[test] Add test for local.tee re #516

test/core/br_on_null.wast

@@ -65,45 +65,30 @@
 (assert_return (invoke "args-null" (i32.const 3)) (i32.const 3))
 (assert_return (invoke "args-f" (i32.const 3)) (i32.const 9))
 
+
 ;; https://github.com/WebAssembly/gc/issues/516
+;; Tests that validators are correctly doing
+;;
+;; pop_operands(label_types)
+;; push_operands(label_types)
+;;
+;; for validating br_on_null, rather than incorrectly doing either
+;;
+;; push_operands(pop_operands(label_types))
+;;
+;; or just inspecting the types on the stack without any pushing or
+;; popping, neither of which handle subtyping correctly.
 (assert_invalid
- (module
- (type $ty (func))
-
- (func $ty_ref_to_func_ref (param (ref null $ty)) (result funcref)
- local.get 0
- )
-
- (func (param funcref) (result funcref)
- ref.null $ty
- local.get 0
-
- ;; This instruction is typed `[funcref funcref] -> [funcref (ref
- ;; func)]`. The stack coming into this instruction is `[(ref null $ty)
- ;; funcref]` which matches because of `(ref null $ty) <: funcref`. However,
- ;; that subtyping relation doesn't mean that this instruction can *push* a
- ;; `(ref null $ty)`. The label type effectively erases the `(ref null
- ;; $ty)`, turning it into an `funcref`. Finally, a type mismatch error
- ;; should be reported at the `call` instruction below, which expects a
- ;; `(ref null $ty)` but is given the `funcref` (that is "actually" a `(ref
- ;; null $ty)`).
- ;;
- ;; This tests that validators are correctly doing
- ;;
- ;; pop_operands(label_types)
- ;; push_operands(label_types)
- ;;
- ;; rather than incorrectly doing either
- ;;
- ;; push_operands(pop_operands(label_types))
- ;;
- ;; or just inspecting the types on the stack without any pushing or
- ;; popping, neither of which handle subtyping correctly.
- br_on_null 0
-
- drop
- call $ty_ref_to_func_ref
- )
- )
-"type mismatch"
+ (module
+ (type $t (func))
+ (func $f (param (ref null $t)) (result funcref) (local.get 0))
+ (func (param funcref) (result funcref)
+ (ref.null $t)
+ (local.get 0)
+ (br_on_null 0) ;; only leaves two funcref's on the stack
+ (drop)
+ (call $f)
+ )
+ )
+ "type mismatch"
 )

test/core/local_tee.wast

@@ -608,6 +608,21 @@
  "type mismatch"
 )
 
+;; https://github.com/WebAssembly/gc/issues/516
+(assert_invalid
+ (module
+ (type $t (func))
+ (func $f (param (ref null $t)))
+ (func
+ (local $x funcref)
+ (ref.null $t)
+ (local.tee $x) ;; leaves only a funcref on the stack
+ (call $f)
+ )
+ )
+ "type mismatch"
+)
+
 
 ;; Invalid local index