diff --git a/compiler/rustc_monomorphize/src/partitioning.rs b/compiler/rustc_monomorphize/src/partitioning.rs
index e663f4486f7fe..f4535fbd58fa0 100644
--- a/compiler/rustc_monomorphize/src/partitioning.rs
+++ b/compiler/rustc_monomorphize/src/partitioning.rs
@@ -187,7 +187,13 @@ where
     }
 
     // Ensure CGUs are sorted by name, so that we get deterministic results.
-    assert!(codegen_units.is_sorted_by(|a, b| Some(a.name().as_str().cmp(b.name().as_str()))));
+    if !codegen_units.is_sorted_by(|a, b| Some(a.name().as_str().cmp(b.name().as_str()))) {
+        let mut names = String::new();
+        for cgu in codegen_units.iter() {
+            names += &format!("- {}\n", cgu.name());
+        }
+        bug!("unsorted CGUs:\n{names}");
+    }
 
     codegen_units
 }
diff --git a/compiler/rustc_trait_selection/src/solve/eval_ctxt/select.rs b/compiler/rustc_trait_selection/src/solve/eval_ctxt/select.rs
index 18332d6811d56..366e9aa793d71 100644
--- a/compiler/rustc_trait_selection/src/solve/eval_ctxt/select.rs
+++ b/compiler/rustc_trait_selection/src/solve/eval_ctxt/select.rs
@@ -213,15 +213,16 @@ fn rematch_object<'tcx>(
     mut nested: Vec<PredicateObligation<'tcx>>,
 ) -> SelectionResult<'tcx, Selection<'tcx>> {
     let self_ty = goal.predicate.self_ty();
-    let source_trait_ref = if let ty::Dynamic(data, _, ty::Dyn) = self_ty.kind() {
-        data.principal().unwrap().with_self_ty(infcx.tcx, self_ty)
-    } else {
+    let ty::Dynamic(data, _, source_kind) = *self_ty.kind()
+    else {
         bug!()
     };
+    let source_trait_ref = data.principal().unwrap().with_self_ty(infcx.tcx, self_ty);
 
     let (is_upcasting, target_trait_ref_unnormalized) = if Some(goal.predicate.def_id())
         == infcx.tcx.lang_items().unsize_trait()
     {
+        assert_eq!(source_kind, ty::Dyn, "cannot upcast dyn*");
         if let ty::Dynamic(data, _, ty::Dyn) = goal.predicate.trait_ref.substs.type_at(1).kind() {
             (true, data.principal().unwrap().with_self_ty(infcx.tcx, self_ty))
         } else {
@@ -288,7 +289,8 @@ fn rematch_object<'tcx>(
         bug!();
     };
 
-    // If we're upcasting, get the offset of the vtable pointer, which is
+    // If we're upcasting, get the offset of the vtable pointer, otherwise get
+    // the base of the vtable.
     Ok(Some(if is_upcasting {
         ImplSource::TraitUpcasting(ImplSourceTraitUpcastingData { vtable_vptr_slot, nested })
     } else {
diff --git a/src/tools/compiletest/src/read2.rs b/src/tools/compiletest/src/read2.rs
index 725f7a1515c62..a455a1badc053 100644
--- a/src/tools/compiletest/src/read2.rs
+++ b/src/tools/compiletest/src/read2.rs
@@ -83,7 +83,7 @@ impl ProcOutput {
                 }
 
                 let new_len = bytes.len();
-                if *filtered_len <= HEAD_LEN + TAIL_LEN {
+                if (*filtered_len).min(new_len) <= HEAD_LEN + TAIL_LEN {
                     return;
                 }
 
diff --git a/src/tools/compiletest/src/runtest.rs b/src/tools/compiletest/src/runtest.rs
index e8d0ebd40b0a1..672779325ae35 100644
--- a/src/tools/compiletest/src/runtest.rs
+++ b/src/tools/compiletest/src/runtest.rs
@@ -4022,8 +4022,11 @@ impl<'test> TestCx<'test> {
     }
 
     fn normalize_output(&self, output: &str, custom_rules: &[(String, String)]) -> String {
+        let rflags = self.props.run_flags.as_ref();
         let cflags = self.props.compile_flags.join(" ");
-        let json = cflags.contains("--error-format json")
+        let json = rflags
+            .map_or(false, |s| s.contains("--format json") || s.contains("--format=json"))
+            || cflags.contains("--error-format json")
             || cflags.contains("--error-format pretty-json")
             || cflags.contains("--error-format=json")
             || cflags.contains("--error-format=pretty-json")
diff --git a/tests/ui/dyn-star/box.rs b/tests/ui/dyn-star/box.rs
index d1f1819d9f35f..87c8356a174ed 100644
--- a/tests/ui/dyn-star/box.rs
+++ b/tests/ui/dyn-star/box.rs
@@ -1,5 +1,7 @@
 // run-pass
-// compile-flags: -C opt-level=0
+// revisions: current next
+//[current] compile-flags: -C opt-level=0
+//[next] compile-flags: -Ztrait-solver=next -C opt-level=0
 
 #![feature(dyn_star)]
 #![allow(incomplete_features)]