Meziantou.Analyzer

A Roslyn analyzer to enforce some good practices in C# in terms of design, usage, security, performance, and style.

Installation

Install the NuGet package https://www.nuget.org/packages/Meziantou.Analyzer/

Rules

If you are already using other analyzers, you can check which rules are duplicated with well-known analyzers

Id	Category	Description	Severity	Is enabled	Code fix
MA0001	Usage	StringComparison is missing	ℹ️	✔️	✔️
MA0002	Usage	IEqualityComparer<string> or IComparer<string> is missing	⚠️	✔️	✔️
MA0003	Style	Add parameter name to improve readability	ℹ️	✔️	✔️
MA0004	Usage	Use Task.ConfigureAwait	⚠️	✔️	✔️
MA0005	Performance	Use Array.Empty<T>()	⚠️	✔️	✔️
MA0006	Usage	Use String.Equals instead of equality operator	⚠️	✔️	✔️
MA0007	Style	Add a comma after the last value	ℹ️	✔️	✔️
MA0008	Performance	Add StructLayoutAttribute	⚠️	✔️	✔️
MA0009	Security	Add regex evaluation timeout	⚠️	✔️	❌
MA0010	Design	Mark attributes with AttributeUsageAttribute	⚠️	✔️	✔️
MA0011	Usage	IFormatProvider is missing	⚠️	✔️	❌
MA0012	Design	Do not raise reserved exception type	⚠️	✔️	❌
MA0013	Design	Types should not extend System.ApplicationException	⚠️	✔️	❌
MA0014	Design	Do not raise System.ApplicationException type	⚠️	✔️	❌
MA0015	Usage	Specify the parameter name in ArgumentException	⚠️	✔️	❌
MA0016	Design	Prefer using collection abstraction instead of implementation	⚠️	✔️	❌
MA0017	Design	Abstract types should not have public or internal constructors	⚠️	✔️	✔️
MA0018	Design	Do not declare static members on generic types (deprecated; use CA1000 instead)	ℹ️	✔️	❌
MA0019	Usage	Use EventArgs.Empty	⚠️	✔️	✔️
MA0020	Performance	Use direct methods instead of LINQ methods	ℹ️	✔️	✔️
MA0021	Usage	Use StringComparer.GetHashCode instead of string.GetHashCode	⚠️	✔️	✔️
MA0022	Design	Return Task.FromResult instead of returning null	⚠️	✔️	✔️
MA0023	Performance	Add RegexOptions.ExplicitCapture	⚠️	✔️	❌
MA0024	Usage	Use an explicit StringComparer when possible	⚠️	✔️	✔️
MA0025	Design	Implement the functionality instead of throwing NotImplementedException	⚠️	✔️	❌
MA0026	Design	Fix TODO comment	⚠️	✔️	❌
MA0027	Usage	Prefer rethrowing an exception implicitly	⚠️	✔️	✔️
MA0028	Performance	Optimize StringBuilder usage	ℹ️	✔️	✔️
MA0029	Performance	Combine LINQ methods	ℹ️	✔️	✔️
MA0030	Performance	Remove useless OrderBy call	⚠️	✔️	✔️
MA0031	Performance	Optimize Enumerable.Count() usage	ℹ️	✔️	✔️
MA0032	Usage	Use an overload with a CancellationToken argument	ℹ️	❌	❌
MA0033	Design	Do not tag instance fields with ThreadStaticAttribute	⚠️	✔️	❌
MA0035	Usage	Do not use dangerous threading methods	⚠️	✔️	❌
MA0036	Design	Make class static	ℹ️	✔️	✔️
MA0037	Usage	Remove empty statement	❌	✔️	✔️
MA0038	Design	Make method static (deprecated, use CA1822 instead)	ℹ️	✔️	✔️
MA0039	Security	Do not write your own certificate validation method	❌	✔️	❌
MA0040	Usage	Forward the CancellationToken parameter to methods that take one	ℹ️	✔️	✔️
MA0041	Design	Make property static (deprecated, use CA1822 instead)	ℹ️	✔️	✔️
MA0042	Design	Do not use blocking calls in an async method	ℹ️	✔️	✔️
MA0043	Usage	Use nameof operator in ArgumentException	ℹ️	✔️	✔️
MA0044	Performance	Remove useless ToString call	ℹ️	✔️	✔️
MA0045	Design	Do not use blocking calls in a sync method (need to make calling method async)	ℹ️	❌	✔️
