mirror of
https://github.com/rust-lang/rust
synced 2024-10-02 06:44:33 +00:00
Always fall back to PartialEq when a constant in a pattern is not recursively structural-eq
This commit is contained in:
Oli Scherer
parent
8d00f762dd
commit
ad424e65d8
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@ -380,7 +380,9 @@ fn compare(
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);
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}
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/// Compare two `&T` values using `<T as std::compare::PartialEq>::eq`
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/// Compare two values using `<T as std::compare::PartialEq>::eq`.
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/// If the values are already references, just call it directly, otherwise
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/// take a reference to the values first and then call it.
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fn non_scalar_compare(
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&mut self,
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block: BasicBlock,
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@ -441,12 +443,36 @@ fn non_scalar_compare(
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}
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}
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let ty::Ref(_, deref_ty, _) = *ty.kind() else {
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bug!("non_scalar_compare called on non-reference type: {}", ty);
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};
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match *ty.kind() {
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ty::Ref(_, deref_ty, _) => ty = deref_ty,
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_ => {
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// non_scalar_compare called on non-reference type
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let temp = self.temp(ty, source_info.span);
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self.cfg.push_assign(block, source_info, temp, Rvalue::Use(expect));
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let ref_ty = self.tcx.mk_imm_ref(self.tcx.lifetimes.re_erased, ty);
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let ref_temp = self.temp(ref_ty, source_info.span);
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self.cfg.push_assign(
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block,
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source_info,
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ref_temp,
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Rvalue::Ref(self.tcx.lifetimes.re_erased, BorrowKind::Shared, temp),
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);
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expect = Operand::Move(ref_temp);
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let ref_temp = self.temp(ref_ty, source_info.span);
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self.cfg.push_assign(
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block,
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source_info,
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ref_temp,
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Rvalue::Ref(self.tcx.lifetimes.re_erased, BorrowKind::Shared, val),
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);
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val = ref_temp;
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}
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}
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let eq_def_id = self.tcx.require_lang_item(LangItem::PartialEq, Some(source_info.span));
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let method = trait_method(self.tcx, eq_def_id, sym::eq, [deref_ty, deref_ty]);
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let method = trait_method(self.tcx, eq_def_id, sym::eq, [ty, ty]);
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let bool_ty = self.tcx.types.bool;
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let eq_result = self.temp(bool_ty, source_info.span);
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@ -62,21 +62,13 @@ struct ConstToPat<'tcx> {
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treat_byte_string_as_slice: bool,
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}
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mod fallback_to_const_ref {
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#[derive(Debug)]
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/// This error type signals that we encountered a non-struct-eq situation behind a reference.
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/// We bubble this up in order to get back to the reference destructuring and make that emit
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/// a const pattern instead of a deref pattern. This allows us to simply call `PartialEq::eq`
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/// on such patterns (since that function takes a reference) and not have to jump through any
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/// hoops to get a reference to the value.
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pub(super) struct FallbackToConstRef(());
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pub(super) fn fallback_to_const_ref(c2p: &super::ConstToPat<'_>) -> FallbackToConstRef {
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assert!(c2p.behind_reference.get());
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FallbackToConstRef(())
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}
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}
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use fallback_to_const_ref::{fallback_to_const_ref, FallbackToConstRef};
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/// This error type signals that we encountered a non-struct-eq situation.
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/// We bubble this up in order to get back to the reference destructuring and make that emit
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/// a const pattern instead of a deref pattern. This allows us to simply call `PartialEq::eq`
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/// on such patterns (since that function takes a reference) and not have to jump through any
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/// hoops to get a reference to the value.
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#[derive(Debug)]
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struct FallbackToConstRef;
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impl<'tcx> ConstToPat<'tcx> {
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fn new(
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@ -236,13 +228,13 @@ fn recur(
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let kind = match cv.ty().kind() {
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ty::Float(_) => {
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tcx.emit_spanned_lint(
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lint::builtin::ILLEGAL_FLOATING_POINT_LITERAL_PATTERN,
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id,
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span,
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FloatPattern,
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);
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PatKind::Constant { value: cv }
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tcx.emit_spanned_lint(
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lint::builtin::ILLEGAL_FLOATING_POINT_LITERAL_PATTERN,
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id,
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span,
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FloatPattern,
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);
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return Err(FallbackToConstRef);
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}
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ty::Adt(adt_def, _) if adt_def.is_union() => {
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// Matching on union fields is unsafe, we can't hide it in constants
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@ -289,7 +281,7 @@ fn recur(
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// Since we are behind a reference, we can just bubble the error up so we get a
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// constant at reference type, making it easy to let the fallback call
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// `PartialEq::eq` on it.
