Dynamic type env fails compilation in v1.17.7

[halvfigur]

Something happened in v1.17.7 causing this snippet to fail

t := reflect.New(reflect.StructOf([]reflect.StructField{
	{
		Name:    "value",
		Type:    reflect.TypeFor[bool](),
		PkgPath: "github.com/some/package",
	},
})).Elem().Interface()

if _, err := expr.Compile("value", expr.Env(t)); err != nil {
	panic(err)
}

it compiles without error in v1.17.6

[antonmedv]

Hmmm. Interesting! But why do you need such strange env?

[halvfigur]

I want to store collections of expr "rules" that I know can be applied to objects (map[string]any representation of JSON) that adhere to a particular JSON schema. So I create a dynamic struct, equivalent to the object described by the JSON schema and then I use an instance of that struct as the env when I compile the expr. That way I know that the expr can be applied to an actual JSON object, all the expected properties are there, the properties' types match expectations etc.

[antonmedv]

I see. For this specific typing on map[string]any we have types.

I need to add some more documentation about it.

[halvfigur]

Thanks! That looks a lot easier to use than reflect :)

[antonmedv]

Lets keep this open so I will remember to update the docs.