❗ This project is no longer maintained, use https://github.com/Vannevelj/SharpSource instead

VSDiagnostics

A collection of code-quality analyzers based on the Roslyn compiler platform. This project aims to ensure code-quality as you type it in your editor rather than having to do this as a separate build-step. By performing static analysis while you're writing code, certain convention violations and hidden pitfalls can be avoided as early in the process as possible.

Get it from NuGet!

Keep in mind that this project is under active development. If you encounter bugs, let us know!

What is an analyzer exactly?

With the release of Visual Studio 2015 RC, we also received the pretty much final implementation of the Diagnostics implementation. This SDK allows us to create our own diagnostics to help us write proper code that’s being verified against those rules in real-time: you don’t have to perform the verification at a separate build-step. What’s more is that we can combine that with a code fix: a shortcut integrated in Visual Studio that provides us a solution to what we determine to be a problem.

This might sound a little abstract but if you’ve been using Visual Studio (and/or Resharper) then you know what I mean: have you ever written your classname as class rather than Class? This is a violation of the C# naming conventions and visual studio will warn you about it and provide you a quickfix to turn it into a proper capitalized word. This is exactly the behaviour we can create and which is integrated seemlessly in Visual Studio.

Full text available on my blog.

What is available?

Currently these diagnostics are implemented:

Category	Name	Description
Arithmetic	VSD0045	The operands of a divisive expression are both integers and result in an implicit rounding.
Async	VSD0001	Asynchronous methods should end with the -Async suffix.
Async	VSD0041	A non-async, non-Task method should not end with -Async.
Async	VSD0064	Async methods should return a Task to make them awaitable.
Attributes	VSD0002	An attribute should not have an empty argument list.
Attributes	VSD0003	Gives an enum the [Flags] attribute.
Attributes	VSD0004	A [Flags] enum its values are not explicit powers of 2
Attributes	VSD0039	A [Flags] enum its values are not explicit powers of 2 and its values dont fit in the specified enum type.
Attributes	VSD0005	The [Obsolete] attribute doesn't have a reason.
Attributes	VSD0006	OnPropertyChanged() can use the [CallerMemberName] attribute to automatically pass the property name.
Exceptions	VSD0007	An ArgumentException should use nameof() to refer to a variable.
Exceptions	VSD0008	Verifies no NullReferenceException is caught.
Exceptions	VSD0009	Verifies whether an ArgumentException is thrown with a message.
Exceptions	VSD0010	Warns when an exception catch block is empty.
Exceptions	VSD0011	Warns when an exception is rethrown in a way that it loses the stacktrace.
Exceptions	VSD0012	Verifies whether a try-catch block does not defer all exception handling to a single Exception clause.
Exceptions	VSD0052	An exception is thrown from an implicit operator.
Exceptions	VSD0053	An exception is thrown from a property getter.
Exceptions	VSD0054	An exception is thrown from a static constructor.
Exceptions	VSD0055	An exception is thrown from a finally block.
Exceptions	VSD0056	An exception is thrown from an equality operator.
Exceptions	VSD0057	An exception is thrown from a Dispose method.
Exceptions	VSD0058	An exception is thrown from a finalizer method.
Exceptions	VSD0059	An exception is thrown from a GetHashCode() method.
Exceptions	VSD0060	An exception is thrown from an Equals() method.
Exceptions	VSD0065	A null object is attempted to get thrown.
General	VSD0013	Changes an as expression to a cast.
General	VSD0014	Changes a cast expression to as.
General	VSD0015	A boolean expression comparing to false can be simplified.
General	VSD0016	A boolean expression comparing to true can be simplified.
General	VSD0017	The conditional operator shouldn't return redundant default options.
General	VSD0018	The conditional operator shouldn't return redundant inverted default options.
General	VSD0019	The condition is a constant (false) and thus unnecessary.
General	VSD0020	The condition is a constant (true) and thus unnecessary.
General	VSD0021	Inserts the default access modifier for a declaration.
General	VSD0022	Detects usage of the goto keyword.
General	VSD0023	Requires braces for if, else, for, foreach, while, do, using, lock, fixed and switch constructs.
General	VSD0025	Implements the most common configuration of naming conventions.
General	VSD0026	A public, internal or protected internal non-const, non-readonly field should be used as a property.
General	VSD0027	Changes Nullable<T> to T?.
General	VSD0028	Use the nameof() operator in conjunction with OnPropertyChanged.
General	VSD0029	Simplify the expression using an expression-bodied member.
General	VSD0030	A constructor is the same as a default constructor and can be removed.
General	VSD0031	Use as/null instead of is/as.
General	VSD0032	Use var instead of the explicit type.
General	VSD0033	Use the built-in type alias instead of the concrete type.
General	VSD0044	Add cases for missing enum members.
General	VSD0043	An instance of type System.Random is created in a loop.
General	VSD0046	Equals() and GetHashCode() must be implemented together.
General	VSD0047	Implement elementary methods for a type used in a collection.
General	VSD0048	A property with a private setter can become a read-only property instead.
General	VSD0049	A switch is missing a default label.\
General	VSD0061	Implement Equals() and GetHashCode() using existing fields and properties.
General	VSD0063	A GetHashCode implementation refers to a mutable field.
General	VSD0066	Recursively using an overloaded operator.
General	VSD0067	Usage of new Guid() rather than Guid.NewGuid() or Guid.Empty
General	VSD0068	Warns when using DateTime.Now
Strings	VSD0034	Replaces an empty string literal with the more expressive string.Empty.
Strings	VSD0035	Orders the arguments of a string.Format() call in ascending order according to index.
Strings	VSD0042	A string.Format() call lacks arguments and will cause a runtime exception.
Structs	VSD0036	Warns when a struct replaces this with a new instance.
Structs	VSD0050	Structs should implement Equals(), GetHashCode(), and ToString().
Tests	VSD0037	A test method should not end with -Test.
Tests	VSD0038	Verifies whether a test method has the public modifier.
Tests	VSD0062	A method might be missing a test attribute.

How do I use this?

Simply head over to NuGet and install it! If you don't immediately find it: make sure you're also looking through the NuGet V2 package source.

Can I request diagnostics?

Yes, you can! Create an issue and we'll take a look at your proposal.

What if I don't like a diagnostic?

Every diagnostic can be turned off for a single line or for the entire project. At most, you will have to ignore the diagnostic once. For this reason every diagnostic is turned on by default. In order to do so, right click on 'Analyzers' under your references and select 'Open Active Rule Set'. This presents you with the following window to configure which diagnostics should be turned on and their default severity. If you wish to do so, you can change the severity to a more strict or more forgiving setting.

What's on the roadmap?

Most things are filed as an issue so if you want the complete picture -- head over there. However in broad terms:

• Supporting more C# 6 features to ease the transition
• Implement diagnostics aimed at removing unused code
• Create a website that gives more detailed information
• Add user-configurable settings for each diagnostic
• Introduce a Visual Studio extension so it doesn't have to be tied to the project
• Introduce a command-line tool so it isn't tied to a Visual Studio instance

Can I contribute?

Definitely! Take a look at the open issues and see if there's anything that interests you. Submit your pull request and we'll take a look at it as soon as possible.

If you think you're going to make larger changes than a single implementation then we would ask you to get in contact with us first so we can discuss it and prevent unneeded work.

You'll need Visual Studio 2015 and the SDK to get started.

Where can I find more information about every diagnostic?

Release 2.0.0 will come with a website where we document every diagnostic including reasoning behind its implementation choices. In the meantime you can take a look at the tests that belong to each diagnostic to see what exact scenarios we have accounted for.