MA0046	Design	Use EventHandler<T> to declare events	⚠️	✔️	❌
MA0047	Design	Declare types in namespaces	⚠️	✔️	❌
MA0048	Design	File name must match type name	⚠️	✔️	❌
MA0049	Design	Type name should not match containing namespace	❌	✔️	❌
MA0050	Design	Validate arguments correctly in iterator methods	ℹ️	✔️	✔️
MA0051	Design	Method is too long	⚠️	✔️	❌
MA0052	Performance	Replace constant Enum.ToString with nameof	ℹ️	✔️	✔️
MA0053	Design	Make class or record sealed	ℹ️	✔️	✔️
MA0054	Design	Embed the caught exception as innerException	⚠️	✔️	❌
MA0055	Design	Do not use finalizer	⚠️	✔️	❌
MA0056	Design	Do not call overridable members in constructor	⚠️	✔️	❌
MA0057	Naming	Class name should end with 'Attribute'	ℹ️	✔️	❌
MA0058	Naming	Class name should end with 'Exception'	ℹ️	✔️	❌
MA0059	Naming	Class name should end with 'EventArgs'	ℹ️	✔️	❌
MA0060	Design	The value returned by Stream.Read/Stream.ReadAsync is not used	⚠️	✔️	❌
MA0061	Design	Method overrides should not change default values	⚠️	✔️	✔️
MA0062	Design	Non-flags enums should not be marked with "FlagsAttribute"	⚠️	✔️	❌
MA0063	Performance	Use Where before OrderBy	ℹ️	✔️	❌
MA0064	Design	Avoid locking on publicly accessible instance	⚠️	✔️	❌
MA0065	Performance	Default ValueType.Equals or HashCode is used for struct equality	⚠️	✔️	❌
MA0066	Performance	Hash table unfriendly type is used in a hash table	⚠️	✔️	❌
MA0067	Design	Use Guid.Empty	ℹ️	✔️	✔️
MA0068	Design	Invalid parameter name for nullable attribute	⚠️	✔️	❌
MA0069	Design	Non-constant static fields should not be visible	⚠️	✔️	❌
MA0070	Design	Obsolete attributes should include explanations	⚠️	✔️	❌
MA0071	Style	Avoid using redundant else	ℹ️	✔️	✔️
MA0072	Design	Do not throw from a finally block	⚠️	✔️	❌
MA0073	Style	Avoid comparison with bool constant	ℹ️	✔️	✔️
MA0074	Usage	Avoid implicit culture-sensitive methods	⚠️	✔️	✔️
MA0075	Design	Do not use implicit culture-sensitive ToString	ℹ️	✔️	❌
MA0076	Design	Do not use implicit culture-sensitive ToString in interpolated strings	ℹ️	✔️	❌
MA0077	Design	A class that provides Equals(T) should implement IEquatable<T>	⚠️	✔️	✔️
MA0078	Performance	Use 'Cast' instead of 'Select' to cast	ℹ️	✔️	✔️
MA0079	Usage	Forward the CancellationToken using .WithCancellation()	ℹ️	✔️	✔️
MA0080	Usage	Use a cancellation token using .WithCancellation()	ℹ️	❌	❌
MA0081	Design	Method overrides should not omit params keyword	⚠️	✔️	✔️
MA0082	Design	NaN should not be used in comparisons	⚠️	✔️	❌
MA0083	Design	ConstructorArgument parameters should exist in constructors	⚠️	✔️	❌
MA0084	Design	Local variables should not hide other symbols	⚠️	✔️	❌
MA0085	Usage	Anonymous delegates should not be used to unsubscribe from Events	⚠️	✔️	❌
MA0086	Design	Do not throw from a finalizer	⚠️	✔️	❌
MA0087	Design	Parameters with [DefaultParameterValue] attributes should also be marked [Optional]	⚠️	✔️	❌
MA0088	Design	Use [DefaultParameterValue] instead of [DefaultValue]	⚠️	✔️	❌
MA0089	Performance	Optimize string method usage	ℹ️	✔️	✔️
MA0090	Design	Remove empty else/finally block	ℹ️	✔️	❌
MA0091	Usage	Sender should be 'this' for instance events	⚠️	✔️	✔️
MA0092	Usage	Sender should be 'null' for static events	⚠️	✔️	❌
MA0093	Usage	EventArgs should not be null	⚠️	✔️	✔️
MA0094	Design	A class that provides CompareTo(T) should implement IComparable<T>	⚠️	✔️	❌
