Inspection for use of SpecialCells with single cell reference, or a sheet.cells reference

[ThunderFrame]

As per Range SpecialCells ClearContents clears whole sheet instead and Determine if cell contains data validation

Range({any single cell}).SpecialCells({whatever}) seems to work off the entire sheet.
Range({more than one cell}).SpecialCells({whatever}) seems to work off the specified cells.

and

If the Range object on which you call SpecialCells represents only a single cell, the entire sheet will be scanned to find matches. If you have a very large amount of data, the methods provided in previous answers may become a bit slow.

Rubberduck should have an inspection for usages of SpecialCells where either:

1. The range object is a single cell, or refers to an address that resolves to a single cell, or;

2. A Range is Intersected with all of the cells on a sheet: Sheet.Cells.SpecialCells, eg (from https://www.pcreview.co.uk/threads/testing-for-cell-validation.991949/, but corrected):

Dim Cell As Range
Set cell = Range("B9")
If Not Intersect(Cell, Cells.SpecialCells(xlCellTypeAllValidation)) Is Nothing Then
    MsgBox Cell.Address & " contains data validation"
Else
    MsgBox Cell.Addres & " does not contain data validation"
End if