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Rollup merge of #121823 - Nadrieril:never-witnesses, r=compiler-errors

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never patterns: suggest `!` patterns on non-exhaustive matches

When a match is non-exhaustive we now suggest never patterns whenever it makes sense.

r? ``@compiler-errors``
This commit is contained in:
Matthias Krüger 2024-03-18 22:24:36 +01:00 committed by GitHub
commit 2d3dcfaade
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GPG Key ID: B5690EEEBB952194
11 changed files with 982 additions and 242 deletions
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74
compiler/rustc_mir_build/src/thir/pattern/check_match.rs
View File

@ -938,9 +938,6 @@ fn report_non_exhaustive_match<'p, 'tcx>(
};
// In the case of an empty match, replace the '`_` not covered' diagnostic with something more
// informative.
let mut err;
let pattern;
let patterns_len;
if is_empty_match && !non_empty_enum {
return cx.tcx.dcx().emit_err(NonExhaustivePatternsTypeNotEmpty {
cx,
@ -948,33 +945,23 @@ fn report_non_exhaustive_match<'p, 'tcx>(
span: sp,
ty: scrut_ty,
});
} else {
// FIXME: migration of this diagnostic will require list support
let joined_patterns = joined_uncovered_patterns(cx, &witnesses);
err = create_e0004(
cx.tcx.sess,
sp,
format!("non-exhaustive patterns: {joined_patterns} not covered"),
);
err.span_label(
sp,
format!(
"pattern{} {} not covered",
rustc_errors::pluralize!(witnesses.len()),
joined_patterns
),
);
patterns_len = witnesses.len();
pattern = if witnesses.len() < 4 {
witnesses
.iter()
.map(|witness| cx.hoist_witness_pat(witness).to_string())
.collect::<Vec<String>>()
.join(" | ")
} else {
"_".to_string()
};
};
}
// FIXME: migration of this diagnostic will require list support
let joined_patterns = joined_uncovered_patterns(cx, &witnesses);
let mut err = create_e0004(
cx.tcx.sess,
sp,
format!("non-exhaustive patterns: {joined_patterns} not covered"),
);
err.span_label(
sp,
format!(
"pattern{} {} not covered",
rustc_errors::pluralize!(witnesses.len()),
joined_patterns
),
);
// Point at the definition of non-covered `enum` variants.
if let Some(AdtDefinedHere { adt_def_span, ty, variants }) =
@ -1021,6 +1008,23 @@ fn report_non_exhaustive_match<'p, 'tcx>(
}
}
// Whether we suggest the actual missing patterns or `_`.
let suggest_the_witnesses = witnesses.len() < 4;
let suggested_arm = if suggest_the_witnesses {
let pattern = witnesses
.iter()
.map(|witness| cx.hoist_witness_pat(witness).to_string())
.collect::<Vec<String>>()
.join(" | ");
if witnesses.iter().all(|p| p.is_never_pattern()) && cx.tcx.features().never_patterns {
// Arms with a never pattern don't take a body.
pattern
} else {
format!("{pattern} => todo!()")
}
} else {
format!("_ => todo!()")
};
let mut suggestion = None;
let sm = cx.tcx.sess.source_map();
match arms {
@ -1033,7 +1037,7 @@ fn report_non_exhaustive_match<'p, 'tcx>(
};
suggestion = Some((
sp.shrink_to_hi().with_hi(expr_span.hi()),
format!(" {{{indentation}{more}{pattern} => todo!(),{indentation}}}",),
format!(" {{{indentation}{more}{suggested_arm},{indentation}}}",),
));
}
[only] => {
@ -1059,7 +1063,7 @@ fn report_non_exhaustive_match<'p, 'tcx>(
};
suggestion = Some((
only.span.shrink_to_hi(),
format!("{comma}{pre_indentation}{pattern} => todo!()"),
format!("{comma}{pre_indentation}{suggested_arm}"),
));
}
[.., prev, last] => {
@ -1082,7 +1086,7 @@ fn report_non_exhaustive_match<'p, 'tcx>(
if let Some(spacing) = spacing {
suggestion = Some((
last.span.shrink_to_hi(),
format!("{comma}{spacing}{pattern} => todo!()"),
format!("{comma}{spacing}{suggested_arm}"),
));
}
}
@ -1093,13 +1097,13 @@ fn report_non_exhaustive_match<'p, 'tcx>(
let msg = format!(
"ensure that all possible cases are being handled by adding a match arm with a wildcard \
pattern{}{}",
if patterns_len > 1 && patterns_len < 4 && suggestion.is_some() {
if witnesses.len() > 1 && suggest_the_witnesses && suggestion.is_some() {
", a match arm with multiple or-patterns"
} else {
// we are either not suggesting anything, or suggesting `_`
""
},
match patterns_len {
match witnesses.len() {
// non-exhaustive enum case
0 if suggestion.is_some() => " as shown",
0 => "",

39
compiler/rustc_pattern_analysis/src/constructor.rs
View File

@ -678,15 +678,19 @@ pub enum Constructor<Cx: PatCx> {
Or,
/// Wildcard pattern.
Wildcard,
/// Never pattern. Only used in `WitnessPat`. An actual never pattern should be lowered as
/// `Wildcard`.
Never,
/// Fake extra constructor for enums that aren't allowed to be matched exhaustively. Also used
/// for those types for which we cannot list constructors explicitly, like `f64` and `str`.
/// for those types for which we cannot list constructors explicitly, like `f64` and `str`. Only
/// used in `WitnessPat`.
NonExhaustive,
/// Fake extra constructor for variants that should not be mentioned in diagnostics.
/// We use this for variants behind an unstable gate as well as
/// `#[doc(hidden)]` ones.
/// Fake extra constructor for variants that should not be mentioned in diagnostics. We use this
/// for variants behind an unstable gate as well as `#[doc(hidden)]` ones. Only used in
/// `WitnessPat`.
Hidden,
/// Fake extra constructor for constructors that are not seen in the matrix, as explained at the
/// top of the file.
/// top of the file. Only used for specialization.
Missing,
/// Fake extra constructor that indicates and empty field that is private. When we encounter one
/// we skip the column entirely so we don't observe its emptiness. Only used for specialization.
@ -708,6 +712,7 @@ impl<Cx: PatCx> Clone for Constructor<Cx> {
Constructor::Str(value) => Constructor::Str(value.clone()),
Constructor::Opaque(inner) => Constructor::Opaque(inner.clone()),
Constructor::Or => Constructor::Or,
Constructor::Never => Constructor::Never,
Constructor::Wildcard => Constructor::Wildcard,
Constructor::NonExhaustive => Constructor::NonExhaustive,
Constructor::Hidden => Constructor::Hidden,
@ -1040,10 +1045,32 @@ impl<Cx: PatCx> ConstructorSet<Cx> {
// In a `MaybeInvalid` place even an empty pattern may be reachable. We therefore
// add a dummy empty constructor here, which will be ignored if the place is
// `ValidOnly`.
missing_empty.push(NonExhaustive);
missing_empty.push(Never);
}
}
SplitConstructorSet { present, missing, missing_empty }
}
/// Whether this set only contains empty constructors.
pub(crate) fn all_empty(&self) -> bool {
match self {
ConstructorSet::Bool
| ConstructorSet::Integers { .. }
| ConstructorSet::Ref
| ConstructorSet::Union
| ConstructorSet::Unlistable => false,
ConstructorSet::NoConstructors => true,
ConstructorSet::Struct { empty } => *empty,
ConstructorSet::Variants { variants, non_exhaustive } => {
!*non_exhaustive
&& variants
.iter()
.all(|visibility| matches!(visibility, VariantVisibility::Empty))
}
ConstructorSet::Slice { array_len, subtype_is_empty } => {
*subtype_is_empty && matches!(array_len, Some(1..))
}
}
}
}

21
compiler/rustc_pattern_analysis/src/pat.rs
View File

@ -208,6 +208,7 @@ impl<Cx: PatCx> fmt::Debug for DeconstructedPat<Cx> {
}
Ok(())
}
Never => write!(f, "!"),
Wildcard | Missing | NonExhaustive | Hidden | PrivateUninhabited => {
write!(f, "_ : {:?}", pat.ty())
}
@ -311,18 +312,24 @@ impl<Cx: PatCx> WitnessPat<Cx> {
pub(crate) fn new(ctor: Constructor<Cx>, fields: Vec<Self>, ty: Cx::Ty) -> Self {
Self { ctor, fields, ty }
}
pub(crate) fn wildcard(ty: Cx::Ty) -> Self {
Self::new(Wildcard, Vec::new(), ty)
/// Create a wildcard pattern for this type. If the type is empty, we create a `!` pattern.
pub(crate) fn wildcard(cx: &Cx, ty: Cx::Ty) -> Self {
let is_empty = cx.ctors_for_ty(&ty).is_ok_and(|ctors| ctors.all_empty());
let ctor = if is_empty { Never } else { Wildcard };
Self::new(ctor, Vec::new(), ty)
}
/// Construct a pattern that matches everything that starts with this constructor.
/// For example, if `ctor` is a `Constructor::Variant` for `Option::Some`, we get the pattern
/// `Some(_)`.
pub(crate) fn wild_from_ctor(cx: &Cx, ctor: Constructor<Cx>, ty: Cx::Ty) -> Self {
if matches!(ctor, Wildcard) {
return Self::wildcard(cx, ty);
}
let fields = cx
.ctor_sub_tys(&ctor, &ty)
.filter(|(_, PrivateUninhabitedField(skip))| !skip)
.map(|(ty, _)| Self::wildcard(ty))
.map(|(ty, _)| Self::wildcard(cx, ty))
.collect();
Self::new(ctor, fields, ty)
}
@ -334,6 +341,14 @@ impl<Cx: PatCx> WitnessPat<Cx> {
&self.ty
}
pub fn is_never_pattern(&self) -> bool {
match self.ctor() {
Never => true,
Or => self.fields.iter().all(|p| p.is_never_pattern()),
_ => self.fields.iter().any(|p| p.is_never_pattern()),
}
}
pub fn iter_fields(&self) -> impl Iterator<Item = &WitnessPat<Cx>> {
self.fields.iter()
}

