VBA Nested On Error GoTo

Question

I have VBA code that is supposed to be nested error checking, but it does not. The code is psuedo as below. However, whenever an error occurs within an error (For instance, an error is tripped in the loop, goto SmallError occurs, and an error occurs in SmallError) The second GoTo is not used. The error then breaks the code.

Ex:

Error in Loop

GoTo SmallError

Error in SmallError

Code Breaks (Here code should GoTo FatalError)

Sub DoThings()
    On Error GoTo SmallError
    'Coding Happens
    Do While(conditionhere)
       'Looping things happen
    GoTo LoopResume
SmallError:
    source = Err.source
    descript = Err.Description
    On Error GoTo Fatal Error
    'Small error processing happens
    Resume LoopResume
FatalError:
    source = Err.source
    descript = Err. Description
    On Error GoTo ExitError
    'Fatal Error processing happens
ExitError:
    Exit Sub
LoopResume:
count = count + 1 
Loop

On Error GoTo FatalError
'Finishing code happens
End Sub

Solution

You can't use an On Error statement within an error handler. See e.g. this article that explains this.

What you CAN do however is to have a separate routine that handles the "regular error". This routine can have a "fatal error" handler. Your code would then look something like this:

(Edit: Edited the code to enable exit when there is a fatal error):

Sub DoThings()
On Error GoTo SmallError
    Dim fatalExit As Boolean
    'Coding Happens
    Do While(conditionhere)
       'Looping things happen
LoopResume:
       count = count + 1 
    Loop
On Error Goto SmallError2
'Finishing code happens
  Exit Sub
SmallError:
    handleError Err.Source, Err.Description, fatalExit
    If fatalExit Then 
       Exit Sub
    Else
      Resume LoopResume
    End If
SmallError2:
    handleError Err.Source, Err.Description, fatalExit
    Exit Sub
End Sub

Private Sub handleError(ByVal source As String,ByVal description As String, ByRef fatalExit As Boolean)
On Error Goto FatalError
  'Do "small error" handling here
   Exit Sub
FatalError:
  fatalExit = True
  'Do "fatal error" handling here
End Sub