ROSLYN.RELIABILITY.CA2021 : Do not call Enumerable.Cast<T> or Enumerable.OfType<T> with incompatible types (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.RELIABILITY.CA2021 : Do not call Enumerable.Cast<T> or Enumerable.OfType<T> with incompatible types (C#)

Summary

Enumerable.Cast<T> and Enumerable.OfType<T> require compatible types to function expectedly. The generic cast (IL 'unbox.any') used by the sequence returned by Enumerable.Cast<T> will throw InvalidCastException at runtime on elements of the types specified. The generic type check (C# 'is' operator/IL 'isinst') used by Enumerable.OfType<T> will never succeed with elements of types specified, resulting in an empty sequence. Widening and user defined conversions are not supported with generic types.

This check corresponds to Roslyn rule CA2021. For full rule details, see the Microsoft website: CA2021.

Properties

Class Name	Do not call Enumerable.Cast<T> or Enumerable.OfType<T> with incompatible types (C#)
Significance	reliability
Mnemonic	ROSLYN.RELIABILITY.CA2021
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="Do not call Enumerable.Cast<T> or Enumerable.OfType<T> with incompatible types (C#)"

Relevant Configuration File Parameters

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