Revert "Reapply "[Clang][Sema] Always use latest redeclaration of primary template" (#114569)" (#115156)

This reverts commit b24650e814e55d90acfc40acf045456c98f32b9c.

Reapply "[Clang][Sema] Always use latest redeclaration of primary template" (#114569)

This patch reapplies #114258, fixing an infinite recursion bug in
`ASTImporter` that occurs when importing the

Reapply "[Clang][Sema] Always use latest redeclaration of primary template" (#114569)

This patch reapplies #114258, fixing an infinite recursion bug in
`ASTImporter` that occurs when importing the primary template of a class
template specialization when the latest redeclaration of that template
is a friend declaration in the primary template.

show more ...

Revert "[Clang][Sema] Always use latest redeclaration of primary template" (#114304)

Clang importer doesn't seem to work well with this change, see
discussion in the original PR.

Reverts llvm/ll

Revert "[Clang][Sema] Always use latest redeclaration of primary template" (#114304)

Clang importer doesn't seem to work well with this change, see
discussion in the original PR.

Reverts llvm/llvm-project#114258

show more ...

[Clang][Sema] Always use latest redeclaration of primary template (#114258)

This patch fixes a couple of regressions introduced in #111852.

Consider:

```
template<typename T>
struct A
{

[Clang][Sema] Always use latest redeclaration of primary template (#114258)

This patch fixes a couple of regressions introduced in #111852.

Consider:

```
template<typename T>
struct A
{
template<bool U>
static constexpr bool f() requires U
{
return true;
}
};

template<>
template<bool U>
constexpr bool A<short>::f() requires U
{
return A<long>::f<U>();
}

template<>
template<bool U>
constexpr bool A<long>::f() requires U
{
return true;
}

static_assert(A<short>::f<true>()); // crash here
```

This crashes because when collecting template arguments from the _first_
declaration of `A<long>::f<true>` for constraint checking, we don't add
the template arguments from the enclosing class template specialization
because there exists another redeclaration that is a member
specialization.

This also fixes the following example, which happens for a similar
reason:
```
// input.cppm

export module input;

export template<int N>
constexpr int f();

template<int N>
struct A {
template<int J>
friend constexpr int f();
};

template struct A<0>;

template<int N>
constexpr int f() {
return N;
}
```

```
// input.cpp

import input;

