mirror of
https://github.com/rust-lang/rust
synced 2024-10-14 04:23:37 +00:00
only require sub type relation on field projection types
This commit is contained in:
parent
00cf19a75a
commit
6e1d228285
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@ -534,7 +534,7 @@ fn sanitize_place(
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return PlaceTy::from_ty(self.tcx().ty_error());
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}
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}
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place_ty = self.sanitize_projection(place_ty, elem, place, location);
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place_ty = self.sanitize_projection(place_ty, elem, place, location, context);
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}
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if let PlaceContext::NonMutatingUse(NonMutatingUseContext::Copy) = context {
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@ -630,12 +630,14 @@ fn sanitize_promoted(&mut self, promoted_body: &'b Body<'tcx>, location: Locatio
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}
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}
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#[instrument(skip(self), level = "debug")]
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fn sanitize_projection(
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&mut self,
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base: PlaceTy<'tcx>,
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pi: PlaceElem<'tcx>,
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place: &Place<'tcx>,
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location: Location,
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context: PlaceContext,
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) -> PlaceTy<'tcx> {
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debug!("sanitize_projection: {:?} {:?} {:?}", base, pi, place);
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let tcx = self.tcx();
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@ -713,8 +715,11 @@ fn sanitize_projection(
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match self.field_ty(place, base, field, location) {
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Ok(ty) => {
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let ty = self.cx.normalize(ty, location);
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if let Err(terr) = self.cx.eq_types(
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debug!(?fty, ?ty);
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if let Err(terr) = self.cx.relate_types(
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ty,
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self.get_ambient_variance(context),
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fty,
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location.to_locations(),
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ConstraintCategory::Boring,
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@ -743,9 +748,10 @@ fn sanitize_projection(
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let ty = self.sanitize_type(place, ty);
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let ty = self.cx.normalize(ty, location);
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self.cx
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.eq_types(
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base.ty,
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.relate_types(
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ty,
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self.get_ambient_variance(context),
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base.ty,
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location.to_locations(),
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ConstraintCategory::TypeAnnotation,
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)
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@ -760,6 +766,13 @@ fn error(&mut self) -> Ty<'tcx> {
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self.tcx().ty_error()
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}
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fn get_ambient_variance(&self, context: PlaceContext) -> ty::Variance {
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match context {
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PlaceContext::MutatingUse(_) => ty::Invariant,
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PlaceContext::NonMutatingUse(_) | PlaceContext::NonUse(_) => ty::Covariant,
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}
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}
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fn field_ty(
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&mut self,
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parent: &dyn fmt::Debug,
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24
tests/ui/mir/field-projection-invariant.rs
Normal file
24
tests/ui/mir/field-projection-invariant.rs
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@ -0,0 +1,24 @@
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// build-pass
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struct Inv<'a>(&'a mut &'a ());
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enum Foo<T> {
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Bar,
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Var(T),
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}
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type Supertype = Foo<for<'a> fn(Inv<'a>, Inv<'a>)>;
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fn foo(x: Foo<for<'a, 'b> fn(Inv<'a>, Inv<'b>)>) {
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match x {
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Supertype::Bar => {}
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Supertype::Var(x) => {}
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}
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}
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fn foo_nested(x: Foo<Foo<for<'a, 'b> fn(Inv<'a>, Inv<'b>)>>) {
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match x {
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Foo::Bar => {}
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Foo::Var(Supertype::Bar) => {}
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Foo::Var(Supertype::Var(x)) => {}
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}
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}
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fn main() {}
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19
tests/ui/mir/field-projection-mutating-context.rs
Normal file
19
tests/ui/mir/field-projection-mutating-context.rs
Normal file
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@ -0,0 +1,19 @@
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use std::sync::Mutex;
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static GLOBAL: Mutex<&'static str> = Mutex::new("global str");
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struct Foo<T>(T); // `T` is covariant.
