Accessing struct field behind interface, lazy run-time resolve

[ii64]

Given this scenaro where a variable defined in run-time

{%%
for path, pathItem := range ctx.Doc.Paths.Map() {
    var selectedOp any = nil 

    // some condition

    debugS("%+#v", selectedOp) // compiled
    if selectedOp {  /* .... */  } // compiled 
    if selectedOp.Tags { /* .... */ } // failed to compile
    if selectedOp && selectedOp.Tags { /* .... */ } // failed to compile
}
%%}

[ii64]

@gazerro Here is the MRE for github.com/open2b/scriggo v0.57.1, this should fail with the following error:

        	Error Trace:	<REDACTED>:70
        	Error:      	Received unexpected error:
        	            	repr.tpl:18:29: selectedOp.Foo undefined (type interface {} has no field or method Foo)
        	Test:       	TestReproducible

func TestReproducible(t *testing.T) {
	type st1 struct {
		Foo string

		A *st1
		B *st1
		C *st1

		Map map[string]*st1
	}
	var ctx any = &st1{
		Foo: "Bar",
		Map: map[string]*st1{
			"/": {
				Foo: "Baz",
				A:   &st1{Foo: "BazA"},
			},
			"/foo": {
				Foo: "BazFoo",
				B:   &st1{Foo: "BazFoo"},
			},
		},
	}
	fsys := scriggo.Files{
		"repr.tpl": []byte(`{%%
		for path, pathItem := range ctx.Map {
			var selectedOp any = nil

			for chk in []any{
				pathItem.A,
				pathItem.B,
				pathItem.C,
			} {
				if chk {
				selectedOp = chk	
				break
				}
			}

			debugS("%+#v %+#v", selectedOp, pathItem)

			debugS("%+#v", selectedOp.Foo) // failed to compile
		}
		%%}`),
	}
	tpl, err := scriggo.BuildTemplate(fsys, "repr.tpl", &scriggo.BuildOptions{
		Globals: native.Declarations{
			"ctx":    ctx,
			"debugS": fmt.Printf,
		},
	})
	require.NoError(t, err)

	var b bytes.Buffer
	err = tpl.Run(&b, nil, nil)
	require.NoError(t, err)

	fmt.Println(b.String())
}