Update src/compiler.ts

Co-authored-by: Max Graey <maxgraey@gmail.com>

Author: surma

src/compiler.ts

@@ -9944,8 +9944,8 @@ export class Compiler extends DiagnosticEmitter {
         // Needs to be true when the ref is _not_ null.
         // Therefore: 1 - <ref.is_null>
         return type.size == 64
-          ? module.binary(BinaryOp.SubI64, module.i64(1), module.ref_is(RefIsOp.RefIsNull, expr))
-          : module.binary(BinaryOp.SubI32, module.i32(1), module.ref_is(RefIsOp.RefIsNull, expr));
+          ? module.unary(BinaryOp.EqzI64, module.ref_is(RefIsOp.RefIsNull, expr))
+          : module.unary(BinaryOp.EqzI32, module.ref_is(RefIsOp.RefIsNull, expr));
 
       }
       default: {