diff --git a/compiler/rustc_symbol_mangling/src/v0.rs b/compiler/rustc_symbol_mangling/src/v0.rs index c0690d93c967b..a70b374fc6d21 100644 --- a/compiler/rustc_symbol_mangling/src/v0.rs +++ b/compiler/rustc_symbol_mangling/src/v0.rs @@ -485,38 +485,59 @@ impl Printer<'tcx> for SymbolMangler<'tcx> { mut self, predicates: &'tcx ty::List>>, ) -> Result { - let mut predicate_iter = predicates.iter().peekable(); - while let Some(predicate) = predicate_iter.next() { - match predicate.as_ref().skip_binder() { - ty::ExistentialPredicate::Trait(trait_ref) => { - self = self.in_binder(&predicate, |mut cx, _predicate| { + // Okay, so this is a bit tricky. Imagine we have a trait object like + // `dyn for<'a> Foo<'a, Bar = &'a ()>`. When we mangle this, the + // output looks really close to the syntax, where the `Bar = &'a ()` bit + // is under the same binders (`['a]`) as the `Foo<'a>` bit. However, we + // actually desugar these into two separate `ExistentialPredicate`s. We + // can't enter/exit the "binder scope" twice though, because then we + // would mangle the binders twice. (Also, side note, we merging these + // two is kind of difficult, because of potential HRTBs in the Projection + // predicate.) + // + // Also worth mentioning: imagine that we instead had + // `dyn for<'a> Foo<'a, Bar = &'a ()> + Send`. In this case, `Send` is + // under the same binders as `Foo`. Currently, this doesn't matter, + // because only *auto traits* are allowed other than the principal trait + // and all auto traits don't have any generics. Two things could + // make this not an "okay" mangling: + // 1) Instead of mangling only *used* + // bound vars, we want to mangle *all* bound vars (`for<'b> Send` is a + // valid trait predicate); + // 2) We allow multiple "principal" traits in the future, or at least + // allow in any form another trait predicate that can take generics. + // + // Here we assume that predicates have the following structure: + // [ [{}]] [{}] + // Since any predicates after the first one shouldn't change the binders, + // just put them all in the binders of the first. + self = self.in_binder(&predicates[0], |mut cx, _| { + for predicate in predicates.iter() { + // It would be nice to be able to validate bound vars here, but + // projections can actually include bound vars from super traits + // because of HRTBs (only in the `Self` type). Also, auto traits + // could have different bound vars *anyways*. + match predicate.as_ref().skip_binder() { + ty::ExistentialPredicate::Trait(trait_ref) => { // Use a type that can't appear in defaults of type parameters. let dummy_self = cx.tcx.mk_ty_infer(ty::FreshTy(0)); let trait_ref = trait_ref.with_self_ty(cx.tcx, dummy_self); cx = cx.print_def_path(trait_ref.def_id, trait_ref.substs)?; - while let Some(projection_pred) = predicate_iter.next_if(|p| { - matches!(p.skip_binder(), ty::ExistentialPredicate::Projection(_)) - }) { - let projection = match projection_pred.skip_binder() { - ty::ExistentialPredicate::Projection(projection) => projection, - _ => unreachable!(), - }; - let name = cx.tcx.associated_item(projection.item_def_id).ident; - cx.push("p"); - cx.push_ident(&name.as_str()); - cx = projection.ty.print(cx)?; - } - Ok(cx) - })?; - } - ty::ExistentialPredicate::Projection(_) => { - unreachable!