mirror of https://github.com/rust-lang/rust.git
suggest wrapping patterns with compatible enum variants
This commit is contained in:
Michael Goulet
parent
d7aca22e7f
commit
dd6683fcda
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@ -65,6 +65,7 @@ use rustc_hir::def_id::DefId;
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use rustc_hir::lang_items::LangItem;
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use rustc_hir::{Item, ItemKind, Node};
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use rustc_middle::dep_graph::DepContext;
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use rustc_middle::ty::print::with_no_trimmed_paths;
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use rustc_middle::ty::{
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self,
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error::TypeError,
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@ -1736,6 +1737,7 @@ impl<'a, 'tcx> InferCtxt<'a, 'tcx> {
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};
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if should_suggest_fixes {
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self.suggest_tuple_pattern(cause, &exp_found, diag);
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self.suggest_as_ref_where_appropriate(span, &exp_found, diag);
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self.suggest_accessing_field_where_appropriate(cause, &exp_found, diag);
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self.suggest_await_on_expect_found(cause, span, &exp_found, diag);
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@ -1766,6 +1768,73 @@ impl<'a, 'tcx> InferCtxt<'a, 'tcx> {
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self.note_error_origin(diag, cause, exp_found, terr);
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}
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fn suggest_tuple_pattern(
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&self,
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cause: &ObligationCause<'tcx>,
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exp_found: &ty::error::ExpectedFound<Ty<'tcx>>,
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diag: &mut Diagnostic,
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) {
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// Heavily inspired by `FnCtxt::suggest_compatible_variants`, with
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// some modifications due to that being in typeck and this being in infer.
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if let ObligationCauseCode::Pattern { .. } = cause.code() {
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if let ty::Adt(expected_adt, substs) = exp_found.expected.kind() {
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let compatible_variants: Vec<_> = expected_adt
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.variants()
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.iter()
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.filter(|variant| {
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variant.fields.len() == 1 && variant.ctor_kind == hir::def::CtorKind::Fn
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})
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.filter_map(|variant| {
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let sole_field = &variant.fields[0];
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let sole_field_ty = sole_field.ty(self.tcx, substs);
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if same_type_modulo_infer(sole_field_ty, exp_found.found) {
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let variant_path =
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with_no_trimmed_paths!(self.tcx.def_path_str(variant.def_id));
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// FIXME #56861: DRYer prelude filtering
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if let Some(path) = variant_path.strip_prefix("std::prelude::") {
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if let Some((_, path)) = path.split_once("::") {
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return Some(path.to_string());
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}
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}
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Some(variant_path)
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} else {
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None
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}
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})
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.collect();
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match &compatible_variants[..] {
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[] => {}
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[variant] => {
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diag.multipart_suggestion_verbose(
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&format!("try wrapping the pattern in `{}`", variant),
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vec![
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(cause.span.shrink_to_lo(), format!("{}(", variant)),
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(cause.span.shrink_to_hi(), ")".to_string()),
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],
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Applicability::MaybeIncorrect,
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);
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}
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_ => {
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// More than one matching variant.
