Currently when clang fails to deduce auto return type of a function,
it does not emit any notes about why it fails. This causes difficulty
for users to fix such errors.
Actually, clang already generates the information for emitting notes
about the failed deduction. There is a TODO for actually emitting
them.
This patch tries to implement the TODO. Basically it passes the
failed template specialization candidate set from the point of
specialization failure back to the point where the deduction starts.
It is not comprehensive but would be a start for further improvement.
Reviewed by: Richard Smith, Matheus Izvekov
Differential Revision: https://reviews.llvm.org/D150212
Fixes: SWDEV-354278
DeduceTemplateArgumentsByTypeMatch() returns null value which is dereferenced without checking since getAsIncompleteArrayType() returns nullptr and we are dereferencing null pointer value for S.Context->getAsIncompleteArrayType(P) when calling getElementType().
This patch adds an assert.
Reviewed By: erichkeane
Differential Revision: https://reviews.llvm.org/D151529
This diff switches the approach to comparison of constraint expressions
to the new one based on template args substitution.
It continues the effort to fix our handling of out-of-line definitions
of constrained templates.
This is a recommit of 3a54022934.
Differential revision: https://reviews.llvm.org/D146178
Sema.h is huge. This makes a small reduction to it by moving
EnterExpressionEvaluationContext into a new header, since it is an
independent component.
Differential Revision: https://reviews.llvm.org/D149796
This diff switches the approach to comparison of constraint expressions
to the new one based on template args substitution.
It continues the effort to fix our handling of out-of-line definitions
of constrained templates.
This is a recommit of e3b1083e00.
Differential revision: https://reviews.llvm.org/D146178
This reverts commit e3b1083e00.
This was reverted because it breaks a number of libstdc++ examples, AND
required a workaround that causes hiding of legitimate bugs.
This diff switches the approach to comparison of constraint expressions
to the new one based on template args substitution.
It continues the effort to fix our handling of out-of-line definitions
of constrained templates.
This is a recommit of 60bee9ff54.
Differential revision: https://reviews.llvm.org/D146178
This is necessary in order for type equality checking, for example
across redeclarations, to require constraints to match. This is also a
prerequisite for including the constraints in manglings.
In passing, fix a bug where TemplateArgument::Profile would produce the
same profile for two structurally different template names, which caused
this change to re-expose the crash previously addressed by D133072,
which it turns out had not quite addressed all problematic cases.
GH58452 is a regression in the 16.0 release branch caused by both:
b8a1b698af and
3a0309c536
This patch reverts both of those to make the 'valid' code stop
diagnosing
at the expense of crashes on invalid + unclear diagnostics.
This patch also adds the tests from GH58452 to prevent any
re-application from breaking this again.
Revert "[clang] Improve diagnostics for expansion length mismatch"
This reverts commit 3a0309c536.
Revert "[clang] fix missing initialization of original number of expansions"
This reverts commit b8a1b698af.
Differential Revision: https://reviews.llvm.org/D145605
This reverts commit b8064374b2.
Based on the report here:
https://github.com/llvm/llvm-project/issues/59271
this produces a significant increase in memory use of the compiler and a
large compile-time regression. This patch reverts this so that we don't
branch for release with that issue.
This was done as a test for D137302 and it makes sense to push these changes
Reviewed By: shafik
Differential Revision: https://reviews.llvm.org/D137491
Per discussions in D128745, remove ClangABICompat checks for implementations
of DR692/DR1395/DR1432. This is a potentially breaking changes, so the release
note is updated accordingly.
Reviewed By: aaron.ballman
Differential Revision: https://reviews.llvm.org/D136120
This makes use of the changes introduced in D134604, in order to
instantiate non-type template parameters and default template arguments
with a final sugared substitution.
This comes at no additional relevant cost.
Since we don't track / unique them in specializations, we wouldn't be
able to resugar them later anyway.
Signed-off-by: Matheus Izvekov <mizvekov@gmail.com>
Differential Revision: https://reviews.llvm.org/D136564
This patch reverts
- commit d4b1964f05
- commit 59f0827e2cf3755834620e7e0b6d946832440f80([clang] Instantiate alias templates with sugar)
As it makes clang fail to pass some code it used to compile.
See comments: https://reviews.llvm.org/D136564#3891065
Since we don't unique specializations for concepts, we can just instantiate
them with the sugared template arguments, at negligible cost.
If we don't track their specializations, we can't resugar them later
anyway, and that would be more expensive than just instantiating them
sugared in the first place since it would require an additional pass.
Signed-off-by: Matheus Izvekov <mizvekov@gmail.com>
Differential Revision: https://reviews.llvm.org/D136566
This makes use of the changes introduced in D134604, in order to
instantiate non-type template parameters and default template arguments
with a final sugared substitution.
This comes at no additional relevant cost.
Since we don't track / unique them in specializations, we wouldn't be
able to resugar them later anyway.
Signed-off-by: Matheus Izvekov <mizvekov@gmail.com>
Differential Revision: https://reviews.llvm.org/D136564
Implements the changes required to perform substitution with
non-canonical template arguments, and to 'finalize' them
by not placing 'Subst' nodes.
