On Fri, Jun 1, 2018 at 5:03 PM, Paolo Carlini <paolo.carlini@oracle.com> wrote:
while working on some bugs I noticed that in a few places in decl.c we could
do better in terms of locations within the current infrastructure, some
simple, straightforward improvements. I'm attaching below a tiny first
patch, more to follow, I hope.
For example, a function which could be improved in many places is
grok_ctor_properties and, before going ahead, I'd like to ask about
something I noticed yesterday:
/* There can be no default arguments. */
for (tree arg = argtypes; arg != void_list_node; arg = TREE_CHAIN (arg))
if (TREE_PURPOSE (arg))
{
TREE_PURPOSE (arg) = NULL_TREE;
if (operator_code == POSTINCREMENT_EXPR
|| operator_code == POSTDECREMENT_EXPR)
pedwarn (input_location, OPT_Wpedantic,
"%qD cannot have default arguments", decl);
else
{
error ("%qD cannot have default arguments", decl);
return false;
}
}
the special casing seems weird, so far I haven't been able to find anything
in the standard about it and all the other compilers I have at hand (Oracle,
Intel, Clang) don't seem to have it. Shall we keep it or not? Maybe with an
additional comment explaining the rationale? The affected testcases would be
parse/defarg11.C and g++.jason/operator.C.
I think in the olden days, with a default argument one function could
support both prefix and postfix inc/decrement syntax:
struct A {
A& operator++(int = 0);
};
int main()
{
A a;
++a;
a++;
}
...but that hasn't actually worked in forever, so it shouldn't be a
problem to make the ++ case an error, too.