Analyzers Library

• May 21, 2025
• 7 minutes to read

The table below lists supported analyzers. Refer to the Static Code Analysis article for information on how to use them.

Code Complexity Analysis

ID	Title	Description	C#	VB
CRR0001	Redundant sub-expressions in a binary operation	The binary operation for identical sub-expressions may contain a redundant expression.
CRR0004	If conditional (ternary) operator has identical branches	Both ternary expression branches are identical.
CRR2007	The IIF function has identical resulting arguments	IIF arguments are identical.
CRR0009	Subsequent if -statements have identical conditions	Subsequent conditional statements with identical conditions can be combined into a single conditional statement.
CRR0012	The logical OR expression has opposite operands	The logical OR expression has opposite terms. This expression is redundant and can be omitted.
CRR0015	Logical OR expression redundancy	The logical OR operation in the expression may be redundant.
CRR0019	Expression contains redundant subsets	The expression contains at least one expression that is a logical subset of another.
CRR0024	Increase precision with a built-in constant or call	The number is a low-precision version of a common constant. Consider changing the number to the suggested reference.
CRR0047	The type can be moved to a separate file	The type can be moved to a separate file
CRR0049	Environment.NewLine can be used	Environment.NewLine can be used. Convert the “\r\n” string value to an Environment.NewLine call.
CRR0050	String.Compare can be used	String.Compare can be used. Use the String.Compare() instead of the == operator or “!=” operator.
CRR0051	String.IsNullOrEmpty can be used	String.IsNullOrEmpty can be used. Use the string.IsNullOrEmpty method call instead of an expression.
CRR0052	String interpolation can be used	String interpolation can be used. Convert an expression into string interpolation.
CRR0053	Missing ‘await’	Async method should be awaited. Add the await operator to the method call.
CRR0054	Async method is called in sync context	The async method is called from regular synchronous code, and the resulting task is ignored. Add the await operator or assign the task returned from this call to a discard.

Mistake Detection

ID	Title	Description	C#	VB
CRR0002	Suspect variable reference in a for -loop condition	The for -loop’s condition expression may use an incorrect variable.
CRR0003	Suspect variable reference in the for -loop iterator section	The for -loop’s iterator section may use an incorrect variable.
CRR0006	Suspect variable reference in null -check following as-cast	The null comparison that follows the typecast may reference an incorrect variable.
CRR0007	String format item/argument mismatch	The string.Format arguments may not match specified format items.
CRR0013	The member always returns the same value	The method’s return statements appear to always return the same constant value.
CRR0017	Null check follows usage	The expression contains a variable that is checked for null after it is referenced.
CRR0020	Integral divide operation cast to float	The divide-by-integral operation is internally cast to the integral type and rounding a floating point value may produce unexpected results.
CRR0027	Possible System.NullReferenceException	The expression is not checked for null and can cause a System.NullReferenceException exception.
CRR0028	Empty event handler	This event handler is empty and can be deleted.
CRR0040	The code metric exceeds the specified threshold	The code element exceeds the specified metric threshold.
CRR0048	The type name does not correspond to the file name	The type name does not correspond to the file name
CRR1000	Name does not correspond to Naming Conventions	The name of the declaration contradicts the existing naming conventions. Use a different name or add a new naming rule.

Async/Await

ID	Title	Description	C#	VB
CRR0029	The ConfigureAwait(true) is called implicitly	You should always call the ConfigureAwait() explicitly because the default behavior may cause a deadlock and should be changed in most cases.
CRR0030	Redundant await	You can delete the await keyword.
CRR0031	The returned Task is null	The returned Task should never be null , use Task.FromResult() instead.
CRR0033	The void async method should be in a try / catch block	The async method which returns nothing should be in a try / catch block. Otherwise, that method’s exceptions may cause a crash.
CRR0034	The asynchronous method should contain the “Async” suffix	The asynchronous method should contain the “Async” suffix.
CRR0035	No CancellationToken parameter in the async method	The async method has no CancellationToken parameter.
CRR0036	The await Task.FromResult() expression is redundant	The await keyword is not required for the Task.FromResult expression.
CRR0037	Task.Wait is used in an async method	Use the Task.When instead of Task.Wait method in an async method.
CRR0038	The CancellationToken parameter is never used	You should use the CancellationToken in the async method’s body to break the task if cancellation is requested.
CRR0039	The await expression without cancellation token	The cancellation token should be passed into the await expression.
CRR0041	Use Task.Run instead of Task.Factory.StartNew	You should use the Task.Run method instead.

Unused Code Detection

ID	Title	Description	C#	VB
CRR0005	The Expression value is always the same	An expression always resolves to the same value.
CRR0008	If -block matches else -block	Both if statement child blocks appear to be identical.
CRR0010	Exception without throw	Precede the instantiation with the throw keyword if you want to throw an exception (so other parts of the program can catch it).
CRR0011	Next if-statement has an identical condition that is never reached	The next if -statement has the same condition as the current one. However, this if -statement breaks the program flow and exits the method block. The next if -statement’s body is never reached.
CRR0014	The variable is assigned twice in succession	The variable receives two assignments in succession. The first assignment may not be needed.
CRR0016	Method call’s return value is ignored	The method call’s return value is not used. This may be unintentional.
CRR0018	Suspect assignment reversal	The assignment reversal is unusual and may be an attempt to bypass side-effects occurring between two assignment statements. This may also indicate brittle code, which cannot be easily maintained.
CRR0021	Subsequent else - if conditions are identical	Nested if - else conditions are equivalent. The code in the nested if -block may never be reached.
CRR0022	Unreachable conditional code block (a similar condition in the else branch)	The conditional expression appears to always evaluate to false. You should check the conditionals above for similar expressions that would prevent the current conditional from being evaluated to true.
CRR0023	Unnecessary conditional	The conditional expression appears to always evaluate to true. The conditional expressions above are likely to ensure that this conditional never evaluates to false.
CRR0025	Unreachable conditional code block (the inversed condition is already satisfied)	The inverse of the current expression is satisfied in a parent conditional - this expression resolves to false (rendering its code block is never reached).
CRR0026	Unused type member	The member is never used and can be deleted.
CRR0042	Unused parameter	This parameter is never used and can be deleted.
CRR0043	Unused type	This type appears to be never used and can be deleted.
CRR0044	Unused local variable	The local variable is never used and can be deleted.
CRR0045	Local variable can be replaced with discard	The local variable is never used and can be replaced with a discard.
CRR0046	Redundant field initialization	Remove the redundant initialization to improve code readability.

Spell Check

ID	Title	C#	VB
CRRSP02[1]	A repeated word was found.
CRRSP03[1]	A misspelled word was found in the file name.
CRRSP04[1]	A misspelled word was found in the XML documentation comment.
CRRSP05[1]	A misspelled word was found in the comment.
CRRSP06[1]	A misspelled word was found in the string.
CRRSP07[1]	A misspelled word was found in the verbatim string.
CRRSP08[1]	A misspelled word was found in the public identifier.
CRRSP09[1]	A misspelled word was found in the internal identifier.
CRRSP10[1]	A misspelled word was found in the protected internal identifier.
CRRSP11[1]	A misspelled word was found in the protected identifier.
CRRSP12[1]	A misspelled word was found in the private identifier.
CRRSP13[1]	A misspelled word was found in the local identifier.

Footnotes

1. Open the quick actions menu and choose the Spell Checker to see a list of possible corrections.