A finalized substitution means we won't resugar them later,
because these templates themselves were eagerly substituted
with the intended arguments at the point of use. We may still
resugar other templates used within those, though.
This patch does not actually implement any uses of this
functionality, those will be added in subsequent patches,
so expect no changes to existing tests.
Signed-off-by: Matheus Izvekov <mizvekov@gmail.com>
Differential Revision: https://reviews.llvm.org/D134604
Makes CheckTemplateArgumentList and the template deduction functions
produce a sugared converted argument list in addition to the canonical one.
This is mostly NFC except that we hook this up to a few diagnostics in
SemaOverload.
The infrastructure here will be used in subsequent patches
where we perform a finalized sugared substitution for entities
which we do not unique per specializations on canonical arguments,
and later on will be used for template specialization resugaring.
Signed-off-by: Matheus Izvekov <mizvekov@gmail.com>
Differential Revision: https://reviews.llvm.org/D133874
Since we don't unique specializations for concepts, we can just instantiate
them with the sugared template arguments, at negligible cost.
If we don't track their specializations, we can't resugar them later
anyway, and that would be more expensive than just instantiating them
sugared in the first place since it would require an additional pass.
Signed-off-by: Matheus Izvekov <mizvekov@gmail.com>
Differential Revision: https://reviews.llvm.org/D136566
This makes use of the changes introduced in D134604, in order to
instantiate non-type template parameters and default template arguments
with a final sugared substitution.
This comes at no additional relevant cost.
Since we don't track / unique them in specializations, we wouldn't be
able to resugar them later anyway.
Signed-off-by: Matheus Izvekov <mizvekov@gmail.com>
Differential Revision: https://reviews.llvm.org/D136564
Implements the changes required to perform substitution with
non-canonical template arguments, and to 'finalize' them
by not placing 'Subst' nodes.
A finalized substitution means we won't resugar them later,
because these templates themselves were eagerly substituted
with the intended arguments at the point of use. We may still
resugar other templates used within those, though.
This patch does not actually implement any uses of this
functionality, those will be added in subsequent patches,
so expect no changes to existing tests.
Signed-off-by: Matheus Izvekov <mizvekov@gmail.com>
Differential Revision: https://reviews.llvm.org/D134604
Makes CheckTemplateArgumentList and the template deduction functions
produce a sugared converted argument list in addition to the canonical one.
This is mostly NFC except that we hook this up to a few diagnostics in
SemaOverload.
The infrastructure here will be used in subsequent patches
where we perform a finalized sugared substitution for entities
which we do not unique per specializations on canonical arguments,
and later on will be used for template specialization resugaring.
Signed-off-by: Matheus Izvekov <mizvekov@gmail.com>
Differential Revision: https://reviews.llvm.org/D133874
Removes a bunch of obsolete methods in favor of a single one returning
an ArrayRef of TemplateArgument.
Signed-off-by: Matheus Izvekov <mizvekov@gmail.com>
Differential Revision: https://reviews.llvm.org/D136602
This is a change to how we represent type subsitution in the AST.
Instead of only storing the replaced type, we track the templated
entity we are substituting, plus an index.
We modify MLTAL to track the templated entity at each level.
Otherwise, it's much more expensive to go from the template parameter back
to the templated entity, and not possible to do in some cases, as when
we instantiate outer templates, parameters might still reference the
original entity.
This also allows us to very cheaply lookup the templated entity we saw in
the naming context and find the corresponding argument it was replaced
from, such as for implementing template specialization resugaring.
Signed-off-by: Matheus Izvekov <mizvekov@gmail.com>
Differential Revision: https://reviews.llvm.org/D131858
D128745 handled DR1432 for the partial ordering of partial specializations, but
missed the handling for the partial ordering of function templates. This patch
implements the latter. While at it, also simplifies the previous implementation to
be more close to the wording without functional changes.
Fixes https://github.com/llvm/llvm-project/issues/56090
Reviewed By: erichkeane, #clang-language-wg, mizvekov
Differential Revision: https://reviews.llvm.org/D133683
As fallout of the Deferred Concept Instantiation patch (babdef27c5), we
got a number of reports of a regression, where we asserted when
instantiating a constraint on a generic lambda inside of a variable
template. See: https://github.com/llvm/llvm-project/issues/57958
The problem was that getTemplateInstantiationArgs function only walked
up declaration contexts, and missed that this is not necessarily the
case with a lambda (which can ALSO be in a separate context).
This patch refactors the getTemplateInstantiationArgs function in a way
that is hopefully more readable, and fixes the problem with the concepts
on a generic lambda.
Differential Revision: https://reviews.llvm.org/D134874
This implements WG14 N2927 and WG14 N2930, which together define the
feature for typeof and typeof_unqual, which get the type of their
argument as either fully qualified or fully unqualified. The argument
to either operator is either a type name or an expression. If given a
type name, the type information is pulled directly from the given name.
