RDC11013 — Variant compared with a String as text

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

A comparison operator - =, <>, <, >, <=, >= - compares a Variant that holds a number, a Date or a Boolean with a String that is not a Variant: a variable declared As String, or a string literal. VBA compares the two as text: the Variant's value is turned into its text first.

So, with v declared As Variant and s declared As String:

v = 10 and s = "9": v > s is False, because the text "10" comes before "9".
v = 1.5 and s = "1.5": v = s is True.
v = 0 and s = ".": v = s is False, and no error is raised.

This is what Microsoft Office VBA does, and what Microsoft Learn documents ("One expression is a String and the other is any Variant except a Null: perform a string comparison"). The language specification says otherwise: MS-VBAL §5.6.9.5 makes the comparison a numeric one, which raises run-time error 13 (Type mismatch) when the String is not a number. RD-VBA runs the code as VBA does, and this warning stands in for that type mismatch: the code depends on a behaviour the specification does not give it.

It is also rarely what is meant. A number compared as text is ordered by its digits, not by its value.

How it is raised

Situation	Example	Resolution
A `Variant` holding a number is compared with a `String` that holds a number.	`If amount > limitText Then`, with `amount` a `Variant` holding `10` and `limitText` holding `"9"`	Convert the `String`: `If amount > CDbl(limitText) Then`.
The two values are meant to be compared as text.	`If code = reference Then`, with `code` holding `5` and `reference` declared `As String`	Say so: `If CStr(code) = reference Then`.

Table of Contents

RDC11013 — Variant compared with a String as text

How it is raised

See also