7
compiler/rustc_pattern_analysis/src/rustc.rs
View File

@ -247,7 +247,7 @@ impl<'p, 'tcx: 'p> RustcPatCtxt<'p, 'tcx> {
_ => bug!("bad slice pattern {:?} {:?}", ctor, ty),
},
Bool(..) | IntRange(..) | F32Range(..) | F64Range(..) | Str(..) | Opaque(..)
| NonExhaustive | Hidden | Missing | PrivateUninhabited | Wildcard => &[],
| Never | NonExhaustive | Hidden | Missing | PrivateUninhabited | Wildcard => &[],
Or => {
bug!("called `Fields::wildcards` on an `Or` ctor")
}
@ -275,7 +275,7 @@ impl<'p, 'tcx: 'p> RustcPatCtxt<'p, 'tcx> {
Ref => 1,
Slice(slice) => slice.arity(),
Bool(..) | IntRange(..) | F32Range(..) | F64Range(..) | Str(..) | Opaque(..)
| NonExhaustive | Hidden | Missing | PrivateUninhabited | Wildcard => 0,
| Never | NonExhaustive | Hidden | Missing | PrivateUninhabited | Wildcard => 0,
Or => bug!("The `Or` constructor doesn't have a fixed arity"),
}
}
@ -824,7 +824,8 @@ impl<'p, 'tcx: 'p> RustcPatCtxt<'p, 'tcx> {
}
}
&Str(value) => PatKind::Constant { value },
Wildcard | NonExhaustive | Hidden | PrivateUninhabited => PatKind::Wild,
Never if self.tcx.features().never_patterns => PatKind::Never,
Never | Wildcard | NonExhaustive | Hidden | PrivateUninhabited => PatKind::Wild,
Missing { .. } => bug!(
"trying to convert a `Missing` constructor into a `Pat`; this is probably a bug,
`Missing` should have been processed in `apply_constructors`"

100
tests/ui/pattern/usefulness/empty-types.exhaustive_patterns.stderr
View File

@ -1,23 +1,23 @@
error: unreachable pattern
--> $DIR/empty-types.rs:49:9
--> $DIR/empty-types.rs:51:9
|
LL | _ => {}
| ^
|
note: the lint level is defined here
--> $DIR/empty-types.rs:15:9
--> $DIR/empty-types.rs:17:9
|
LL | #![deny(unreachable_patterns)]
| ^^^^^^^^^^^^^^^^^^^^
error: unreachable pattern
--> $DIR/empty-types.rs:52:9
--> $DIR/empty-types.rs:54:9
|
LL | _x => {}
| ^^
error[E0004]: non-exhaustive patterns: type `&!` is non-empty
--> $DIR/empty-types.rs:56:11
--> $DIR/empty-types.rs:58:11
|
LL | match ref_never {}
| ^^^^^^^^^
@ -32,31 +32,31 @@ LL + }
|
error: unreachable pattern
--> $DIR/empty-types.rs:71:9
--> $DIR/empty-types.rs:73:9
|
LL | (_, _) => {}
| ^^^^^^
error: unreachable pattern
--> $DIR/empty-types.rs:78:9
--> $DIR/empty-types.rs:80:9
|
LL | _ => {}
| ^
error: unreachable pattern
--> $DIR/empty-types.rs:81:9
--> $DIR/empty-types.rs:83:9
|
LL | (_, _) => {}
| ^^^^^^
error: unreachable pattern
--> $DIR/empty-types.rs:85:9
--> $DIR/empty-types.rs:87:9
|
LL | _ => {}
| ^
error[E0004]: non-exhaustive patterns: `Ok(_)` not covered
--> $DIR/empty-types.rs:89:11
--> $DIR/empty-types.rs:91:11
|
LL | match res_u32_never {}
| ^^^^^^^^^^^^^ pattern `Ok(_)` not covered
@ -75,19 +75,19 @@ LL + }
|
error: unreachable pattern
--> $DIR/empty-types.rs:97:9
--> $DIR/empty-types.rs:99:9
|
LL | Err(_) => {}
| ^^^^^^
error: unreachable pattern
--> $DIR/empty-types.rs:102:9
--> $DIR/empty-types.rs:104:9
|
LL | Err(_) => {}
| ^^^^^^
error[E0004]: non-exhaustive patterns: `Ok(1_u32..=u32::MAX)` not covered
--> $DIR/empty-types.rs:99:11
--> $DIR/empty-types.rs:101:11
|
LL | match res_u32_never {
| ^^^^^^^^^^^^^ pattern `Ok(1_u32..=u32::MAX)` not covered
@ -105,7 +105,7 @@ LL ~ Ok(1_u32..=u32::MAX) => todo!()
|
error[E0005]: refutable pattern in local binding
--> $DIR/empty-types.rs:106:9
--> $DIR/empty-types.rs:108:9
|
LL | let Ok(_x) = res_u32_never.as_ref();
| ^^^^^^ pattern `Err(_)` not covered
@ -119,121 +119,121 @@ LL | let Ok(_x) = res_u32_never.as_ref() else { todo!() };
| ++++++++++++++++
error: unreachable pattern
--> $DIR/empty-types.rs:117:9
--> $DIR/empty-types.rs:119:9
|
LL | _ => {}
| ^
error: unreachable pattern
--> $DIR/empty-types.rs:121:9
--> $DIR/empty-types.rs:123:9
|
LL | Ok(_) => {}
| ^^^^^
error: unreachable pattern
--> $DIR/empty-types.rs:124:9
--> $DIR/empty-types.rs:126:9
|
LL | Ok(_) => {}
| ^^^^^
error: unreachable pattern
--> $DIR/empty-types.rs:125:9
--> $DIR/empty-types.rs:127:9
|
LL | _ => {}
| ^
error: unreachable pattern
--> $DIR/empty-types.rs:128:9
--> $DIR/empty-types.rs:130:9
|
LL | Ok(_) => {}
| ^^^^^
error: unreachable pattern
--> $DIR/empty-types.rs:129:9
--> $DIR/empty-types.rs:131:9
|
LL | Err(_) => {}
| ^^^^^^
error: unreachable pattern
--> $DIR/empty-types.rs:138:13
--> $DIR/empty-types.rs:140:13
|
LL | _ => {}
| ^
error: unreachable pattern
--> $DIR/empty-types.rs:141:13
--> $DIR/empty-types.rs:143:13
|
LL | _ if false => {}
| ^
error: unreachable pattern
--> $DIR/empty-types.rs:150:13
--> $DIR/empty-types.rs:152:13
|
LL | Some(_) => {}
| ^^^^^^^
error: unreachable pattern
--> $DIR/empty-types.rs:154:13
--> $DIR/empty-types.rs:156:13
|
LL | _ => {}
| ^
error: unreachable pattern
--> $DIR/empty-types.rs:206:13
--> $DIR/empty-types.rs:208:13
|
LL | _ => {}
| ^
error: unreachable pattern
--> $DIR/empty-types.rs:211:13
--> $DIR/empty-types.rs:213:13
|
LL | _ => {}
| ^
error: unreachable pattern
--> $DIR/empty-types.rs:216:13
--> $DIR/empty-types.rs:218:13
|
LL | _ => {}
| ^
error: unreachable pattern
--> $DIR/empty-types.rs:221:13
--> $DIR/empty-types.rs:223:13
|
LL | _ => {}
| ^
error: unreachable pattern
--> $DIR/empty-types.rs:227:13
--> $DIR/empty-types.rs:229:13
|
LL | _ => {}
| ^
error: unreachable pattern
--> $DIR/empty-types.rs:286:9
--> $DIR/empty-types.rs:288:9
|
LL | _ => {}
| ^
error: unreachable pattern
--> $DIR/empty-types.rs:289:9
--> $DIR/empty-types.rs:291:9
|
LL | (_, _) => {}
| ^^^^^^
error: unreachable pattern
--> $DIR/empty-types.rs:292:9
--> $DIR/empty-types.rs:294:9
|
LL | Ok(_) => {}
| ^^^^^
error: unreachable pattern
--> $DIR/empty-types.rs:293:9
--> $DIR/empty-types.rs:295:9
|
LL | Err(_) => {}
| ^^^^^^
error[E0004]: non-exhaustive patterns: type `&[!]` is non-empty
--> $DIR/empty-types.rs:325:11
--> $DIR/empty-types.rs:327:11
|
LL | match slice_never {}
| ^^^^^^^^^^^
@ -247,7 +247,7 @@ LL + }
|
error[E0004]: non-exhaustive patterns: `&[]` not covered
--> $DIR/empty-types.rs:336:11
--> $DIR/empty-types.rs:338:11
|
LL | match slice_never {
| ^^^^^^^^^^^ pattern `&[]` not covered
@ -260,7 +260,7 @@ LL + &[] => todo!()
|
error[E0004]: non-exhaustive patterns: `&[]` not covered
--> $DIR/empty-types.rs:349:11
--> $DIR/empty-types.rs:352:11
|
LL | match slice_never {
| ^^^^^^^^^^^ pattern `&[]` not covered
@ -274,7 +274,7 @@ LL + &[] => todo!()
|
error[E0004]: non-exhaustive patterns: type `[!]` is non-empty
--> $DIR/empty-types.rs:355:11
--> $DIR/empty-types.rs:359:11
|
LL | match *slice_never {}
| ^^^^^^^^^^^^
@ -288,25 +288,25 @@ LL + }
|
error: unreachable pattern
--> $DIR/empty-types.rs:365:9
--> $DIR/empty-types.rs:369:9
|
LL | _ => {}
| ^
error: unreachable pattern
--> $DIR/empty-types.rs:368:9
--> $DIR/empty-types.rs:372:9
|
LL | [_, _, _] => {}
| ^^^^^^^^^
error: unreachable pattern
--> $DIR/empty-types.rs:371:9
--> $DIR/empty-types.rs:375:9
|
LL | [_, ..] => {}
| ^^^^^^^
error[E0004]: non-exhaustive patterns: type `[!; 0]` is non-empty
--> $DIR/empty-types.rs:385:11
--> $DIR/empty-types.rs:389:11
|
LL | match array_0_never {}
| ^^^^^^^^^^^^^
@ -320,13 +320,13 @@ LL + }
|
error: unreachable pattern
--> $DIR/empty-types.rs:392:9
--> $DIR/empty-types.rs:396:9
|
LL | _ => {}
| ^
error[E0004]: non-exhaustive patterns: `[]` not covered
--> $DIR/empty-types.rs:394:11
--> $DIR/empty-types.rs:398:11
|
LL | match array_0_never {
| ^^^^^^^^^^^^^ pattern `[]` not covered
@ -340,49 +340,49 @@ LL + [] => todo!()
|
error: unreachable pattern
--> $DIR/empty-types.rs:413:9
--> $DIR/empty-types.rs:417:9
|
LL | Some(_) => {}
| ^^^^^^^
error: unreachable pattern
--> $DIR/empty-types.rs:418:9
--> $DIR/empty-types.rs:422:9
|
LL | Some(_a) => {}
| ^^^^^^^^
error: unreachable pattern
--> $DIR/empty-types.rs:423:9
--> $DIR/empty-types.rs:427:9
|
LL | _ => {}
| ^
error: unreachable pattern
--> $DIR/empty-types.rs:428:9
--> $DIR/empty-types.rs:432:9
|
LL | _a => {}
| ^^
error: unreachable pattern
--> $DIR/empty-types.rs:600:9
--> $DIR/empty-types.rs:604:9
|
LL | _ => {}
| ^
error: unreachable pattern
--> $DIR/empty-types.rs:603:9
--> $DIR/empty-types.rs:607:9
|
LL | _x => {}
| ^^
error: unreachable pattern
--> $DIR/empty-types.rs:606:9
--> $DIR/empty-types.rs:610:9
|
LL | _ if false => {}
| ^
error: unreachable pattern
--> $DIR/empty-types.rs:609:9
--> $DIR/empty-types.rs:613:9
|
LL | _x if false => {}
| ^^

