Fixes PR35682. When a template in instantiated with an incomplete typo corrected type an assertion can trigger if the -ferror-limit is used to reduce the number of errors.
Patch by Mark de Wever.
llvm-svn: 371320
containing designators. The C++20 wording doesn't actually say what
happens in this case, but treating this as a non-deduced context seems
like the most natural behavior.
(We might want to consider deducing through array designators as an
extension in the future, but will need to be careful to deduce the array
bound properly if we do so. That's not permitted herein.)
llvm-svn: 370555
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
Summary:
Clang performs various recursive operations (such as template instantiation),
and may use non-trivial amounts of stack space in each recursive step (for
instance, due to recursive AST walks). While we try to keep the stack space
used by such steps to a minimum and we have explicit limits on the number of
such steps we perform, it's impractical to guarantee that we won't blow out the
stack on deeply recursive template instantiations on complex ASTs, even with
only a moderately high instantiation depth limit.
The user experience in these cases is generally terrible: we crash with
no hint of what went wrong. Under this patch, we attempt to do better:
* Detect when the stack is nearly exhausted, and produce a warning with a
nice template instantiation backtrace, telling the user that we might
run slowly or crash.
* For cases where we're forced to trigger recursive template
instantiation in arbitrarily-deeply-nested contexts, check whether
we're nearly out of stack space and allocate a new stack (by spawning
a new thread) after producing the warning.
Reviewers: rnk, aaron.ballman
Subscribers: mgorny, cfe-commits
Tags: #clang
Differential Revision: https://reviews.llvm.org/D66361
llvm-svn: 369940
default template argument expression.
We already did this for type template parameters and template template
parameters, but apparently forgot to do so for non-type template
parameters. This causes the substituted default argument expression to
be substituted in the proper context, and in particular to properly mark
its subexpressions as odr-used.
llvm-svn: 369834
Clang currently crashes for switch statements inside a template when
the condition is a non-integer field. The crash is due to incorrect
type-dependency of field. Type-dependency of member expressions is
currently set based on the containing class. This patch changes this for
'members of the current instantiation' to set the type dependency based
on the member's type instead.
A few lit tests started to fail once I applied this patch because errors
are now diagnosed earlier (does not wait till instantiation). I've modified
these tests in this patch as well.
Patch fixes PR#40982
Differential Revision: https://reviews.llvm.org/D61027
llvm-svn: 368706
As discussed in D64780 the wording of this warning message is being
changed to say 'is not supported' instead of 'ignored', and the
diag ID itself is being changed to warn_cconv_not_supported.
llvm-svn: 366368
Summary:
This case is particularly important for clangd, as it is triggered after
inserting the snippet for variadic functions.
Reviewers: kadircet, ilya-biryukov
Subscribers: llvm-commits
Tags: #llvm
Differential Revision: https://reviews.llvm.org/D64677
llvm-svn: 366200
type-dependent argument packs.
We need to strip off the PackExpansionExpr to get the real (dependent)
type rather than an opaque DependentTy.
llvm-svn: 364165
template argument contains a backreference to a dependently-typed
earlier parameter.
In a case like:
template<typename T, T A, decltype(A) = A> struct X {};
template<typename U> auto Y = X<U, 0>();
we previously treated both references to `A` in the third parameter as
being of type `int` when checking the template-id in `Y`. That`s wrong;
the type of `A` in these contexts is the dependent type `U`.
When we encounter a non-type template argument that we can't convert to
the parameter type because of type-dependence, we now insert a dependent
conversion node so that the SubstNonTypeTemplateParmExpr for the
template argument will have the parameter's type rather than whatever
type the argument had.
llvm-svn: 363972
packs.
Two changes:
* Track odr-use via FunctionParmPackExprs to properly handle dependent
odr-uses of packs in generic lambdas.
* Do not instantiate implicit captures; instead, regenerate them by
instantiating the body of the lambda. This is necessary to
distinguish between cases where only one element of a pack is
captured and cases where the entire pack is captured.
This reinstates r362358 (reverted in r362375) with a fix for an
uninitialized variable use in UpdateMarkingForLValueToRValue.
llvm-svn: 362531
Two changes:
* Track odr-use via FunctionParmPackExprs to properly handle dependent
odr-uses of packs in generic lambdas.
* Do not instantiate implicit captures; instead, regenerate them by
instantiating the body of the lambda. This is necessary to
distinguish between cases where only one element of a pack is
captured and cases where the entire pack is captured.
........
Fixes http://lab.llvm.org:8011/builders/llvm-clang-x86_64-expensive-checks-win buildbot failures
llvm-svn: 362375
packs.
Two changes:
* Track odr-use via FunctionParmPackExprs to properly handle dependent
odr-uses of packs in generic lambdas.
