On Wed, 13 May 2026 19:52:05 +0000, Seifeddine Gmati wrote:
Hi Daniil,
Thanks for the support. That matters a lot.
> 1) Turbofish at callsite: this was already brought up before, while I understand the precedence issues that led to this choice, having written some rust myself, I *still* don’t like the syntax, and would very much prefer normal diamond syntax at callsite, like for declarations.
I personally like Turbofish; however, I understand that some people
might not find it "pretty". But the reason it has to stay as turbofish
is parser-level: `[A(D)]` is ambiguous between a single-element
array calling generic A and a two-element array of comparisons, and
there's no context-sensitive disambiguation that works inside
attributes, array expressions, and ternaries without introducing rules
that bite at exactly the worst places. Forcing parentheses around the
call (`[(A(D))]`) was suggested earlier in the thread and is
uglier than turbofish; it also closes the door on tuple syntax I'd
like to keep open for a future RFC. Turbofish costs two characters and
keeps the parser non-context-sensitive, which is the trade I'd rather
take.The `[self::foo::(1), self::foo::(2)]` case genuinely looks
the worst. The same call without turbofish (`[self::foo(1),
self::foo(2)]`) reads fine and is what the vast majority of call sites
will look like, since turbofish is opt-in for ambiguity resolution
(because inference is hard), and most calls won't need it.> 2) -/+ for variant bounds: also brought up before, while it *can* be somewhat mnemonic (- consumes for input params, + produces for output params), in/out would indeed be much more descriptive IMO (or at the very least, both options could be provided at the same time).
Secondary vote added on this. `+T`/`-T` vs `in T`/`out T`. I have no
strong preference; the vote will decide.> I will implement support for this RFC in Psalm immediately after the RFC is approved
Side note: I'm optimistic
feat: add support for native generic types by azjezz · Pull Request #1826 · carthage-software/mago · GitHubThanks again for the careful read.
Cheers,
Seifeddine.
Leaving-the-door-open-for-tuples is a good additional argument for using the turbofish syntax; I'd say it's important enough to mention in the RFC.