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return Err(fallback_to_const_ref(self));
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return Err(FallbackToConstRef);
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}
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ty::Adt(adt_def, _) if !self.type_marked_structural(cv.ty()) => {
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debug!(
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@ -411,7 +403,7 @@ fn recur(
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IndirectStructuralMatch { non_sm_ty: *pointee_ty },
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);
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}
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PatKind::Constant { value: cv }
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return Err(FallbackToConstRef);
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} else {
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if !self.saw_const_match_error.get() {
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self.saw_const_match_error.set(true);
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@ -439,12 +431,9 @@ fn recur(
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// we fall back to a const pattern. If we do not do this, we may end up with
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// a !structural-match constant that is not of reference type, which makes it
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// very hard to invoke `PartialEq::eq` on it as a fallback.
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let val = match self.recur(tcx.deref_mir_constant(self.param_env.and(cv)), false) {
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Ok(subpattern) => PatKind::Deref { subpattern },
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Err(_) => PatKind::Constant { value: cv },
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};
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let subpattern = self.recur(tcx.deref_mir_constant(self.param_env.and(cv)), false)?;
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self.behind_reference.set(old);
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val
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PatKind::Deref { subpattern }
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}
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}
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},
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@ -452,7 +441,7 @@ fn recur(
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PatKind::Constant { value: cv }
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}
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ty::RawPtr(pointee) if pointee.ty.is_sized(tcx, param_env) => {
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PatKind::Constant { value: cv }
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return Err(FallbackToConstRef);
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}
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// FIXME: these can have very surprising behaviour where optimization levels or other
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// compilation choices change the runtime behaviour of the match.
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@ -469,7 +458,7 @@ fn recur(
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PointerPattern
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);
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}
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PatKind::Constant { value: cv }
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return Err(FallbackToConstRef);
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}
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_ => {
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self.saw_const_match_error.set(true);
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@ -20,11 +20,12 @@ impl Eq for Bar {}
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#[derive(PartialEq)]
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enum Baz {
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Baz1,
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Baz2
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Baz2,
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}
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impl Eq for Baz {}
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const BAZ: Baz = Baz::Baz1;
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#[rustfmt::skip]
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fn main() {
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match FOO {
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FOO => {}
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@ -124,8 +125,16 @@ fn quux(a: usize, b: usize) -> usize { a + b }
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match WRAPQUUX {
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Wrap(_) => {}
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WRAPQUUX => {} // detected unreachable because we do inspect the `Wrap` layer
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//~^ ERROR unreachable pattern
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WRAPQUUX => {}
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}
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match WRAPQUUX {
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Wrap(_) => {}
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}
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match WRAPQUUX {
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//~^ ERROR: non-exhaustive patterns: `Wrap(_)` not covered
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WRAPQUUX => {}
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}
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#[derive(PartialEq, Eq)]
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@ -138,8 +147,7 @@ enum WhoKnows<T> {
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match WHOKNOWSQUUX {
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WHOKNOWSQUUX => {}
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WhoKnows::Yay(_) => {}
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WHOKNOWSQUUX => {} // detected unreachable because we do inspect the `WhoKnows` layer
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//~^ ERROR unreachable pattern
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WHOKNOWSQUUX => {}
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WhoKnows::Nope => {}
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}
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}
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@ -1,5 +1,5 @@
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error: to use a constant of type `Foo` in a pattern, `Foo` must be annotated with `#[derive(PartialEq, Eq)]`
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--> $DIR/consts-opaque.rs:30:9
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--> $DIR/consts-opaque.rs:31:9
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LL | FOO => {}
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| ^^^
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@ -8,7 +8,7 @@ LL | FOO => {}
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= note: see https://doc.rust-lang.org/stable/std/marker/trait.StructuralEq.html for details
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error: to use a constant of type `Foo` in a pattern, `Foo` must be annotated with `#[derive(PartialEq, Eq)]`
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--> $DIR/consts-opaque.rs:37:9
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--> $DIR/consts-opaque.rs:38:9
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LL | FOO_REF => {}
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| ^^^^^^^
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@ -17,7 +17,7 @@ LL | FOO_REF => {}
