ROSLYN.PERFORMANCE.CA1831 : Use AsSpan or AsMemory instead of Range-based indexers when appropriate (C#)

JavaScript is not currently enabled, but is required for full CodeSonar manual search and browse functionality.

If you are viewing this file in your hub's Web GUI, enable JavaScript in your browser: you will also need it for GUI functionality.

If you opened this file directly from disk, your browser may be directly suppressing JavaScript functionality: certain browsers perform this suppression on local files (but not files delivered by web servers) for security reasons.

If you access the manual through the hub's Web GUI, the functionality will not be suppressed because the hub is a web server.
Alternatively, your browser may allow you to explicitly disable the security setting that suppresses functionality. See the CodeSonar FAQ for more information.

CodeSonar^® 9.2p0

CONFIDENTIAL

CodeSecure Inc

ROSLYN.PERFORMANCE.CA1831 : Use AsSpan or AsMemory instead of Range-based indexers when appropriate (C#)

Summary

The Range-based indexer on string values produces a copy of requested portion of the string. This copy is usually unnecessary when it is implicitly used as a ReadOnlySpan or ReadOnlyMemory value. Use the AsSpan method to avoid the unnecessary copy.

This check corresponds to Roslyn rule CA1831. For full rule details, see the Microsoft website: CA1831.

Properties

Class Name	Use AsSpan or AsMemory instead of Range-based indexers when appropriate (C#)
Significance	reliability
Mnemonic	ROSLYN.PERFORMANCE.CA1831
Categories	None
Availability	Available for C# only.
Enabling	Checks for this warning class are enabled by default. To disable them, add the following WARNING_FILTER rule to the project configuration file. WARNING_FILTER += discard class="Use AsSpan or AsMemory instead of Range-based indexers when appropriate (C#)"

Relevant Configuration File Parameters

The following configuration file parameters affect checks for this warning class.