DiagnosticCatalog.CodeStyle 1.0.0

DiagnosticCatalog.CodeStyle

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The Roslyn IDE code-style rules as strongly referenced constants, so that SuppressMessageAttribute takes compile-checked references instead of magic strings.

🪞 Mirrors Microsoft.CodeAnalysis.CSharp.CodeStyle 5.6.0

120 rules, 3 categories, every identifier and category read from that release's own analyzers. Regenerated 2026-08-05.

Unofficial. Not affiliated with, endorsed by, or supported by Microsoft.

Why

The IDExxxx rules are the ones most projects meet first, because they arrive with the .NET SDK rather than with a package: turn on EnforceCodeStyleInBuild, give a rule a severity in .editorconfig, and it starts failing builds. What almost nobody knows is which category each one belongs to.

[SuppressMessage("Style", "IDE0008:Use explicit type", Justification = "...")]

Three strings, and nothing checks any of them. Get the id wrong and the suppression silently does nothing — the warning simply stays. Get the category wrong and nothing happens at all, ever: the .NET platform never reads that argument, so no error, no warning and no failing test will tell you. Would you have known that IDE0008 is "Style" but IDE0076 is "CodeQuality", and that IDE0043 is "Compiler"?

using DiagnosticCatalog.CodeStyle;

[SuppressMessage(
    CodeStyleRule.IDE0008.Category,
    CodeStyleRule.IDE0008.Id,
    Justification = "The generated shape is clearer with var here.")]

The day a rule moves to another category, the second version follows it and the first is left naming a category the rule no longer carries — silently, and for as long as the line survives.

Installation

<PackageReference Include="DiagnosticCatalog.CodeStyle" Version="1.0.0" />

That is the only reference you need. This package depends on DiagnosticCatalog, which carries the DCAT analyzers and code fixes beside its attributes, so referencing this catalogue is what switches on the checks that validate rule declarations and their use sites. A literal suppression a catalogue reference would replace is an error by default, and a code fix rewrites it for you.

What is in the package

120 rules across 3 categories:

119 of the 120 carry the title their descriptor declares; RemoveUnnecessaryImportsFixable declares none, so it documents itself with its identifier and category instead. 117 carry a help link, 116 of them into Microsoft's style-rule reference and one — EnableGenerateDocumentationFile — into the Roslyn issue that tracks it:

[DiagnosticRule]
public static class IDE0008
{
    public const string Id = nameof(IDE0008);
    public const string Category = CodeStyleCategory.Style;
    public const string HelpLinkUri =
        "https://learn.microsoft.com/dotnet/fundamentals/code-analysis/style-rules/ide0008";
}

Three identifiers are not of the IDExxxx shape, and they are here because the analyzers declare them: IDE0005_gen (the generated-code half of using directive is unnecessary), EnableGenerateDocumentationFile (set MSBuild property GenerateDocumentationFile to true, which is what makes IDE0005 work in a build) and RemoveUnnecessaryImportsFixable. A catalogue reports what its upstream declares rather than what would look tidy.

IDE0079 is not here, and its absence is deliberate. Remove unnecessary suppression is declared by an analyzer that carries no [DiagnosticAnalyzer] attribute: the IDE drives it through a separate interface, and no compiler ever loads it — with the rule set to warning and code-style enforcement on, a build reports it on an unnecessary suppression not at all. A catalogue exists to make a suppression's arguments checkable, and a rule no build can raise is a reference this package cannot make mean anything (ADR-0031).

A note on versions

Microsoft.CodeAnalysis.CSharp.CodeStyle is versioned with the compiler, not with the SDK. A release that declares a newer compiler than the one running is refused outright:

warning CS9057: Analyzer assembly '...' cannot be used because it references version
'5.6.0.0' of the compiler, which is newer than the currently running version '5.0.0.0'.

That constrains which release you can install, and it is why this catalogue rides a train of its own rather than sharing anyone else's pace. It does not constrain what is read here: the generator reads descriptors and runs no analyzer, so a catalogue can mirror a release that your compiler would decline to load.

