From 043bd767688281d574ea8cc0c368156021baa61d Mon Sep 17 00:00:00 2001 From: =?UTF-8?q?John=20K=C3=A5re=20Alsaker?= Date: Fri, 27 Feb 2026 06:23:06 +0100 Subject: [PATCH 1/3] Make `layout_of` cycles fatal errors --- compiler/rustc_codegen_llvm/src/context.rs | 6 +----- .../src/interpret/eval_context.rs | 3 +-- .../src/hir_ty_lowering/cmse.rs | 3 +-- compiler/rustc_middle/src/ty/layout.rs | 6 +----- .../src/handle_cycle_error.rs | 4 +--- compiler/rustc_transmute/src/layout/tree.rs | 1 - .../html/templates/type_layout.html | 5 ----- tests/ui/layout/layout-cycle.rs | 1 - tests/ui/layout/layout-cycle.stderr | 16 ++------------ tests/ui/layout/post-mono-layout-cycle.stderr | 6 ------ ...ck-overflow-trait-infer-98842.64bit.stderr | 21 ------------------- .../sized/stack-overflow-trait-infer-98842.rs | 4 +--- ...> stack-overflow-trait-infer-98842.stderr} | 13 +++--------- 13 files changed, 11 insertions(+), 78 deletions(-) delete mode 100644 tests/ui/sized/stack-overflow-trait-infer-98842.64bit.stderr rename tests/ui/sized/{stack-overflow-trait-infer-98842.32bit.stderr => stack-overflow-trait-infer-98842.stderr} (55%) diff --git a/compiler/rustc_codegen_llvm/src/context.rs b/compiler/rustc_codegen_llvm/src/context.rs index e02c4ae6ea695..80d939a25701e 100644 --- a/compiler/rustc_codegen_llvm/src/context.rs +++ b/compiler/rustc_codegen_llvm/src/context.rs @@ -1134,11 +1134,7 @@ impl<'tcx> FnAbiOfHelpers<'tcx> for CodegenCx<'_, 'tcx> { fn_abi_request: FnAbiRequest<'tcx>, ) -> ! { match err { - FnAbiError::Layout( - LayoutError::SizeOverflow(_) - | LayoutError::Cycle(_) - | LayoutError::InvalidSimd { .. }, - ) => { + FnAbiError::Layout(LayoutError::SizeOverflow(_) | LayoutError::InvalidSimd { .. }) => { self.tcx.dcx().emit_fatal(Spanned { span, node: err }); } _ => match fn_abi_request { diff --git a/compiler/rustc_const_eval/src/interpret/eval_context.rs b/compiler/rustc_const_eval/src/interpret/eval_context.rs index 0bfe012bfe7a4..04f0e7099d840 100644 --- a/compiler/rustc_const_eval/src/interpret/eval_context.rs +++ b/compiler/rustc_const_eval/src/interpret/eval_context.rs @@ -107,8 +107,7 @@ impl<'tcx, M: Machine<'tcx>> LayoutOfHelpers<'tcx> for InterpCx<'tcx, M> { | LayoutError::SizeOverflow(_) | LayoutError::InvalidSimd { .. } | LayoutError::TooGeneric(_) - | LayoutError::ReferencesError(_) - | LayoutError::Cycle(_) => {} + | LayoutError::ReferencesError(_) => {} } err_inval!(Layout(err)) } diff --git a/compiler/rustc_hir_analysis/src/hir_ty_lowering/cmse.rs b/compiler/rustc_hir_analysis/src/hir_ty_lowering/cmse.rs index 58c296d92c24e..a1b169c6a1661 100644 --- a/compiler/rustc_hir_analysis/src/hir_ty_lowering/cmse.rs +++ b/compiler/rustc_hir_analysis/src/hir_ty_lowering/cmse.rs @@ -194,8 +194,7 @@ fn should_emit_layout_error<'tcx>(abi: ExternAbi, layout_err: &'tcx LayoutError< | SizeOverflow(..) | InvalidSimd { .. } | NormalizationFailure(..) - | ReferencesError(..) - | Cycle(..) => { + | ReferencesError(..) => { false // not our job to report these } } diff --git a/compiler/rustc_middle/src/ty/layout.rs b/compiler/rustc_middle/src/ty/layout.rs index 4ca51c078bef5..46682abc823d8 100644 --- a/compiler/rustc_middle/src/ty/layout.rs +++ b/compiler/rustc_middle/src/ty/layout.rs @@ -260,8 +260,6 @@ pub enum LayoutError<'tcx> { NormalizationFailure(Ty<'tcx>, NormalizationError<'tcx>), /// A non-layout error is reported elsewhere. ReferencesError(ErrorGuaranteed), - /// A type has cyclic layout, i.e. the type contains itself without indirection. - Cycle(ErrorGuaranteed), } impl<'tcx> fmt::Display for LayoutError<'tcx> { @@ -286,7 +284,6 @@ impl<'tcx> fmt::Display for LayoutError<'tcx> { t, e.get_type_for_failure() ), - LayoutError::Cycle(_) => write!(f, "a cycle occurred during layout computation"), LayoutError::ReferencesError(_) => write!