[clang] require template arg list after template kw (#80801)

Require a template argument list after an identifier prefixed by the
template keyword. Introduced by [CWG
96](https://www.open-std.org/

[clang] require template arg list after template kw (#80801)

Require a template argument list after an identifier prefixed by the
template keyword. Introduced by [CWG
96](https://www.open-std.org/jtc1/sc22/wg21/docs/cwg_defects.html#96),
but the current wording of
[[temp.names]p5](https://eel.is/c++draft/temp.names#6) was introduced in
[P1787R6](https://www.open-std.org/jtc1/sc22/wg21/docs/papers/2020/p1787r6.html),
and became [temp.names]p6 somewhere else.

Fixes #53095

---------

Co-authored-by: Shafik Yaghmour <shafik.yaghmour@intel.com>

show more ...

[Clang][Sema] Diagnose current instantiation used as an incomplete base class (#92597)

Consider the following:
```
template<typename T>
struct A
{
struct B : A { };
};
```
According to [

[Clang][Sema] Diagnose current instantiation used as an incomplete base class (#92597)

Consider the following:
```
template<typename T>
struct A
{
struct B : A { };
};
```
According to [class.derived.general] p2:
> [...] A _class-or-decltype_ shall denote a (possibly cv-qualified)
class type that is not an incompletely defined class; any cv-qualifiers
are ignored. [...]

Although GCC and EDG rejects this, Clang accepts it. This is incorrect,
as `A` is incomplete within its own definition (outside of a
complete-class context). This patch correctly diagnoses instances where
the current instantiation is used as a base class before it is complete.

Conversely, Clang erroneously rejects the following:
```
template<typename T>
struct A
{
struct B;

struct C : B { };

struct B : C { }; // error: circular inheritance between 'C' and 'A::B'
};
```
Though it may seem like no valid specialization of this template can be
instantiated, an explicit specialization of either member classes for an
implicit instantiated specialization of `A` would permit the definition
of the other member class to be instantiated, e.g.:
```
template<>
struct A<int>::B { };

A<int>::C c; // ok
```
So this patch also does away with this error. This means that circular
inheritance is diagnosed during instantiation of the definition as a
consequence of requiring the base class type to be complete (matching
the behavior of GCC and EDG).

show more ...

[clang][TypePrinter] Teach isSubstitutedDefaultArgument about integral types

This patch handles default integral non-type template parameters.

After this patch the clang TypePrinter will omit defau

[clang][TypePrinter] Teach isSubstitutedDefaultArgument about integral types

This patch handles default integral non-type template parameters.

After this patch the clang TypePrinter will omit default integral
template arguments when the `PrintingPolicy::SuppressDefaultTemplateArgs`
option is specified and sets us up to be able to re-use
`clang::isSubstitutedDefaultArgument` from the DWARF CodeGen
component.

Differential Revision: https://reviews.llvm.org/D139986

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/

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.

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

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

show more ...

PR48339: Improve diagnostics for invalid dependent unqualified function calls.

Fix bogus diagnostics that would get confused and think a "no viable
fuctions" case was an "undeclared identifiers" cas

PR48339: Improve diagnostics for invalid dependent unqualified function calls.

Fix bogus diagnostics that would get confused and think a "no viable
fuctions" case was an "undeclared identifiers" case, resulting in an
incorrect diagnostic preceding the correct one. Use overload resolution
to determine which function we should select when we can find call
candidates from a dependent base class. Make the diagnostics for a call
that could call a function from a dependent base class more specific,
and use a different diagnostic message for the case where the call
target is instead declared later in the same class. Plus some minor
diagnostic wording improvements.

show more ...

[AST][RecoveryAST] Preserve the type by default for recovery expression.

Differential Revision: https://reviews.llvm.org/D82657

Reapply "Fix crash on switch conditions of non-integer types in templates"

This patch reapplies commit 759948467ea. Patch was reverted due to a
clang-tidy test fail on Windows. The test has been mod

Reapply "Fix crash on switch conditions of non-integer types in templates"

This patch reapplies commit 759948467ea. Patch was reverted due to a
clang-tidy test fail on Windows. The test has been modified. There
are no additional code changes.

Patch was tested with ninja check-all on Windows and Linux.

Summary of code changes:

Clang currently crashes for switch statements inside a template when the
condition is a non-integer field member because contextual implicit
conversion is skipped when parsing the condition. This conversion is
however later checked in an assert when the case statement is handled.
The conversion is skipped when parsing the condition because
the field member is set as type-dependent based on its containing class.
This patch sets the type dependency based on the field's type instead.

