Support the constexpr specifier on lambda expressions - and support its inference from the lambda call operator's body.
i.e.
auto L = [] () constexpr { return 5; };
static_assert(L() == 5); // OK
auto Implicit = [] (auto a) { return a; };
static_assert(Implicit(5) == 5);
We do not support evaluation of lambda's within constant expressions just yet.
Implementation Strategy:
- teach ParseLambdaExpressionAfterIntroducer to expect a constexpr specifier and mark the invented function call operator's declarator's decl-specifier with it; Have it emit fixits for multiple decl-specifiers (mutable or constexpr) in this location.
- for cases where constexpr is not explicitly specified, have buildLambdaExpr check whether the invented function call operator satisfies the requirements of a constexpr function, by calling CheckConstexprFunctionDecl/Body.
Much obliged to Richard Smith for his patience and his care, in ensuring the code is clang-worthy.
llvm-svn: 264513
use. In order for this to fire, the function needed to be a templated function
marked 'constexpr' and declared but not defined. This weird pattern appears in
libstdc++'s alloc_traits.h.
llvm-svn: 264471
non-deterministic diagnostics (and non-deterministic PCH files). Check these
when building a module rather than serializing it; it's not reasonable for a
module's use to be satisfied by a definition in the user of the module.
llvm-svn: 264466
lambda-expression. We don't actually instantiate the closure type / operator()
in the template in order to produce the closure type / operator() in the
instantiation, so this isn't caught by the normal path.
llvm-svn: 264184
This commit adds a named argument to AvailabilityAttr, while r263652 adds an
optional string argument to __attribute__((deprecated)).
This was commited in r263687 and reverted in 263752 due to misaligned
access.
rdar://20588929
llvm-svn: 263958
Implement lambda capture of *this by copy.
For e.g.:
struct A {
int d = 10;
auto foo() { return [*this] (auto a) mutable { d+=a; return d; }; }
};
auto L = A{}.foo(); // A{}'s lifetime is gone.
// Below is still ok, because *this was captured by value.
assert(L(10) == 20);
assert(L(100) == 120);
If the capture was implicit, or [this] (i.e. *this was captured by reference), this code would be otherwise undefined.
Implementation Strategy:
- amend the parser to accept *this in the lambda introducer
- add a new king of capture LCK_StarThis
- teach Sema::CheckCXXThisCapture to handle by copy captures of the
enclosing object (i.e. *this)
- when CheckCXXThisCapture does capture by copy, the corresponding
initializer expression for the closure's data member
direct-initializes it thus making a copy of '*this'.
- in codegen, when assigning to CXXThisValue, if *this was captured by
copy, make sure it points to the corresponding field member, and
not, unlike when captured by reference, what the field member points
to.
- mark feature as implemented in svn
Much gratitude to Richard Smith for his carefully illuminating reviews!
llvm-svn: 263921
Some functions can't have their address taken. If we encounter an
overload set where only one of the candidates can have its address
taken, we should automatically select that candidate's type in type
deduction.
Differential Revision: http://reviews.llvm.org/D15591
llvm-svn: 263888
Some functions can't have their address taken. If we encounter an
overload set where only one of the candidates can have its address
taken, we should automatically select that candidate in cast
expressions.
Differential Revision: http://reviews.llvm.org/D17701
llvm-svn: 263887
This commit adds a named argument to AvailabilityAttr, while r263652 adds an
optional string argument to __attribute__((deprecated)). This enables the
compiler to provide Fix-Its for deprecated declarations.
rdar://20588929
llvm-svn: 263687
The declaration of the destructor of an invalid class was not properly marked
as noexcept. As a result, the definition of the same destructor, which was
properly implicitly marked as noexcept, would not match the definition.
This would cause the definition CXXDestructorDecl to be matked as invalid
and omited from the AST.
Differential Revision: http://reviews.llvm.org/D17988
llvm-svn: 263639
r263299 added a fixit for the -Wformat-security warning, but that runs
into complications with our guideline that error recovery should be done
as-if the fixit had been applied. Putting the fixit on a note avoids that.
llvm-svn: 263584
Original patch by Stefan Bühler http://reviews.llvm.org/D12834
Difference between original and this one:
- fixed all comments in original code review
- added more tests, all new diagnostics now covered by tests
- moved abi_tag on re-declaration checks to Sema::mergeDeclAttributes
where they actually may work as designed
- clang-format + other stylistic changes
Mangle part will be sent for review as a separate patch.
Differential Revision: http://reviews.llvm.org/D17567
llvm-svn: 263015
Similar to the template cases in r262050, when a C++ method in an
unavailable struct/class calls unavailable API, don't diagnose an error.
I.e., this case was failing:
void foo() __attribute__((unavailable));
struct __attribute__((unavailable)) A {
void bar() { foo(); }
};
Since A is unavailable, A::bar is allowed to call foo. However, we were
emitting a diagnostic here. This commit checks up the context chain
from A::bar, in a manner inspired by SemaDeclAttr.cpp:isDeclUnavailable.
I expected to find other related issues but failed to trigger them:
- I wondered if DeclBase::getAvailability should check for
`TemplateDecl` instead of `FunctionTemplateDecl`, but I couldn't find
a way to trigger this. I left behind a few extra tests to make sure
we don't regress.
