Referential transparency
Methods marked with [PureMethod] are checked for mutable static state, non-pure calls, and I/O operations.
Functional programming support for C#
PureSharp
A Roslyn-based toolset that brings compile-time checks for referential transparency, local-variable immutability, and safer functional-style control flow to C#.
PureSharp helps developers make purity and immutability explicit and mechanically verifiable instead of relying only on conventions and code review.
What PureSharp checks
Immutable local variables
Locals using PureSharp's underscore convention can be required to initialize once and never be reassigned.
Fluent conditional flow
Fluent.If chains are checked so incomplete conditional expressions do not silently escape validation.
Why use it?
C# supports functional programming techniques, but the language does not mechanically enforce referential transparency or immutable local variables. PureSharp uses Roslyn diagnostics to turn selected functional-programming constraints into build-time feedback.
Open source and configurable
Diagnostics use standard .editorconfig severity controls. PureSharp is MIT licensed and its analyzer behavior is documented in a versioned diagnostic contract.