148
tests/ui/pattern/usefulness/empty-types.min_exh_pats.stderr
View File

@ -1,23 +1,23 @@
error: unreachable pattern
--> $DIR/empty-types.rs:49:9
--> $DIR/empty-types.rs:51:9
|
LL | _ => {}
| ^
|
note: the lint level is defined here
--> $DIR/empty-types.rs:15:9
--> $DIR/empty-types.rs:17:9
|
LL | #![deny(unreachable_patterns)]
| ^^^^^^^^^^^^^^^^^^^^
error: unreachable pattern
--> $DIR/empty-types.rs:52:9
--> $DIR/empty-types.rs:54:9
|
LL | _x => {}
| ^^
error[E0004]: non-exhaustive patterns: type `&!` is non-empty
--> $DIR/empty-types.rs:56:11
--> $DIR/empty-types.rs:58:11
|
LL | match ref_never {}
| ^^^^^^^^^
@ -32,31 +32,31 @@ LL + }
|
error: unreachable pattern
--> $DIR/empty-types.rs:71:9
--> $DIR/empty-types.rs:73:9
|
LL | (_, _) => {}
| ^^^^^^
error: unreachable pattern
--> $DIR/empty-types.rs:78:9
--> $DIR/empty-types.rs:80:9
|
LL | _ => {}
| ^
error: unreachable pattern
--> $DIR/empty-types.rs:81:9
--> $DIR/empty-types.rs:83:9
|
LL | (_, _) => {}
| ^^^^^^
error: unreachable pattern
--> $DIR/empty-types.rs:85:9
--> $DIR/empty-types.rs:87:9
|
LL | _ => {}
| ^
error[E0004]: non-exhaustive patterns: `Ok(_)` not covered
--> $DIR/empty-types.rs:89:11
--> $DIR/empty-types.rs:91:11
|
LL | match res_u32_never {}
| ^^^^^^^^^^^^^ pattern `Ok(_)` not covered
@ -75,19 +75,19 @@ LL + }
|
error: unreachable pattern
--> $DIR/empty-types.rs:97:9
--> $DIR/empty-types.rs:99:9
|
LL | Err(_) => {}
| ^^^^^^
error: unreachable pattern
--> $DIR/empty-types.rs:102:9
--> $DIR/empty-types.rs:104:9
|
LL | Err(_) => {}
| ^^^^^^
error[E0004]: non-exhaustive patterns: `Ok(1_u32..=u32::MAX)` not covered
--> $DIR/empty-types.rs:99:11
--> $DIR/empty-types.rs:101:11
|
LL | match res_u32_never {
| ^^^^^^^^^^^^^ pattern `Ok(1_u32..=u32::MAX)` not covered
@ -105,7 +105,7 @@ LL ~ Ok(1_u32..=u32::MAX) => todo!()
|
error[E0005]: refutable pattern in local binding
--> $DIR/empty-types.rs:106:9
--> $DIR/empty-types.rs:108:9
|
LL | let Ok(_x) = res_u32_never.as_ref();
| ^^^^^^ pattern `Err(_)` not covered
@ -119,7 +119,7 @@ LL | let Ok(_x) = res_u32_never.as_ref() else { todo!() };
| ++++++++++++++++
error[E0005]: refutable pattern in local binding
--> $DIR/empty-types.rs:110:9
--> $DIR/empty-types.rs:112:9
|
LL | let Ok(_x) = &res_u32_never;
| ^^^^^^ pattern `&Err(_)` not covered
@ -133,67 +133,67 @@ LL | let Ok(_x) = &res_u32_never else { todo!() };
| ++++++++++++++++
error: unreachable pattern
--> $DIR/empty-types.rs:117:9
--> $DIR/empty-types.rs:119:9
|
LL | _ => {}
| ^
error: unreachable pattern
--> $DIR/empty-types.rs:121:9
--> $DIR/empty-types.rs:123:9
|
LL | Ok(_) => {}
| ^^^^^
error: unreachable pattern
--> $DIR/empty-types.rs:124:9
--> $DIR/empty-types.rs:126:9
|
LL | Ok(_) => {}
| ^^^^^
error: unreachable pattern
--> $DIR/empty-types.rs:125:9
--> $DIR/empty-types.rs:127:9
|
LL | _ => {}
| ^
error: unreachable pattern
--> $DIR/empty-types.rs:128:9
--> $DIR/empty-types.rs:130:9
|
LL | Ok(_) => {}
| ^^^^^
error: unreachable pattern
--> $DIR/empty-types.rs:129:9
--> $DIR/empty-types.rs:131:9
|
LL | Err(_) => {}
| ^^^^^^
error: unreachable pattern
--> $DIR/empty-types.rs:138:13
--> $DIR/empty-types.rs:140:13
|
LL | _ => {}
| ^
error: unreachable pattern
--> $DIR/empty-types.rs:141:13
--> $DIR/empty-types.rs:143:13
|
LL | _ if false => {}
| ^
error: unreachable pattern
--> $DIR/empty-types.rs:150:13
--> $DIR/empty-types.rs:152:13
|
LL | Some(_) => {}
| ^^^^^^^
error: unreachable pattern
--> $DIR/empty-types.rs:154:13
--> $DIR/empty-types.rs:156:13
|
LL | _ => {}
| ^
error[E0004]: non-exhaustive patterns: `Some(_)` not covered
--> $DIR/empty-types.rs:163:15
--> $DIR/empty-types.rs:165:15
|
LL | match *ref_opt_void {
| ^^^^^^^^^^^^^ pattern `Some(_)` not covered
@ -211,61 +211,61 @@ LL + Some(_) => todo!()
|
error: unreachable pattern
--> $DIR/empty-types.rs:206:13
--> $DIR/empty-types.rs:208:13
|
LL | _ => {}
| ^
error: unreachable pattern
--> $DIR/empty-types.rs:211:13
--> $DIR/empty-types.rs:213:13
|
LL | _ => {}
| ^
error: unreachable pattern
--> $DIR/empty-types.rs:216:13
--> $DIR/empty-types.rs:218:13
|
LL | _ => {}
| ^
error: unreachable pattern
--> $DIR/empty-types.rs:221:13
--> $DIR/empty-types.rs:223:13
|
LL | _ => {}
| ^
error: unreachable pattern
--> $DIR/empty-types.rs:227:13
--> $DIR/empty-types.rs:229:13
|
LL | _ => {}
| ^
error: unreachable pattern
--> $DIR/empty-types.rs:286:9
--> $DIR/empty-types.rs:288:9
|
LL | _ => {}
| ^
error: unreachable pattern
--> $DIR/empty-types.rs:289:9
--> $DIR/empty-types.rs:291:9
|
LL | (_, _) => {}
| ^^^^^^
error: unreachable pattern
--> $DIR/empty-types.rs:292:9
--> $DIR/empty-types.rs:294:9
|
LL | Ok(_) => {}
| ^^^^^
error: unreachable pattern
--> $DIR/empty-types.rs:293:9
--> $DIR/empty-types.rs:295:9
|
LL | Err(_) => {}
| ^^^^^^
error[E0004]: non-exhaustive patterns: type `(u32, !)` is non-empty
--> $DIR/empty-types.rs:314:11
--> $DIR/empty-types.rs:316:11
|
LL | match *x {}
| ^^
@ -279,7 +279,7 @@ LL ~ }
|
error[E0004]: non-exhaustive patterns: type `(!, !)` is non-empty
--> $DIR/empty-types.rs:316:11
--> $DIR/empty-types.rs:318:11
|
LL | match *x {}
| ^^
@ -293,7 +293,7 @@ LL ~ }
|
error[E0004]: non-exhaustive patterns: `Ok(_)` and `Err(_)` not covered
--> $DIR/empty-types.rs:318:11
--> $DIR/empty-types.rs:320:11
|
LL | match *x {}
| ^^ patterns `Ok(_)` and `Err(_)` not covered
@ -315,7 +315,7 @@ LL ~ }
|
error[E0004]: non-exhaustive patterns: type `[!; 3]` is non-empty
--> $DIR/empty-types.rs:320:11
--> $DIR/empty-types.rs:322:11
