https://gcc.gnu.org/bugzilla/show_bug.cgi?id=67981
Casey Carter <Casey at Carter dot net> changed:
What |Removed |Added
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CC| |Casey at Carter dot net
--- Comment #1 from Casey Carter <Casey at Carter dot net> ---
I think this is a bug in the standard, and not a bug in GCC.
noptr-new-declarator has two grammar productions:
noptr-new-declarator:
[ expression ] attribute-specifier-seq_opt
noptr-new-declarator [ constant-expression ] attribute-specifier-seq_opt
with the intent being that all but the first dimension in a multi-dimensional
array new expression must be constant expressions, while the first dimension
can be a non-constant expression. It would be peculiar if "new int[0]" were to
be ill-formed whereas "int n = 0; new int[n];" were to be well-formed, which it
very clearly is by 5.3.4/7: "... When the value of the expression is zero, the
allocation function is called to allocate an array with no elements."
The confusion arises here because the wording uses "constant-expression" to
describe occurrences of the second grammar production of noptr-new-declarator,
and "expression" to describe occurrences of the first production, which is
ambiguous when the expression also happens to be a constant-expression.
