bjoernager/rust
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Split TypeFolder and FallibleTypeFolder

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This commit is contained in:
Michael Goulet 2025-04-14 15:10:43 +00:00
parent 13b4734e31
commit c774adcbb5
10 changed files with 396 additions and 187 deletions
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60
compiler/rustc_macros/src/type_foldable.rs
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@ -14,31 +14,33 @@ pub(super) fn type_foldable_derive(mut s: synstructure::Structure<'_>) -> proc_m
s.add_bounds(synstructure::AddBounds::Generics);
s.bind_with(|_| synstructure::BindStyle::Move);
let try_body_fold = s.each_variant(|vi| {
let bindings = vi.bindings();
vi.construct(|_, index| {
let bind = &bindings[index];
// retain value of fields with #[type_foldable(identity)]
if has_ignore_attr(&bind.ast().attrs, "type_foldable", "identity") {
bind.to_token_stream()
} else {
quote! {
::rustc_middle::ty::TypeFoldable::try_fold_with(#bind, __folder)?
}
}
})
});
let body_fold = s.each_variant(|vi| {
let bindings = vi.bindings();
vi.construct(|_, index| {
let bind = &bindings[index];
let mut fixed = false;
// retain value of fields with #[type_foldable(identity)]
bind.ast().attrs.iter().for_each(|x| {
if !x.path().is_ident("type_foldable") {
return;
}
let _ = x.parse_nested_meta(|nested| {
if nested.path.is_ident("identity") {
fixed = true;
}
Ok(())
});
});
if fixed {
if has_ignore_attr(&bind.ast().attrs, "type_foldable", "identity") {
bind.to_token_stream()
} else {
quote! {
::rustc_middle::ty::TypeFoldable::try_fold_with(#bind, __folder)?
::rustc_middle::ty::TypeFoldable::fold_with(#bind, __folder)
}
}
})
@ -51,8 +53,32 @@ pub(super) fn type_foldable_derive(mut s: synstructure::Structure<'_>) -> proc_m
self,
__folder: &mut __F
) -> Result<Self, __F::Error> {
Ok(match self { #body_fold })
Ok(match self { #try_body_fold })
}
fn fold_with<__F: ::rustc_middle::ty::TypeFolder<::rustc_middle::ty::TyCtxt<'tcx>>>(
self,
__folder: &mut __F
) -> Self {
match self { #body_fold }
}
},
)
}
fn has_ignore_attr(attrs: &[syn::Attribute], name: &'static str, meta: &'static str) -> bool {
let mut ignored = false;
attrs.iter().for_each(|attr| {
if !attr.path().is_ident(name) {
return;
}
let _ = attr.parse_nested_meta(|nested| {
if nested.path.is_ident(meta) {
ignored = true;
}
Ok(())
});
});
ignored
}