static_assert(f<1>() == 1); // error: static assertion failed
```

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[clang] Preserve Qualifiers and type sugar in TemplateNames (#93433)

This patch improves the preservation of qualifiers and loss of type
sugar in TemplateNames.

This problem is analogous to https:/

[clang] Preserve Qualifiers and type sugar in TemplateNames (#93433)

This patch improves the preservation of qualifiers and loss of type
sugar in TemplateNames.

This problem is analogous to https://reviews.llvm.org/D112374 and this
patch takes a very similar approach to that patch, except the impact
here is much lesser.

When a TemplateName was written bare, without qualifications, we
wouldn't produce a QualifiedTemplate which could be used to disambiguate
it from a Canonical TemplateName. This had effects in the TemplateName
printer, which had workarounds to deal with this, and wouldn't print the
TemplateName as-written in most situations.

There are also some related fixes to help preserve this type sugar along
the way into diagnostics, so that this patch can be properly tested.

- Fix dropping the template keyword.
- Fix type deduction to preserve sugar in TST TemplateNames.

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[clang] Improve ast-dumper text printing of TemplateArgument (#93431)

This improves and unifies our approach to printing all template
arguments.

The same approach to printing types is extended t

[clang] Improve ast-dumper text printing of TemplateArgument (#93431)

This improves and unifies our approach to printing all template
arguments.

The same approach to printing types is extended to all
TemplateArguments: A sugared version is printed in quotes, followed by
printing the canonical form, unless they would print the same.

Special improvements are done to add more detail to template template
arguments.

It's planned in a future patch to use this improved TemplateName printer
for other places besides TemplateArguments.

Note: The sugared/desugared printing does not show up for TemplateNames
in tests yet, because we do a poor job of preserving their type sugar.
This will be improved in a future patch.

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[clang] NFCI: use TemplateArgumentLoc for NTTP DefaultArgument (#92852)

This is an enabler for https://github.com/llvm/llvm-project/pull/92855

This allows an NTTP default argument to be set as an a

[clang] NFCI: use TemplateArgumentLoc for NTTP DefaultArgument (#92852)

This is an enabler for https://github.com/llvm/llvm-project/pull/92855

This allows an NTTP default argument to be set as an arbitrary
TemplateArgument, not just an expression.
This allows template parameter packs to have default arguments in the
AST, even though the language proper doesn't support the syntax for it.

This allows NTTP default arguments to be other kinds of arguments, like
packs, integral constants, and such.

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Reapply "[Clang] Unify interface for accessing template arguments as written for class/variable template specializations (#81642)" (#91393)

Reapplies #81642, fixing the crash which occurs when runni

Reapply "[Clang] Unify interface for accessing template arguments as written for class/variable template specializations (#81642)" (#91393)

Reapplies #81642, fixing the crash which occurs when running the lldb test suite.

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[AST] Only dump desugared type when visibly different (#65214)

These are an artifact of how types are structured but serve little
purpose, merely showing that the type is sugared in some way. For

[AST] Only dump desugared type when visibly different (#65214)

These are an artifact of how types are structured but serve little
purpose, merely showing that the type is sugared in some way. For
example, ElaboratedType's existence means struct S gets printed as
'struct S':'struct S' in the AST, which is unnecessary visual clutter.
Note that skipping the second print when the types have the same string
matches what we do for diagnostics, where the aka will be skipped.

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[clang] remove ClassScopeFunctionSpecializationDecl (#66636)

This removes the `ClassScopeFunctionSpecializationDecl` `Decl` node, and
instead uses `DependentFunctionTemplateSpecializationInfo` to h

[clang] remove ClassScopeFunctionSpecializationDecl (#66636)

This removes the `ClassScopeFunctionSpecializationDecl` `Decl` node, and
instead uses `DependentFunctionTemplateSpecializationInfo` to handle
such declarations. `DependentFunctionTemplateSpecializationInfo` is also
changed to store a `const ASTTemplateArgumentListInfo*` to be more in
line with `FunctionTemplateSpecializationInfo`.

This also changes `FunctionDecl::isFunctionTemplateSpecialization` to
return `true` for dependent specializations, and
`FunctionDecl::getTemplateSpecializationKind`/`FunctionDecl::getTemplateSpecializationKindForInstantiation`
to return `TSK_ExplicitSpecialization` for non-friend dependent
specializations (the same behavior as dependent class scope
`ClassTemplateSepcializationDecl` & `VarTemplateSepcializationDecl`).

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[AST] Fix nested name specifiers printing as NamespaceNamespace (#65266)

This happens because we print both the kind of the NNS and the kind of
decl (when it refers to one). These are always the sam