- I wondered if Sema::isFunctionConsideredUnavailable should be
symmetric, checking up the context chain of the callee (this commit
only checks up the context chain of the caller). However, I couldn't
think of a testcase that didn't require first referencing the
unavailable type; this, we already diagnose.
rdar://problem/25030656
llvm-svn: 262921
exactly the same as clang's existing [[clang::fallthrough]] attribute, which
has been updated to have the same semantics. The one significant difference
is that [[fallthrough]] is ill-formed if it's not used immediately before a
switch label (even when -Wimplicit-fallthrough is disabled). To support that,
we now build a CFG of any function that uses a '[[fallthrough]];' statement
to check.
In passing, fix some bugs with our support for statement attributes -- in
particular, diagnose their use on declarations, rather than asserting.
llvm-svn: 262881
Previously, the failed capture of a variable in nested lambdas may crash when
the lambda pointer is null. Only give the note if a location can be retreived
from the lambda pointer.
llvm-svn: 262765
with a prior UsingDecl -- those should not even really be found by the lookup
here, except that we use the same lookup results for two different checks, and
the other check needs them.
This happens to work in *almost all* cases, because either the lookup results
list the UsingDecl first (and the NonTag result gets replaced by something
else) or because the problematic declaration is a function (which causes us to
use different logic to detect conflicts). This can also be triggered from a
state only reachable through modules (where the name lookup results can contain
multiple UsingDecls in the same scope).
llvm-svn: 262105
If the availability context is `FunctionTemplateDecl`, we should look
through it to the `FunctionDecl`. This prevents a diagnostic in the
following case:
class C __attribute__((unavailable));
template <class T> void foo(C&) __attribute__((unavailable));
This adds tests for availability in templates in many other cases, but
that was the only case that failed before this patch.
I added a feature `__has_feature(attribute_availability_in_templates)`
so users can test for this.
rdar://problem/24561029
llvm-svn: 262050
A member expression's base doesn't always have an impact on what the
member decl would evaluate to. In such a case, the base is used as a
poor man's scope qualifier.
This fixes PR26738.
Differential Revision: http://reviews.llvm.org/D17619
llvm-svn: 261975
r261297 called hasUserProvidedDefaultConstructor() to check if defining a
const object is ok. This is incorrect for this example:
struct X { template<typename ...T> X(T...); int n; };
const X x; // formerly OK, now bogus error
Instead, track if a class has a defaulted default constructor, and disallow
a const object for classes that either have defaulted default constructors or
if they need an implicit constructor.
Bug report and fix approach by Richard Smith, thanks!
llvm-svn: 261770
C++11 requires const objects to have a user-provided constructor, even for
classes without any fields. DR 253 relaxes this to say "If the implicit default
constructor initializes all subobjects, no initializer should be required."
clang is currently the only compiler that implements this C++11 rule, and e.g.
libstdc++ relies on something like DR 253 to compile in newer versions. This
change makes it possible to build code that says `const vector<int> v;' again
when using libstdc++5.2 and _GLIBCXX_DEBUG
(https://gcc.gnu.org/bugzilla/show_bug.cgi?id=60284).
Fixes PR23381.
http://reviews.llvm.org/D16552
llvm-svn: 261297
Fixes crash referenced in PR25181 where dyn_cast is called on a null
instance of LM.Method.
Reviewers: majnemer, rnk
Patch by Don Hinton
Differential Revision: http://reviews.llvm.org/D17072
llvm-svn: 261292
-Wcomma will detect and warn on most uses of the builtin comma operator. It
currently whitelists the first and third statements of the for-loop. For other
cases, the warning can be silenced by casting the first operand of the comma
operator to void.
Differential Revision: http://reviews.llvm.org/D3976
llvm-svn: 261278
Previously we would leave behind the old name specifier prefix, which
creates an invalid AST. Other callers of CorrectTypo update their
CXXScopeSpec objects with the correction specifier if one is present.
llvm-svn: 260993
In my previous commit (rL260881) I forget to svn add tests. This commit adds
them.
Differential Revision: http://reviews.llvm.org/D16846
llvm-svn: 260882
In the case that the array indexing itself is within a type dependent context,
bail out of the evaluation. We would previously try to symbolically evaluate
the expression which would then try to evaluate a non-address expression as an
address, triggering an assertion in Asserts builds.
We only need to consider the array subscript expression itself as in the case
that the base itself being type dependent is handled appropriately in EvalAddr.
Resolves PR26599.
llvm-svn: 260867
When a null constant is used in a macro, walk through the macro stack to
determine where the null constant is written and where the context is located.
Only warn if both locations are within the same macro expansion. This helps
function-like macros which involve pointers be treated as if they were
functions.
llvm-svn: 260776
Fix a crash while parsing this code:
struct X {
friend constexpr int foo(X*) { return 12; }
static constexpr int j = foo(static_cast<X*>(nullptr));
};
Differential Revision: http://reviews.llvm.org/D16973
llvm-svn: 260675
If the typo happens after a successful deduction for an earlier
return statement, we should check if the deduced type is null
before using it.
The typo correction happens after we try to deduce the return
type and we ignore the deduction from the typo and continue
to typo correction.
rdar://24342247
llvm-svn: 259820
When performing a cast from an __unknown_anytype function call to a
non-void type, we need to make sure that type is complete. Fixes
rdar://problem/23959960.
llvm-svn: 259681
C++14 generic lambdas. It conflicts with the C++14 return type deduction
mechanism, and results in us failing to actually deduce the lambda's return
type in some cases.
llvm-svn: 259609
Faisal Vali