The C++ rules briefly allowed this, but the rule changed nearly 10 years
ago and we never updated our implementation to match. However, we've
warned on this by default for a long time, and no other compiler accepts
(even as an extension).
This has two significant effects:
1) Direct relational comparisons between null pointer constants (0 and nullopt)
and pointers are now ill-formed. This was always the case for C, and it
appears that C++ only ever permitted by accident. For instance, cases like
nullptr < &a
are now rejected.
2) Comparisons and conditional operators between differently-cv-qualified
pointer types now work, and produce a composite type that both source
pointer types can convert to (when possible). For instance, comparison
between 'int **' and 'const int **' is now valid, and uses an intermediate
type of 'const int *const *'.
Clang previously supported #2 as an extension.
We do not accept the cases in #1 as an extension. I've tested a fair amount of
code to check that this doesn't break it, but if it turns out that someone is
relying on this, we can easily add it back as an extension.
This is a re-commit of r284800.
llvm-svn: 284890
This has two significant effects:
1) Direct relational comparisons between null pointer constants (0 and nullopt)
and pointers are now ill-formed. This was always the case for C, and it
appears that C++ only ever permitted by accident. For instance, cases like
nullptr < &a
are now rejected.
2) Comparisons and conditional operators between differently-cv-qualified
pointer types now work, and produce a composite type that both source
pointer types can convert to (when possible). For instance, comparison
between 'int **' and 'const int **' is now valid, and uses an intermediate
type of 'const int *const *'.
Clang previously supported #2 as an extension.
We do not accept the cases in #1 as an extension. I've tested a fair amount of
code to check that this doesn't break it, but if it turns out that someone is
relying on this, we can easily add it back as an extension.
llvm-svn: 284800
designator" diagnostic with more correct and more human-friendly "cannot take
address of rvalue of type 'T'".
For the case of & &T::f, provide a custom diagnostic, rather than unhelpfully
saying "cannot take address of rvalue of type '<overloaded function type>'".
For the case of &array_temporary, treat it just like a class temporary
(including allowing it as an extension); the existing diagnostic wording
for the class temporary case works fine.
llvm-svn: 174262
A conditional operator between glvalues of types cv1 T and cv2 T produces a
glvalue if the expressions are of the same value kind and one of cv1 and cv2
is a subset of the other.
A conditional operator between two null pointer constants is permitted if one
of them is of type std::nullptr_t.
llvm-svn: 161476
minor issues along the way:
- Non-type template parameters of type 'std::nullptr_t' were not
permitted.
- We didn't properly introduce built-in operators for nullptr ==,
!=, <, <=, >=, or > as candidate functions .
To my knowledge, there's only one (minor but annoying) part of nullptr
that hasn't been implemented: catching a thrown 'nullptr' as a pointer
or pointer-to-member, per C++0x [except.handle]p4.
llvm-svn: 131813
small bug fixes in SemaInit, switch over SemaDecl to use it more often, and
change a bunch of diagnostics which are different with the new initialization
code.
llvm-svn: 91767
- 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
Richard Smith