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diag.multipart_suggestions(
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&format!(
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"try wrapping the pattern in a variant of `{}`",
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self.tcx.def_path_str(expected_adt.did())
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),
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compatible_variants.into_iter().map(|variant| {
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vec![
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(cause.span.shrink_to_lo(), format!("{}(", variant)),
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(cause.span.shrink_to_hi(), ")".to_string()),
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]
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}),
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Applicability::MaybeIncorrect,
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);
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}
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}
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}
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}
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}
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pub fn get_impl_future_output_ty(&self, ty: Ty<'tcx>) -> Option<Binder<'tcx, Ty<'tcx>>> {
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if let ty::Opaque(def_id, substs) = ty.kind() {
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let future_trait = self.tcx.require_lang_item(LangItem::Future, None);
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@ -0,0 +1,41 @@
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enum Foo {
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Bar(Bar),
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}
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struct Bar {
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x: i32,
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}
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fn a(f: Foo) {
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match f {
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Bar { x } => {
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//~^ ERROR mismatched types
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//~| HELP try wrapping
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}
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}
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}
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struct S;
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fn b(s: Option<S>) {
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match s {
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S => {
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//~^ ERROR mismatched types
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//~| HELP try wrapping
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//~| HELP introduce a new binding instead
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}
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_ => {}
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}
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}
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fn c(s: Result<S, S>) {
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match s {
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S => {
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//~^ ERROR mismatched types
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//~| HELP try wrapping
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//~| HELP introduce a new binding instead
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}
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_ => {}
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}
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}
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fn main() {}
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@ -0,0 +1,68 @@
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error[E0308]: mismatched types
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--> $DIR/compatible-variants-in-pat.rs:10:9
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LL | match f {
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| - this expression has type `Foo`
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LL | Bar { x } => {
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| ^^^^^^^^^ expected enum `Foo`, found struct `Bar`
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help: try wrapping the pattern in `Foo::Bar`
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LL | Foo::Bar(Bar { x }) => {
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| +++++++++ +
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error[E0308]: mismatched types
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--> $DIR/compatible-variants-in-pat.rs:21:9
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LL | struct S;
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| --------- unit struct defined here
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...
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LL | match s {
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| - this expression has type `Option<S>`
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LL | S => {
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| ^
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| |
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| expected enum `Option`, found struct `S`
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| `S` is interpreted as a unit struct, not a new binding
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= note: expected enum `Option<S>`
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found struct `S`
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help: try wrapping the pattern in `Some`
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LL | Some(S) => {
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| +++++ +
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help: introduce a new binding instead
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LL | other_s => {
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| ~~~~~~~
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error[E0308]: mismatched types
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--> $DIR/compatible-variants-in-pat.rs:32:9
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LL | struct S;
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| --------- unit struct defined here
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...
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LL | match s {
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| - this expression has type `Result<S, S>`
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LL | S => {
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| ^
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| |
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| expected enum `Result`, found struct `S`
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| `S` is interpreted as a unit struct, not a new binding
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= note: expected enum `Result<S, S>`
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found struct `S`
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help: try wrapping the pattern in a variant of `Result`
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LL | Ok(S) => {
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| +++ +
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LL | Err(S) => {
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| ++++ +
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help: introduce a new binding instead
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LL | other_s => {
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| ~~~~~~~
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error: aborting due to 3 previous errors
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For more information about this error, try `rustc --explain E0308`.
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@ -8,6 +8,10 @@ LL | Some(k) => match k {
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= note: expected enum `Result<_, {integer}>`
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found enum `Option<_>`
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help: try wrapping the pattern in `Ok`
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LL | Ok(Some(k)) => match k {
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| +++ +
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error[E0308]: mismatched types
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--> $DIR/issue-12552.rs:9:5
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@ -20,6 +24,10 @@ LL | None => ()
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= note: expected enum `Result<_, {integer}>`
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found enum `Option<_>`
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help: try wrapping the pattern in `Ok`
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LL | Ok(None) => ()
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| +++ +
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error: aborting due to 2 previous errors
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@ -8,6 +8,10 @@ LL | Err(_) => ()
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= note: expected enum `Option<_>`
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found enum `Result<_, _>`
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help: try wrapping the pattern in `Some`
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LL | Some(Err(_)) => ()
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| +++++ +
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error: aborting due to previous error
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@ -8,6 +8,10 @@ LL | Either::Right(_) => {}
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= note: expected struct `S`
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found enum `Either<_, _>`
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help: try wrapping the pattern in `S`
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LL | S(Either::Right(_)) => {}
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| ++ +
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help: you might have meant to use field `0` whose type is `Either<usize, usize>`
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LL | match S(Either::Left(5)).0 {
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