* Do not instantiate implicit captures; instead, regenerate them by
instantiating the body of the lambda. This is necessary to
distinguish between cases where only one element of a pack is
captured and cases where the entire pack is captured.
llvm-svn: 362358
This permits an init-capture to introduce a new pack:
template<typename ...T> auto x = [...a = T()] { /* a is a pack */ };
To support this, the mechanism for allowing ParmVarDecls to be packs has
been extended to support arbitrary local VarDecls.
llvm-svn: 361300
(and less wrong).
It's not correct to assume that X<something, Type> is always a
template-id; there are a few cases where the comma takes us into a
non-expression syntactic context in which 'Type' might be permissible.
Stop doing that.
This slightly regresses our error recovery on the cases where the
construct is intended to be a template-id. We typically do still manage
to diagnose a missing 'template' keyword, but we realize this too late
to properly recover from the error.
This fixes a regression introduced by r360308.
llvm-svn: 360827
template name is not visible to unqualified lookup.
In order to support this without a severe degradation in our ability to
diagnose typos in template names, this change significantly restructures
the way we handle template-id-shaped syntax for which lookup of the
template name finds nothing.
Instead of eagerly diagnosing an undeclared template name, we now form a
placeholder template-name representing a name that is known to not find
any templates. When the parser sees such a name, it attempts to
disambiguate whether we have a less-than comparison or a template-id.
Any diagnostics or typo-correction for the name are delayed until its
point of use.
The upshot should be a small improvement of our diagostic quality
overall: we now take more syntactic context into account when trying to
resolve an undeclared identifier on the left hand side of a '<'. In
fact, this works well enough that the backwards-compatible portion (for
an undeclared identifier rather than a lookup that finds functions but
no function templates) is enabled in all language modes.
llvm-svn: 360308
After https://reviews.llvm.org/rL355317 we noticed that quite a decent
amount of code redeclares builtins (memcpy in particular, I believe
reduced from an MSVC header) with a calling convention specified.
This gets particularly troublesome when the user specifies a new
'default' calling convention on the command line.
When looking to add a diagnostic for this case, it was noticed that we
had 3 other diagnostics that differed only slightly. This patch ALSO
unifies those under a 'select'. Unfortunately, the order of words in
ONE of these diagnostics was reversed ("'thiscall' calling convention"
vs "calling convention 'thiscall'"), so this patch also standardizes on
the former.
Differential Revision: https://reviews.llvm.org/D59560
Change-Id: I79f99fe7c2301640755ffdd774b46eb44526bb22
llvm-svn: 356663
Before this commit, we emit unavailable errors for calls to functions during
overload resolution, and for references to all other declarations in
DiagnoseUseOfDecl. The early checks during overload resolution aren't as good as
the DiagnoseAvailabilityOfDecl based checks, as they error on the code from
PR40991. This commit fixes this by removing the early checking.
llvm.org/PR40991
rdar://48564179
Differential revision: https://reviews.llvm.org/D59394
llvm-svn: 356599
When a template-name is looked up, we need to give injected-class-name
declarations of class templates special treatment, as they denote a
template rather than a type.
Previously we achieved this by applying a filter to the lookup results
after completing name lookup, but that is incorrect in various ways, not
least of which is that it lost all information about access and how
members were named, and the filtering caused us to generally lose
all ambiguity errors between templates and non-templates.
We now preserve the lookup results exactly, and the few places that need
to map from a declaration found by name lookup into a declaration of a
template do so explicitly. Deduplication of repeated lookup results of
the same injected-class-name declaration is done by name lookup instead
of after the fact.
This reinstates r354091, which was previously reverted in r354097
because it exposed bugs in lldb and compiler-rt. Those bugs were fixed
in r354173 and r354174 respectively.
llvm-svn: 354176
When a template-name is looked up, we need to give injected-class-name
declarations of class templates special treatment, as they denote a
template rather than a type.
Previously we achieved this by applying a filter to the lookup results
after completing name lookup, but that is incorrect in various ways, not
least of which is that it lost all information about access and how
members were named, and the filtering caused us to generally lose
all ambiguity errors between templates and non-templates.
We now preserve the lookup results exactly, and the few places that need
to map from a declaration found by name lookup into a declaration of a
template do so explicitly. Deduplication of repeated lookup results of
the same injected-class-name declaration is done by name lookup instead
of after the fact.
llvm-svn: 354091
When Clang/LLVM is built with the CLANG_DEFAULT_STD_CXX CMake macro that sets
the default standard to something other than C++14, there are a number of lit
tests that fail as they rely on the C++14 default.
This patch just adds the language standard option explicitly to such test cases.
Differential revision: https://reviews.llvm.org/D57581
llvm-svn: 353163
function declaration.
