BRO1525: Attributes should not be followed by a blank line

No blank line between an attribute list and the element it applies to, or between two attribute lists of the same element. Not a StyleCop rule: StyleCop proposed it as SA1521 (AttributesMustNotBeFollowedByBlankLine, issue #738) and never implemented it.

Example

Before

using System;

public class Order
{
    public void Ship()
    {
    }

    [Obsolete("Use Ship.")]

    public void Send()
    {
    }

    public int Count
    {
        [Obsolete("Use Size.")]

        get => 0;
    }
}

After

using System;

public class Order
{
    public void Ship()
    {
    }

    [Obsolete("Use Ship.")]
    public void Send()
    {
    }

    public int Count
    {
        [Obsolete("Use Size.")]
        get => 0;
    }
}

Why

An attribute is part of the declaration below it. A blank line after it makes it look like it belongs to nothing, or to the code above; BRO1511 asks the same of documentation comments.

How the fix works

It removes the blank lines between the attribute list and the next line of code. BRO1505 (elements separated by a blank line) doesn't count those lines, since an element's code starts at its first attribute: a member whose only blank line sits below its attribute gets BRO1505's blank line above the attribute, in the same dotnet format run.

Not reported

• A comment, documentation comment or directive between the attribute and the element ([Theory], a blank line, a // ... comment): BRO1504 wants a blank line above a comment that follows code, and an #if changes which element the attribute applies to.
• Assembly and module attributes ([assembly: ...]): they apply to no element below them.
• Code with syntax errors around the element.

Compared with StyleCop

StyleCop has no such rule. Its maintainers gave it the id SA1521 in issue #738 ("up for grabs" since 2015), but it was never implemented and has no documentation page. stylebro-migrate turns this rule off, so migrating doesn't change a StyleCop-clean repository.