textDocument/definition doesn't work if the definition is in another file

[masterSunflowers]

I have code simple program to use language server get definition of code element like this: https://gist.github.com/masterSunflowers/c9e463950e8766067cc5b9a0f0105a6b. Here is my input project structure

The "Vector" at position 25, 21 is defined in Vector file. But result from language server is just {'jsonrpc': '2.0', 'id': 1, 'result': []}. I have check the folder, where language server save indexed project and it only includes Calculator file. I don't know how to config language server to index full files in the root directory.

[masterSunflowers]

I need to send textDocument/didOpen notify request first before send textDocument/definition request