Fix Instance.getByIndex

src/instance.zig

@@ -90,10 +90,10 @@ pub const Instance = extern struct {
         comptime T: type,
     ) !struct { result: T, name: []const u8 } {
         var result: Extern = undefined;
-        var name: [*]const u8 = null;
+        var name: [*]const u8 = undefined;
         var name_len: usize = undefined;
         return if (wasmtime_instance_export_nth(context, self, index, &name, &name_len, &result))
-            .{ .result = result.as(T), .name = name[0..name_len] }
+            .{ .result = try result.as(T), .name = name[0..name_len] }
         else
             error.ExportNotFound;
     }