Re: Variadic templates, fourth revision (1/2)

[Jason Merrill <jason at redhat dot com>]

Sorry about the delay.  This version looks quite good, just a few things 
I'd like to clear up:

In dump_parameters, pre-existing code clears "first", and then you check
and clear it in the argument pack loop; I don't see any way it can be
other than 0 going into that loop.

In cp_walk_subtrees, I'd combine the expansion cases and use
PACK_EXPANSION_PATTERN.

The comment for FUNCTION_PARAMETER_PACK_P should mention PARM_DECL.

I'd like to use template_parameter_pack_p more places rather than open
code the DECL_INITIAL or TREE_TYPE: in pp_cxx_direct_declarator,
push_template_decl_real, and for setting parm_is_parameter_pack in
coerce_template_parms.

As an aside, the standardese added to [class.base.init] could use an
example; I had to look at the testsuite patch to see what a
mem-initializer expansion is supposed to look like.

I notice that for a mem-initializer expansion we make a type expansion
for the bases to be initialized, but leave the initializer as a plain
expression (possibly involving parameter packs); please add a comment
about why you don't make an expansion for the initializer as well.  The
comment in finish_mem_initializers that handles the other end seems not
quite right; we skip checking the TREE_VALUE in that case because it's
part of the expansion even though that isn't represented in the tree
structure.

Please replace "unpacking" with "expansion" everywhere.

The ARGUMENT_PACK_SELECT stuff looks good.