|
LL | match *x {}
| ^^
@ -329,7 +329,7 @@ LL ~ }
|
error[E0004]: non-exhaustive patterns: type `&[!]` is non-empty
--> $DIR/empty-types.rs:325:11
--> $DIR/empty-types.rs:327:11
|
LL | match slice_never {}
| ^^^^^^^^^^^
@ -343,7 +343,7 @@ LL + }
|
error[E0004]: non-exhaustive patterns: `&[_, ..]` not covered
--> $DIR/empty-types.rs:327:11
--> $DIR/empty-types.rs:329:11
|
LL | match slice_never {
| ^^^^^^^^^^^ pattern `&[_, ..]` not covered
@ -356,7 +356,7 @@ LL + &[_, ..] => todo!()
|
error[E0004]: non-exhaustive patterns: `&[]`, `&[_]` and `&[_, _]` not covered
--> $DIR/empty-types.rs:336:11
--> $DIR/empty-types.rs:338:11
|
LL | match slice_never {
| ^^^^^^^^^^^ patterns `&[]`, `&[_]` and `&[_, _]` not covered
@ -369,7 +369,7 @@ LL + &[] | &[_] | &[_, _] => todo!()
|
error[E0004]: non-exhaustive patterns: `&[]` and `&[_, ..]` not covered
--> $DIR/empty-types.rs:349:11
--> $DIR/empty-types.rs:352:11
|
LL | match slice_never {
| ^^^^^^^^^^^ patterns `&[]` and `&[_, ..]` not covered
@ -383,7 +383,7 @@ LL + &[] | &[_, ..] => todo!()
|
error[E0004]: non-exhaustive patterns: type `[!]` is non-empty
--> $DIR/empty-types.rs:355:11
--> $DIR/empty-types.rs:359:11
|
LL | match *slice_never {}
| ^^^^^^^^^^^^
@ -397,25 +397,25 @@ LL + }
|
error: unreachable pattern
--> $DIR/empty-types.rs:365:9
--> $DIR/empty-types.rs:369:9
|
LL | _ => {}
| ^
error: unreachable pattern
--> $DIR/empty-types.rs:368:9
--> $DIR/empty-types.rs:372:9
|
LL | [_, _, _] => {}
| ^^^^^^^^^
error: unreachable pattern
--> $DIR/empty-types.rs:371:9
--> $DIR/empty-types.rs:375:9
|
LL | [_, ..] => {}
| ^^^^^^^
error[E0004]: non-exhaustive patterns: type `[!; 0]` is non-empty
--> $DIR/empty-types.rs:385:11
--> $DIR/empty-types.rs:389:11
|
LL | match array_0_never {}
| ^^^^^^^^^^^^^
@ -429,13 +429,13 @@ LL + }
|
error: unreachable pattern
--> $DIR/empty-types.rs:392:9
--> $DIR/empty-types.rs:396:9
|
LL | _ => {}
| ^
error[E0004]: non-exhaustive patterns: `[]` not covered
--> $DIR/empty-types.rs:394:11
--> $DIR/empty-types.rs:398:11
|
LL | match array_0_never {
| ^^^^^^^^^^^^^ pattern `[]` not covered
@ -449,31 +449,31 @@ LL + [] => todo!()
|
error: unreachable pattern
--> $DIR/empty-types.rs:413:9
--> $DIR/empty-types.rs:417:9
|
LL | Some(_) => {}
| ^^^^^^^
error: unreachable pattern
--> $DIR/empty-types.rs:418:9
--> $DIR/empty-types.rs:422:9
|
LL | Some(_a) => {}
| ^^^^^^^^
error: unreachable pattern
--> $DIR/empty-types.rs:423:9
--> $DIR/empty-types.rs:427:9
|
LL | _ => {}
| ^
error: unreachable pattern
--> $DIR/empty-types.rs:428:9
--> $DIR/empty-types.rs:432:9
|
LL | _a => {}
| ^^
error[E0004]: non-exhaustive patterns: `&Some(_)` not covered
--> $DIR/empty-types.rs:448:11
--> $DIR/empty-types.rs:452:11
|
LL | match ref_opt_never {
| ^^^^^^^^^^^^^ pattern `&Some(_)` not covered
@ -491,7 +491,7 @@ LL + &Some(_) => todo!()
|
error[E0004]: non-exhaustive patterns: `Some(_)` not covered
--> $DIR/empty-types.rs:489:11
--> $DIR/empty-types.rs:493:11
|
LL | match *ref_opt_never {
| ^^^^^^^^^^^^^^ pattern `Some(_)` not covered
@ -509,7 +509,7 @@ LL + Some(_) => todo!()
|
error[E0004]: non-exhaustive patterns: `Err(_)` not covered
--> $DIR/empty-types.rs:537:11
--> $DIR/empty-types.rs:541:11
|
LL | match *ref_res_never {
| ^^^^^^^^^^^^^^ pattern `Err(_)` not covered
@ -527,7 +527,7 @@ LL + Err(_) => todo!()
|
error[E0004]: non-exhaustive patterns: `Err(_)` not covered
--> $DIR/empty-types.rs:548:11
--> $DIR/empty-types.rs:552:11
|
LL | match *ref_res_never {
| ^^^^^^^^^^^^^^ pattern `Err(_)` not covered
@ -545,7 +545,7 @@ LL + Err(_) => todo!()
|
error[E0004]: non-exhaustive patterns: type `(u32, !)` is non-empty
--> $DIR/empty-types.rs:567:11
--> $DIR/empty-types.rs:571:11
|
LL | match *ref_tuple_half_never {}
| ^^^^^^^^^^^^^^^^^^^^^
@ -559,31 +559,31 @@ LL + }
|
error: unreachable pattern
--> $DIR/empty-types.rs:600:9
--> $DIR/empty-types.rs:604:9
|
LL | _ => {}
| ^
error: unreachable pattern
--> $DIR/empty-types.rs:603:9
--> $DIR/empty-types.rs:607:9
|
LL | _x => {}
| ^^
error: unreachable pattern
--> $DIR/empty-types.rs:606:9
--> $DIR/empty-types.rs:610:9
|
LL | _ if false => {}
| ^
error: unreachable pattern
--> $DIR/empty-types.rs:609:9
--> $DIR/empty-types.rs:613:9
|
LL | _x if false => {}
| ^^
error[E0004]: non-exhaustive patterns: `&_` not covered
--> $DIR/empty-types.rs:634:11
--> $DIR/empty-types.rs:638:11
|
LL | match ref_never {
| ^^^^^^^^^ pattern `&_` not covered
@ -597,8 +597,26 @@ LL ~ &_a if false => {},
LL + &_ => todo!()
|
error[E0004]: non-exhaustive patterns: `Ok(_)` not covered
--> $DIR/empty-types.rs:654:11
|
LL | match *ref_result_never {
| ^^^^^^^^^^^^^^^^^ pattern `Ok(_)` not covered
|
note: `Result<!, !>` defined here
--> $SRC_DIR/core/src/result.rs:LL:COL
::: $SRC_DIR/core/src/result.rs:LL:COL
|
= note: not covered
= note: the matched value is of type `Result<!, !>`
help: ensure that all possible cases are being handled by adding a match arm with a wildcard pattern or an explicit pattern as shown
|
LL ~ Err(_) => {},
LL + Ok(_) => todo!()
|
error[E0004]: non-exhaustive patterns: `Some(_)` not covered
--> $DIR/empty-types.rs:662:11
--> $DIR/empty-types.rs:674:11
|
LL | match *x {
| ^^ pattern `Some(_)` not covered
@ -615,7 +633,7 @@ LL ~ None => {},
LL + Some(_) => todo!()
|
error: aborting due to 63 previous errors
error: aborting due to 64 previous errors
Some errors have detailed explanations: E0004, E0005.
For more information about an error, try `rustc --explain E0004`.

