Rollup merge of #120782 - oli-obk:track_errors8, r=WaffleLapkin

Fix mir pass ICE in the presence of other errors

fixes #120779

it is impossible to add a ui test for this, because it only reproduces in build-fail, but a test that also has errors in check-fail mode can't be made build-fail 🙃

I would have to add a run-make test or sth, which is overkill for such a tiny thing imo.

compiler/rustc_errors/src/lib.rs

@@ -847,6 +847,7 @@ impl DiagCtxt {
         self.struct_span_warn(span, msg).emit()
     }
 
+    #[track_caller]
     pub fn span_bug(&self, span: impl Into<MultiSpan>, msg: impl Into<DiagnosticMessage>) -> ! {
         self.struct_span_bug(span, msg).emit()
     }

compiler/rustc_mir_transform/src/abort_unwinding_calls.rs

@@ -41,6 +41,7 @@ impl<'tcx> MirPass<'tcx> for AbortUnwindingCalls {
             ty::Closure(..) => Abi::RustCall,
             ty::CoroutineClosure(..) => Abi::RustCall,
             ty::Coroutine(..) => Abi::Rust,
+            ty::Error(_) => return,
             _ => span_bug!(body.span, "unexpected body ty: {:?}", body_ty),
         };
         let body_can_unwind = layout::fn_can_unwind(tcx, Some(def_id), body_abi);