RDC11011 — Variant number compared with a Variant String

Severity: Warning · Family: RDC (Rubberduck Core analyzers) · Raised by: VariantNumberStringComparisonAnalyzer

A comparison operator - =, <>, <, >, <=, >= - compares a Variant that holds a number with a Variant that holds a String. The number is always less than the String, whatever the two values are.

This is how VBA compares them (MS-VBAL §5.6.9.5 Relational Operators): when both operands are Variant values, a number is never compared with the text of a String. So, with a and b both declared As Variant:

a = 5 and b = "4": a < b is True, although 5 is more than 4.
a = 10 and b = "9": a > b is False.
a = 5 and b = "5": a = b is False.

When either operand is declared with a type, the values are compared: with a declared As Long, a < b is False.

The code is legitimate, but it is almost never what is meant. A number typed into an InputBox, read from a cell or from a text file is a String, and a Variant holding it compares as one: For i = 1 To n then counts up to a String that every number is less than, and If i <= n Then is always True. The result does not depend on the values, which is why this is a warning.

How it is raised

Situation	Example	Resolution
A `Variant` holding a number is compared with a `Variant` holding a `String`.	`n = InputBox("How many?")` then `If i <= n Then`, with `n` and `i` declared `As Variant`	Convert the `String` to the number it stands for: `n = CLng(InputBox("How many?"))`, or declare `n As Long`.
The two values are meant to be compared as text.	`If code = reference Then`, where `code` holds `5` and `reference` holds `"5"`	Convert the number: `If CStr(code) = reference Then`.

Table of Contents

RDC11011 — Variant number compared with a Variant String

How it is raised

See also