644
tests/ui/pattern/usefulness/empty-types.never_pats.stderr Normal file
View File

@ -0,0 +1,644 @@
warning: the feature `never_patterns` is incomplete and may not be safe to use and/or cause compiler crashes
--> $DIR/empty-types.rs:14:33
|
LL | #![cfg_attr(never_pats, feature(never_patterns))]
| ^^^^^^^^^^^^^^
|
= note: see issue #118155 <https://github.com/rust-lang/rust/issues/118155> for more information
= note: `#[warn(incomplete_features)]` on by default
error: unreachable pattern
--> $DIR/empty-types.rs:51:9
|
LL | _ => {}
| ^
|
note: the lint level is defined here
--> $DIR/empty-types.rs:17:9
|
LL | #![deny(unreachable_patterns)]
| ^^^^^^^^^^^^^^^^^^^^
error: unreachable pattern
--> $DIR/empty-types.rs:54:9
|
LL | _x => {}
| ^^
error[E0004]: non-exhaustive patterns: type `&!` is non-empty
--> $DIR/empty-types.rs:58:11
|
LL | match ref_never {}
| ^^^^^^^^^
|
= note: the matched value is of type `&!`
= note: references are always considered inhabited
help: ensure that all possible cases are being handled by adding a match arm with a wildcard pattern as shown
|
LL ~ match ref_never {
LL + _ => todo!(),
LL + }
|
error[E0004]: non-exhaustive patterns: type `(u32, !)` is non-empty
--> $DIR/empty-types.rs:70:11
|
LL | match tuple_half_never {}
| ^^^^^^^^^^^^^^^^
|
= note: the matched value is of type `(u32, !)`
help: ensure that all possible cases are being handled by adding a match arm with a wildcard pattern as shown
|
LL ~ match tuple_half_never {
LL + _ => todo!(),
LL + }
|
error[E0004]: non-exhaustive patterns: type `(!, !)` is non-empty
--> $DIR/empty-types.rs:77:11
|
LL | match tuple_never {}
| ^^^^^^^^^^^
|
= note: the matched value is of type `(!, !)`
help: ensure that all possible cases are being handled by adding a match arm with a wildcard pattern as shown
|
LL ~ match tuple_never {
LL + _ => todo!(),
LL + }
|
error: unreachable pattern
--> $DIR/empty-types.rs:87:9
|
LL | _ => {}
| ^
error[E0004]: non-exhaustive patterns: `Ok(_)` and `Err(!)` not covered
--> $DIR/empty-types.rs:91:11
|
LL | match res_u32_never {}
| ^^^^^^^^^^^^^ patterns `Ok(_)` and `Err(!)` not covered
|
note: `Result<u32, !>` defined here
--> $SRC_DIR/core/src/result.rs:LL:COL
::: $SRC_DIR/core/src/result.rs:LL:COL
|
= note: not covered
::: $SRC_DIR/core/src/result.rs:LL:COL
|
= note: not covered
= note: the matched value is of type `Result<u32, !>`
help: ensure that all possible cases are being handled by adding a match arm with a wildcard pattern, a match arm with multiple or-patterns as shown, or multiple match arms
|
LL ~ match res_u32_never {
LL + Ok(_) | Err(!) => todo!(),
LL + }
|
error[E0004]: non-exhaustive patterns: `Err(!)` not covered
--> $DIR/empty-types.rs:93:11
|
LL | match res_u32_never {
| ^^^^^^^^^^^^^ pattern `Err(!)` not covered
|
note: `Result<u32, !>` defined here
--> $SRC_DIR/core/src/result.rs:LL:COL
::: $SRC_DIR/core/src/result.rs:LL:COL
|
= note: not covered
= note: the matched value is of type `Result<u32, !>`
help: ensure that all possible cases are being handled by adding a match arm with a wildcard pattern or an explicit pattern as shown
|
LL ~ Ok(_) => {},
LL + Err(!)
|
error[E0004]: non-exhaustive patterns: `Ok(1_u32..=u32::MAX)` not covered
--> $DIR/empty-types.rs:101:11
|
LL | match res_u32_never {
| ^^^^^^^^^^^^^ pattern `Ok(1_u32..=u32::MAX)` not covered
|
note: `Result<u32, !>` defined here
--> $SRC_DIR/core/src/result.rs:LL:COL
::: $SRC_DIR/core/src/result.rs:LL:COL
|
= note: not covered
= note: the matched value is of type `Result<u32, !>`
help: ensure that all possible cases are being handled by adding a match arm with a wildcard pattern or an explicit pattern as shown
|
LL ~ Err(_) => {},
LL ~ Ok(1_u32..=u32::MAX) => todo!()
|
error[E0005]: refutable pattern in local binding
--> $DIR/empty-types.rs:106:9
|
LL | let Ok(_x) = res_u32_never;
| ^^^^^^ pattern `Err(!)` not covered
|
= note: `let` bindings require an "irrefutable pattern", like a `struct` or an `enum` with only one variant
= note: for more information, visit https://doc.rust-lang.org/book/ch18-02-refutability.html
= note: the matched value is of type `Result<u32, !>`
help: you might want to use `let else` to handle the variant that isn't matched
|
LL | let Ok(_x) = res_u32_never else { todo!() };
| ++++++++++++++++
error[E0005]: refutable pattern in local binding
--> $DIR/empty-types.rs:108:9
|
LL | let Ok(_x) = res_u32_never.as_ref();
| ^^^^^^ pattern `Err(_)` not covered
|
= note: `let` bindings require an "irrefutable pattern", like a `struct` or an `enum` with only one variant
= note: for more information, visit https://doc.rust-lang.org/book/ch18-02-refutability.html
= note: the matched value is of type `Result<&u32, &!>`
help: you might want to use `let else` to handle the variant that isn't matched
|
LL | let Ok(_x) = res_u32_never.as_ref() else { todo!() };
| ++++++++++++++++
error[E0005]: refutable pattern in local binding
--> $DIR/empty-types.rs:112:9
|
LL | let Ok(_x) = &res_u32_never;
| ^^^^^^ pattern `&Err(!)` not covered
|
= note: `let` bindings require an "irrefutable pattern", like a `struct` or an `enum` with only one variant
= note: for more information, visit https://doc.rust-lang.org/book/ch18-02-refutability.html
= note: the matched value is of type `&Result<u32, !>`
help: you might want to use `let else` to handle the variant that isn't matched
|
LL | let Ok(_x) = &res_u32_never else { todo!() };
| ++++++++++++++++
error[E0004]: non-exhaustive patterns: `Ok(!)` and `Err(!)` not covered
--> $DIR/empty-types.rs:116:11
|
LL | match result_never {}
| ^^^^^^^^^^^^ patterns `Ok(!)` and `Err(!)` not covered
|
note: `Result<!, !>` defined here
--> $SRC_DIR/core/src/result.rs:LL:COL
::: $SRC_DIR/core/src/result.rs:LL:COL
|
= note: not covered
::: $SRC_DIR/core/src/result.rs:LL:COL
|
= note: not covered
= note: the matched value is of type `Result<!, !>`
help: ensure that all possible cases are being handled by adding a match arm with a wildcard pattern, a match arm with multiple or-patterns as shown, or multiple match arms
|
LL ~ match result_never {
LL + Ok(!) | Err(!),
LL + }
|
error[E0004]: non-exhaustive patterns: `Err(!)` not covered
--> $DIR/empty-types.rs:121:11
|
LL | match result_never {
| ^^^^^^^^^^^^ pattern `Err(!)` not covered
|
note: `Result<!, !>` defined here
--> $SRC_DIR/core/src/result.rs:LL:COL
::: $SRC_DIR/core/src/result.rs:LL:COL
|
= note: not covered
= note: the matched value is of type `Result<!, !>`
help: ensure that all possible cases are being handled by adding a match arm with a wildcard pattern or an explicit pattern as shown
|
LL | Ok(_) => {}, Err(!)
| ++++++++
error: unreachable pattern
--> $DIR/empty-types.rs:140:13
|
LL | _ => {}
| ^
error: unreachable pattern
--> $DIR/empty-types.rs:143:13
|
LL | _ if false => {}
| ^
error[E0004]: non-exhaustive patterns: `Some(!)` not covered
--> $DIR/empty-types.rs:146:15
|
LL | match opt_void {
| ^^^^^^^^ pattern `Some(!)` not covered
|
note: `Option<Void>` defined here
--> $SRC_DIR/core/src/option.rs:LL:COL
::: $SRC_DIR/core/src/option.rs:LL:COL
|
= note: not covered
= note: the matched value is of type `Option<Void>`
help: ensure that all possible cases are being handled by adding a match arm with a wildcard pattern or an explicit pattern as shown
|
LL ~ None => {},
LL + Some(!)
|
error[E0004]: non-exhaustive patterns: `Some(!)` not covered
--> $DIR/empty-types.rs:165:15
|
LL | match *ref_opt_void {
| ^^^^^^^^^^^^^ pattern `Some(!)` not covered
|
note: `Option<Void>` defined here
--> $SRC_DIR/core/src/option.rs:LL:COL
::: $SRC_DIR/core/src/option.rs:LL:COL
|
= note: not covered
= note: the matched value is of type `Option<Void>`
help: ensure that all possible cases are being handled by adding a match arm with a wildcard pattern or an explicit pattern as shown
|
LL ~ None => {},
LL + Some(!)
|
error: unreachable pattern
--> $DIR/empty-types.rs:208:13
|
LL | _ => {}
| ^
error: unreachable pattern
--> $DIR/empty-types.rs:213:13
|
LL | _ => {}
| ^
error: unreachable pattern
--> $DIR/empty-types.rs:218:13
|
LL | _ => {}
| ^
error: unreachable pattern
--> $DIR/empty-types.rs:223:13
|
LL | _ => {}
| ^
error: unreachable pattern
--> $DIR/empty-types.rs:229:13
|
LL | _ => {}
| ^
error: unreachable pattern
--> $DIR/empty-types.rs:288:9
|
LL | _ => {}
| ^
error[E0004]: non-exhaustive patterns: type `(u32, !)` is non-empty
--> $DIR/empty-types.rs:316:11
|
LL | match *x {}
| ^^
|
= note: the matched value is of type `(u32, !)`
help: ensure that all possible cases are being handled by adding a match arm with a wildcard pattern as shown
|
LL ~ match *x {
LL + _ => todo!(),
LL ~ }
|
error[E0004]: non-exhaustive patterns: type `(!, !)` is non-empty
--> $DIR/empty-types.rs:318:11
|
LL | match *x {}
| ^^
|
= note: the matched value is of type `(!, !)`
help: ensure that all possible cases are being handled by adding a match arm with a wildcard pattern as shown
