From 121d9f5b16cae379c6b57e27ff14f25e431c44fa Mon Sep 17 00:00:00 2001
From: Michael Goulet <michael@errs.io>
Date: Wed, 8 Nov 2023 05:13:35 +0000
Subject: [PATCH] make LayoutError::Cycle carry ErrorGuaranteed

---
 compiler/rustc_middle/src/ty/layout.rs         | 10 +++++-----
 compiler/rustc_middle/src/values.rs            |  5 ++---
 src/librustdoc/html/templates/type_layout.html |  2 +-
 3 files changed, 8 insertions(+), 9 deletions(-)

diff --git a/compiler/rustc_middle/src/ty/layout.rs b/compiler/rustc_middle/src/ty/layout.rs
index 4223e503f5e22..aca6acd783b92 100644
--- a/compiler/rustc_middle/src/ty/layout.rs
+++ b/compiler/rustc_middle/src/ty/layout.rs
@@ -215,7 +215,7 @@ pub enum LayoutError<'tcx> {
     SizeOverflow(Ty<'tcx>),
     NormalizationFailure(Ty<'tcx>, NormalizationError<'tcx>),
     ReferencesError(ErrorGuaranteed),
-    Cycle,
+    Cycle(ErrorGuaranteed),
 }
 
 impl<'tcx> LayoutError<'tcx> {
@@ -226,7 +226,7 @@ impl<'tcx> LayoutError<'tcx> {
             Unknown(_) => middle_unknown_layout,
             SizeOverflow(_) => middle_values_too_big,
             NormalizationFailure(_, _) => middle_cannot_be_normalized,
-            Cycle => middle_cycle,
+            Cycle(_) => middle_cycle,
             ReferencesError(_) => middle_layout_references_error,
         }
     }
@@ -240,7 +240,7 @@ impl<'tcx> LayoutError<'tcx> {
             NormalizationFailure(ty, e) => {
                 E::NormalizationFailure { ty, failure_ty: e.get_type_for_failure() }
             }
-            Cycle => E::Cycle,
+            Cycle(_) => E::Cycle,
             ReferencesError(_) => E::ReferencesError,
         }
     }
@@ -261,7 +261,7 @@ impl<'tcx> fmt::Display for LayoutError<'tcx> {
                 t,
                 e.get_type_for_failure()
             ),
-            LayoutError::Cycle => write!(f, "a cycle occurred during layout computation"),
+            LayoutError::Cycle(_) => write!(f, "a cycle occurred during layout computation"),
             LayoutError::ReferencesError(_) => write!(f, "the type has an unknown layout"),
         }
     }
@@ -333,7 +333,7 @@ impl<'tcx> SizeSkeleton<'tcx> {
             Err(err @ LayoutError::Unknown(_)) => err,
             // We can't extract SizeSkeleton info from other layout errors
             Err(
-                e @ LayoutError::Cycle
+                e @ LayoutError::Cycle(_)
                 | e @ LayoutError::SizeOverflow(_)
                 | e @ LayoutError::NormalizationFailure(..)
                 | e @ LayoutError::ReferencesError(_),
diff --git a/compiler/rustc_middle/src/values.rs b/compiler/rustc_middle/src/values.rs
index f30993c9a694d..2b4ae37362699 100644
--- a/compiler/rustc_middle/src/values.rs
+++ b/compiler/rustc_middle/src/values.rs
@@ -114,12 +114,11 @@ impl<'tcx> Value<TyCtxt<'tcx>> for ty::EarlyBinder<ty::Binder<'_, ty::FnSig<'_>>
 }
 
 impl<'tcx, T> Value<TyCtxt<'tcx>> for Result<T, &'_ ty::layout::LayoutError<'_>> {
-    fn from_cycle_error(_tcx: TyCtxt<'tcx>, _cycle: &[QueryInfo], _guar: ErrorGuaranteed) -> Self {
+    fn from_cycle_error(_tcx: TyCtxt<'tcx>, _cycle: &[QueryInfo], guar: ErrorGuaranteed) -> Self {
         // tcx.arena.alloc cannot be used because we are not allowed to use &'tcx LayoutError under
         // min_specialization. Since this is an error path anyways, leaking doesn't matter (and really,
         // tcx.arena.alloc is pretty much equal to leaking).
-        // FIXME: `Cycle` should carry the ErrorGuaranteed
-        Err(Box::leak(Box::new(ty::layout::LayoutError::Cycle)))
+        Err(Box::leak(Box::new(ty::layout::LayoutError::Cycle(guar))))
     }
 }
 
diff --git a/src/librustdoc/html/templates/type_layout.html b/src/librustdoc/html/templates/type_layout.html
index b8b7785a2a191..c75fc34a9dfe7 100644
--- a/src/librustdoc/html/templates/type_layout.html
+++ b/src/librustdoc/html/templates/type_layout.html
@@ -54,7 +54,7 @@ <h2 id="layout" class="small-section-header"> {# #}
             <strong>Note:</strong> Encountered an error during type layout; {#+ #}
             the type failed to be normalized. {# #}
         </p> {# #}
-        {% when Err(LayoutError::Cycle) %}
+        {% when Err(LayoutError::Cycle(_)) %}
         <p> {# #}
             <strong>Note:</strong> Encountered an error during type layout; {#+ #}
             the type's layout depended on the type's layout itself. {# #}