explicit functions that are not candidates.
It's not always obvious that the reason a conversion was not possible is
because the function you wanted to call is 'explicit', so explicitly say
if that's the case.
It would be nice to rank the explicit candidates higher in the
diagnostic if an implicit conversion sequence exists for their
arguments, but unfortunately we can't determine that without potentially
triggering non-immediate-context errors that we're not permitted to
produce.
(Re-submission of D39937 with fixed tests.)
Adjust wording for const-qualification mismatch to be a little more clear.
Also add another diagnostic for a ref qualifier mismatch, which previously produced a useless error (this error path is simply very old; see rL119336):
Before:
error: cannot initialize object parameter of type 'X0' with an expression of type 'X0'
After:
error: 'this' argument to member function 'rvalue' is an lvalue, but function has rvalue ref-qualifier
Reviewers: aaron.ballman
Reviewed By: aaron.ballman
Subscribers: lebedev.ri, cfe-commits
Differential Revision: https://reviews.llvm.org/D41646
llvm-svn: 321609
Summary:
Adjust wording for const-qualification mismatch to be a little more clear.
Also add another diagnostic for a ref qualifier mismatch, which previously produced a useless error (this error path is simply very old; see rL119336):
Before:
error: cannot initialize object parameter of type 'X0' with an expression of type 'X0'
After:
error: 'this' argument to member function 'rvalue' is an lvalue, but function has rvalue ref-qualifier
Reviewers: rsmith, aaron.ballman
Reviewed By: aaron.ballman
Subscribers: lebedev.ri, aaron.ballman, cfe-commits
Differential Revision: https://reviews.llvm.org/D39937
llvm-svn: 321592
copy-initialization. We previously got this wrong in a couple of ways:
- we only looked for copy / move constructors and constructor templates for
this copy, and thus would fail to copy in cases where doing so should use
some other constructor (but see core issue 670),
- we mishandled the special case for disabling user-defined conversions that
blocks infinite recursion through repeated application of a copy constructor
(applying it in slightly too many cases) -- though as far as I can tell,
this does not ever actually affect the result of overload resolution, and
- we misapplied the special-case rules for constructors taking a parameter
whose type is a (reference to) the same class type by incorrectly assuming
that only happens for copy/move constructors (it also happens for
constructors instantiated from templates and those inherited from base
classes).
These changes should only affect strange corner cases (for instance, where the
copy constructor exists but has a non-const-qualified parameter type), so for
the most part it only causes us to produce more 'candidate' notes, but see the
test changes for other cases whose behavior is affected.
llvm-svn: 280776
cv-unqualified type. This is essential in order to allow move-only objects of
const-qualified types to be copy-initialized via a converting constructor.
llvm-svn: 150309
temporary object. This is blindingly obvious from reading C++
[over.match.ctor]p1, but somehow I'd missed it and it took DR152 to
educate me. Adjust one test that was relying on this non-standard
behavior.
llvm-svn: 101688
resolution. There are two sources of problems involving user-defined
conversions that this change eliminates, along with providing simpler
interfaces for checking implicit conversions:
- It eliminates a case of infinite recursion found in Boost.
- It eliminates the search for the constructor needed to copy a temporary
generated by an implicit conversion from overload
resolution. Overload resolution assumes that, if it gets a value
of the parameter's class type (or a derived class thereof), there
is a way to copy if... even if there isn't. We now model this
properly.
llvm-svn: 101680
poor (and wrong) approximation of the actual rules governing when to
build a copy and when it can be elided.
The correct implementation is actually simpler than the
approximation. When we only enumerate constructors as part of
initialization (e.g., for direct initialization or when we're copying
from a class type or one of its derived classes), we don't create a
copy. When we enumerate all conversion functions, we do create a
copy. Before, we created some extra copies and missed some
others. The new test copy-initialization.cpp shows a case where we
missed creating a (required, non-elidable) copy as part of a
user-defined conversion, which resulted in a miscompile. This commit
also fixes PR6757, where the missing copy made us reject well-formed
code in the ternary operator.
This commit also cleans up our handling of copy elision in the case
where we create an extra copy of a temporary object, which became
necessary now that we produce the right copies. The code that seeks to
find the temporary object being copied has moved into
Expr::getTemporaryObject(); it used to have two different
not-quite-the-same implementations, one in Sema and one in CodeGen.
Note that we still do not attempt to perform the named return value
optimization, so we miss copy elisions for return values and throw
expressions.
llvm-svn: 100196
therefore not creating ElaboratedTypes, which are still pretty-printed
with the written tag).
Most of these testcase changes were done by script, so don't feel too
sorry for my fingers.
llvm-svn: 98149
InitializationSequence. Specially, switch initialization of a C++
class type (either copy- or direct-initialization).
Also, make sure that we create an elidable copy-construction when
performing copy initialization of a C++ class variable. Fixes PR5826.
llvm-svn: 91750
- 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
semantics and improve our handling of default arguments. Specifically,
we follow this order:
- As soon as the see the '}' in the class definition, the class is
complete and we add any implicit declarations (default constructor,
copy constructor, etc.) to the class.
- If there are any default function arguments, parse them
- If there were any inline member function definitions, parse them
As part of this change, we now keep track of the the fact that we've
seen unparsed default function arguments within the AST. See the new
ParmVarDecl::hasUnparsedDefaultArg member. This allows us to properly
cope with calls inside default function arguments to other functions
where we're making use of the default arguments.
Made some C++ error messages regarding failed initializations more
specific.
llvm-svn: 61406
duplication in the handling of copy-initialization by constructor,
which occurs both for initialization of a declaration and for
overloading. The initialization code is due for some refactoring.
llvm-svn: 58756
Richard Smith