This patch fixes Bug 40982.

show more ...

Revert "Reapply "Fix crash on switch conditions of non-integer types in templates""

This reverts commit 759948467ea3181615d44d80f74ffeb260180fd0.
There were build bot failures in clang-tidy

Reapply "Fix crash on switch conditions of non-integer types in templates"

This patch reapplies commit 76945821b9cad3. The first version broke
buildbots due to clang-tidy test fails. The fails are b

Reapply "Fix crash on switch conditions of non-integer types in templates"

This patch reapplies commit 76945821b9cad3. The first version broke
buildbots due to clang-tidy test fails. The fails are because some
errors in templates are now diagnosed earlier (does not wait till
instantiation). I have modified the tests to add checks for these
diagnostics/prevent these diagnostics. There are no additional code
changes.

Summary of code changes:

Clang currently crashes for switch statements inside a template when the
condition is a non-integer field member because contextual implicit
conversion is skipped when parsing the condition. This conversion is
however later checked in an assert when the case statement is handled.
The conversion is skipped when parsing the condition because
the field member is set as type-dependent based on its containing class.
This patch sets the type dependency based on the field's type instead.

This patch fixes Bug 40982.

Reviewers: rnk, gribozavr2

Patch by: Elizabeth Andrews (eandrews)

Differential revision: https://reviews.llvm.org/D69950

show more ...

Revert "Fix crash on switch conditions of non-integer types in templates"

This reverts commit r368706. It broke ClangTidy tests.

llvm-svn: 368738

Fix crash on switch conditions of non-integer types in templates

Clang currently crashes for switch statements inside a template when
the condition is a non-integer field. The crash is due to incorr

Fix crash on switch conditions of non-integer types in templates

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

show more ...

PR37680: fix faulty assertion condition.

When looking up a template name, we can find an overload set containing a
function template and an unresolved non-type using declaration.

llvm-svn: 334106

Fix regression in r332076.

If the name after 'template' is an unresolved using declaration (not containing
'typename'), then we don't yet know if it's a valid template-name, so don't
reject it prior

Fix regression in r332076.

If the name after 'template' is an unresolved using declaration (not containing
'typename'), then we don't yet know if it's a valid template-name, so don't
reject it prior to instantiation. Instead, treat it as naming a dependent
member of the current instantiation.

llvm-svn: 332291

show more ...

Fix crash on qualified template name instantiation if the template name has no
template argument list.

llvm-svn: 330881

Weaken an assertion that isn't true for invalid input.

llvm-svn: 227540

PR19936: Fix a really dumb bug where we would profile dependent operator* expressions incorrectly.

llvm-svn: 210296

Revert "Don't require -re suffix on -verify directives with regexes."

This patch was submitted to the list for review and didn't receive a LGTM.

(In fact one explicit objection and one query were r

Revert "Don't require -re suffix on -verify directives with regexes."

This patch was submitted to the list for review and didn't receive a LGTM.

(In fact one explicit objection and one query were raised.)

This reverts commit r197295.

llvm-svn: 197299

show more ...

Don't require -re suffix on -verify directives with regexes.

Differential Revision: http://llvm-reviews.chandlerc.com/D2392

llvm-svn: 197295

Change semantics of regex expectations in the diagnostic verifier

Previously, a line like

// expected-error-re {{foo}}

treats the entirety of foo as a regex. This is inconvenient when matching t

Change semantics of regex expectations in the diagnostic verifier

Previously, a line like

// expected-error-re {{foo}}

treats the entirety of foo as a regex. This is inconvenient when matching type
names containing regex characters. For example, to match
"void *(class test8::A::*)(void)" inside such a regex, one would have to type
"void \*\(class test8::A::\*\)\(void\)".

This patch changes the semantics of expected-error-re to only treat the parts
of the directive wrapped in double curly braces as regexes. This avoids the
escaping problem and leads to nicer patterns for those cases; see e.g. the
change to test/Sema/format-strings-scanf.c.

(The balanced search for closing }} of a directive also makes us handle the
full directive in test\SemaCXX\constexpr-printing.cpp:41 and :53.)

Differential Revision: http://llvm-reviews.chandlerc.com/D2388

llvm-svn: 197092

show more ...

Don't suggest putting 'operator new' or 'operator delete' in a namespace to fix a two-phase lookup issue. That's not permitted.

llvm-svn: 183874

Implement DR85: Redeclaration of member is forbidden

Disallow the existence of a declaration of a member class that isn't a
forward declaration before it's definition.

llvm-svn: 183722