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= note: see https://doc.rust-lang.org/stable/std/marker/trait.StructuralEq.html for details
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warning: to use a constant of type `Foo` in a pattern, `Foo` must be annotated with `#[derive(PartialEq, Eq)]`
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--> $DIR/consts-opaque.rs:45:9
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--> $DIR/consts-opaque.rs:46:9
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LL | FOO_REF_REF => {}
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| ^^^^^^^^^^^
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@ -29,7 +29,7 @@ LL | FOO_REF_REF => {}
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= note: `#[warn(indirect_structural_match)]` on by default
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error: to use a constant of type `Bar` in a pattern, `Bar` must be annotated with `#[derive(PartialEq, Eq)]`
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--> $DIR/consts-opaque.rs:53:9
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--> $DIR/consts-opaque.rs:54:9
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LL | BAR => {} // should not be emitting unreachable warning
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| ^^^
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@ -38,7 +38,7 @@ LL | BAR => {} // should not be emitting unreachable warning
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= note: see https://doc.rust-lang.org/stable/std/marker/trait.StructuralEq.html for details
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error: to use a constant of type `Bar` in a pattern, `Bar` must be annotated with `#[derive(PartialEq, Eq)]`
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--> $DIR/consts-opaque.rs:61:9
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--> $DIR/consts-opaque.rs:62:9
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LL | BAR => {}
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| ^^^
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@ -47,7 +47,7 @@ LL | BAR => {}
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= note: see https://doc.rust-lang.org/stable/std/marker/trait.StructuralEq.html for details
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error: to use a constant of type `Bar` in a pattern, `Bar` must be annotated with `#[derive(PartialEq, Eq)]`
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--> $DIR/consts-opaque.rs:70:9
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--> $DIR/consts-opaque.rs:71:9
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LL | BAR => {}
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| ^^^
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@ -56,7 +56,7 @@ LL | BAR => {}
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= note: see https://doc.rust-lang.org/stable/std/marker/trait.StructuralEq.html for details
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error: to use a constant of type `Bar` in a pattern, `Bar` must be annotated with `#[derive(PartialEq, Eq)]`
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--> $DIR/consts-opaque.rs:72:9
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--> $DIR/consts-opaque.rs:73:9
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LL | BAR => {} // should not be emitting unreachable warning
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| ^^^
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@ -65,7 +65,7 @@ LL | BAR => {} // should not be emitting unreachable warning
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= note: see https://doc.rust-lang.org/stable/std/marker/trait.StructuralEq.html for details
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error: to use a constant of type `Baz` in a pattern, `Baz` must be annotated with `#[derive(PartialEq, Eq)]`
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--> $DIR/consts-opaque.rs:80:9
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--> $DIR/consts-opaque.rs:81:9
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|
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LL | BAZ => {}
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| ^^^
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@ -74,7 +74,7 @@ LL | BAZ => {}
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= note: see https://doc.rust-lang.org/stable/std/marker/trait.StructuralEq.html for details
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error: to use a constant of type `Baz` in a pattern, `Baz` must be annotated with `#[derive(PartialEq, Eq)]`
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--> $DIR/consts-opaque.rs:90:9
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--> $DIR/consts-opaque.rs:91:9
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|
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LL | BAZ => {}
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| ^^^
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@ -83,7 +83,7 @@ LL | BAZ => {}
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= note: see https://doc.rust-lang.org/stable/std/marker/trait.StructuralEq.html for details
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error: to use a constant of type `Baz` in a pattern, `Baz` must be annotated with `#[derive(PartialEq, Eq)]`
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--> $DIR/consts-opaque.rs:97:9
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--> $DIR/consts-opaque.rs:98:9
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|
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LL | BAZ => {}
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| ^^^
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@ -92,7 +92,7 @@ LL | BAZ => {}
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= note: see https://doc.rust-lang.org/stable/std/marker/trait.StructuralEq.html for details
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error: unreachable pattern
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--> $DIR/consts-opaque.rs:32:9
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--> $DIR/consts-opaque.rs:33:9
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|
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LL | FOO => {}
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| --- matches any value
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@ -107,7 +107,7 @@ LL | #![deny(unreachable_patterns)]
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| ^^^^^^^^^^^^^^^^^^^^
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error: unreachable pattern
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--> $DIR/consts-opaque.rs:39:9
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--> $DIR/consts-opaque.rs:40:9
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|
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LL | FOO_REF => {}
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| ------- matches any value
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@ -116,7 +116,7 @@ LL | Foo(_) => {} // should not be emitting unreachable warning
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| ^^^^^^ unreachable pattern
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error: unreachable pattern
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--> $DIR/consts-opaque.rs:53:9
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--> $DIR/consts-opaque.rs:54:9
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|
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LL | Bar => {}
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| --- matches any value
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@ -124,7 +124,7 @@ LL | BAR => {} // should not be emitting unreachable warning
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| ^^^ unreachable pattern
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error: unreachable pattern
