Missing errors

I noticed that the language server is unable to see all errors. E.g. for the modified code below from App.kt in [https://github.com/fwcd/kotlin-quick-start/](url) no error is reported:

package quick.start


shouldMarkThisAsError

class App {

    val greeting: String

        get() = "Hello world."

}

however running `./gradlew compileKotlin` reports:
`e: [...]/kotlin-quick-start/src/main/kotlin/quick/start/App.kt: (3, 1): Expecting a top level declaration`

Reproduce the issue with the modified App.kt example from kotlin-quick-start and compare language-server diagnostics with ./gradlew compileKotlin. Start by tracing how the language server reports syntax errors, then ensure the top-level declaration error at shouldMarkThisAsError is surfaced. Done means the language server reports the missing error for this example.

Written by the indexing model from the issue text.