(f, "the type has an unknown layout"), } } @@ -358,8 +355,7 @@ impl<'tcx> SizeSkeleton<'tcx> { Err(err @ LayoutError::TooGeneric(_)) => err, // We can't extract SizeSkeleton info from other layout errors Err( - e @ LayoutError::Cycle(_) - | e @ LayoutError::Unknown(_) + e @ LayoutError::Unknown(_) | e @ LayoutError::SizeOverflow(_) | e @ LayoutError::InvalidSimd { .. } | e @ LayoutError::NormalizationFailure(..) diff --git a/compiler/rustc_query_impl/src/handle_cycle_error.rs b/compiler/rustc_query_impl/src/handle_cycle_error.rs index 5676669bf1c0e..22f8ac9837f6d 100644 --- a/compiler/rustc_query_impl/src/handle_cycle_error.rs +++ b/compiler/rustc_query_impl/src/handle_cycle_error.rs @@ -12,7 +12,6 @@ use rustc_middle::bug; use rustc_middle::queries::{QueryVTables, TaggedQueryKey}; use rustc_middle::query::Cycle; use rustc_middle::query::erase::erase_val; -use rustc_middle::ty::layout::LayoutError; use rustc_middle::ty::{self, Ty, TyCtxt}; use rustc_span::def_id::{DefId, LocalDefId}; use rustc_span::{ErrorGuaranteed, Span}; @@ -203,8 +202,7 @@ fn layout_of<'tcx>(tcx: TyCtxt<'tcx>, cycle: Cycle<'tcx>) -> &'tcx ty::layout::L || create_cycle_error(tcx, &cycle), ); - let guar = diag.emit(); - tcx.arena.alloc(LayoutError::Cycle(guar)) + diag.emit().raise_fatal() } // item_and_field_ids should form a cycle where each field contains the diff --git a/compiler/rustc_transmute/src/layout/tree.rs b/compiler/rustc_transmute/src/layout/tree.rs index 1202ed2384315..1bfe6e94cc3b6 100644 --- a/compiler/rustc_transmute/src/layout/tree.rs +++ b/compiler/rustc_transmute/src/layout/tree.rs @@ -282,7 +282,6 @@ pub(crate) mod rustc { | LayoutError::InvalidSimd { .. } | LayoutError::NormalizationFailure(..) => Self::UnknownLayout, LayoutError::SizeOverflow(..) => Self::SizeOverflow, - LayoutError::Cycle(err) => Self::TypeError(*err), } } } diff --git a/src/librustdoc/html/templates/type_layout.html b/src/librustdoc/html/templates/type_layout.html index 49153d58fe98c..4d4222a34956a 100644 --- a/src/librustdoc/html/templates/type_layout.html +++ b/src/librustdoc/html/templates/type_layout.html @@ -60,11 +60,6 @@

{# #} Note: Encountered an error during type layout; {#+ #} the type failed to be normalized. {# #}

- {% when Err(LayoutError::Cycle(_)) %} -

{# #} - Note: Encountered an error during type layout; {#+ #} - the type's layout depended on the type's layout itself. {# #} -

{% when Err(LayoutError::InvalidSimd {..}) %}

{# #} Note: Encountered an error during type layout; {#+ #} diff --git a/tests/ui/layout/layout-cycle.rs b/tests/ui/layout/layout-cycle.rs index b38bd52c6ade9..846ce0882cad1 100644 --- a/tests/ui/layout/layout-cycle.rs +++ b/tests/ui/layout/layout-cycle.rs @@ -1,6 +1,5 @@ //@ build-fail //~^ ERROR: cycle detected when computing layout of -//~? ERROR: a cycle occurred during layout computation // Issue #111176 -- ensure that we do not emit ICE on layout cycles diff --git a/tests/ui/layout/layout-cycle.stderr b/tests/ui/layout/layout-cycle.stderr index e05ff614567c4..28c35d431226e 100644 --- a/tests/ui/layout/layout-cycle.stderr +++ b/tests/ui/layout/layout-cycle.stderr @@ -6,18 +6,6 @@ note: cycle used when const-evaluating + checking `core::mem::SizedTypePropertie --> $SRC_DIR/core/src/mem/mod.rs:LL:COL = 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 -error[E0080]: a cycle occurred during layout computation - --> $SRC_DIR/core/src/mem/mod.rs:LL:COL - | - = note: evaluation of `> as std::mem::SizedTypeProperties>::SIZE` failed here - -note: the above error was encountered while instantiating `fn std::mem::size_of::>>` - --> $DIR/layout-cycle.rs:26:5 - | -LL | mem::size_of::>() - | ^^^^^^^^^^^^^^^^^^^^^^ - -error: aborting due to 2 previous errors +error: aborting due to 1 previous error -Some errors have detailed explanations: E0080, E0391. -For more information about an error, try `rustc --explain E0080`. +For more information about this error, try `rustc --explain E0391`. diff --git a/tests/ui/layout/post-mono-layout-cycle.stderr b/tests/ui/layout/post-mono-layout-cycle.stderr index 7f246b3d409ad..b9b1b988499e6 100644 --- a/tests/ui/layout/post-mono-layout-cycle.stderr +++ b/tests/ui/layout/post-mono-layout-cycle.stderr @@ -5,12 +5,6 @@ error[E0391]: cycle detected when computing layout of `Wrapper<()>` = note: cycle used when computing layout of `core::option::Option>` = 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 -note: the above error was encountered while instantiating `fn abi::<()>` - --> $DIR/post-mono-layout-cycle.rs:19:5 - | -LL | abi::(None); - | ^^^^^^^^^^^^^^ - error: aborting due to 1 previous error For more information about this error, try `rustc --explain E0391`. diff --git a/tests/ui/sized/stack-overflow-trait-infer-98842.64bit.stderr b/tests/ui/sized/stack-overflow-trait-infer-98842.64bit.stderr deleted file mode 100644 index d097b809b5698..0000000000000 --- a/tests/ui/sized/stack-overflow-trait-infer-98842.64bit.stderr +++ /dev/null @@ -1,21 +0,0 @@ -error[E0391]: cycle detected when computing layout of `Foo` - | - = note: ...which requires computing layout of `<&'static Foo as core::ops::deref::Deref>::Target`... - = note: ...which again requires computing layout of `Foo`, completing the cycle -note: cycle used when const-evaluating + checking `_` - --> $DIR/stack-overflow-trait-infer-98842.rs:14:1 - | -LL | const _: *const Foo = 0 as _; - | ^^^^^^^^^^^^^^^^^^^ - = 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 - -error[E0080]: a cycle occurred during layout computation - --> $DIR/stack-overflow-trait-infer-98842.rs:14:1 - | -LL | const _: *const Foo = 0 as _; - | ^^^^^^^^^^^^^^^^^^^ evaluation of `_` failed here - -error: aborting due to 2 previous errors - -Some errors have detailed explanations: E0080, E0391. -For more information about an error, try `rustc --explain E0080`. diff --git a/tests/ui/sized/stack-overflow-trait-infer-98842.rs b/tests/ui/sized/stack-overflow-trait-infer-98842.rs index 1c9f6c593f447..d6522e3cfb643 100644 --- a/tests/ui/sized/stack-overflow-trait-infer-98842.rs +++ b/tests/ui/sized/stack-overflow-trait-infer-98842.rs @@ -2,8 +2,7 @@ // issue: rust-lang/rust#98842 //@ check-fail //@ edition:2021 -//@ stderr-per-bitwidth -//~^^^^^ ERROR cycle detected when computing layout of `Foo` +//~^^^^ ERROR cycle detected when computing layout of `Foo` // If the inner `Foo` is named through an associated type, // the "infinite size" error does not occur. @@ -12,6 +11,5 @@ struct Foo(<&'static Foo as ::core::ops::Deref>::Target); // and it will infinitely recurse somewhere trying to figure out the // size of this pointer (is my guess): const _: *const Foo = 0 as _; -//~^ ERROR a cycle occurred during layout computation pub fn main() {} diff --git a/tests/ui/sized/stack-overflow-trait-infer-98842.32bit.stderr b/tests/ui/sized/stack-overflow-trait-infer-98842.stderr similarity index 55% rename from tests/ui/sized/stack-overflow-trait-infer-98842.32bit.stderr rename to tests/ui/sized/stack-overflow-trait-infer-98842.stderr index d097b809b5698..5557a6fc45b89 100644 --- a/tests/ui/sized/stack-overflow-trait-infer-98842.32bit.stderr +++ b/tests/ui/sized/stack-overflow-trait-infer-98842.stderr @@ -3,19 +3,12 @@ error[E0391]: cycle detected when computing layout of `Foo` = note: ...which requires computing layout of `<&'static Foo as core::ops::deref::Deref>::Target`... = note: ...which again requires computing layout of `Foo`, completing the cycle note: cycle used when const-evaluating + checking `_` - --> $DIR/stack-overflow-trait-infer-98842.rs:14:1 + --> $DIR/stack-overflow-trait-infer-98842.rs:13:1 | LL | const _: *const Foo = 0 as _; | ^^^^^^^^^^^^^^^^^^^ = 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 -error[E0080]: a cycle occurred during layout computation - --> $DIR/stack-overflow-trait-infer-98842.rs:14:1 - | -LL | const _: *const Foo = 0 as _; - | ^^^^^^^^^^^^^^^^^^^ evaluation of `_` failed here - -error: aborting due to 2 previous errors +error: aborting due to 1 previous error -Some errors have detailed explanations: E0080, E0391. -For more information about an error, try `rustc --explain E0080`. +For more information about this error, try `rustc --explain E0391`. From 4fd1d9713af32df00514bb57e5e888b84d34291d Mon Sep 17 00:00:00 2001 From: =?UTF-8?q?John=20K=C3=A5re=20Alsaker?= Date: Mon, 16 Mar 2026 22:18:59 +0100 Subject: [PATCH 2/3] Skip ICE message for fatal errors --- src/tools/miri/src/eval.rs | 7 ++++++- 1 file changed, 6 insertions(+), 1 deletion(-) diff --git a/src/tools/miri/src/eval.rs b/src/tools/miri/src/eval.rs index 1e75df7d278fb..cf4f7d689ac22 100644 --- a/src/tools/miri/src/eval.rs +++ b/src/tools/miri/src/eval.rs @@ -10,6 +10,7 @@ use std::{iter, thread}; use rustc_abi::ExternAbi; use rustc_data_structures::fx::{FxHashMap, FxHashSet}; +use rustc_errors::FatalErrorMarker; use rustc_hir::def::Namespace; use rustc_hir::def_id::DefId; use rustc_middle::ty::layout::{HasTyCtxt, HasTypingEnv, LayoutCx}; @@ -477,7 +478,11 @@ pub fn eval_entry<'tcx>( let res: thread::Result> = panic::catch_unwind(AssertUnwindSafe(|| ecx.run_threads())); let res = res.unwrap_or_else(|panic_payload| { - ecx.handle_ice(); + // rustc "handles" some errors by unwinding with FatalErrorMarker + // (after emitting suitable diagnostics), so do not treat those as ICEs. + if !panic_payload.is::() { + ecx.handle_ice(); + } panic::resume_unwind(panic_payload) }); // Obtain the result of the execution. This is always an `Err`, but that doesn't necessarily From db30a36c8edb360eb16de681ff07972980dfbba1 Mon Sep 17 00:00:00 2001 From: =?UTF-8?q?John=20K=C3=A5re=20Alsaker?= Date: Mon, 16 Mar 2026 22:19:21 +0100 Subject: [PATCH 3/3] Update tests --- src/tools/miri/tests/fail/layout_cycle.rs | 3 +-- src/tools/miri/tests/fail/layout_cycle.stderr | 11 ++--------- 2 files changed, 3 insertions(+), 11 deletions(-) diff --git a/src/tools/miri/tests/fail/layout_cycle.rs b/src/tools/miri/tests/fail/layout_cycle.rs index 3e0dd881db84e..8d5f1914d0c32 100644 --- a/src/tools/miri/tests/fail/layout_cycle.rs +++ b/src/tools/miri/tests/fail/layout_cycle.rs @@ -1,5 +1,4 @@ -//@error-in-other-file: a cycle occurred during layout computation -//~^ ERROR: cycle detected when computing layout of +//~ ERROR: cycle detected when computing layout of use std::mem; diff --git a/src/tools/miri/tests/fail/layout_cycle.stderr b/src/tools/miri/tests/fail/layout_cycle.stderr index dae6934931228..f8d555e5a10b8 100644 --- a/src/tools/miri/tests/fail/layout_cycle.stderr +++ b/src/tools/miri/tests/fail/layout_cycle.stderr @@ -9,13 +9,6 @@ LL | const SIZE: usize = intrinsics::size_of::(); | ^^^^^^^^^^^^^^^^^ = 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 -error[E0080]: a cycle occurred during layout computation - --> RUSTLIB/core/src/mem/mod.rs:LL:CC - | -LL | const SIZE: usize = intrinsics::size_of::(); - | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ evaluation of `> as std::mem::SizedTypeProperties>::SIZE` failed here - -error: aborting due to 2 previous errors +error: aborting due to 1 previous error -Some errors have detailed explanations: E0080, E0391. -For more information about an error, try `rustc --explain E0080`. +For more information about this error, try `rustc --explain E0391`.