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fn foo() {
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let mut x: Foo<for<'a> fn(&'a str)> = Foo(|_| ());
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let Foo(ref mut y): Foo<fn(&'static str)> = x;
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//~^ ERROR mismatched types
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*y = |s| *GLOBAL.lock().unwrap() = s;
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let string = String::from("i am shortlived");
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(x.0)(&string);
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}
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fn main() {
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foo();
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println!("{}", GLOBAL.lock().unwrap());
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}
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12
tests/ui/mir/field-projection-mutating-context.stderr
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12
tests/ui/mir/field-projection-mutating-context.stderr
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@ -0,0 +1,12 @@
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error[E0308]: mismatched types
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--> $DIR/field-projection-mutating-context.rs:9:13
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LL | let Foo(ref mut y): Foo<fn(&'static str)> = x;
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| ^^^^^^^^^ one type is more general than the other
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= note: expected fn pointer `for<'a> fn(&'a str)`
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found fn pointer `fn(&str)`
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error: aborting due to previous error
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For more information about this error, try `rustc --explain E0308`.
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17
tests/ui/mir/field-projection-mutating-context2.rs
Normal file
17
tests/ui/mir/field-projection-mutating-context2.rs
Normal file
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@ -0,0 +1,17 @@
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use std::sync::Mutex;
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static GLOBAL: Mutex<&'static str> = Mutex::new("global str");
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struct Foo<T>(T); // `T` is covariant.
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fn foo<'a>(mut x: Foo<fn(&'a str)>, string: &'a str) {
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let Foo(ref mut y): Foo<fn(&'static str)> = x;
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//~^ ERROR lifetime may not live long enough
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*y = |s| *GLOBAL.lock().unwrap() = s;
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(x.0)(&string);
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}
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fn main() {
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foo(Foo(|_| ()), &String::from("i am shortlived"));
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println!("{}", GLOBAL.lock().unwrap());
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}
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10
tests/ui/mir/field-projection-mutating-context2.stderr
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10
tests/ui/mir/field-projection-mutating-context2.stderr
Normal file
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@ -0,0 +1,10 @@
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error: lifetime may not live long enough
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--> $DIR/field-projection-mutating-context2.rs:8:25
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LL | fn foo<'a>(mut x: Foo<fn(&'a str)>, string: &'a str) {
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| -- lifetime `'a` defined here
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LL | let Foo(ref mut y): Foo<fn(&'static str)> = x;
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| ^^^^^^^^^^^^^^^^^^^^^ type annotation requires that `'a` must outlive `'static`
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error: aborting due to previous error
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15
tests/ui/mir/field-ty-ascription-enums.rs
Normal file
15
tests/ui/mir/field-ty-ascription-enums.rs
Normal file
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@ -0,0 +1,15 @@
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// build-pass
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enum Foo<T> {
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Var(T),
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} // `T` is covariant.
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fn foo<'b>(x: Foo<for<'a> fn(&'a ())>) {
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let Foo::Var(x): Foo<fn(&'b ())> = x;
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}
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fn foo_nested<'b>(x: Foo<Foo<for<'a> fn(&'a ())>>) {
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let Foo::Var(Foo::Var(x)): Foo<Foo<fn(&'b ())>> = x;
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}
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fn main() {}
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37
tests/ui/mir/field-ty-ascription.rs
Normal file
37
tests/ui/mir/field-ty-ascription.rs
Normal file
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@ -0,0 +1,37 @@
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// build-pass
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struct Foo<T>(T); // `T` is covariant.
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struct Bar<T> {
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x: T,
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} // `T` is covariant.
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fn bar<'b>(x: Bar<for<'a> fn(&'a ())>) {
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let Bar { x }: Bar<fn(&'b ())> = x;
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}
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fn bar_nested<'b>(x: Bar<Bar<for<'a> fn(&'a ())>>) {
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let Bar { x: Bar { x } }: Bar<Bar<fn(&'b ())>> = x;
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}
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fn bar_foo_nested<'b>(x: Bar<Foo<for<'a> fn(&'a ())>>) {
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let Bar { x: Foo ( x ) }: Bar<Foo<fn(&'b ())>> = x;
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}
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fn foo<'b>(x: Foo<for<'a> fn(&'a ())>) {
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let Foo(y): Foo<fn(&'b ())> = x;
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}
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fn foo_nested<'b>(x: Foo<Foo<for<'a> fn(&'a ())>>) {
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let Foo(Foo(y)): Foo<Foo<fn(&'b ())>> = x;
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}
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fn tuple<'b>(x: (u32, for<'a> fn(&'a ()))) {
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let (_, y): (u32, fn(&'b ())) = x;
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}
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fn tuple_nested<'b>(x: (u32, (u32, for<'a> fn(&'a ())))) {
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let (_, (_, y)): (u32, (u32, fn(&'b ()))) = x;
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}
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fn main() {}
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