Invalid map optimization result in unreliable subscript resolution

[r3c]

Version: 1.6.1

Code:

var document = Document.CreateDefault("{[x: 42][0]}");
var context = Context.CreateCustom(new Dictionary<Value, Value> { ["x"] = 0 });

return document.DocumentOrThrow.Render(context);

Expected result:
"42"

Actual result:
string.Empty

Description:
Document optimizer performs invalid optimization of maps with non-constant indices and constant subscript. In the example above, it will assume map doesn't contain a value at index 0 while variable x can take this value at render time, making the assumption wrong.

[r3c]

Introduced by 9dcb205, fixed in d5078d8.