Got a warning in VS Code saying:

... Differs from Already Included ... Only in Casing

This is caused by the framework I'm using, It actually includes the same file twice, but with different casing.

To fix this, I need to disable forceConsistentCasingInFileNames in tsconfig.json:

{
    "compilerOptions": {
        "forceConsistentCasingInFileNames": false
    }
}