C# grammar for tree-sitter based upon the Roslyn grammar with changes in order to:

• Deal with differences between the parsing technologies
• Work around some bugs in that grammar
• Handle #if, #else, #elif, #endif blocks
• Support syntax highlighting/parsing of fragments
• Simplify the output tree
• Reduce parser state count and complexity
• Be in-line with tree-sitter's convention where applicable

Comprehensive supports C# 1 through 13.0 with the following exception:

• [ ] async, var and await cannot be used as identifiers everywhere they are valid

• Official C# 6 Language Spec provides chapters that formally define the language grammar.
• Roslyn C# language grammar export
• SharpLab (web-based syntax tree playground based on Roslyn)