interpret: do not ICE when a promoted fails with OOM

3 files changed, 24 insertions, 3 deletions

diff --git a/compiler/rustc_const_eval/src/const_eval/error.rs b/compiler/rustc_const_eval/src/const_eval/error.rs
index 6686413bf02..1271d9d2d0d 100644
--- a/compiler/rustc_const_eval/src/const_eval/error.rs
+++ b/compiler/rustc_const_eval/src/const_eval/error.rs
@@ -152,13 +152,20 @@ where
             let span = span.substitute_dummy(our_span);
             let err = mk(span, frames);
             let mut err = tcx.dcx().create_err(err);
+            let can_be_spurious = matches!(error, InterpErrorKind::ResourceExhaustion(_));
 
             let msg = error.diagnostic_message();
             error.add_args(&mut err);
 
             // Use *our* span to label the interp error
             err.span_label(our_span, msg);
-            ErrorHandled::Reported(err.emit().into(), span)
+            let g = err.emit();
+            let reported = if can_be_spurious {
+                ReportedErrorInfo::spurious(g)
+            } else {
+                ReportedErrorInfo::from(g)
+            };
+            ErrorHandled::Reported(reported, span)
         }
     }
 }
diff --git a/compiler/rustc_const_eval/src/interpret/eval_context.rs b/compiler/rustc_const_eval/src/interpret/eval_context.rs
index ff6d5b28b3b..eb574bd5f77 100644
--- a/compiler/rustc_const_eval/src/interpret/eval_context.rs
+++ b/compiler/rustc_const_eval/src/interpret/eval_context.rs
@@ -596,6 +596,9 @@ impl<'tcx, M: Machine<'tcx>> InterpCx<'tcx, M> {
                                 // const-eval will return "tainted" errors if e.g. the layout cannot
                                 // be computed as the type references non-existing names.
                                 // See <https://github.com/rust-lang/rust/issues/124348>.
+                            } else if reported.can_be_spurious() {
+                                // These errors can just sometimes happen, even when the expression
+                                // is nominally "infallible", e.g. when running out of memory.
                             } else {
                                 // Looks like the const is not captured by `required_consts`, that's bad.
                                 span_bug!(span, "interpret const eval failure of {val:?} which is not in required_consts");
diff --git a/compiler/rustc_middle/src/mir/interpret/error.rs b/compiler/rustc_middle/src/mir/interpret/error.rs
index 8ec7e1851a5..08afa33c6b4 100644
--- a/compiler/rustc_middle/src/mir/interpret/error.rs
+++ b/compiler/rustc_middle/src/mir/interpret/error.rs
@@ -59,22 +59,33 @@ impl ErrorHandled {
 pub struct ReportedErrorInfo {
     error: ErrorGuaranteed,
     is_tainted_by_errors: bool,
+    /// Whether this is the kind of error that can sometimes occur, and sometimes not.
+    /// Used for resource exhaustion errors.
+    can_be_spurious: bool,
 }
 
 impl ReportedErrorInfo {
     #[inline]
     pub fn tainted_by_errors(error: ErrorGuaranteed) -> ReportedErrorInfo {
-        ReportedErrorInfo { is_tainted_by_errors: true, error }
+        ReportedErrorInfo { is_tainted_by_errors: true, can_be_spurious: false, error }
     }
+    #[inline]
+    pub fn spurious(error: ErrorGuaranteed) -> ReportedErrorInfo {
+        ReportedErrorInfo { can_be_spurious: true, is_tainted_by_errors: false, error }
+    }
+
     pub fn is_tainted_by_errors(&self) -> bool {
         self.is_tainted_by_errors
     }
+    pub fn can_be_spurious(&self) -> bool {
+        self.can_be_spurious
+    }
 }
 
 impl From<ErrorGuaranteed> for ReportedErrorInfo {
     #[inline]
     fn from(error: ErrorGuaranteed) -> ReportedErrorInfo {
-        ReportedErrorInfo { is_tainted_by_errors: false, error }
+        ReportedErrorInfo { is_tainted_by_errors: false, can_be_spurious: false, error }
     }
 }