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Rollup merge of #133153 - maxcabrajac:flat_maps, r=petrochenkov

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Add visits to nodes that already have flat_maps in ast::MutVisitor

This PR aims to add `visit_` methods for every node that has a `flat_map_` in MutVisitor, giving implementers free choice over overriding `flat_map` for 1-to-n conversions or `visit` for a 1-to-1.

There is one major problem: `flat_map_stmt`.
While all other default implementations of `flat_map`s are 1-to-1 conversion, as they either only call visits or a internal 1-to-many conversions are natural, `flat_map_stmt` doesn't follow this pattern.

`flat_map_stmt`'s default implementation is a 1-to-n conversion that panics if n > 1 (effectively being a 1-to-[0;1]). This means that it cannot be used as is for a default `visit_stmt`, which would be required to be a 1-to-1.

Implementing `visit_stmt` without runtime checks would require it to reach over a potential `flat_map_item` or `filter_map_expr` overrides and call for their `visit` counterparts directly.
Other than that, if we want to keep the behavior of `flat_map_stmt` it cannot call `visit_stmt` internally.

To me, it seems reasonable to make all default implementations 1-to-1 conversions and let implementers handle `visit_stmt` if they need it, but I don't know if calling `visit` directly when a 1-to-1 is required is ok or not.

related to #128974 & #127615

r? ``@petrochenkov``
This commit is contained in:
Matthias Krüger 2024-11-21 07:56:12 +01:00 • committed by GitHub
commit 9d70af54e4
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7 changed files with 178 additions and 89 deletions
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17
compiler/rustc_lint/src/early.rs
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@ -230,15 +230,16 @@ impl<'a, T: EarlyLintPass> ast_visit::Visitor<'a> for EarlyContextAndPass<'a, T>
}
fn visit_assoc_item(&mut self, item: &'a ast::AssocItem, ctxt: ast_visit::AssocCtxt) {
self.with_lint_attrs(item.id, &item.attrs, |cx| match ctxt {
ast_visit::AssocCtxt::Trait => {
lint_callback!(cx, check_trait_item, item);
ast_visit::walk_assoc_item(cx, item, ctxt);
}
ast_visit::AssocCtxt::Impl => {
lint_callback!(cx, check_impl_item, item);
ast_visit::walk_assoc_item(cx, item, ctxt);
self.with_lint_attrs(item.id, &item.attrs, |cx| {
match ctxt {
ast_visit::AssocCtxt::Trait => {
lint_callback!(cx, check_trait_item, item);
}
ast_visit::AssocCtxt::Impl => {
lint_callback!(cx, check_impl_item, item);
}
}
ast_visit::walk_assoc_item(cx, item, ctxt);
});
}