|
LL ~ match *x {
LL + _ => todo!(),
LL ~ }
|
error[E0004]: non-exhaustive patterns: `Ok(!)` and `Err(!)` not covered
--> $DIR/empty-types.rs:320:11
|
LL | match *x {}
| ^^ patterns `Ok(!)` and `Err(!)` not covered
|
note: `Result<!, !>` defined here
--> $SRC_DIR/core/src/result.rs:LL:COL
::: $SRC_DIR/core/src/result.rs:LL:COL
|
= note: not covered
::: $SRC_DIR/core/src/result.rs:LL:COL
|
= note: not covered
= note: the matched value is of type `Result<!, !>`
help: ensure that all possible cases are being handled by adding a match arm with a wildcard pattern, a match arm with multiple or-patterns as shown, or multiple match arms
|
LL ~ match *x {
LL + Ok(!) | Err(!),
LL ~ }
|
error[E0004]: non-exhaustive patterns: type `[!; 3]` is non-empty
--> $DIR/empty-types.rs:322:11
|
LL | match *x {}
| ^^
|
= note: the matched value is of type `[!; 3]`
help: ensure that all possible cases are being handled by adding a match arm with a wildcard pattern as shown
|
LL ~ match *x {
LL + _ => todo!(),
LL ~ }
|
error[E0004]: non-exhaustive patterns: type `&[!]` is non-empty
--> $DIR/empty-types.rs:327:11
|
LL | match slice_never {}
| ^^^^^^^^^^^
|
= note: the matched value is of type `&[!]`
help: ensure that all possible cases are being handled by adding a match arm with a wildcard pattern as shown
|
LL ~ match slice_never {
LL + _ => todo!(),
LL + }
|
error[E0004]: non-exhaustive patterns: `&[!, ..]` not covered
--> $DIR/empty-types.rs:329:11
|
LL | match slice_never {
| ^^^^^^^^^^^ pattern `&[!, ..]` not covered
|
= note: the matched value is of type `&[!]`
help: ensure that all possible cases are being handled by adding a match arm with a wildcard pattern or an explicit pattern as shown
|
LL ~ [] => {},
LL + &[!, ..]
|
error[E0004]: non-exhaustive patterns: `&[]`, `&[!]` and `&[!, !]` not covered
--> $DIR/empty-types.rs:338:11
|
LL | match slice_never {
| ^^^^^^^^^^^ patterns `&[]`, `&[!]` and `&[!, !]` not covered
|
= note: the matched value is of type `&[!]`
help: ensure that all possible cases are being handled by adding a match arm with a wildcard pattern, a match arm with multiple or-patterns as shown, or multiple match arms
|
LL ~ [_, _, _, ..] => {},
LL + &[] | &[!] | &[!, !] => todo!()
|
error[E0004]: non-exhaustive patterns: `&[]` and `&[!, ..]` not covered
--> $DIR/empty-types.rs:352:11
|
LL | match slice_never {
| ^^^^^^^^^^^ patterns `&[]` and `&[!, ..]` not covered
|
= note: the matched value is of type `&[!]`
= note: match arms with guards don't count towards exhaustivity
help: ensure that all possible cases are being handled by adding a match arm with a wildcard pattern, a match arm with multiple or-patterns as shown, or multiple match arms
|
LL ~ &[..] if false => {},
LL + &[] | &[!, ..] => todo!()
|
error[E0004]: non-exhaustive patterns: type `[!]` is non-empty
--> $DIR/empty-types.rs:359:11
|
LL | match *slice_never {}
| ^^^^^^^^^^^^
|
= note: the matched value is of type `[!]`
help: ensure that all possible cases are being handled by adding a match arm with a wildcard pattern as shown
|
LL ~ match *slice_never {
LL + _ => todo!(),
LL + }
|
error[E0004]: non-exhaustive patterns: type `[!; 3]` is non-empty
--> $DIR/empty-types.rs:366:11
|
LL | match array_3_never {}
| ^^^^^^^^^^^^^
|
= note: the matched value is of type `[!; 3]`
help: ensure that all possible cases are being handled by adding a match arm with a wildcard pattern as shown
|
LL ~ match array_3_never {
LL + _ => todo!(),
LL + }
|
error[E0004]: non-exhaustive patterns: type `[!; 0]` is non-empty
--> $DIR/empty-types.rs:389:11
|
LL | match array_0_never {}
| ^^^^^^^^^^^^^
|
= note: the matched value is of type `[!; 0]`
help: ensure that all possible cases are being handled by adding a match arm with a wildcard pattern as shown
|
LL ~ match array_0_never {
LL + _ => todo!(),
LL + }
|
error: unreachable pattern
--> $DIR/empty-types.rs:396:9
|
LL | _ => {}
| ^
error[E0004]: non-exhaustive patterns: `[]` not covered
--> $DIR/empty-types.rs:398:11
|
LL | match array_0_never {
| ^^^^^^^^^^^^^ pattern `[]` not covered
|
= note: the matched value is of type `[!; 0]`
= note: match arms with guards don't count towards exhaustivity
help: ensure that all possible cases are being handled by adding a match arm with a wildcard pattern or an explicit pattern as shown
|
LL ~ [..] if false => {},
LL + [] => todo!()
|
error[E0004]: non-exhaustive patterns: `&Some(!)` not covered
--> $DIR/empty-types.rs:452:11
|
LL | match ref_opt_never {
| ^^^^^^^^^^^^^ pattern `&Some(!)` not covered
|
note: `Option<!>` defined here
--> $SRC_DIR/core/src/option.rs:LL:COL
::: $SRC_DIR/core/src/option.rs:LL:COL
|
= note: not covered
= note: the matched value is of type `&Option<!>`
help: ensure that all possible cases are being handled by adding a match arm with a wildcard pattern or an explicit pattern as shown
|
LL ~ &None => {},
LL + &Some(!)
|
error[E0004]: non-exhaustive patterns: `Some(!)` not covered
--> $DIR/empty-types.rs:493:11
|
LL | match *ref_opt_never {
| ^^^^^^^^^^^^^^ pattern `Some(!)` not covered
|
note: `Option<!>` defined here
--> $SRC_DIR/core/src/option.rs:LL:COL
::: $SRC_DIR/core/src/option.rs:LL:COL
|
= note: not covered
= note: the matched value is of type `Option<!>`
help: ensure that all possible cases are being handled by adding a match arm with a wildcard pattern or an explicit pattern as shown
|
LL ~ None => {},
LL + Some(!)
|
error[E0004]: non-exhaustive patterns: `Err(!)` not covered
--> $DIR/empty-types.rs:541:11
|
LL | match *ref_res_never {
| ^^^^^^^^^^^^^^ pattern `Err(!)` not covered
|
note: `Result<!, !>` defined here
--> $SRC_DIR/core/src/result.rs:LL:COL
::: $SRC_DIR/core/src/result.rs:LL:COL
|
= note: not covered
= note: the matched value is of type `Result<!, !>`
help: ensure that all possible cases are being handled by adding a match arm with a wildcard pattern or an explicit pattern as shown
|
LL ~ Ok(_) => {},
LL + Err(!)
|
error[E0004]: non-exhaustive patterns: `Err(!)` not covered
--> $DIR/empty-types.rs:552:11
|
LL | match *ref_res_never {
| ^^^^^^^^^^^^^^ pattern `Err(!)` not covered
|
note: `Result<!, !>` defined here
--> $SRC_DIR/core/src/result.rs:LL:COL
::: $SRC_DIR/core/src/result.rs:LL:COL
|
= note: not covered
= note: the matched value is of type `Result<!, !>`
help: ensure that all possible cases are being handled by adding a match arm with a wildcard pattern or an explicit pattern as shown
|
LL ~ Ok(_a) => {},
LL + Err(!)
|
error[E0004]: non-exhaustive patterns: type `(u32, !)` is non-empty
--> $DIR/empty-types.rs:571:11
|
LL | match *ref_tuple_half_never {}
| ^^^^^^^^^^^^^^^^^^^^^
|
= note: the matched value is of type `(u32, !)`
help: ensure that all possible cases are being handled by adding a match arm with a wildcard pattern as shown
|
LL ~ match *ref_tuple_half_never {
LL + _ => todo!(),
LL + }
|
error: unreachable pattern
--> $DIR/empty-types.rs:604:9
|
LL | _ => {}
| ^
error: unreachable pattern
--> $DIR/empty-types.rs:607:9
|
LL | _x => {}
| ^^
error: unreachable pattern
--> $DIR/empty-types.rs:610:9
|
LL | _ if false => {}
| ^
error: unreachable pattern
--> $DIR/empty-types.rs:613:9
|
LL | _x if false => {}
| ^^
error[E0004]: non-exhaustive patterns: `&!` not covered
--> $DIR/empty-types.rs:638:11
|
LL | match ref_never {
| ^^^^^^^^^ pattern `&!` not covered
|
= note: the matched value is of type `&!`
= note: references are always considered inhabited
= note: match arms with guards don't count towards exhaustivity
help: ensure that all possible cases are being handled by adding a match arm with a wildcard pattern or an explicit pattern as shown
|
LL ~ &_a if false => {},
LL + &!
|
error[E0004]: non-exhaustive patterns: `Ok(!)` not covered
--> $DIR/empty-types.rs:654:11
|
LL | match *ref_result_never {
| ^^^^^^^^^^^^^^^^^ pattern `Ok(!)` not covered
|
note: `Result<!, !>` defined here
--> $SRC_DIR/core/src/result.rs:LL:COL
::: $SRC_DIR/core/src/result.rs:LL:COL
|
= note: not covered
= note: the matched value is of type `Result<!, !>`
help: ensure that all possible cases are being handled by adding a match arm with a wildcard pattern or an explicit pattern as shown
|
LL ~ Err(_) => {},
LL + Ok(!)
|
error[E0004]: non-exhaustive patterns: `Some(!)` not covered
--> $DIR/empty-types.rs:674:11
|
LL | match *x {
| ^^ pattern `Some(!)` not covered
|
note: `Option<Result<!, !>>` defined here
--> $SRC_DIR/core/src/option.rs:LL:COL
::: $SRC_DIR/core/src/option.rs:LL:COL
|
= note: not covered
= note: the matched value is of type `Option<Result<!, !>>`
help: ensure that all possible cases are being handled by adding a match arm with a wildcard pattern or an explicit pattern as shown
|
LL ~ None => {},
LL + Some(!)
|
error: aborting due to 49 previous errors; 1 warning emitted
Some errors have detailed explanations: E0004, E0005.
For more information about an error, try `rustc --explain E0004`.

