Flags modules that specify Option Base 1.

Inspection type: MaintainabilityAndReadabilityIssues

Default severity: Hint


Implicit array lower bound is 0 by default, and Option Base 1 makes it 1. While compelling in a 1-based environment like the Excel object model, having an implicit lower bound of 1 for implicitly-sized user arrays does not change the fact that arrays are always better off with explicit boundaries. Because 0 is always the lower array bound in many other programming languages, this option may trip a reader/maintainer with a different background


The following quick-fixes are available for this inspection:

  • IgnoreOnce: Adds an '@Ignore annotation to ignore a specific inspection result. Applicable to all inspections whose results can be annotated in a module.
  • IgnoreInModule: Adds an '@IgnoreModule annotation to ignore a inspection results for a specific inspection inside a whole module. Applicable to all inspections whose results can be annotated in a module.


Each example is a self-contained MCVE showing the feature in a single specific scenario.

Standard Module
Named Module1 by default, these are general-purpose standard procedural modules.
Class Module
Named Class1 by default, these modules define the default interface for an object of that type.
Predeclared Class
A class module with its VB_PredeclaredId attribute set to True (with or without a @PredeclaredId annotation).
Interface Module
Abstract interfaces are class modules (with or without an @Interface annotation) whose default interface is not a class type intended to be instantiated.
UserForm Module
A predeclared class with a design-time visual designer using the MSForms UI framework.
Document Module
Owned by the host application, these class modules belong to the host document and may handle various events fired by the host application.

The following code should trigger this inspection:


Option Explicit
Option Base 1
Public Sub DoSomething()
    Dim foo(10) As Long ' implicit lower bound is 1, array has 10 items.
    ' ...
End Sub

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