Fix assertion failure for non-concrete continuation types

This patch fixes the assertion failures listed in issue
#117 that were
not fixed prior to closing the issue.

Author: dhil

interpreter/valid/valid.ml

@@ -441,15 +441,15 @@ let check_resume_table (c : context) ts2 (xys : (idx * hdl) list) at =
         let FuncT (ts3, ts4) = func_type_of_tag_type c (tag c x1) x1.at in
         let ts' = label c x2 in
         (match Lib.List.last_opt ts' with
-        | Some (RefT (nul', ht)) ->
+        | Some (RefT (nul', ((VarHT _ | DefHT _) as ht))) ->
           let ct = cont_type_of_heap_type c ht x2.at in
           let ft' = func_type_of_cont_type c ct x2.at in
           require (match_func_type c.types (FuncT (ts4, ts2)) ft') x2.at
             "type mismatch in continuation type";
           match_stack c (ts3 @ [RefT (nul', ht)]) ts' x2.at
         | _ ->
            error at
-             ("type mismatch: instruction requires continuation reference type" ^
+             ("type mismatch: instruction requires concrete continuation reference type" ^
                 " but label has " ^ string_of_result_type ts'))
       | OnSwitch ->
         let FuncT (ts3, ts4) = func_type_of_tag_type c (tag c x1) x1.at in

test/core/stack-switching/cont.wast

@@ -1141,3 +1141,45 @@
     (func (param $k (ref $ct))
       (switch $ct $t)))
   "type mismatch in switch tag")
+
+;; Synthesized from https://github.com/WebAssembly/stack-switching/issues/117
+(assert_invalid
+  (module
+    (type $ft (func))
+    (type $ct (cont $ft))
+    (tag $t)
+
+    (func
+      (block $on_t (result (ref cont))
+        (resume $ct (on $t $on_t) (cont.new $ct (ref.null $ft)))
+        (unreachable)
+      )
+      (drop)
+    ))
+  "type mismatch: instruction requires concrete continuation reference type but label has [(ref cont)]")
+
+(assert_invalid
+  (module
+    (type $ft (func))
+    (type $ct (cont $ft))
+    (tag $t)
+
+    (func
+      (block $on_t (result (ref nocont))
+        (resume $ct (on $t $on_t) (cont.new $ct (ref.null $ft)))
+        (unreachable)
+      )
+      (drop)
+    ))
+  "type mismatch: instruction requires concrete continuation reference type but label has [(ref nocont)]")
+
+;; https://github.com/WebAssembly/stack-switching/issues/117#issuecomment-2908974084
+(module
+  (type $f (func))
+  (type $c (sub (cont $f)))
+  (tag $e)
+  (func (param $c (ref $c))
+    (local.get $c)
+    (resume $c)
+  )
+)