MA0095	Design	A class that implements IEquatable<T> should override Equals(object)	⚠️	✔️	❌
MA0096	Design	A class that implements IComparable<T> should also implement IEquatable<T>	⚠️	✔️	❌
MA0097	Design	A class that implements IComparable<T> or IComparable should override comparison operators	⚠️	✔️	❌
MA0098	Performance	Use indexer instead of LINQ methods	ℹ️	✔️	✔️
MA0099	Usage	Use Explicit enum value instead of 0	⚠️	✔️	❌
MA0100	Usage	Await task before disposing of resources	⚠️	✔️	❌
MA0101	Usage	String contains an implicit end of line character	👻	✔️	✔️
MA0102	Design	Make member readonly	ℹ️	✔️	✔️
MA0103	Usage	Use SequenceEqual instead of equality operator	⚠️	✔️	✔️
MA0104	Design	Do not create a type with a name from the BCL	⚠️	❌	❌
MA0105	Performance	Use the lambda parameters instead of using a closure	ℹ️	✔️	❌
MA0106	Performance	Avoid closure by using an overload with the 'factoryArgument' parameter	ℹ️	✔️	❌
MA0107	Design	Do not use object.ToString	ℹ️	❌	❌
MA0108	Usage	Remove redundant argument value	ℹ️	✔️	✔️
MA0109	Design	Consider adding an overload with a Span<T> or Memory<T>	ℹ️	❌	❌
MA0110	Performance	Use the Regex source generator	ℹ️	✔️	✔️
MA0111	Performance	Use string.Create instead of FormattableString	ℹ️	✔️	✔️
MA0112	Performance	Use 'Count > 0' instead of 'Any()'	ℹ️	❌	❌
MA0113	Design	Use DateTime.UnixEpoch	ℹ️	✔️	✔️
MA0114	Design	Use DateTimeOffset.UnixEpoch	ℹ️	✔️	✔️
MA0115	Usage	Unknown component parameter	⚠️	✔️	❌
MA0116	Design	Parameters with [SupplyParameterFromQuery] attributes should also be marked as [Parameter]	⚠️	✔️	✔️
MA0117	Design	Parameters with [EditorRequired] attributes should also be marked as [Parameter]	⚠️	✔️	✔️
MA0118	Design	[JSInvokable] methods must be public	⚠️	✔️	❌
MA0119	Design	JSRuntime must not be used in OnInitialized or OnInitializedAsync	⚠️	✔️	❌
MA0120	Performance	Use InvokeVoidAsync when the returned value is not used	ℹ️	✔️	✔️
MA0121	Design	Do not overwrite parameter value	ℹ️	❌	❌
MA0122	Design	Parameters with [SupplyParameterFromQuery] attributes are only valid in routable components (@page)	ℹ️	✔️	❌
MA0123	Design	Sequence number must be a constant	⚠️	✔️	❌
MA0124	Design	Log parameter type is not valid	⚠️	✔️	❌
MA0125	Design	The list of log parameter types contains an invalid type	⚠️	✔️	❌
MA0126	Design	The list of log parameter types contains a duplicate	⚠️	✔️	❌
MA0127	Usage	Use String.Equals instead of is pattern	⚠️	❌	❌
MA0128	Usage	Use 'is' operator instead of SequenceEqual	ℹ️	✔️	✔️
MA0129	Usage	Await task in using statement	⚠️	✔️	❌
MA0130	Usage	GetType() should not be used on System.Type instances	⚠️	✔️	❌
MA0131	Usage	ArgumentNullException.ThrowIfNull should not be used with non-nullable types	⚠️	✔️	❌
MA0132	Design	Do not convert implicitly to DateTimeOffset	⚠️	✔️	❌
MA0133	Design	Use DateTimeOffset instead of relying on the implicit conversion	ℹ️	✔️	❌
MA0134	Usage	Observe result of async calls	⚠️	✔️	❌
MA0135	Design	The log parameter has no configured type	⚠️	❌	❌
MA0136	Usage	Raw String contains an implicit end of line character	👻	✔️	❌
MA0137	Design	Use 'Async' suffix when a method returns an awaitable type	⚠️	❌	❌
MA0138	Design	Do not use 'Async' suffix when a method does not return an awaitable type	⚠️	❌	❌
MA0139	Design	Log parameter type is not valid	⚠️	✔️	❌
MA0140	Design	Both if and else branch have identical code	⚠️	✔️	❌
