bjoernager/rust
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Remove unnecessary fields from EnumNonMatchingCollapsed.

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The `&[ast::Variant]` field isn't used.

The `Vec<Ident>` field is only used for its length, but that's always
the same as the length of the `&[Ident]` and so isn't necessary.
This commit is contained in:
Nicholas Nethercote 2022-06-28 08:56:54 +10:00
parent 72a1621061
commit 7a4fdcbbc5
4 changed files with 14 additions and 30 deletions
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34
compiler/rustc_builtin_macros/src/deriving/generic/mod.rs
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@ -146,8 +146,6 @@
//!
//! ```{.text}
//! EnumNonMatchingCollapsed(
//! vec![<ident of self>, <ident of __arg_1>],
//! &[<ast::Variant for C0>, <ast::Variant for C1>],
//! &[<ident for self index value>, <ident of __arg_1 index value>])
//! ```
//!
@ -299,13 +297,10 @@ pub enum SubstructureFields<'a> {
/// variant.
EnumMatching(usize, usize, &'a ast::Variant, Vec<FieldInfo<'a>>),
/// Non-matching variants of the enum, but with all state hidden from
/// the consequent code. The first component holds `Ident`s for all of
/// the `Self` arguments; the second component is a slice of all of the
/// variants for the enum itself, and the third component is a list of
/// `Ident`s bound to the variant index values for each of the actual
/// input `Self` arguments.
EnumNonMatchingCollapsed(Vec<Ident>, &'a [ast::Variant], &'a [Ident]),
/// Non-matching variants of the enum, but with all state hidden from the
/// consequent code. The field is a list of `Ident`s bound to the variant
/// index values for each of the actual input `Self` arguments.
EnumNonMatchingCollapsed(&'a [Ident]),
/// A static method where `Self` is a struct.
StaticStruct(&'a ast::VariantData, StaticFields),
@ -318,13 +313,10 @@ pub enum SubstructureFields<'a> {
pub type CombineSubstructureFunc<'a> =
Box<dyn FnMut(&mut ExtCtxt<'_>, Span, &Substructure<'_>) -> P<Expr> + 'a>;
/// Deal with non-matching enum variants. The tuple is a list of
/// identifiers (one for each `Self` argument, which could be any of the
/// variants since they have been collapsed together) and the identifiers
/// holding the variant index value for each of the `Self` arguments. The
/// last argument is all the non-`Self` args of the method being derived.
/// Deal with non-matching enum variants. The slice is the identifiers holding
/// the variant index value for each of the `Self` arguments.
pub type EnumNonMatchCollapsedFunc<'a> =
Box<dyn FnMut(&mut ExtCtxt<'_>, Span, (&[Ident], &[Ident]), &[P<Expr>]) -> P<Expr> + 'a>;
Box<dyn FnMut(&mut ExtCtxt<'_>, Span, &[Ident]) -> P<Expr> + 'a>;
pub fn combine_substructure(
f: CombineSubstructureFunc<'_>,
@ -1184,11 +1176,6 @@ impl<'a> MethodDef<'a> {
)
.collect::<Vec<String>>();
let self_arg_idents = self_arg_names
.iter()
.map(|name| Ident::from_str_and_span(name, span))
.collect::<Vec<Ident>>();
// The `vi_idents` will be bound, solely in the catch-all, to
// a series of let statements mapping each self_arg to an int
// value corresponding to its discriminant.
@ -1203,8 +1190,7 @@ impl<'a> MethodDef<'a> {
// Builds, via callback to call_substructure_method, the
// delegated expression that handles the catch-all case,
// using `__variants_tuple` to drive logic if necessary.
let catch_all_substructure =
EnumNonMatchingCollapsed(self_arg_idents, &variants, &vi_idents);
let catch_all_substructure = EnumNonMatchingCollapsed(&vi_idents);
let first_fieldless = variants.iter().find(|v| v.data.fields().is_empty());
@ -1657,9 +1643,7 @@ pub fn cs_fold_enumnonmatch(
substructure: &Substructure<'_>,
) -> P<Expr> {
match *substructure.fields {
EnumNonMatchingCollapsed(ref all_args, _, tuple) => {
enum_nonmatch_f(cx, trait_span, (&all_args[..], tuple), substructure.nonself_args)
}
EnumNonMatchingCollapsed(tuple) => enum_nonmatch_f(cx, trait_span, tuple),
_ => cx.span_bug(trait_span, "cs_fold_enumnonmatch expected an EnumNonMatchingCollapsed"),
}
}