If given an expression, the type information is pulled from the
expression. Recursive use of these operators is allowed and has the
expected behavior (the innermost operator is resolved to a type, and
that's used to resolve the next layer of typeof specifier, until a
fully resolved type is determined.
Note, we already supported typeof in GNU mode as a non-conforming
extension and we are *not* exposing typeof_unqual as a non-conforming
extension in that mode, nor are we exposing typeof or typeof_unqual as
a nonconforming extension in other language modes. The GNU variant of
typeof supports a form where the parentheses are elided from the
operator when given an expression (e.g., typeof 0 i = 12;). When in C2x
mode, we do not support this extension.
Differential Revision: https://reviews.llvm.org/D134286
This reverts commit 95d94a6775.
This implements the deferred concepts instantiation, which should allow
the libstdc++ ranges to properly compile, and for the CRTP to work for
constrained functions.
Since the last attempt, this has fixed the issues from @wlei and
@mordante.
Differential Revision: https://reviews.llvm.org/D126907
We change the template specialization of builtin templates to
behave like aliases.
Though unlike real alias templates, these might still produce a canonical
TemplateSpecializationType when some important argument is dependent.
For example, we can't do anything about make_integer_seq when the
count is dependent, or a type_pack_element when the index is dependent.
We change type deduction to not try to deduce canonical TSTs of
builtin templates.
We also change those buitin templates to produce substitution sugar,
just like a real instantiation would, making the resulting type correctly
represent the template arguments used to specialize the underlying template.
And make_integer_seq will now produce a TST for the specialization
of it's first argument, which we use as the underlying type of
the builtin alias.
When performing member access on the resulting type, it's now
possible to map from a Subst* node to the template argument
as-written used in a regular fashion, without special casing.
And this fixes a bunch of bugs with relation to these builtin
templates factoring into deduction.
Fixes GH42102 and GH51928.
Depends on D133261
Signed-off-by: Matheus Izvekov <mizvekov@gmail.com>
Differential Revision: https://reviews.llvm.org/D133262
This continues D111283 by extending the getCommonSugaredType
implementation to also merge non-canonical type nodes.
We merge these nodes by going up starting from the canonical
node, calculating their merged properties on the way.
If we reach a pair that is too different, or which we could not
otherwise unify, we bail out and don't try to keep going on to
the next pair, in effect striping out all the remaining top-level
sugar nodes. This avoids mismatching 'companion' nodes, such as
ElaboratedType, so that they don't end up elaborating some other
unrelated thing.
Signed-off-by: Matheus Izvekov <mizvekov@gmail.com>
Differential Revision: https://reviews.llvm.org/D130308
After upgrading the type deduction machinery to retain type sugar in
D110216, we were left with a situation where there is no general
well behaved mechanism in Clang to unify the type sugar of multiple
deductions of the same type parameter.
So we ended up making an arbitrary choice: keep the sugar of the first
deduction, ignore subsequent ones.
In general, we already had this problem, but in a smaller scale.
The result of the conditional operator and many other binary ops
could benefit from such a mechanism.
This patch implements such a type sugar unification mechanism.
The basics:
This patch introduces a `getCommonSugaredType(QualType X, QualType Y)`
method to ASTContext which implements this functionality, and uses it
for unifying the results of type deduction and return type deduction.
This will return the most derived type sugar which occurs in both X and
Y.
Example:
Suppose we have these types:
```
using Animal = int;
using Cat = Animal;
using Dog = Animal;
using Tom = Cat;
using Spike = Dog;
using Tyke = Dog;
```
For `X = Tom, Y = Spike`, this will result in `Animal`.
For `X = Spike, Y = Tyke`, this will result in `Dog`.
How it works:
We take two types, X and Y, which we wish to unify as input.
These types must have the same (qualified or unqualified) canonical
type.
We dive down fast through top-level type sugar nodes, to the
underlying canonical node. If these canonical nodes differ, we
build a common one out of the two, unifying any sugar they had.
Note that this might involve a recursive call to unify any children
of those. We then return that canonical node, handling any qualifiers.
If they don't differ, we walk up the list of sugar type nodes we dived
through, finding the last identical pair, and returning that as the
result, again handling qualifiers.
Note that this patch will not unify sugar nodes if they are not
identical already. We will simply strip off top-level sugar nodes that
differ between X and Y. This sugar node unification will instead be
implemented in a subsequent patch.
This patch also implements a few users of this mechanism:
* Template argument deduction.
* Auto deduction, for functions returning auto / decltype(auto), with
special handling for initializer_list as well.
Further users will be implemented in a subsequent patch.
Signed-off-by: Matheus Izvekov <mizvekov@gmail.com>
Differential Revision: https://reviews.llvm.org/D111283
This reverts commit d200db3863, which causes a
clang crash. See https://reviews.llvm.org/D111283#3785755
Test case for convenience:
```
template <typename T>
using P = int T::*;
template <typename T, typename... A>
void j(P<T>, T, A...);
template <typename T>
void j(P<T>, T);
struct S {
int b;
};
void g(P<S> k, S s) { j(k, s); }
```