[AST] Fix nested name specifiers printing as NamespaceNamespace (#65266)

This happens because we print both the kind of the NNS and the kind of
decl (when it refers to one). These are always the same string.

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[clang][AST] TextNodeDumper learned to output friend information for functions

Reviewed By: aaron.ballman

Differential Revision: https://reviews.llvm.org/D158188

[clang][AST] TextNodeDumper learned to output instantiated_from information

Reviewed By: aaron.ballman

Differential Revision: https://reviews.llvm.org/D158165

[clang][AST] TextNodeDumper learned to dump qualifiers (NestedNameSpecifier)

Reviewed By: aaron.ballman

Differential Revision: https://reviews.llvm.org/D157681

[clang][AST] TextNodeDumper learned to dump NRVO candidates of return stmts

Reviewed By: aaron.ballman

Differential Revision: https://reviews.llvm.org/D157687

[clang][AST] TextNodeDumper learned to output template specialization kind

Reviewed By: aaron.ballman

Differential Revision: https://reviews.llvm.org/D157705

[clang][AST] TextNodeDumper should not evaluate the initializer of constexpr variable declaration when it has a dependent type

`TextNodeDumper` enabed through `-ast-dump` flag should not evlauate th

[clang][AST] TextNodeDumper should not evaluate the initializer of constexpr variable declaration when it has a dependent type

`TextNodeDumper` enabed through `-ast-dump` flag should not evlauate the initializer when it visits a constexpr `VarDecl` node if it has a dependent type.

I found a crashing case fixed by this change and added it as a test case.
`template <typename T> constexpr T call_init(0);`
Link: https://godbolt.org/z/3bG9Pjj5E

This is a fix for the regression caused by D146358

Differential Revision: https://reviews.llvm.org/D151033

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[clang] Evaluate non-type default template argument when it is required

Before this change a default template argument for a non-type template
parameter was evaluated and checked immediately after i

[clang] Evaluate non-type default template argument when it is required

Before this change a default template argument for a non-type template
parameter was evaluated and checked immediately after it is met by
parser. In some cases it is too early.

Fixes https://github.com/llvm/llvm-project/issues/62224
Fixes https://github.com/llvm/llvm-project/issues/62596

Reviewed By: shafik, erichkeane, cor3ntin

Differential Revision: https://reviews.llvm.org/D150108

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[clang] Add ElaboratedType sugaring for types on implicit special members

Extend the change from commit 15f3cd6bfc67 ([clang] Implement
ElaboratedType sugaring for types written bare, 2021-10-11, D1

[clang] Add ElaboratedType sugaring for types on implicit special members

Extend the change from commit 15f3cd6bfc67 ([clang] Implement
ElaboratedType sugaring for types written bare, 2021-10-11, D112374)
to cover types in the signatures of implicit copy-constructor,
copy-assignment, move-constructor, and move-assignment members in
C++ record types.

With this fix, diagnostic messages print types of special members
consistently whether they are explicitly or implicitly defined.

Fixes: https://github.com/llvm/llvm-project/issues/59557

Reviewed By: rsmith

Differential Revision: https://reviews.llvm.org/D141441

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[AST] include decls owned by FriendDecl in -ast-dump

Differential Revision: https://reviews.llvm.org/D141362

[clang] Add [is|set]Nested methods to NamespaceDecl

Adds support for NamespaceDecl to inform if its part of a nested namespace.
This flag only corresponds to the inner namespaces in a nested namespa

[clang] Add [is|set]Nested methods to NamespaceDecl

Adds support for NamespaceDecl to inform if its part of a nested namespace.
This flag only corresponds to the inner namespaces in a nested namespace declaration.
In this example:
namespace <X>::<Y>::<Z> {}
Only <Y> and <Z> will be classified as nested.

This flag isn't meant for assisting in building the AST, more for static analysis and refactorings.

Reviewed By: aaron.ballman

Differential Revision: https://reviews.llvm.org/D90568

show more ...

[clang] Implement ElaboratedType sugaring for types written bare

Without this patch, clang will not wrap in an ElaboratedType node types written
without a keyword and nested name qualifier, which go

[clang] Implement ElaboratedType sugaring for types written bare

Without this patch, clang will not wrap in an ElaboratedType node types written
without a keyword and nested name qualifier, which goes against the intent that
we should produce an AST which retains enough details to recover how things are
written.

The lack of this sugar is incompatible with the intent of the type printer
default policy, which is to print types as written, but to fall back and print
them fully qualified when they are desugared.

An ElaboratedTypeLoc without keyword / NNS uses no storage by itself, but still
requires pointer alignment due to pre-existing bug in the TypeLoc buffer
handling.

---

Troubleshooting list to deal with any breakage seen with this patch:

1) The most likely effect one would see by this patch is a change in how
a type is printed. The type printer will, by design and default,
print types as written. There are customization options there, but
not that many, and they mainly apply to how to print a type that we
