make_node does memset, but the loop above is after the call to
make_node.
I guess we didn't hit the problem just because tsubst_copy_and_build()
(where build_x_binary_op (ARRAY_REF is) is never called for
array_ref when processing_template_decl is non zero.
Probably.
Unfortunately, TREE_OPERAND checks the static lookup table for how
many operands the tree code is supposed to have, *not* how many
operands were actually allocated to the thing.
My suggestion would be to simply add some gcc_asserts that we don't
ever get ARRAY_REF there :)
I guess that sort of assertions need at least a comment or
gcc_assert().
Alex.
