Currently, Clang accepts this code in C mode (where the tag is required
to be used) but rejects it in C++ mode thinking that the association is
defining a new type.
void foo(void) {
struct S { int a; };
_Generic(something, struct S : 1);
}
Clang thinks this in C++ because it sees struct S : when parsing the
class specifier and decides that must be a type definition (because the
colon signifies the presence of a base class type). This patch adds a
new declarator context to represent a _Generic association so that we
can distinguish these situations properly.
Fixes#55562
Differential Revision: https://reviews.llvm.org/D126969
New diagnostics were added for unreachable generic selection expression
associations in ca75ac5f04, but it did
not account for a difference in behavior between C and C++ regarding
lvalue to rvalue conversions. So we would issue diagnostics about a
selection being unreachable and then reach it. This corrects the
diagnostic behavior in that case.
Differential Revision: https://reviews.llvm.org/D125882
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.
Aaron Ballman