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Auto merge of rust-lang#134504 - oli-obk:push-rltsvnyttwll, r=compiler-errors
Use trait definition cycle detection for trait alias definitions, too fixes rust-lang#133901 In general doing this for `All` is not right, but this code path is specifically for traits and trait aliases, and there we only ever use `All` for trait aliases.
2 parents 8a6878a + 37f2998 commit 99db273

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+72
-8
lines changed

6 files changed

+72
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lines changed

‎compiler/rustc_hir_analysis/src/collect/predicates_of.rs

+1-1
Original file line numberDiff line numberDiff line change
@@ -653,7 +653,7 @@ pub(super) fn implied_predicates_with_filter<'tcx>(
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}
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}
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}
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PredicateFilter::SelfAndAssociatedTypeBounds => {
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PredicateFilter::All | PredicateFilter::SelfAndAssociatedTypeBounds => {
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for &(pred, span) in implied_bounds {
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debug!("superbound: {:?}", pred);
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if let ty::ClauseKind::Trait(bound) = pred.kind().skip_binder()

‎compiler/rustc_middle/src/ty/sty.rs

+37-2
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@@ -401,7 +401,7 @@ impl<'tcx> Ty<'tcx> {
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/// The more specific methods will often optimize their creation.
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#[allow(rustc::usage_of_ty_tykind)]
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#[inline]
404-
pub fn new(tcx: TyCtxt<'tcx>, st: TyKind<'tcx>) -> Ty<'tcx> {
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fn new(tcx: TyCtxt<'tcx>, st: TyKind<'tcx>) -> Ty<'tcx> {
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tcx.mk_ty_from_kind(st)
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}
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@@ -613,6 +613,41 @@ impl<'tcx> Ty<'tcx> {
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#[inline]
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pub fn new_adt(tcx: TyCtxt<'tcx>, def: AdtDef<'tcx>, args: GenericArgsRef<'tcx>) -> Ty<'tcx> {
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tcx.debug_assert_args_compatible(def.did(), args);
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if cfg!(debug_assertions) {
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match tcx.def_kind(def.did()) {
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DefKind::Struct | DefKind::Union | DefKind::Enum => {}
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DefKind::Mod
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| DefKind::Variant
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| DefKind::Trait
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| DefKind::TyAlias
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| DefKind::ForeignTy
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| DefKind::TraitAlias
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| DefKind::AssocTy
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| DefKind::TyParam
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| DefKind::Fn
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| DefKind::Const
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| DefKind::ConstParam
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| DefKind::Static { .. }
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| DefKind::Ctor(..)
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| DefKind::AssocFn
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| DefKind::AssocConst
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| DefKind::Macro(..)
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| DefKind::ExternCrate
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| DefKind::Use
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| DefKind::ForeignMod
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| DefKind::AnonConst
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| DefKind::InlineConst
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| DefKind::OpaqueTy
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| DefKind::Field
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| DefKind::LifetimeParam
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| DefKind::GlobalAsm
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| DefKind::Impl { .. }
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| DefKind::Closure
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| DefKind::SyntheticCoroutineBody => {
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bug!("not an adt: {def:?} ({:?})", tcx.def_kind(def.did()))
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}
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}
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}
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Ty::new(tcx, Adt(def, args))
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}
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@@ -772,7 +807,7 @@ impl<'tcx> Ty<'tcx> {
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}
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}
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});
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Ty::new(tcx, Adt(adt_def, args))
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Ty::new_adt(tcx, adt_def, args)
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}
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#[inline]

‎tests/ui/infinite/infinite-trait-alias-recursion.rs

+1-1
Original file line numberDiff line numberDiff line change
@@ -1,7 +1,7 @@
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#![feature(trait_alias)]
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trait T1 = T2;
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//~^ ERROR cycle detected when computing the super predicates of `T1`
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//~^ ERROR cycle detected when computing the implied predicates of `T1`
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trait T2 = T3;
77

‎tests/ui/infinite/infinite-trait-alias-recursion.stderr

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Original file line numberDiff line numberDiff line change
@@ -1,20 +1,20 @@
1-
error[E0391]: cycle detected when computing the super predicates of `T1`
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error[E0391]: cycle detected when computing the implied predicates of `T1`
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--> $DIR/infinite-trait-alias-recursion.rs:3:12
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|
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LL | trait T1 = T2;
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| ^^
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|
7-
note: ...which requires computing the super predicates of `T2`...
7+
note: ...which requires computing the implied predicates of `T2`...
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--> $DIR/infinite-trait-alias-recursion.rs:6:12
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|
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LL | trait T2 = T3;
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| ^^
12-
note: ...which requires computing the super predicates of `T3`...
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note: ...which requires computing the implied predicates of `T3`...
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--> $DIR/infinite-trait-alias-recursion.rs:8:12
1414
|
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LL | trait T3 = T1 + T3;
1616
| ^^
17-
= note: ...which again requires computing the super predicates of `T1`, completing the cycle
17+
= note: ...which again requires computing the implied predicates of `T1`, completing the cycle
1818
= note: trait aliases cannot be recursive
1919
note: cycle used when checking that `T1` is well-formed
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--> $DIR/infinite-trait-alias-recursion.rs:3:1

‎tests/ui/traits/alias/infinite_normalization.rs

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@@ -0,0 +1,11 @@
1+
//! This test used to get stuck in an infinite
2+
//! recursion during normalization.
3+
//!
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//! issue: https://github.com/rust-lang/rust/issues/133901
5+
6+
#![feature(trait_alias)]
7+
fn foo<T: Baz<i32>>() {}
8+
trait Baz<A> = Baz<Option<A>>;
9+
//~^ ERROR: cycle detected when computing the implied predicates of `Baz`
10+
11+
fn main() {}

‎tests/ui/traits/alias/infinite_normalization.stderr

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Original file line numberDiff line numberDiff line change
@@ -0,0 +1,18 @@
1+
error[E0391]: cycle detected when computing the implied predicates of `Baz`
2+
--> $DIR/infinite_normalization.rs:8:16
3+
|
4+
LL | trait Baz<A> = Baz<Option<A>>;
5+
| ^^^^^^^^^^^^^^
6+
|
7+
= note: ...which immediately requires computing the implied predicates of `Baz` again
8+
= note: trait aliases cannot be recursive
9+
note: cycle used when computing normalized predicates of `foo`
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--> $DIR/infinite_normalization.rs:7:1
11+
|
12+
LL | fn foo<T: Baz<i32>>() {}
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| ^^^^^^^^^^^^^^^^^^^^^
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= note: see https://rustc-dev-guide.rust-lang.org/overview.html#queries and https://rustc-dev-guide.rust-lang.org/query.html for more information
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error: aborting due to 1 previous error
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For more information about this error, try `rustc --explain E0391`.

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