118
tests/ui/pattern/usefulness/empty-types.normal.stderr
View File

@ -1,23 +1,23 @@
error: unreachable pattern
--> $DIR/empty-types.rs:49:9
--> $DIR/empty-types.rs:51:9
|
LL | _ => {}
| ^
|
note: the lint level is defined here
--> $DIR/empty-types.rs:15:9
--> $DIR/empty-types.rs:17:9
|
LL | #![deny(unreachable_patterns)]
| ^^^^^^^^^^^^^^^^^^^^
error: unreachable pattern
--> $DIR/empty-types.rs:52:9
--> $DIR/empty-types.rs:54:9
|
LL | _x => {}
| ^^
error[E0004]: non-exhaustive patterns: type `&!` is non-empty
--> $DIR/empty-types.rs:56:11
--> $DIR/empty-types.rs:58:11
|
LL | match ref_never {}
| ^^^^^^^^^
@ -32,7 +32,7 @@ LL + }
|
error[E0004]: non-exhaustive patterns: type `(u32, !)` is non-empty
--> $DIR/empty-types.rs:68:11
--> $DIR/empty-types.rs:70:11
|
LL | match tuple_half_never {}
| ^^^^^^^^^^^^^^^^
@ -46,7 +46,7 @@ LL + }
|
error[E0004]: non-exhaustive patterns: type `(!, !)` is non-empty
--> $DIR/empty-types.rs:75:11
--> $DIR/empty-types.rs:77:11
|
LL | match tuple_never {}
| ^^^^^^^^^^^
@ -60,13 +60,13 @@ LL + }
|
error: unreachable pattern
--> $DIR/empty-types.rs:85:9
--> $DIR/empty-types.rs:87:9
|
LL | _ => {}
| ^
error[E0004]: non-exhaustive patterns: `Ok(_)` and `Err(_)` not covered
--> $DIR/empty-types.rs:89:11
--> $DIR/empty-types.rs:91:11
|
LL | match res_u32_never {}
| ^^^^^^^^^^^^^ patterns `Ok(_)` and `Err(_)` not covered
@ -88,7 +88,7 @@ LL + }
|
error[E0004]: non-exhaustive patterns: `Err(_)` not covered
--> $DIR/empty-types.rs:91:11
--> $DIR/empty-types.rs:93:11
|
LL | match res_u32_never {
| ^^^^^^^^^^^^^ pattern `Err(_)` not covered
@ -106,7 +106,7 @@ LL + Err(_) => todo!()
|
error[E0004]: non-exhaustive patterns: `Ok(1_u32..=u32::MAX)` not covered
--> $DIR/empty-types.rs:99:11
--> $DIR/empty-types.rs:101:11
|
LL | match res_u32_never {
| ^^^^^^^^^^^^^ pattern `Ok(1_u32..=u32::MAX)` not covered
@ -124,7 +124,7 @@ LL ~ Ok(1_u32..=u32::MAX) => todo!()
|
error[E0005]: refutable pattern in local binding
--> $DIR/empty-types.rs:104:9
--> $DIR/empty-types.rs:106:9
|
LL | let Ok(_x) = res_u32_never;
| ^^^^^^ pattern `Err(_)` not covered
@ -138,7 +138,7 @@ LL | let Ok(_x) = res_u32_never else { todo!() };
| ++++++++++++++++
error[E0005]: refutable pattern in local binding
--> $DIR/empty-types.rs:106:9
--> $DIR/empty-types.rs:108:9
|
LL | let Ok(_x) = res_u32_never.as_ref();
| ^^^^^^ pattern `Err(_)` not covered
@ -152,7 +152,7 @@ LL | let Ok(_x) = res_u32_never.as_ref() else { todo!() };
| ++++++++++++++++
error[E0005]: refutable pattern in local binding
--> $DIR/empty-types.rs:110:9
--> $DIR/empty-types.rs:112:9
|
LL | let Ok(_x) = &res_u32_never;
| ^^^^^^ pattern `&Err(_)` not covered
@ -166,7 +166,7 @@ LL | let Ok(_x) = &res_u32_never else { todo!() };
| ++++++++++++++++
error[E0004]: non-exhaustive patterns: `Ok(_)` and `Err(_)` not covered
--> $DIR/empty-types.rs:114:11
--> $DIR/empty-types.rs:116:11
|
LL | match result_never {}
| ^^^^^^^^^^^^ patterns `Ok(_)` and `Err(_)` not covered
@ -188,7 +188,7 @@ LL + }
|
error[E0004]: non-exhaustive patterns: `Err(_)` not covered
--> $DIR/empty-types.rs:119:11
--> $DIR/empty-types.rs:121:11
|
LL | match result_never {
| ^^^^^^^^^^^^ pattern `Err(_)` not covered
@ -205,19 +205,19 @@ LL | Ok(_) => {}, Err(_) => todo!()
| +++++++++++++++++++
error: unreachable pattern
--> $DIR/empty-types.rs:138:13
--> $DIR/empty-types.rs:140:13
|
LL | _ => {}
| ^
error: unreachable pattern
--> $DIR/empty-types.rs:141:13
--> $DIR/empty-types.rs:143:13
|
LL | _ if false => {}
| ^
error[E0004]: non-exhaustive patterns: `Some(_)` not covered
--> $DIR/empty-types.rs:144:15
--> $DIR/empty-types.rs:146:15
|
LL | match opt_void {
| ^^^^^^^^ pattern `Some(_)` not covered
@ -235,7 +235,7 @@ LL + Some(_) => todo!()
|
error[E0004]: non-exhaustive patterns: `Some(_)` not covered
--> $DIR/empty-types.rs:163:15
--> $DIR/empty-types.rs:165:15
|
LL | match *ref_opt_void {
| ^^^^^^^^^^^^^ pattern `Some(_)` not covered
@ -253,43 +253,43 @@ LL + Some(_) => todo!()
|
error: unreachable pattern
--> $DIR/empty-types.rs:206:13
--> $DIR/empty-types.rs:208:13
|
LL | _ => {}
| ^
error: unreachable pattern
--> $DIR/empty-types.rs:211:13
--> $DIR/empty-types.rs:213:13
|
LL | _ => {}
| ^
error: unreachable pattern
--> $DIR/empty-types.rs:216:13
--> $DIR/empty-types.rs:218:13
|
LL | _ => {}
| ^
error: unreachable pattern
--> $DIR/empty-types.rs:221:13
--> $DIR/empty-types.rs:223:13
|
LL | _ => {}
| ^
error: unreachable pattern
--> $DIR/empty-types.rs:227:13
--> $DIR/empty-types.rs:229:13
|
LL | _ => {}
| ^
error: unreachable pattern
--> $DIR/empty-types.rs:286:9
--> $DIR/empty-types.rs:288:9
|
LL | _ => {}
| ^
error[E0004]: non-exhaustive patterns: type `(u32, !)` is non-empty
--> $DIR/empty-types.rs:314:11
--> $DIR/empty-types.rs:316:11
|
LL | match *x {}
| ^^
@ -303,7 +303,7 @@ LL ~ }
|
error[E0004]: non-exhaustive patterns: type `(!, !)` is non-empty
--> $DIR/empty-types.rs:316:11
--> $DIR/empty-types.rs:318:11
|
LL | match *x {}
| ^^
@ -317,7 +317,7 @@ LL ~ }
|
error[E0004]: non-exhaustive patterns: `Ok(_)` and `Err(_)` not covered
--> $DIR/empty-types.rs:318:11
--> $DIR/empty-types.rs:320:11
|
LL | match *x {}
| ^^ patterns `Ok(_)` and `Err(_)` not covered
@ -339,7 +339,7 @@ LL ~ }
|
error[E0004]: non-exhaustive patterns: type `[!; 3]` is non-empty
--> $DIR/empty-types.rs:320:11
--> $DIR/empty-types.rs:322:11
|
LL | match *x {}
| ^^
@ -353,7 +353,7 @@ LL ~ }
|
error[E0004]: non-exhaustive patterns: type `&[!]` is non-empty
--> $DIR/empty-types.rs:325:11
--> $DIR/empty-types.rs:327:11
|
LL | match slice_never {}
| ^^^^^^^^^^^
@ -367,7 +367,7 @@ LL + }
|
error[E0004]: non-exhaustive patterns: `&[_, ..]` not covered
--> $DIR/empty-types.rs:327:11
--> $DIR/empty-types.rs:329:11
|
LL | match slice_never {
| ^^^^^^^^^^^ pattern `&[_, ..]` not covered
@ -380,7 +380,7 @@ LL + &[_, ..] => todo!()
|
error[E0004]: non-exhaustive patterns: `&[]`, `&[_]` and `&[_, _]` not covered
--> $DIR/empty-types.rs:336:11
--> $DIR/empty-types.rs:338:11
|
LL | match slice_never {
| ^^^^^^^^^^^ patterns `&[]`, `&[_]` and `&[_, _]` not covered
@ -393,7 +393,7 @@ LL + &[] | &[_] | &[_, _] => todo!()
|
error[E0004]: non-exhaustive patterns: `&[]` and `&[_, ..]` not covered
--> $DIR/empty-types.rs:349:11
--> $DIR/empty-types.rs:352:11
|
LL | match slice_never {
| ^^^^^^^^^^^ patterns `&[]` and `&[_, ..]` not covered
@ -407,7 +407,7 @@ LL + &[] | &[_, ..] => todo!()
|
error[E0004]: non-exhaustive patterns: type `[!]` is non-empty
--> $DIR/empty-types.rs:355:11
--> $DIR/empty-types.rs:359:11
|
LL | match *slice_never {}
| ^^^^^^^^^^^^
@ -421,7 +421,7 @@ LL + }
|
error[E0004]: non-exhaustive patterns: type `[!; 3]` is non-empty
--> $DIR/empty-types.rs:362:11
--> $DIR/empty-types.rs:366:11
|
LL | match array_3_never {}
| ^^^^^^^^^^^^^
@ -435,7 +435,7 @@ LL + }
|
error[E0004]: non-exhaustive patterns: type `[!; 0]` is non-empty
--> $DIR/empty-types.rs:385:11
--> $DIR/empty-types.rs:389:11
|
LL | match array_0_never {}
| ^^^^^^^^^^^^^
@ -449,13 +449,13 @@ LL + }
|
error: unreachable pattern
--> $DIR/empty-types.rs:392:9
--> $DIR/empty-types.rs:396:9
|
LL | _ => {}
| ^
error[E0004]: non-exhaustive patterns: `[]` not covered
--> $DIR/empty-types.rs:394:11
--> $DIR/empty-types.rs:398:11
|
LL | match array_0_never {
| ^^^^^^^^^^^^^ pattern `[]` not covered
@ -469,7 +469,7 @@ LL + [] => todo!()
|
error[E0004]: non-exhaustive patterns: `&Some(_)` not covered
--> $DIR/empty-types.rs:448:11
--> $DIR/empty-types.rs:452:11
|
LL | match ref_opt_never {
| ^^^^^^^^^^^^^ pattern `&Some(_)` not covered
@ -487,7 +487,7 @@ LL + &Some(_) => todo!()
|
error[E0004]: non-exhaustive patterns: `Some(_)` not covered
--> $DIR/empty-types.rs:489:11
--> $DIR/empty-types.rs:493:11
|
LL | match *ref_opt_never {
| ^^^^^^^^^^^^^^ pattern `Some(_)` not covered
@ -505,7 +505,7 @@ LL + Some(_) => todo!()
|
error[E0004]: non-exhaustive patterns: `Err(_)` not covered
--> $DIR/empty-types.rs:537:11
--> $DIR/empty-types.rs:541:11
|
LL | match *ref_res_never {
| ^^^^^^^^^^^^^^ pattern `Err(_)` not covered
@ -523,7 +523,7 @@ LL + Err(_) => todo!()
|
error[E0004]: non-exhaustive patterns: `Err(_)` not covered
--> $DIR/empty-types.rs:548:11
--> $DIR/empty-types.rs:552:11
|
LL | match *ref_res_never {
| ^^^^^^^^^^^^^^ pattern `Err(_)` not covered
@ -541,7 +541,7 @@ LL + Err(_) => todo!()
|
error[E0004]: non-exhaustive patterns: type `(u32, !)` is non-empty
--> $DIR/empty-types.rs:567:11
--> $DIR/empty-types.rs:571:11
|
LL | match *ref_tuple_half_never {}
| ^^^^^^^^^^^^^^^^^^^^^
@ -555,31 +555,31 @@ LL + }
|
error: unreachable pattern
--> $DIR/empty-types.rs:600:9
--> $DIR/empty-types.rs:604:9
|
LL | _ => {}
| ^
error: unreachable pattern
--> $DIR/empty-types.rs:603:9
--> $DIR/empty-types.rs:607:9
|
LL | _x => {}
| ^^
error: unreachable pattern
--> $DIR/empty-types.rs:606:9
--> $DIR/empty-types.rs:610:9
|
LL | _ if false => {}
| ^
error: unreachable pattern
--> $DIR/empty-types.rs:609:9
--> $DIR/empty-types.rs:613:9
|
LL | _x if false => {}
| ^^
error[E0004]: non-exhaustive patterns: `&_` not covered
--> $DIR/empty-types.rs:634:11
--> $DIR/empty-types.rs:638:11
|
LL | match ref_never {
| ^^^^^^^^^ pattern `&_` not covered
@ -593,8 +593,26 @@ LL ~ &_a if false => {},
LL + &_ => todo!()
|
error[E0004]: non-exhaustive patterns: `Ok(_)` not covered
--> $DIR/empty-types.rs:654:11
|
LL | match *ref_result_never {
| ^^^^^^^^^^^^^^^^^ pattern `Ok(_)` not covered
|
note: `Result<!, !>` defined here
--> $SRC_DIR/core/src/result.rs:LL:COL
::: $SRC_DIR/core/src/result.rs:LL:COL
|
= note: not covered
= note: the matched value is of type `Result<!, !>`
help: ensure that all possible cases are being handled by adding a match arm with a wildcard pattern or an explicit pattern as shown
|
LL ~ Err(_) => {},
LL + Ok(_) => todo!()
|
error[E0004]: non-exhaustive patterns: `Some(_)` not covered
--> $DIR/empty-types.rs:662:11
--> $DIR/empty-types.rs:674:11
|
LL | match *x {
| ^^ pattern `Some(_)` not covered
@ -611,7 +629,7 @@ LL ~ None => {},
LL + Some(_) => todo!()
|
error: aborting due to 48 previous errors
error: aborting due to 49 previous errors
Some errors have detailed explanations: E0004, E0005.
For more information about an error, try `rustc --explain E0004`.

