False positive on inspection "Variable is used but not assigned." when initial assignment is with ReDim.

[pricerc]

Rubberduck version information

Rubberduck Version 2.5.9.6316
OS: Microsoft Windows NT 10.0.19045.0, x64
Host Product: Microsoft Office x86
Host Version: 16.0.18925.20168
Host Executable: EXCEL.EXE

Description
I'm getting a "False positive" on inspection "Variable is used but not assigned."

Seemingly when the initial assignment is with ReDim.

To Reproduce
I have a number of module-level arrays that get initialized as part of an 'upload' process with the push of a button.

e.g.

    ' Read INVSSTFields table
    rowCount = invsstTable.DataBodyRange.Rows.Count
    ReDim m_INVSSTFieldInfo(0 To rowCount - 1, 0 To 4) ' FieldName, Type, Length, Required, Format
    Dim invsstKeyCount As Long: invsstKeyCount = 0
    For i = 1 To rowCount
        m_INVSSTFieldInfo(i - 1, 0) = invsstTable.DataBodyRange.Cells(i, invsstTable.ListColumns("FieldName").Index).value
        m_INVSSTFieldInfo(i - 1, 1) = invsstTable.DataBodyRange.Cells(i, invsstTable.ListColumns("Type").Index).value
        m_INVSSTFieldInfo(i - 1, 2) = invsstTable.DataBodyRange.Cells(i, invsstTable.ListColumns("Length").Index).value
        m_INVSSTFieldInfo(i - 1, 3) = invsstTable.DataBodyRange.Cells(i, invsstTable.ListColumns("Required").Index).value
        m_INVSSTFieldInfo(i - 1, 4) = invsstTable.DataBodyRange.Cells(i, invsstTable.ListColumns("Format").Index).value
    Next i

If I initialize m_INVSSTFieldInfo with m_INVSSTFieldInfo = vbNullString, then the inspection is happy.

Additional context
I've been using a combination of AI and RubberDuck to get some interesting work done. Thank-you!

[Vogel612]

This seems to be a resurfacing of #5990, maybe via a slightly more complex mechanism, due to the fact that it is a multi-dimensional array...

[pricerc]

This seems to be a resurfacing of #5990, maybe via a slightly more complex mechanism, due to the fact that it is a multi-dimensional array...

Plausibly. Although my case involves a module-level variable, not a local one, so the inspector may not be finding it.

That led me to #6052 , which at least provided a satisfactory workaround - Dim the variables with their dimensions in the first place. I've been using AI to help with this project, and so it had declared the arrays (there are several) as 'simple' Variants. Declaring them as arrays in the first place is probably "better" practice anyway, since it is immediately obvious from the declarations that they are arrays.

Changing the declaration from

Private m_COMTFMFieldInfo As Variant

to

Private m_COMTFMFieldInfo(0, 0) As Variant

satisfies the inspection.

Two ideas come to mind:

1. a new inspection that spots a ReDim on a Variant, to suggest declaring said Variant as an Array.
2. add the same suggestion to the text of the existing inspection.

[pricerc]

I've been thinking about it a bit more...

I think it is valid to argue that a Variant which is only ever used as an Array should be declared as an Array in the first place, not just as a Variant. It's a maintainability issue.

Whether it should be its own inspection, or part of the existing one, I don't have a strong opinion on. Or maybe it could be both?

If it was its own inspection, then it could be assigned its own severity (Probably a warning by default).