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--> $DIR/consts-opaque.rs:56:9
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--> $DIR/consts-opaque.rs:57:9
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|
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LL | Bar => {}
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| --- matches any value
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@ -133,7 +133,7 @@ LL | _ => {}
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| ^ unreachable pattern
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error: unreachable pattern
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--> $DIR/consts-opaque.rs:63:9
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--> $DIR/consts-opaque.rs:64:9
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|
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LL | BAR => {}
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| --- matches any value
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@ -142,7 +142,7 @@ LL | Bar => {} // should not be emitting unreachable warning
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| ^^^ unreachable pattern
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error: unreachable pattern
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--> $DIR/consts-opaque.rs:65:9
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--> $DIR/consts-opaque.rs:66:9
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|
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LL | BAR => {}
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| --- matches any value
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@ -151,7 +151,7 @@ LL | _ => {}
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| ^ unreachable pattern
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error: unreachable pattern
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--> $DIR/consts-opaque.rs:72:9
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--> $DIR/consts-opaque.rs:73:9
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|
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LL | BAR => {}
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| --- matches any value
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|
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@ -160,7 +160,7 @@ LL | BAR => {} // should not be emitting unreachable warning
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| ^^^ unreachable pattern
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error: unreachable pattern
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--> $DIR/consts-opaque.rs:75:9
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--> $DIR/consts-opaque.rs:76:9
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|
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LL | BAR => {}
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| --- matches any value
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|
|
@ -169,7 +169,7 @@ LL | _ => {} // should not be emitting unreachable warning
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| ^ unreachable pattern
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error: unreachable pattern
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--> $DIR/consts-opaque.rs:82:9
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--> $DIR/consts-opaque.rs:83:9
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|
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LL | BAZ => {}
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| --- matches any value
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|
|
@ -178,7 +178,7 @@ LL | Baz::Baz1 => {} // should not be emitting unreachable warning
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| ^^^^^^^^^ unreachable pattern
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error: unreachable pattern
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--> $DIR/consts-opaque.rs:84:9
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--> $DIR/consts-opaque.rs:85:9
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|
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LL | BAZ => {}
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| --- matches any value
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|
|
@ -187,7 +187,7 @@ LL | _ => {}
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| ^ unreachable pattern
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error: unreachable pattern
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--> $DIR/consts-opaque.rs:92:9
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--> $DIR/consts-opaque.rs:93:9
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|
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LL | BAZ => {}
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| --- matches any value
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|
|
@ -196,7 +196,7 @@ LL | _ => {}
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| ^ unreachable pattern
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error: unreachable pattern
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--> $DIR/consts-opaque.rs:99:9
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--> $DIR/consts-opaque.rs:100:9
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|
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LL | BAZ => {}
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| --- matches any value
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|
|
@ -205,7 +205,7 @@ LL | Baz::Baz2 => {} // should not be emitting unreachable warning
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| ^^^^^^^^^ unreachable pattern
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error: unreachable pattern
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--> $DIR/consts-opaque.rs:101:9
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--> $DIR/consts-opaque.rs:102:9
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|
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LL | BAZ => {}
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| --- matches any value
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|
|
@ -213,19 +213,24 @@ LL | BAZ => {}
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LL | _ => {} // should not be emitting unreachable warning
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| ^ unreachable pattern
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error: unreachable pattern
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--> $DIR/consts-opaque.rs:127:9
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error[E0004]: non-exhaustive patterns: `Wrap(_)` not covered
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--> $DIR/consts-opaque.rs:135:11
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|
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LL | Wrap(_) => {}
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||||
| ------- matches any value
|
||||
LL | WRAPQUUX => {} // detected unreachable because we do inspect the `Wrap` layer
|
||||
| ^^^^^^^^ unreachable pattern
|
||||
|
||||
error: unreachable pattern
|
||||
--> $DIR/consts-opaque.rs:141:9
|
||||
LL | match WRAPQUUX {
|
||||
| ^^^^^^^^ pattern `Wrap(_)` not covered
|
||||
|
|
||||
note: `Wrap<fn(usize, usize) -> usize>` defined here
|
||||
--> $DIR/consts-opaque.rs:117:12
|
||||
|
|
||||
LL | struct Wrap<T>(T);
|
||||
| ^^^^
|
||||
= note: the matched value is of type `Wrap<fn(usize, usize) -> usize>`
|
||||
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 ~ WRAPQUUX => {},
|
||||
LL + Wrap(_) => todo!()
|
||||
|
|
||||
LL | WHOKNOWSQUUX => {} // detected unreachable because we do inspect the `WhoKnows` layer
|
||||
| ^^^^^^^^^^^^
|
||||
|
||||
error: aborting due to 24 previous errors; 1 warning emitted
|
||||
error: aborting due to 23 previous errors; 1 warning emitted
|
||||
|
||||
For more information about this error, try `rustc --explain E0004`.
|
||||
|
|
|
|||
Loading…
Reference in a new issue