[NFC] Make Literal::makeNull take a HeapType (#4664)

Taking a Type is redundant as we only care about the heap type -
the nullability must be Nullable.

This avoids needing an assertion in the function, that is, it makes
the API more type-safe.

1 files changed, 2 insertions, 3 deletions

diff --git a/src/literal.h b/src/literal.h
index 555f89e5c..4caeab9d4 100644
--- a/src/literal.h
+++ b/src/literal.h
@@ -248,9 +248,8 @@ public:
         WASM_UNREACHABLE("unexpected type");
     }
   }
-  static Literal makeNull(Type type) {
-    assert(type.isNullable());
-    return Literal(type);
+  static Literal makeNull(HeapType type) {
+    return Literal(Type(type, Nullable));
   }
   static Literal makeFunc(Name func, Type type = Type::funcref) {
     return Literal(func, type);