somehow failed to track how it was written. This patch fixes a
problem where we failed to distinguish between a type
that was written without any elaborated-type qualifiers,
such as a 'struct'/'class' tags and name spacifiers such as 'std::',
and one that has been stripped of any 'metadata' that identifies such,
the so called canonical types.
Example:
```
namespace foo {
struct A {};
A a;
};
```
If one were to print the type of `foo::a`, prior to this patch, this
would result in `foo::A`. This is how the type printer would have,
by default, printed the canonical type of A as well.
As soon as you add any name qualifiers to A, the type printer would
suddenly start accurately printing the type as written. This patch
will make it print it accurately even when written without
qualifiers, so we will just print `A` for the initial example, as
the user did not really write that `foo::` namespace qualifier.

2) This patch could expose a bug in some AST matcher. Matching types
is harder to get right when there is sugar involved. For example,
if you want to match a type against being a pointer to some type A,
then you have to account for getting a type that is sugar for a
pointer to A, or being a pointer to sugar to A, or both! Usually
you would get the second part wrong, and this would work for a
very simple test where you don't use any name qualifiers, but
you would discover is broken when you do. The usual fix is to
either use the matcher which strips sugar, which is annoying
to use as for example if you match an N level pointer, you have
to put N+1 such matchers in there, beginning to end and between
all those levels. But in a lot of cases, if the property you want
to match is present in the canonical type, it's easier and faster
to just match on that... This goes with what is said in 1), if
you want to match against the name of a type, and you want
the name string to be something stable, perhaps matching on
the name of the canonical type is the better choice.

3) This patch could expose a bug in how you get the source range of some
TypeLoc. For some reason, a lot of code is using getLocalSourceRange(),
which only looks at the given TypeLoc node. This patch introduces a new,
and more common TypeLoc node which contains no source locations on itself.
This is not an inovation here, and some other, more rare TypeLoc nodes could
also have this property, but if you use getLocalSourceRange on them, it's not
going to return any valid locations, because it doesn't have any. The right fix
here is to always use getSourceRange() or getBeginLoc/getEndLoc which will dive
into the inner TypeLoc to get the source range if it doesn't find it on the
top level one. You can use getLocalSourceRange if you are really into
micro-optimizations and you have some outside knowledge that the TypeLocs you are
dealing with will always include some source location.

4) Exposed a bug somewhere in the use of the normal clang type class API, where you
have some type, you want to see if that type is some particular kind, you try a
`dyn_cast` such as `dyn_cast<TypedefType>` and that fails because now you have an
ElaboratedType which has a TypeDefType inside of it, which is what you wanted to match.
Again, like 2), this would usually have been tested poorly with some simple tests with
no qualifications, and would have been broken had there been any other kind of type sugar,
be it an ElaboratedType or a TemplateSpecializationType or a SubstTemplateParmType.
The usual fix here is to use `getAs` instead of `dyn_cast`, which will look deeper
into the type. Or use `getAsAdjusted` when dealing with TypeLocs.
For some reason the API is inconsistent there and on TypeLocs getAs behaves like a dyn_cast.

5) It could be a bug in this patch perhaps.

Let me know if you need any help!

Signed-off-by: Matheus Izvekov <mizvekov@gmail.com>

Differential Revision: https://reviews.llvm.org/D112374

show more ...

Revert "[clang] Implement ElaboratedType sugaring for types written bare"

This reverts commit 7c51f02effdbd0d5e12bfd26f9c3b2ab5687c93f because it
stills breaks the LLDB tests. This was re-landed wi

Revert "[clang] Implement ElaboratedType sugaring for types written bare"

This reverts commit 7c51f02effdbd0d5e12bfd26f9c3b2ab5687c93f because it
stills breaks the LLDB tests. This was re-landed without addressing the
issue or even agreement on how to address the issue. More details and
discussion in https://reviews.llvm.org/D112374.

show more ...

[clang] Implement ElaboratedType sugaring for types written bare

Without this patch, clang will not wrap in an ElaboratedType node types written
without a keyword and nested name qualifier, which go

[clang] Implement ElaboratedType sugaring for types written bare

Without this patch, clang will not wrap in an ElaboratedType node types written
without a keyword and nested name qualifier, which goes against the intent that
we should produce an AST which retains enough details to recover how things are
written.

The lack of this sugar is incompatible with the intent of the type printer
default policy, which is to print types as written, but to fall back and print
them fully qualified when they are desugared.

An ElaboratedTypeLoc without keyword / NNS uses no storage by itself, but still
requires pointer alignment due to pre-existing bug in the TypeLoc buffer
handling.

---

Troubleshooting list to deal with any breakage seen with this patch:

1) The most likely effect one would see by this patch is a change in how
