope for tracking the instantiated
parameters. Additionally, unusually, we're substituting at depth 1 and leaving
depth 0 alone; make sure that we don't reduce template parameter depth by 2 for
inner parameters in the process. (This is probably also broken for alias
templates in the case where they're expanded within a dependent context, but
this patch doesn't fix that.)
llvm-svn: 295696
instantiation.
In preparation for converting the template stack to a more general context
stack (so we can include context notes for other kinds of context).
llvm-svn: 295686
guide from a constructor.
The purpose of this change is to avoid triggering instantiation of the class
when substituting back into the deduction guide if it uses a typedef member.
We will still instantiate the class if the constructor (explicitly or
implicitly, directly or indirectly) uses the current instantiation in a way
that we can't canonicalize out, but that seems unavoidable.
llvm-svn: 295016
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
Summary:
This adds associated constraints as a property of class templates.
An error is produced if redeclarations are not similarly constrained.
Reviewers: rsmith, faisalv, aaron.ballman
Reviewed By: rsmith
Subscribers: cfe-commits, nwilson
Differential Revision: https://reviews.llvm.org/D25674
llvm-svn: 294697
name. If the dependent name happened to end in a template-id (X<T>::Y<U>), we
would fail to notice that the 'typename' keyword is missing when resolving it
to a type.
It turns out that GCC has a similar bug. If this shows up in much real code, we
can easily downgrade this to an ExtWarn.
llvm-svn: 293815
This change adds a new type node, DeducedTemplateSpecializationType, to
represent a type template name that has been used as a type. This is modeled
around AutoType, and shares a common base class for representing a deduced
placeholder type.
We allow deduced class template types in a few more places than the standard
does: in conditions and for-range-declarators, and in new-type-ids. This is
consistent with GCC and with discussion on the core reflector. This patch
does not yet support deduced class template types being named in typename
specifiers.
llvm-svn: 293207
Under this defect resolution, the injected-class-name of a class or class
template cannot be used except in very limited circumstances (when declaring a
constructor, in a nested-name-specifier, in a base-specifier, or in an
elaborated-type-specifier). This is apparently done to make parsing easier, but
it's a pain for us since we don't know whether a template-id using the
injected-class-name is valid at the point when we annotate it (we don't yet
know whether the template-id will become part of an elaborated-type-specifier).
As a tentative resolution to a perceived language defect, mem-initializer-ids
are added to the list of exceptions here (they generally follow the same rules
as base-specifiers).
When the reference to the injected-class-name uses the 'typename' or 'template'
keywords, we permit it to be used to name a type or template as an extension;
other compilers also accept some cases in this area. There are also a couple of
corner cases with dependent template names that we do not yet diagnose, but
which will also get this treatment.
llvm-svn: 292518
This rule permits the injected-class-name of a class template to be used as
both a template type argument and a template template argument, with no extra
syntax required to disambiguate.
llvm-svn: 292426
The rules around typechecking deduced template arguments during partial
ordering are not clear, and while the prior behavior does not seem to be
correct (it doesn't follow the general model of partial ordering where each
template parameter is replaced by a non-dependent but unique value), the new
behavior is also not clearly right and breaks some existing idioms.
The new behavior is retained for dealing with non-type template parameters
with 'auto' types, as without it even the most basic uses of that feature
don't work. We can revisit this once CWG has come to an agreement on how
partial ordering with 'auto' non-type template parameters is supposed to
work.
llvm-svn: 292183
In the case where the template class itself is already `dllexport`, the
implicit instantiation will have already emitted all members. When we
check the explicit instantiation definition, the `Specialization` will
have inherited the `dllexport` attribute, so we'll attempt to emit all
members for a second time, which causes an assertion failure. Restrict
the exporting to when the `dllexport` attribute is newly introduced by
the explicit instantiation definition.
Fixes PR31608.
Differential Revision: https://reviews.llvm.org/D28590
llvm-svn: 291877
Fixes a crash in modules where the template class decl becomes the most recent
decl in the redeclaration chain and forcing the template instantiator try to
instantiate the friend declaration, rather than the template definition.
In practice, A::list<int> produces a TemplateSpecializationType
A::__1::list<int, allocator<type-parameter-0-0> >' failing to replace to
subsitute the default argument to allocator<int>.
Kudos Richard Smith (D28399).
llvm-svn: 291753
properly even when a non-type template parameter has a dependent type.
Previously, if a non-type template parameter was dependent, but not dependent
on an outer level of template parameter, we would not match the type of the
parameter. Under [temp.arg.template], we are supposed to check that the types
are equivalent, which means checking for syntactic equivalence in the dependent
case.
This also fixes some accepts-invalids when passing templates with auto-typed
non-type template parameters as template template arguments.
llvm-svn: 291512
dependent context and can't be used in a constant expression.
Per C++ [temp.inst]p2, "the instantiation of a static data member does not
occur unless the static data member is used in a way that requires the
definition to exist".
This doesn't /quite/ match that, as we still instantiate static data members
that are usable in constant expressions even if the use doesn't require a
definition. A followup patch will fix that for both variables and functions.
llvm-svn: 291295
In many translation units I have tried, the calls to isIgnored() removed
in this patch are more expensive than doing the analysis that is behind
it. The speed-up in translation units I have tried is between 10 and
20%.
Review: https://reviews.llvm.org/D28208
llvm-svn: 290842
to be specified for a template template parameter whenever the parameter is at
least as specialized as the argument (when there's an obvious and correct
mapping from uses of the parameter to uses of the argument). For example, a
template with more parameters can be passed to a template template parameter
with fewer, if those trailing parameters have default arguments.
This is disabled by default, despite being a DR resolution, as it's fairly
broken in its current state: there are no partial ordering rules to cope with
template template parameters that have different parameter lists, meaning that
code that attempts to decompose template-ids based on arity can hit unavoidable
ambiguity issues.
The diagnostics produced on a non-matching argument are also pretty bad right
now, but I aim to improve them in a subsequent commit.
llvm-svn: 290792
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
