This reverts commit de21704ba9.
Regressed/causes this to error due to ambiguity:
void f(const int * const &);
void f(int *);
int main() {
int * x;
f(x);
}
(in case it's important - the original case where this turned up was a
member function overload in a class template with, essentially:
f(const T1&)
f(T2*)
(where T1 == X const *, T2 == X))
It's not super clear to me if this ^ is expected behavior, in which case
I'm sorry about the revert & happy to look into ways to fix the original
code.
Added support for constraint satisfaction checking and partial ordering of constraints in constrained partial specialization and function template overloads.
Re-commit after fixing another crash (added regression test).
Differential Revision: https://reviews.llvm.org/D41910
Added support for constraint satisfaction checking and partial ordering of constraints in constrained partial specialization and function template overloads.
Re-commit after fixing some crashes and warnings.
Differential Revision: https://reviews.llvm.org/D41910
The language wording change forgot to update overload resolution to rank
implicit conversion sequences based on qualification conversions in
reference bindings. The anticipated resolution for that oversight is
implemented here -- we order candidates based on qualification
conversion, not only on top-level cv-qualifiers.
For OpenCL/C++, this allows reference binding between pointers with
differing (nested) address spaces. This makes the behavior of reference
binding consistent with that of implicit pointer conversions, as is the
purpose of this change, but that pre-existing behavior for pointer
conversions is itself probably not correct. In any case, it's now
consistently the same behavior and implemented in only one place.
Added support for constraint satisfaction checking and partial ordering of constraints in constrained partial specialization and function template overloads.
Phabricator: D41910
This covers:
* usual arithmetic conversions (comparisons, arithmetic, conditionals)
between different enumeration types
* usual arithmetic conversions between enums and floating-point types
* comparisons between two operands of array type
The deprecation warnings are on-by-default (in C++20 compilations); it
seems likely that these forms will become ill-formed in C++23, so
warning on them now by default seems wise.
For the first two bullets, off-by-default warnings were also added for
all the cases where we didn't already have warnings (covering language
modes prior to C++20). These warnings are in subgroups of the existing
-Wenum-conversion (except that the first case is not warned on if either
enumeration type is anonymous, consistent with our existing
-Wenum-conversion warnings).
This requires us to essentially fully form the body of the defaulted
comparison, but from an unevaluated context. Naively this would require
generating the function definition twice; instead, we ensure that the
function body is implicitly defined before performing the check, and
walk the actual body where possible.
function.
We need to perform unqualified lookups from the context of a defaulted
comparison, but not until we implicitly define the function, at which
point we can't do those lookups any more. So perform the lookup from the
end of the class containing the =default declaration and store the
lookup results on the defaulted function until we synthesize the body.
Array members are not yet handled. In addition, defaulted comparisons
can't yet find comparison operators by unqualified lookup (only by
member lookup and ADL). These issues will be fixed in follow-on changes.
Part of the C++20 concepts implementation effort.
- Associated constraints (requires clauses, currently) are now enforced when instantiating/specializing templates and when considering partial specializations and function overloads.
- Elaborated diagnostics give helpful insight as to why the constraints were not satisfied.
Phabricator: D41569
Re-commit, after fixing some memory bugs.
Part of the C++20 concepts implementation effort.
- Associated constraints (requires clauses, currently) are now enforced when instantiating/specializing templates and when considering partial specializations and function overloads.
- Elaborated diagnostics give helpful insight as to why the constraints were not satisfied.
Phabricator: D41569
This adds support for rewriting <, >, <=, and >= to a normal or reversed
call to operator<=>, for rewriting != to a normal or reversed call to
operator==, and for rewriting <=> and == to reversed forms of those same
operators.
Note that this is a breaking change for various C++17 code patterns,
including some in use in LLVM. The most common patterns (where an
operator== becomes ambiguous with a reversed form of itself) are still
accepted under this patch, as an extension (with a warning). I'm hopeful
that we can get the language rules fixed before C++20 ships, and the
extension warning is aimed primarily at providing data to inform that
decision.
llvm-svn: 375306
Part of C++20 Concepts implementation effort. Added Concept Specialization Expressions that are created when a concept is refe$
D41217 on Phabricator.
(recommit after fixing failing Parser test on windows)
llvm-svn: 374903
Part of C++20 Concepts implementation effort. Added Concept Specialization Expressions that are created when a concept is referenced with arguments, and tests thereof.
llvm-svn: 374882
Summary:
The overload resolution for enums with a fixed underlying type has changed in the C++14 standard. This patch implements the new rule.
