Use impl Trait instead of generic type names with trait bound
#1153
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So this is far less trivial than anticipated, and not how I planned to spend my sunday! There's still some trouble with trampolines now that I made aliases optional but the Other than that the current "heuristic" to detect whether to use I'll be out for a while, but feel more than welcome to go over the |
| // TODO: This is just a heuristic for now, based on what we do in codegen! | ||
| // Theoretically the surrounding function should determine whether it needs to | ||
| // reuse an alias (ie. to use in `call_func::<P, Q, R>`) or not. | ||
| // In the latter case an `impl` is generated instead of a type name/alias. | ||
| pub fn has_alias(&self) -> bool { | ||
| matches!(*self, Self::NoWrapper) | ||
| } |
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Anyone have a suggestion how to determine this?
| pub alias: char, | ||
| /// Bound does not have an alias when `param: impl type_str` is used | ||
| pub alias: Option<char>, |
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What this change is all about :)
| .filter(|bound| skip.contains(&bound.alias)) | ||
| // TODO: False or true? | ||
| .filter(|bound| bound.alias.map_or(false, |alias| skip.contains(&alias))) |
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Note to self: Try and remember what was up here.
| let bounds = bounds.iter().filter(|bound| { | ||
| bound.alias.map_or(true, |alias| !skip.contains(&alias)) | ||
| && (!filter_callback_modified || !bound.callback_modified) | ||
| }); |
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I need to revisit this: can't be a trait bound if it doesn't have an alias, then it's only written in-place with impl.
| // TODO: enforce that this is only used on NoWrapper! | ||
| // TODO: Analyze if alias is used in function, otherwise set to None! | ||
| .chain(bounds.filter_map(|b| b.alias).map(|a| a.to_string())) |
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Ambiguity between NoWrapper and impl (no alias) again.
`impl` is quite a bit more concise and readable when a type parameter with trait bound is only used once. Aside that, this simplifies some of the type handling in trampolines by using `P: IsA<>` directly instead of through a `where P: ...` indirection.
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@GuillaumeGomez Should we get this in now then? |
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This is good enough for now. Thanks @MarijnS95 ! |
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@MarijnS95 You update your gtk-rs-core/gtk3-rs/gtk4-rs/gstreamer-rs PRs? :) |
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@sdroege Updated everything |
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For gtk-rs/gtk-rs-core#89 (comment)
implis quite a bit more concise and readable when a type parameter with trait bound is only used once. Aside that, this simplifies some of the type handling in trampolines by usingP: IsA<>directly instead of through awhere P: ...indirection.Related MRs:
https://gitlab.freedesktop.org/gstreamer/gstreamer-rs/-/merge_requests/778
gtk-rs/gtk-rs-core#95
gtk-rs/gtk3-rs#547
gtk-rs/gtk4-rs#404