Fix crash when using bitwise not on incompatible type

Author: cknitt

compiler/ml/typecore.ml

@@ -3453,9 +3453,15 @@ and translate_unified_ops (env : Env.t) (funct : Typedtree.expression)
         | Tconstr (path, _, _), {string = Some _}
           when Path.same path Predef.path_string ->
           instance_def Predef.type_string
-        | _ ->
-          unify env lhs_type (instance_def Predef.type_int);
-          instance_def Predef.type_int
+        | _ -> (
+          try
+            unify env lhs_type (instance_def Predef.type_int);
+            instance_def Predef.type_int
+          with
+          | Ctype.Unify trace ->
+            raise
+              (Error
+                 (lhs.exp_loc, env, Expr_type_clash {trace; context = None})))
       in
       let targs = [(lhs_label, Some lhs)] in
       Some (targs, result_type)

tests/build_tests/super_errors/expected/incorrect_tilde_usage.res.expected

@@ -0,0 +1,10 @@
+
+  We've found a bug for you!
+  /.../fixtures/incorrect_tilde_usage.res:2:10
+
+  1 │ let x = []
+  2 │ let _ = ~x
+  3 │ 
+
+  This has type: array<'a>
+  But it's expected to have type: int

tests/build_tests/super_errors/fixtures/incorrect_tilde_usage.res

@@ -0,0 +1,2 @@
+let x = []
+let _ = ~x