BRO1103: Constants should be on the right-hand side of comparisons

0 == count should be written as count == 0. Replaces StyleCop SA1131.

Example

Before

public class Stock
{
    public bool IsEmpty(int count) => 0 == count;

    public bool IsLow(int count) => 10 > count;
}

After

public class Stock
{
    public bool IsEmpty(int count) => count == 0;

    public bool IsLow(int count) => count < 10;
}

Why

count == 0 reads the way you'd say it: "count is zero". The "constant first" style (0 == count) guarded against typing = for == in C, but in C# that mistake doesn't compile for most types anyway.

What is reported

Comparisons (==, !=, <, >, <=, >=) with a constant on the left and a non-constant on the right. Like StyleCop, "constant" means literals, null, default, const fields, enum members, nameof(...), constant expressions such as 1 + 1, and static readonly fields such as string.Empty.

How the fix works

The fix swaps the operands and flips relational operators (10 > count becomes count < 10). Line breaks and comments stay where they are. 1 == 2 == b becomes b == (1 == 2), keeping its meaning. Nested comparisons are fixed in one pass.

Not reported

• Comparisons that use a type's own operator, such as null == money where Money defines ==. A hand-written operator isn't guaranteed to give the same result with its operands reversed, and reversing them can even pick a different overload. Operators from the .NET core library (string, decimal, DateTime, Guid, ...) are symmetric, so Guid.Empty == id is still reported.
• Comparisons with a constant on both sides (1 == 2), like StyleCop.

Compared with StyleCop

StyleCop also swaps comparisons that use a type's own operator.