List access errors are ambiguous

[dstephan1]

Describe the bug
If you have an expression like mylistundef[0] == 'hi', and 'mylistundef' is undefined, you get an ambiguous error "fails with no such attribute: id: 2, names: []".

To Reproduce
Check which components this affects: (not sure)

Sample expression and input that reproduces the issue:

mylistundef[0] == 'hi'

Test setup:

// test case in go
func testList() error {
	env, err := cel.NewEnv(
		cel.Variable("mylist", cel.ListType(cel.StringType)),
	)
	if err != nil {
		return err
	}
	ast, issues := env.Parse(`mylistundef[0] == 'hi'`)
	if err := issues.Err(); err != nil {
		return err
	}
	program, err := env.Program(ast)

	varmap := map[string]any{}
	varmap["mylist"] = []string{"hi"}
	val, _, err := program.Eval(varmap)
	if err != nil { // fails with no such attribute: id: 2, names: []
		return err
	}

	match, ok := val.Value().(bool)
	if !ok {
		return fmt.Errorf("type convert failed: type is %v", val.Type())
	}
	return nil
}

func TestList(t *testing.T) {
	if err := testList(); err != nil {
		t.Error(err)
	}
}

Expected behavior
There should be a clear error, such as "mylistundef is undefined"

[dstephan1]

https://github.com/google/cel-go/blob/master/interpreter/attributes.go

Resolve returns the first error it sees. Which is dereference of the deepest variable. Ex: 'foo.bar.baz[0]' will error in this order: no such attr: 2 -> no such attr baz -> no such attr bar -> no such attr foo.

And what you end up with is a vague "no such attribute: id: 2".