We'd previously often just drop these on the floor, and friend
redeclaration matching would usually (but not always) figure out the
right redeclaration anyway.
Also, don't try to match a dependent friend function template
specialization to a template until instantiation, and don't forget to
reject qualified friend declarations in dependent contexts that don't
name an already-declared entity.
llvm-svn: 350915
render the function deleted instead of rendering the program ill-formed.
This change also adds an enabled-by-default warning for the case where
an explicitly-defaulted special member function of a non-template class
is implicitly deleted by the type checking rules. (This fires either due
to this language change or due to pre-C++20 reasons for the member being
implicitly deleted). I've tested this on a large codebase and found only
bugs (where the program means something that's clearly different from
what the programmer intended), so this is enabled by default, but we
should revisit this if there are problems with this being enabled by
default.
llvm-svn: 343285
destructors.
We previously tried to patch up the exception specification after
completing the class, which went wrong when the exception specification
was needed within the class body (in particular, by a friend
redeclaration of the destructor in a nested class). We now mark the
destructor as having a not-yet-computed exception specification
immediately after creating it.
This requires delaying various checks against the exception
specification (where we'd previously have just got the wrong exception
specification, and now find we have an exception specification that we
can't compute yet) when those checks fire while the class is being
defined.
This also exposed an issue that we were missing a CodeSynthesisContext
for computation of exception specifications (otherwise we'd fail to make
the module containing the definition of the class visible when computing
its members' exception specs). Adding that incidentally also gives us a
diagnostic quality improvement.
This has also exposed an pre-existing problem: making the exception
specification evaluation context a non-SFINAE context (as it should be)
results in a bootstrap failure; PR38850 filed for this.
llvm-svn: 341499
Changes the default Windows target triple returned by
GetHostTriple.cmake from the old environment names (which we wanted to
move away from) to newer, normalized ones. This also requires updating
all tests to use the new systems names in constraints.
Differential Revision: https://reviews.llvm.org/D47381
llvm-svn: 339307
The dependent auto was getting stripped away while rebuilding the template
parameter type, so substitute it in.
rdar://41852459
Differential revision: https://reviews.llvm.org/D50088
llvm-svn: 339198
Recommit of r335084 after revert in r335516.
... instead of prepending it at the beginning (the original behavior
since implemented in r122535 2010-12-23). This builds up an
AttributeList in the the order in which the attributes appear in the
source.
The reverse order caused nodes for attributes in the AST (e.g. LoopHint)
to be in the reverse order, and therefore printed in the wrong order in
-ast-dump. Some TODO comments mention this. The order was explicitly
reversed for enable_if attribute overload resolution and name mangling,
which is not necessary anymore with this patch.
The change unfortunately has some secondary effect, especially on
diagnostic output. In the simplest cases, the CHECK lines or expected
diagnostic were changed to the the new output. If the kind of
error/warning changed, the attributes' order was changed instead.
This unfortunately causes some 'previous occurrence here' hints to be
textually after the main marker. This typically happens when attributes
are merged, but are incompatible to each other. Interchanging the role
of the the main and note SourceLocation will also cause the case where
two different declaration's attributes (in contrast to multiple
attributes of the same declaration) are merged to be reverse. There is
no easy fix because sometimes previous attributes are merged into a new
declaration's attribute list, sometimes new attributes are added to a
previous declaration's attribute list. Since 'previous occurrence here'
pointing to locations after the main marker is not rare, I left the
markers as-is; it is only relevant when the attributes are declared in
the same declaration anyway.
Differential Revision: https://reviews.llvm.org/D48100
llvm-svn: 338800
provided by an outer template.
We made the incorrect assumption in various places that the only way we
can have any arguments already provided for a pack during template
argument deduction was from a partially-specified pack. That's not true;
we can also have arguments from an enclosing already-instantiated
template, and that can even result in the function template's own pack
parameters having a fixed length and not being packs for the purposes of
template argument deduction.
llvm-svn: 337481
binary operator.
Factor out the checking for a comma within potential angle brackets and
also call it from contexts where we parse a comma-separated list of
arguments or initializers.
llvm-svn: 335699
We track when we see a name-shaped expression followed by a '<' token
and parse the '<' as a comparison. Then:
* if we see a token sequence that cannot possibly be an expression but
can be a template argument (in particular, a type-id) that follows
either a ',' or the '<', diagnose that the '<' was supposed to start
a template argument list, and
* if we see '>()', diagnose that the '<' was supposed to start a
template argument list.
This only changes the diagnostic for error cases, and in practice
appears to catch the most common cases where a missing 'template'
keyword leads to parse errors within a template.
Differential Revision: https://reviews.llvm.org/D48571
llvm-svn: 335687
Nicholas Allegra