57
tests/ui/pattern/usefulness/empty-types.rs
View File

@ -1,4 +1,4 @@
//@ revisions: normal min_exh_pats exhaustive_patterns
//@ revisions: normal min_exh_pats exhaustive_patterns never_pats
// gate-test-min_exhaustive_patterns
//
// This tests correct handling of empty types in exhaustiveness checking.
@ -11,6 +11,8 @@
#![feature(never_type_fallback)]
#![cfg_attr(exhaustive_patterns, feature(exhaustive_patterns))]
#![cfg_attr(min_exh_pats, feature(min_exhaustive_patterns))]
#![cfg_attr(never_pats, feature(never_patterns))]
//[never_pats]~^ WARN the feature `never_patterns` is incomplete
#![allow(dead_code, unreachable_code)]
#![deny(unreachable_patterns)]
@ -66,14 +68,14 @@ fn basic(x: NeverBundle) {
let tuple_half_never: (u32, !) = x.tuple_half_never;
match tuple_half_never {}
//[normal]~^ ERROR non-empty
//[normal,never_pats]~^ ERROR non-empty
match tuple_half_never {
(_, _) => {} //[exhaustive_patterns,min_exh_pats]~ ERROR unreachable pattern
}
let tuple_never: (!, !) = x.tuple_never;
match tuple_never {}
//[normal]~^ ERROR non-empty
//[normal,never_pats]~^ ERROR non-empty
match tuple_never {
_ => {} //[exhaustive_patterns,min_exh_pats]~ ERROR unreachable pattern
}
@ -89,7 +91,7 @@ fn basic(x: NeverBundle) {
match res_u32_never {}
//~^ ERROR non-exhaustive
match res_u32_never {
//[normal]~^ ERROR non-exhaustive
//[normal,never_pats]~^ ERROR non-exhaustive
Ok(_) => {}
}
match res_u32_never {
@ -102,22 +104,22 @@ fn basic(x: NeverBundle) {
Err(_) => {} //[exhaustive_patterns,min_exh_pats]~ ERROR unreachable pattern
}
let Ok(_x) = res_u32_never;
//[normal]~^ ERROR refutable
//[normal,never_pats]~^ ERROR refutable
let Ok(_x) = res_u32_never.as_ref();
//~^ ERROR refutable
// Non-obvious difference: here there's an implicit dereference in the patterns, which makes the
// inner place !known_valid. `exhaustive_patterns` ignores this.
let Ok(_x) = &res_u32_never;
//[normal,min_exh_pats]~^ ERROR refutable
//[normal,min_exh_pats,never_pats]~^ ERROR refutable
let result_never: Result<!, !> = x.result_never;
match result_never {}
//[normal]~^ ERROR non-exhaustive
//[normal,never_pats]~^ ERROR non-exhaustive
match result_never {
_ => {} //[exhaustive_patterns,min_exh_pats]~ ERROR unreachable pattern
}
match result_never {
//[normal]~^ ERROR non-exhaustive
//[normal,never_pats]~^ ERROR non-exhaustive
Ok(_) => {} //[exhaustive_patterns,min_exh_pats]~ ERROR unreachable pattern
}
match result_never {
@ -142,7 +144,7 @@ fn void_same_as_never(x: NeverBundle) {
}
let opt_void: Option<Void> = None;
match opt_void {
//[normal]~^ ERROR non-exhaustive
//[normal,never_pats]~^ ERROR non-exhaustive
None => {}
}
match opt_void {
@ -161,7 +163,7 @@ fn void_same_as_never(x: NeverBundle) {
}
let ref_opt_void: &Option<Void> = &None;
match *ref_opt_void {
//[normal,min_exh_pats]~^ ERROR non-exhaustive
//[normal,min_exh_pats,never_pats]~^ ERROR non-exhaustive
None => {}
}
match *ref_opt_void {
@ -311,13 +313,13 @@ fn invalid_empty_match(bundle: NeverBundle) {
match *x {}
let x: &(u32, !) = &bundle.tuple_half_never;
match *x {} //[normal,min_exh_pats]~ ERROR non-exhaustive
match *x {} //[normal,min_exh_pats,never_pats]~ ERROR non-exhaustive
let x: &(!, !) = &bundle.tuple_never;
match *x {} //[normal,min_exh_pats]~ ERROR non-exhaustive
match *x {} //[normal,min_exh_pats,never_pats]~ ERROR non-exhaustive
let x: &Result<!, !> = &bundle.result_never;
match *x {} //[normal,min_exh_pats]~ ERROR non-exhaustive
match *x {} //[normal,min_exh_pats,never_pats]~ ERROR non-exhaustive
let x: &[!; 3] = &bundle.array_3_never;
match *x {} //[normal,min_exh_pats]~ ERROR non-exhaustive
match *x {} //[normal,min_exh_pats,never_pats]~ ERROR non-exhaustive
}
fn arrays_and_slices(x: NeverBundle) {
@ -325,7 +327,7 @@ fn arrays_and_slices(x: NeverBundle) {
match slice_never {}
//~^ ERROR non-empty
match slice_never {
//[normal,min_exh_pats]~^ ERROR not covered
//[normal,min_exh_pats,never_pats]~^ ERROR not covered
[] => {}
}
match slice_never {
@ -336,6 +338,7 @@ fn arrays_and_slices(x: NeverBundle) {
match slice_never {
//[normal,min_exh_pats]~^ ERROR `&[]`, `&[_]` and `&[_, _]` not covered
//[exhaustive_patterns]~^^ ERROR `&[]` not covered
//[never_pats]~^^^ ERROR `&[]`, `&[!]` and `&[!, !]` not covered
[_, _, _, ..] => {}
}
match slice_never {
@ -349,6 +352,7 @@ fn arrays_and_slices(x: NeverBundle) {
match slice_never {
//[normal,min_exh_pats]~^ ERROR `&[]` and `&[_, ..]` not covered
//[exhaustive_patterns]~^^ ERROR `&[]` not covered
//[never_pats]~^^^ ERROR `&[]` and `&[!, ..]` not covered
&[..] if false => {}
}
@ -360,7 +364,7 @@ fn arrays_and_slices(x: NeverBundle) {
let array_3_never: [!; 3] = x.array_3_never;
match array_3_never {}
//[normal]~^ ERROR non-empty
//[normal,never_pats]~^ ERROR non-empty
match array_3_never {
_ => {} //[exhaustive_patterns,min_exh_pats]~ ERROR unreachable pattern
}
@ -446,7 +450,7 @@ fn bindings(x: NeverBundle) {
&_a => {}
}
match ref_opt_never {
//[normal,min_exh_pats]~^ ERROR non-exhaustive
//[normal,min_exh_pats,never_pats]~^ ERROR non-exhaustive
&None => {}
}
match ref_opt_never {
@ -487,7 +491,7 @@ fn bindings(x: NeverBundle) {
ref _a => {}
}
match *ref_opt_never {
//[normal,min_exh_pats]~^ ERROR non-exhaustive
//[normal,min_exh_pats,never_pats]~^ ERROR non-exhaustive
None => {}
}
match *ref_opt_never {
@ -535,7 +539,7 @@ fn bindings(x: NeverBundle) {
let ref_res_never: &Result<!, !> = &x.result_never;
match *ref_res_never {
//[normal,min_exh_pats]~^ ERROR non-exhaustive
//[normal,min_exh_pats,never_pats]~^ ERROR non-exhaustive
// useful, reachable
Ok(_) => {}
}
@ -546,7 +550,7 @@ fn bindings(x: NeverBundle) {
_ => {}
}
match *ref_res_never {
//[normal,min_exh_pats]~^ ERROR non-exhaustive
//[normal,min_exh_pats,never_pats]~^ ERROR non-exhaustive
// useful, !reachable
Ok(_a) => {}
}
@ -565,7 +569,7 @@ fn bindings(x: NeverBundle) {
let ref_tuple_half_never: &(u32, !) = &x.tuple_half_never;
match *ref_tuple_half_never {}
//[normal,min_exh_pats]~^ ERROR non-empty
//[normal,min_exh_pats,never_pats]~^ ERROR non-empty
match *ref_tuple_half_never {
// useful, reachable
(_, _) => {}
@ -632,7 +636,7 @@ fn guards_and_validity(x: NeverBundle) {
_a if false => {}
}
match ref_never {
//[normal,min_exh_pats]~^ ERROR non-exhaustive
//[normal,min_exh_pats,never_pats]~^ ERROR non-exhaustive
// useful, !reachable
&_a if false => {}
}
@ -647,6 +651,14 @@ fn guards_and_validity(x: NeverBundle) {
// useful, !reachable
Err(_) => {}
}
match *ref_result_never {
//[normal,min_exh_pats]~^ ERROR `Ok(_)` not covered
//[never_pats]~^^ ERROR `Ok(!)` not covered
// useful, reachable
Ok(_) if false => {}
// useful, reachable
Err(_) => {}
}
let ref_tuple_never: &(!, !) = &x.tuple_never;
match *ref_tuple_never {
// useful, !reachable
@ -661,6 +673,7 @@ fn diagnostics_subtlety(x: NeverBundle) {
let x: &Option<Result<!, !>> = &None;
match *x {
//[normal,min_exh_pats]~^ ERROR `Some(_)` not covered
//[never_pats]~^^ ERROR `Some(!)` not covered
None => {}
}
}

4
tests/ui/rfcs/rfc-0000-never_patterns/check.rs
View File

@ -15,12 +15,12 @@ fn no_arms_or_guards(x: Void) {
//~^ ERROR a never pattern is always unreachable
None => {}
}
match None::<Void> { //~ ERROR: `Some(_)` not covered
match None::<Void> { //~ ERROR: `Some(!)` not covered
Some(!) if true,
//~^ ERROR guard on a never pattern
None => {}
}
match None::<Void> { //~ ERROR: `Some(_)` not covered
match None::<Void> { //~ ERROR: `Some(!)` not covered
Some(!) if true => {}
//~^ ERROR a never pattern is always unreachable
None => {}

12
tests/ui/rfcs/rfc-0000-never_patterns/check.stderr
View File

@ -31,11 +31,11 @@ LL | Some(never!()) => {}
| this will never be executed
| help: remove this expression
error[E0004]: non-exhaustive patterns: `Some(_)` not covered
error[E0004]: non-exhaustive patterns: `Some(!)` not covered
--> $DIR/check.rs:18:11
|
LL | match None::<Void> {
| ^^^^^^^^^^^^ pattern `Some(_)` not covered
| ^^^^^^^^^^^^ pattern `Some(!)` not covered
|
note: `Option<Void>` defined here
--> $SRC_DIR/core/src/option.rs:LL:COL
@ -46,14 +46,14 @@ note: `Option<Void>` defined here
help: ensure that all possible cases are being handled by adding a match arm with a wildcard pattern or an explicit pattern as shown
|
LL ~ None => {},
LL + Some(_) => todo!()
LL + Some(!)
|
error[E0004]: non-exhaustive patterns: `Some(_)` not covered
error[E0004]: non-exhaustive patterns: `Some(!)` not covered
--> $DIR/check.rs:23:11
|
LL | match None::<Void> {
| ^^^^^^^^^^^^ pattern `Some(_)` not covered
| ^^^^^^^^^^^^ pattern `Some(!)` not covered
|
note: `Option<Void>` defined here
--> $SRC_DIR/core/src/option.rs:LL:COL
@ -64,7 +64,7 @@ note: `Option<Void>` defined here
help: ensure that all possible cases are being handled by adding a match arm with a wildcard pattern or an explicit pattern as shown
|
LL ~ None => {},
LL + Some(_) => todo!()
LL + Some(!)
|
error: aborting due to 6 previous errors