Thanks for your suggestions. I will apply them in the upcoming patch (v3). On Mon, May 6, 2024 at 7:46 PM Patrick Palka <ppa...@redhat.com> wrote: > We could also/instead consider defining > > int want = TEMPLATE_TYPE_ORIG_LEVEL (auto_node); > int have = TMPL_ARGS_DEPTH (full_targs); > > and express the logic in terms of these instead of the possibly > negative 'missing_levels'. The 'want < have' case could have a comment > mentioning that this occurs for a constrained auto within an explicit > specialization.)
I converted missing_levels into want and have variables. Additionally, I added an assertion to explicitly state that our trimming logic assumes the context to be one of adc_variable_type, adc_return_type, or adc_decomp_type. > > > Note that, for the case where there are real missing levels, we are > > > putting irrelevant template arguments for the missing levels instead > > > of make_tree_vec(0). By this change: > > > - If the type is independent of those missing levels: it works fine > > > either way. > > > - If the type is dependent on those missing levels: Instead of raising > > > an ICE, the compiler exhibits undefined behavior. > > Makes sense. For the record, I have looked into the history of this hack to find out in which scenarios we may have to deal with missing levels. https://gcc.gnu.org/git/?p=gcc.git;a=commit;h=b49d23f3e238c08bdbc5b892b2ed0a57b5f5caf9 As far as I can understand, it was limited to the adc_unify context at that time, but it might have been changed since then. Since I was not sure about it, I have not added an assertion for this case. Many thanks!
