CA1842: Do not use 'WhenAll' with a single task

Property	Value
Rule ID	CA1842
Title	Do not use 'WhenAll' with a single task
Category	Performance
Fix is breaking or non-breaking	Non-breaking
Enabled by default in .NET 8	As suggestion

Cause

WhenAll is called with a single task.

Rule description

Using WhenAll with a single task may result in performance loss.

How to fix violations

You should await or return the task instead.

When to suppress warnings

Do not suppress a warning from this rule.

See also

• CA1843: Do not use 'WaitAll' with a single task
• Performance rules