Sergio0694/PolySharp

Health v2 · maintenance only

Adoption not part of the score

2222 stars · 72 forks observed · 2026-08-28

What it is AI-extracted, prompt v1, taxonomy v1, 2026-08-30, confidence not recorded

PolySharp is a Roslyn source generator that emits source-only polyfill types (nullability attributes, Index/Range, records support types, etc.) so newer C# language features can be used on older .NET runtimes like .NET Framework or UWP. You add the NuGet reference, set the language version to latest, and the generator automatically supplies the compiler-required 'magic types' for your target framework.

Use cases

• use latest C# language features on .NET Framework
• enable nullable reference type attributes in old projects
• use records and pattern matching on UWP or .NET Standard 2.0
• avoid upgrading runtime just to use new compiler features
• polyfill compiler-required types via source generator

When to choose

• you're stuck on an older .NET runtime but want modern C# syntax
• you maintain libraries targeting .NET Standard 2.0 or .NET Framework
• you want zero-runtime-dependency, source-only polyfills

When to avoid

• you already target the latest .NET runtime with all BCL APIs
• you need features requiring runtime support like static abstract interface members
• you're on .NET Framework 3.5 where many polyfills are limited

Facets

library · maturity active

compiler developer-tools plugin-system developer-tools programming-languages compilers dotnet cross-platform csharp roslyn-source-generator polyfills nuget-package language-features downlevel

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