diff --git a/fine/tests/expression/alternates.fine b/fine/tests/expression/alternates.fine
index 963f1a8e..d2567276 100644
--- a/fine/tests/expression/alternates.fine
+++ b/fine/tests/expression/alternates.fine
@@ -14,6 +14,20 @@ fun extract_value(v: Foo or Bar) -> f64 {
   } // No error; exhaustivity analysis should work.
 }
 
+// Some type compatibility nonsense
+fun bottom() -> string or nothing {
+  "woooo"
+}
+
+fun same_but_wrong_way_around_should_be_compatible() -> nothing or string {
+  bottom()
+}
+
+fun same_but_larger_should_be_compatible() -> nothing or f64 or string {
+  bottom()
+}
+
+
 // This is Bob Nystrom's example from
 // https://journal.stuffwithstuff.com/2023/08/04/representing-heterogeneous-data/
 //
diff --git a/fine/tests/expression/if_mismatched_arms.fine b/fine/tests/expression/if_mismatched_arms.fine
new file mode 100644
index 00000000..0f9531a6
--- /dev/null
+++ b/fine/tests/expression/if_mismatched_arms.fine
@@ -0,0 +1,3 @@
+if true { "blarg" } else { 23 }
+
+// @type: 0 f64 or string