("handled in trait predicate arm") - } - ty::ExistentialPredicate::AutoTrait(def_id) => { - self = self.print_def_path(*def_id, &[])?; + } + ty::ExistentialPredicate::Projection(projection) => { + let name = cx.tcx.associated_item(projection.item_def_id).ident; + cx.push("p"); + cx.push_ident(&name.as_str()); + cx = projection.ty.print(cx)?; + } + ty::ExistentialPredicate::AutoTrait(def_id) => { + cx = cx.print_def_path(*def_id, &[])?; + } } } - } + Ok(cx) + })?; + self.push("E"); Ok(self) } diff --git a/compiler/rustc_typeck/src/astconv/mod.rs b/compiler/rustc_typeck/src/astconv/mod.rs index 2f2e90e4bd66f..c2e451670ed1c 100644 --- a/compiler/rustc_typeck/src/astconv/mod.rs +++ b/compiler/rustc_typeck/src/astconv/mod.rs @@ -1386,11 +1386,13 @@ impl<'o, 'tcx> dyn AstConv<'tcx> + 'o { let auto_trait_predicates = auto_traits.into_iter().map(|trait_ref| { ty::Binder::dummy(ty::ExistentialPredicate::AutoTrait(trait_ref.trait_ref().def_id())) }); + // N.b. principal, projections, auto traits + // FIXME: This is actually wrong with multiple principals in regards to symbol mangling let mut v = regular_trait_predicates - .chain(auto_trait_predicates) .chain( existential_projections.map(|x| x.map_bound(ty::ExistentialPredicate::Projection)), ) + .chain(auto_trait_predicates) .collect::>(); v.sort_by(|a, b| a.skip_binder().stable_cmp(tcx, &b.skip_binder())); v.dedup(); diff --git a/src/test/ui/symbol-names/trait-objects.legacy.stderr b/src/test/ui/symbol-names/trait-objects.legacy.stderr new file mode 100644 index 0000000000000..200280c358f5b --- /dev/null +++ b/src/test/ui/symbol-names/trait-objects.legacy.stderr @@ -0,0 +1,56 @@ +error: symbol-name(_ZN136_$LT$$RF$dyn$u20$core..ops..function..FnMut$LT$$LP$$RF$u8$C$$RP$$GT$$u2b$Output$u20$$u3d$$u20$$LP$$RP$$u20$as$u20$trait_objects..Bar$GT$6method17h1e14a5f2d365272fE) + --> $DIR/trait-objects.rs:15:5 + | +LL | #[rustc_symbol_name] + | ^^^^^^^^^^^^^^^^^^^^ + +error: demangling(<&dyn core::ops::function::FnMut<(&u8,)>+Output = () as trait_objects::Bar>::method::h1e14a5f2d365272f) + --> $DIR/trait-objects.rs:15:5 + | +LL | #[rustc_symbol_name] + | ^^^^^^^^^^^^^^^^^^^^ + +error: demangling-alt(<&dyn core::ops::function::FnMut<(&u8,)>+Output = () as trait_objects::Bar>::method) + --> $DIR/trait-objects.rs:15:5 + | +LL | #[rustc_symbol_name] + | ^^^^^^^^^^^^^^^^^^^^ + +error: symbol-name(_ZN159_$LT$$RF$dyn$u20$core..ops..function..FnMut$LT$$LP$$RF$u8$C$$RP$$GT$$u2b$Output$u20$$u3d$$u20$$LP$$RP$$u2b$core..marker..Send$u20$as$u20$trait_objects..Foo$GT$6method17he7a07961c9aaa367E) + --> $DIR/trait-objects.rs:30:5 + | +LL | #[rustc_symbol_name] + | ^^^^^^^^^^^^^^^^^^^^ + +error: demangling(<&dyn core::ops::function::FnMut<(&u8,)>+Output = ()+core::marker::Send as trait_objects::Foo>::method::he7a07961c9aaa367) + --> $DIR/trait-objects.rs:30:5 + | +LL | #[rustc_symbol_name] + | ^^^^^^^^^^^^^^^^^^^^ + +error: demangling-alt(<&dyn core::ops::function::FnMut<(&u8,)>+Output = ()+core::marker::Send as trait_objects::Foo>::method) + --> $DIR/trait-objects.rs:30:5 + | +LL | #[rustc_symbol_name] + | ^^^^^^^^^^^^^^^^^^^^ + +error: symbol-name(_ZN159_$LT$$RF$dyn$u20$core..ops..function..FnMut$LT$$LP$$RF$u8$C$$RP$$GT$$u2b$Output$u20$$u3d$$u20$$LP$$RP$$u2b$core..marker..Send$u20$as$u20$trait_objects..Baz$GT$6method17ha53e6f99bf033f0bE) + --> $DIR/trait-objects.rs:45:5 + | +LL | #[rustc_symbol_name] + | ^^^^^^^^^^^^^^^^^^^^ + +error: demangling(<&dyn core::ops::function::FnMut<(&u8,)>+Output = ()+core::marker::Send as trait_objects::Baz>::method::ha53e6f99bf033f0b) + --> $DIR/trait-objects.rs:45:5 + | +LL | #[rustc_symbol_name] + | ^^^^^^^^^^^^^^^^^^^^ + +error: demangling-alt(<&dyn core::ops::function::FnMut<(&u8,)>+Output = ()+core::marker::Send as trait_objects::Baz>::method) + --> $DIR/trait-objects.rs:45:5 + | +LL | #[rustc_symbol_name] + | ^^^^^^^^^^^^^^^^^^^^ + +error: aborting due to 9 previous errors + diff --git a/src/test/ui/symbol-names/trait-objects.rs b/src/test/ui/symbol-names/trait-objects.rs new file mode 100644 index 0000000000000..ffbd3901b8e2a --- /dev/null +++ b/src/test/ui/symbol-names/trait-objects.rs @@ -0,0 +1,56 @@ +// Ensure that trait objects don't