a type is printed. The type printer will, by design and default,
print types as written. There are customization options there, but
not that many, and they mainly apply to how to print a type that we
somehow failed to track how it was written. This patch fixes a
problem where we failed to distinguish between a type
that was written without any elaborated-type qualifiers,
such as a 'struct'/'class' tags and name spacifiers such as 'std::',
and one that has been stripped of any 'metadata' that identifies such,
the so called canonical types.
Example:
```
namespace foo {
struct A {};
A a;
};
```
If one were to print the type of `foo::a`, prior to this patch, this
would result in `foo::A`. This is how the type printer would have,
by default, printed the canonical type of A as well.
As soon as you add any name qualifiers to A, the type printer would
suddenly start accurately printing the type as written. This patch
will make it print it accurately even when written without
qualifiers, so we will just print `A` for the initial example, as
the user did not really write that `foo::` namespace qualifier.

2) This patch could expose a bug in some AST matcher. Matching types
is harder to get right when there is sugar involved. For example,
if you want to match a type against being a pointer to some type A,
then you have to account for getting a type that is sugar for a
pointer to A, or being a pointer to sugar to A, or both! Usually
you would get the second part wrong, and this would work for a
very simple test where you don't use any name qualifiers, but
you would discover is broken when you do. The usual fix is to
either use the matcher which strips sugar, which is annoying
to use as for example if you match an N level pointer, you have
to put N+1 such matchers in there, beginning to end and between
all those levels. But in a lot of cases, if the property you want
to match is present in the canonical type, it's easier and faster
to just match on that... This goes with what is said in 1), if
you want to match against the name of a type, and you want
the name string to be something stable, perhaps matching on
the name of the canonical type is the better choice.

3) This patch could exposed a bug in how you get the source range of some
TypeLoc. For some reason, a lot of code is using getLocalSourceRange(),
which only looks at the given TypeLoc node. This patch introduces a new,
and more common TypeLoc node which contains no source locations on itself.
This is not an inovation here, and some other, more rare TypeLoc nodes could
also have this property, but if you use getLocalSourceRange on them, it's not
going to return any valid locations, because it doesn't have any. The right fix
here is to always use getSourceRange() or getBeginLoc/getEndLoc which will dive
into the inner TypeLoc to get the source range if it doesn't find it on the
top level one. You can use getLocalSourceRange if you are really into
micro-optimizations and you have some outside knowledge that the TypeLocs you are
dealing with will always include some source location.

4) Exposed a bug somewhere in the use of the normal clang type class API, where you
have some type, you want to see if that type is some particular kind, you try a
`dyn_cast` such as `dyn_cast<TypedefType>` and that fails because now you have an
ElaboratedType which has a TypeDefType inside of it, which is what you wanted to match.
Again, like 2), this would usually have been tested poorly with some simple tests with
no qualifications, and would have been broken had there been any other kind of type sugar,
be it an ElaboratedType or a TemplateSpecializationType or a SubstTemplateParmType.
The usual fix here is to use `getAs` instead of `dyn_cast`, which will look deeper
into the type. Or use `getAsAdjusted` when dealing with TypeLocs.
For some reason the API is inconsistent there and on TypeLocs getAs behaves like a dyn_cast.

5) It could be a bug in this patch perhaps.

Let me know if you need any help!

Signed-off-by: Matheus Izvekov <mizvekov@gmail.com>

Differential Revision: https://reviews.llvm.org/D112374

show more ...

Revert "[clang] Implement ElaboratedType sugaring for types written bare"

This reverts commit bdc6974f92304f4ed542241b9b89ba58ba6b20aa because it
breaks all the LLDB tests that import the std module

Revert "[clang] Implement ElaboratedType sugaring for types written bare"

This reverts commit bdc6974f92304f4ed542241b9b89ba58ba6b20aa because it
breaks all the LLDB tests that import the std module.

import-std-module/array.TestArrayFromStdModule.py
import-std-module/deque-basic.TestDequeFromStdModule.py
import-std-module/deque-dbg-info-content.TestDbgInfoContentDequeFromStdModule.py
import-std-module/forward_list.TestForwardListFromStdModule.py
import-std-module/forward_list-dbg-info-content.TestDbgInfoContentForwardListFromStdModule.py
import-std-module/list.TestListFromStdModule.py
import-std-module/list-dbg-info-content.TestDbgInfoContentListFromStdModule.py
import-std-module/queue.TestQueueFromStdModule.py
import-std-module/stack.TestStackFromStdModule.py
import-std-module/vector.TestVectorFromStdModule.py
import-std-module/vector-bool.TestVectorBoolFromStdModule.py
import-std-module/vector-dbg-info-content.TestDbgInfoContentVectorFromStdModule.py
import-std-module/vector-of-vectors.TestVectorOfVectorsFromStdModule.py

https://green.lab.llvm.org/green/view/LLDB/job/lldb-cmake/45301/

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