MA0141	Usage	Use pattern matching instead of inequality operators for null check	ℹ️	❌	✔️
MA0142	Usage	Use pattern matching instead of equality operators for null check	ℹ️	❌	✔️
MA0143	Design	Primary constructor parameters should be readonly	⚠️	✔️	❌
MA0144	Performance	Use System.OperatingSystem to check the current OS	⚠️	✔️	❌
MA0145	Usage	Signature for [UnsafeAccessorAttribute] method is not valid	⚠️	✔️	❌
MA0146	Usage	Name must be set explicitly on local functions	⚠️	✔️	❌
MA0147	Usage	Avoid async void method for delegate	⚠️	✔️	❌
MA0148	Usage	Use pattern matching instead of equality operators for discrete value	ℹ️	❌	✔️
MA0149	Usage	Use pattern matching instead of inequality operators for discrete value	ℹ️	❌	✔️
MA0150	Design	Do not call the default object.ToString explicitly	⚠️	✔️	❌
MA0151	Usage	DebuggerDisplay must contain valid members	⚠️	✔️	❌
MA0152	Performance	Use Unwrap instead of using await twice	ℹ️	✔️	❌
MA0153	Design	Do not log symbols decorated with DataClassificationAttribute directly	⚠️	✔️	❌
MA0154	Design	Use langword in XML comment	ℹ️	✔️	✔️
MA0155	Design	Do not use async void methods	⚠️	❌	❌
MA0156	Design	Use 'Async' suffix when a method returns IAsyncEnumerable<T>	⚠️	❌	❌
MA0157	Design	Do not use 'Async' suffix when a method returns IAsyncEnumerable<T>	⚠️	❌	❌
MA0158	Performance	Use System.Threading.Lock	⚠️	✔️	❌
MA0159	Performance	Use 'Order' instead of 'OrderBy'	ℹ️	✔️	✔️
MA0160	Performance	Use ContainsKey instead of TryGetValue	ℹ️	✔️	❌
MA0161	Usage	UseShellExecute must be explicitly set	ℹ️	❌	❌
MA0162	Usage	Use Process.Start overload with ProcessStartInfo	ℹ️	❌	❌
MA0163	Usage	UseShellExecute must be false when redirecting standard input or output	⚠️	✔️	❌
MA0164	Style	Use parentheses to make not pattern clearer	⚠️	✔️	✔️
MA0165	Usage	Make interpolated string	👻	✔️	✔️
MA0166	Usage	Forward the TimeProvider to methods that take one	ℹ️	✔️	✔️
MA0167	Usage	Use an overload with a TimeProvider argument	ℹ️	❌	❌
MA0168	Performance	Use readonly struct for in or ref readonly parameter	ℹ️	❌	❌
MA0169	Design	Use Equals method instead of operator	⚠️	✔️	❌
MA0170	Design	Type cannot be used as an attribute argument	⚠️	❌	❌
MA0171	Usage	Use pattern matching instead of HasValue for Nullable<T> check	ℹ️	❌	✔️
MA0172	Usage	Both sides of the logical operation are identical	⚠️	❌	❌
MA0173	Design	Use LazyInitializer.EnsureInitialize	ℹ️	✔️	❌
MA0174	Style	Record should use explicit 'class' keyword	ℹ️	❌	❌
MA0175	Style	Record should not use explicit 'class' keyword	ℹ️	❌	❌
MA0176	Performance	Optimize guid creation	ℹ️	✔️	✔️
MA0177	Style	Use single-line XML comment syntax when possible	ℹ️	❌	✔️

Suppressions

Id	Suppressed rule	Justification
MAS0001	CA1822	Suppress CA1822 on methods decorated with BenchmarkDotNet attributes.
MAS0002	CA1822	Suppress CA1822 on methods decorated with a System.Text.Json attribute such as [JsonPropertyName] or [JsonInclude].
MAS0003	IDE0058	Suppress IDE0058 on well-known types
MAS0004	CA1507	Suppress CA1507 on methods decorated with a [Newtonsoft.Json.JsonPropertyAttribute].

Configuration

You can set the <MeziantouAnalysisMode> MSBuild property to configure the default severity of the rules. The default value is Default. You can set it to None to disable all rules by default.

<Project>
  <PropertyGroup>
    <MeziantouAnalysisMode>None</MeziantouAnalysisMode>
  </PropertyGroup>
</Project>