Introduction

Diagnostic analyzers are extensions to the Roslyn C# compiler and Visual Studio IDE to analyze user code and report diagnostics. The user will see these diagnostics in the error list after building the project from Visual Studio and even when building the project on the command line. They will also see the diagnostics live while editing the source code in the Visual Studio IDE. Analyzers can report diagnostics to enforce specific code styles, improve code quality and maintenance, recommend design guidelines, or even report very domain-specific issues, which cannot be covered by the core compiler.

Analyzers can be installed in a .NET project either as a NuGet package or as a VSIX. To get a better understanding of these packaging schemes and learn about the differences in the analyzer experience when installed as a NuGet package versus a VSIX, it is recommended that you read the introduction part of the recipe Publishing NuGet package and VSIX for an analyzer project in Chapter 1, Writing Diagnostic Analyzers.