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exceptionf#rethrow

Tell F# that reraise returns no value

How do I help the F# compiler interpret re-throwing an exception as having no return value?

For example, consider wrapping an operation to log the exception:

let doDivision() =
    try
        2 / 0
    with ex ->
        log ex
        reraise

The compiler reports this error for reraise:

This expression was expected to have type int but here has type unit -> 'a

Solution

  • "reraise" is a function. You need to pass unit to it.

    let doDivision() =
    try
        2 / 0
    with ex ->
        log ex
        reraise ()