You most likely do not need that package at all. The same analyzers reach almost every project through the .NET SDK, where EnforceCodeStyleInBuild turns them on and .editorconfig sets their severity. This catalogue names the rules; where they come from is your build's business.

Categories declared once

CodeStyleCategory holds each category once, and the rules reference it — so a category's spelling exists in exactly one place. It is internal by design: a suppression reaches a category through the rule that carries it, CodeStyleRule.IDE0008.Category, and never through the category constant on its own. The two fold to the same string today and stop agreeing the day Roslyn moves the rule (ADR-0026).

How it is produced

Not transcribed from documentation. The generator reads the analyzer assemblies' metadata for the types they mark with [DiagnosticAnalyzer], constructs those, and reads the DiagnosticDescriptor instances they actually declare — the only source that cannot have drifted.

dotnet run --project src/DiagnosticCatalog.Cli -- generate \
    --package Microsoft.CodeAnalysis.CSharp.CodeStyle --package-version latest \
    --namespace DiagnosticCatalog.CodeStyle --container CodeStyleRule \
    --output src/DiagnosticCatalog.CodeStyle/CodeStyleRules.g.cs

How it stays current

A nightly workflow regenerates every catalogue from its upstream package and opens a pull request when anything the catalogue publishes has moved. It never publishes: a category or an id that changed upstream changes a published contract, and since the platform never reads a suppression's category, a wrong value merged unreviewed would produce no symptom anywhere. A human reads the diff.

A rule retired upstream is never deleted. It is kept and marked [Obsolete] naming the version that dropped it, so a project still referencing it gets a CS0618 warning telling it to remove the suppression — rather than a hard error from a member that vanished. Consumers inline constant values at their own compile time, so deleting one breaks their recompilation.

How it reaches nuget.org

This catalogue rides the codestyle release train and versions independently of the foundation, so it can follow Roslyn's releases without dragging anything else along.

Publishing is not part of the nightly. A maintainer pushes a codestyle-vX.Y.Z tag, and the release workflow packs the package, embeds an SPDX SBOM, and publishes through NuGet Trusted Publishing with signed build provenance — no long-lived API key exists anywhere to leak.

Limits

[SuppressMessage] cannot suppress compiler warnings — CS0219 and friends need #pragma warning disable, which takes bare identifiers and so can never reference a constant. The Compiler category above is not an exception to that: IDE0043 is an analyzer rule that Roslyn files under that category, not a CSxxxx diagnostic.

Many IDExxxx rules are configured in .editorconfig rather than suppressed in source, and that is usually the better tool: a severity applies to a whole project, where a suppression applies to one member. This package is for the cases where the exception is local and deserves a Justification next to the code.

See also

Every catalogue this repository publishes is listed in one place — pick the one that matches an analyzer you run:

The ready-made catalogues

Want a catalogue of your own? Your analyzer's rules, or an internal ruleset, are declared exactly the way these are: a static class of constants marked [DiagnosticRule], referenced by consumers instead of retyped. That marker ships in DiagnosticCatalog, the foundation this catalogue is built on, and its README is the guide.

Documentation

For using a catalogue, in the order the work happens:

• Getting started — ten minutes: reference this package, rewrite one suppression, break it on purpose and watch the compiler catch it.
• Writing suppressions that the compiler checks — the full version, including migrating the literals you already have.
• Adopting a catalogue on an existing codebase — the severity ramp, Fix all occurrences, scoping by folder, and what order to convert in.
• Configuration — every severity key, the category-wide switch, and the PrivateAssets mistake that silences everything.
• Troubleshooting — by symptom: nothing is reported, CS0117, CS0618 after an upgrade.

The documentation map picks a page by what you are trying to do; every guide exists in English and French. The specification is the normative version of all of it.

License

Apache-2.0. The rule identifiers, categories, titles and help links are read from a third-party analyzer, which is itself MIT-licensed.