Given the following invalid code,
```cpp
template <class T>
struct S {
T *a;
};
S s = {1};
```
we produce such diagnostics currently:
```
<source>:2:8: note: candidate template ignored: could not match 'S<T>' against 'int'
2 | struct S {
| ^
<source>:2:8: note: candidate template ignored: could not match 'T *' against 'int'
```
Which I think is confusing because there's no `S<T>` nor `T *` at the
location it points to. This is because we're deducing the initializer
against implicitly generated deduction guides, and their source
locations just point to the corresponding `RecordDecl`. Hence the
misleading notes.
This patch alleviates the issue by adding extra notes demonstrating
which implicit deduction guide we're deducing against. In other words,
in addition to the note of `could not match 'T *' against 'int'`, we
would also say the implicit deduction guide we're trying to use:
`template <class T> S(T *) -> S<T>`, which looks clearer IMO.
---------
Co-authored-by: Sirraide <aeternalmail@gmail.com>
We have a new policy in place making links to private resources
something we try to avoid in source and test files. Normally, we'd
organically switch to the new policy rather than make a sweeping change
across a project. However, Clang is in a somewhat special circumstance
currently: recently, I've had several new contributors run into rdar
links around test code which their patch was changing the behavior of.
This turns out to be a surprisingly bad experience, especially for
newer folks, for a handful of reasons: not understanding what the link
is and feeling intimidated by it, wondering whether their changes are
actually breaking something important to a downstream in some way,
having to hunt down strangers not involved with the patch to impose on
them for help, accidental pressure from asking for potentially private
IP to be made public, etc. Because folks run into these links entirely
by chance (through fixing bugs or working on new features), there's not
really a set of problematic links to focus on -- all of the links have
basically the same potential for causing these problems. As a result,
this is an omnibus patch to remove all such links.
This was not a mechanical change; it was done by manually searching for
rdar, radar, radr, and other variants to find all the various
problematic links. From there, I tried to retain or reword the
surrounding comments so that we would lose as little context as
possible. However, because most links were just a plain link with no
supporting context, the majority of the changes are simple removals.
Differential Review: https://reviews.llvm.org/D158071
If a default template type argument is manually specified to be of the default
type, then it is committed when printing the template.
Differential revision: https://reviews.llvm.org/D103040
arguments of types by default.
This somewhat improves the worst-case printing of types like
std::string, std::vector, etc., where many irrelevant default arguments
can be included in the type as printed if we've lost the type sugar.
nested names as id-expressions, using the annot_primary_expr annotation, where
possible. This removes some redundant lookups, and also allows us to
typo-correct within tentative parsing, and to carry on disambiguating past an
identifier which we can determine will fail lookup as both a type and as a
non-type, allowing us to disambiguate more declarations (and thus offer
improved error recovery for such cases).
This also introduces to the parser the notion of a tentatively-declared name,
which is an identifier which we *might* have seen a declaration for in a
tentative parse (but only if we end up disambiguating the tokens as a
declaration). This is necessary to correctly disambiguate cases where a
variable is used within its own initializer.
llvm-svn: 162159
new InitializationSequence. This fixes some bugs (e.g., PR5808),
changed some diagnostics, and caused more churn than expected. What's
new:
- InitializationSequence now has a "C conversion sequence" category
and step kind, which falls back to
- Changed the diagnostics for returns to always have the result type
of the function first and the type of the expression second.
CheckSingleAssignmentConstraints to peform checking in C.
- Improved ASTs for initialization of return values. The ASTs now
capture all of the temporaries we need to create, but
intentionally do not bind the tempoary that is actually returned,
so that it won't get destroyed twice.
- Make sure to perform an (elidable!) copy of the class object that
is returned from a class.
- Fix copy elision in CodeGen to properly see through the
subexpressions that occur with elidable copies.
- Give "new" its own entity kind; as with return values and thrown
objects, we don't bind the expression so we don't call a
destructor for it.
Note that, with this patch, I've broken returning move-only types in
C++0x. We'll fix it later, when we tackle NRVO.
llvm-svn: 91669
- This is designed to make it obvious that %clang_cc1 is a "test variable"
which is substituted. It is '%clang_cc1' instead of '%clang -cc1' because it
can be useful to redefine what gets run as 'clang -cc1' (for example, to set
a default target).
llvm-svn: 91446
ValueDecl, because that isn't always the case in ill-formed
code. Diagnose a common mistake (forgetting to provide a template
argument list for a class template, PR5655) and dyn_cast so that we
handle the general problem of referring to a non-value declaration
gracefully.
llvm-svn: 90239
CXXRecordDecl that is used to represent class template
specializations. These are canonical declarations that can refer to
either an actual class template specialization in the code, e.g.,
template<> class vector<bool> { };
or to a template instantiation. However, neither of these features is
actually implemented yet, so really we're just using (and uniqing) the
declarations to make sure that, e.g., A<int> is a different type from
A<float>. Note that we carefully distinguish between what the user
wrote in the source code (e.g., "A<FLOAT>") and the semantic entity it
represents (e.g., "A<float, int>"); the former is in the sugared Type,
the latter is an actual Decl.
llvm-svn: 64716
to a class template. For example, the template-id 'vector<int>' now
has a nice, sugary type in the type system. What we can do now:
- Parse template-ids like 'vector<int>' (where 'vector' names a
class template) and form proper types for them in the type system.
- Parse icky template-ids like 'A<5>' and 'A<(5 > 0)>' properly,
using (sadly) a bool in the parser to tell it whether '>' should
be treated as an operator or not.
This is a baby-step, with major problems and limitations:
- There are currently two ways that we handle template arguments
(whether they are types or expressions). These will be merged, and,
most likely, TemplateArg will disappear.
- We don't have any notion of the declaration of class template
specializations or of template instantiations, so all template-ids
are fancy names for 'int' :)
llvm-svn: 64153