Patch by Mark de Wever!
Reviewers: rsmith
Reviewed By: rsmith
Subscribers: cfe-commits
Tags: #clang
Differential Revision: https://reviews.llvm.org/D65695
llvm-svn: 373866
has a constexpr destructor.
For constexpr variables, reject if the variable does not have constant
destruction. In all cases, do not emit runtime calls to the destructor
for variables with constant destruction.
llvm-svn: 373159
appropriate during constant evaluation.
Note that the evaluator is sometimes invoked on incomplete expressions.
In such cases, if an object is constructed but we never reach the point
where it would be destroyed (and it has non-trivial destruction), we
treat the expression as having an unmodeled side-effect.
llvm-svn: 372538
Summary:
Microsoft seems to do this regardless of the language mode, so we must
also do it in order to be ABI compatible.
Fixes PR36125
Reviewers: thakis
Subscribers: cfe-commits
Differential Revision: https://reviews.llvm.org/D47956
llvm-svn: 371642
This is mostly the same as the
[[clang::require_constant_initialization]] attribute, but has a couple
of additional syntactic and semantic restrictions.
In passing, I added a warning for the attribute form being added after
we have already seen the initialization of the variable (but before we
see the definition); that case previously slipped between the cracks and
the attribute was silently ignored.
llvm-svn: 370972
initializers.
This has some interesting interactions with our existing extensions to
support C99 designated initializers as an extension in C++. Those are
resolved as follows:
* We continue to permit the full breadth of C99 designated initializers
in C++, with the exception that we disallow a partial overwrite of an
initializer with a non-trivially-destructible type. (Full overwrite
is OK, because we won't run the first initializer at all.)
* The C99 extensions are disallowed in SFINAE contexts and during
overload resolution, where they could change the meaning of valid
programs.
* C++20 disallows reordering of initializers. We only check for that for
the simple cases that the C++20 rules permit (designators of the form
'.field_name =' and continue to allow reordering in other cases).
It would be nice to improve this behavior in future.
* All C99 designated initializer extensions produce a warning by
default in C++20 mode. People are going to learn the C++ rules based
on what Clang diagnoses, so it's important we diagnose these properly
by default.
* In C++ <= 17, we apply the C++20 rules rather than the C99 rules, and
so still diagnose C99 extensions as described above. We continue to
accept designated C++20-compatible initializers in C++ <= 17 silently
by default (but naturally still reject under -pedantic-errors).
This is not a complete implementation of P0329R4. In particular, that
paper introduces new non-C99-compatible syntax { .field { init } }, and
we do not support that yet.
This is based on a previous patch by Don Hinton, though I've made
substantial changes when addressing the above interactions.
Differential Revision: https://reviews.llvm.org/D59754
llvm-svn: 370544
Allow implementations to provide complete definitions of
std::tuple_size<T>, but to omit the 'value' member to signal that T is
not tuple-like. The Microsoft standard library implements
std::tuple_size<const T> this way.
If the value member exists, clang still validates that it is an ICE, but
if it does not, then the type is considered to not be tuple-like.
Fixes PR33236
Reviewers: rsmith
Differential Revision: https://reviews.llvm.org/D66040
llvm-svn: 369043
When handling a member access into a non-class, non-ObjC-object type, we
would perform a lookup into the surrounding scope as if for an
unqualified lookup. If the member access was followed by a '<' and this
lookup (or the typo-correction for it) found a template name, we'd treat
the member access as naming that template.
Now we treat such accesses as never naming a template if the type of the
object expression is of vector type, so that vector component accesses
are never misinterpreted as naming something else. This is not entirely
correct, since it is in fact valid to name a template from the enclosing
scope in this context, when invoking a pseudo-destructor for the vector
type via an alias template, but that's very much a corner case, and this
change leaves that case only as broken as the corresponding case for
Objective-C types is.
This incidentally adds support for dr2292, which permits a 'template'
keyword at the start of a member access naming a pseudo-destructor.
llvm-svn: 368940
For consistency with normal instructions and clarity when reading IR,
it's best to print the %0, %1, ... names of function arguments in
definitions.
Also modifies the parser to accept IR in that form for obvious reasons.
llvm-svn: 367755
check the formal rules rather than seeing if the normal checks produce a
diagnostic.
This fixes the handling of C++2a extensions in lambdas in C++17 mode,
as well as some corner cases in earlier language modes where we issue
diagnostics for things other than not satisfying the formal constexpr
requirements.
llvm-svn: 367254
David Blaikie