Rollup merge of #131420 - compiler-errors:post-mono-layout-cycle, r=wesleywiser

Dont ICE when encountering post-mono layout cycle error

It's possible to encounter post-mono layout cycle errors in `fn_abi_of_instance`. Don't ICE in those cases.

This was originally discovered in an async fn, but that's not the only way to encounter such an error (which the other test I added should demonstrate).

Error messsages suck, but this fix is purely about suppressing the ICE.

Fixes #131409

1 files changed, 6 insertions, 5 deletions

diff --git a/compiler/rustc_codegen_llvm/src/context.rs b/compiler/rustc_codegen_llvm/src/context.rs
index 81b82840472..0a116971e07 100644
--- a/compiler/rustc_codegen_llvm/src/context.rs
+++ b/compiler/rustc_codegen_llvm/src/context.rs
@@ -1187,10 +1187,11 @@ impl<'tcx> FnAbiOfHelpers<'tcx> for CodegenCx<'_, 'tcx> {
         span: Span,
         fn_abi_request: FnAbiRequest<'tcx>,
     ) -> ! {
-        if let FnAbiError::Layout(LayoutError::SizeOverflow(_)) = err {
-            self.tcx.dcx().emit_fatal(Spanned { span, node: err })
-        } else {
-            match fn_abi_request {
+        match err {
+            FnAbiError::Layout(LayoutError::SizeOverflow(_) | LayoutError::Cycle(_)) => {
+                self.tcx.dcx().emit_fatal(Spanned { span, node: err });
+            }
+            _ => match fn_abi_request {
                 FnAbiRequest::OfFnPtr { sig, extra_args } => {
                     span_bug!(span, "`fn_abi_of_fn_ptr({sig}, {extra_args:?})` failed: {err:?}",);
                 }
@@ -1200,7 +1201,7 @@ impl<'tcx> FnAbiOfHelpers<'tcx> for CodegenCx<'_, 'tcx> {
                         "`fn_abi_of_instance({instance}, {extra_args:?})` failed: {err:?}",
                     );
                 }
-            }
+            },
         }
     }
 }