include more than one binder. See #83611 + +// build-fail +// revisions: legacy v0 +//[legacy]compile-flags: -Z symbol-mangling-version=legacy + //[v0]compile-flags: -Z symbol-mangling-version=v0 + +#![feature(rustc_attrs)] + +trait Bar { + fn method(&self) {} +} + +impl Bar for &dyn FnMut(&u8) { + #[rustc_symbol_name] + //[legacy]~^ ERROR symbol-name + //[legacy]~| ERROR demangling + //[legacy]~| ERROR demangling-alt + //[v0]~^^^^ ERROR symbol-name + //[v0]~| ERROR demangling + //[v0]~| ERROR demangling-alt + fn method(&self) {} +} + +trait Foo { + fn method(&self) {} +} + +impl Foo for &(dyn FnMut(&u8) + for<'b> Send) { + #[rustc_symbol_name] + //[legacy]~^ ERROR symbol-name + //[legacy]~| ERROR demangling + //[legacy]~| ERROR demangling-alt + //[v0]~^^^^ ERROR symbol-name + //[v0]~| ERROR demangling + //[v0]~| ERROR demangling-alt + fn method(&self) {} +} + +trait Baz { + fn method(&self) {} +} + +impl Baz for &(dyn for<'b> Send + FnMut(&u8)) { + #[rustc_symbol_name] + //[legacy]~^ ERROR symbol-name + //[legacy]~| ERROR demangling + //[legacy]~| ERROR demangling-alt + //[v0]~^^^^ ERROR symbol-name + //[v0]~| ERROR demangling + //[v0]~| ERROR demangling-alt + fn method(&self) {} +} + +fn main() { +} diff --git a/src/test/ui/symbol-names/trait-objects.v0.stderr b/src/test/ui/symbol-names/trait-objects.v0.stderr new file mode 100644 index 0000000000000..7a29f44718af9 --- /dev/null +++ b/src/test/ui/symbol-names/trait-objects.v0.stderr @@ -0,0 +1,56 @@ +error: symbol-name(_RNvXCs21hi0yVfW1J_13trait_objectsRDG_INtNtNtCs54lBhuwykzk_4core3ops8function5FnMutTRL0_hEEp6OutputuEL_NtB2_3Bar6method) + --> $DIR/trait-objects.rs:15:5 + | +LL | #[rustc_symbol_name] + | ^^^^^^^^^^^^^^^^^^^^ + +error: demangling(<&dyn for<'a> core[3b0e14d6e1ad42d0]::ops::function::FnMut<(&'a u8,), Output = ()> as trait_objects[17891616a171812d]::Bar>::method) + --> $DIR/trait-objects.rs:15:5 + | +LL | #[rustc_symbol_name] + | ^^^^^^^^^^^^^^^^^^^^ + +error: demangling-alt(<&dyn for<'a> core::ops::function::FnMut<(&'a u8,), Output = ()> as trait_objects::Bar>::method) + --> $DIR/trait-objects.rs:15:5 + | +LL | #[rustc_symbol_name] + | ^^^^^^^^^^^^^^^^^^^^ + +error: symbol-name(_RNvXs_Cs21hi0yVfW1J_13trait_objectsRDG_INtNtNtCs54lBhuwykzk_4core3ops8function5FnMutTRL0_hEEp6OutputuNtNtBI_6marker4SendEL_NtB4_3Foo6method) + --> $DIR/trait-objects.rs:30:5 + | +LL | #[rustc_symbol_name] + | ^^^^^^^^^^^^^^^^^^^^ + +error: demangling(<&dyn for<'a> core[3b0e14d6e1ad42d0]::ops::function::FnMut<(&'a u8,), Output = ()> + core[3b0e14d6e1ad42d0]::marker::Send as trait_objects[17891616a171812d]::Foo>::method) + --> $DIR/trait-objects.rs:30:5 + | +LL | #[rustc_symbol_name] + | ^^^^^^^^^^^^^^^^^^^^ + +error: demangling-alt(<&dyn for<'a> core::ops::function::FnMut<(&'a u8,), Output = ()> + core::marker::Send as trait_objects::Foo>::method) + --> $DIR/trait-objects.rs:30:5 + | +LL | #[rustc_symbol_name] + | ^^^^^^^^^^^^^^^^^^^^ + +error: symbol-name(_RNvXs0_Cs21hi0yVfW1J_13trait_objectsRDG_INtNtNtCs54lBhuwykzk_4core3ops8function5FnMutTRL0_hEEp6OutputuNtNtBJ_6marker4SendEL_NtB5_3Baz6method) + --> $DIR/trait-objects.rs:45:5 + | +LL | #[rustc_symbol_name] + | ^^^^^^^^^^^^^^^^^^^^ + +error: demangling(<&dyn for<'a> core[3b0e14d6e1ad42d0]::ops::function::FnMut<(&'a u8,), Output = ()> + core[3b0e14d6e1ad42d0]::marker::Send as trait_objects[17891616a171812d]::Baz>::method) + --> $DIR/trait-objects.rs:45:5 + | +LL | #[rustc_symbol_name] + | ^^^^^^^^^^^^^^^^^^^^ + +error: demangling-alt(<&dyn for<'a> core::ops::function::FnMut<(&'a u8,), Output = ()> + core::marker::Send as trait_objects::Baz>::method) + --> $DIR/trait-objects.rs:45:5 + | +LL | #[rustc_symbol_name] + | ^^^^^^^^^^^^^^^^^^^^ + +error: aborting due to 9 previous errors +