Neal expanded stackalloc usage in the dotnet/csharpstandard repository by relaxing constraints and enabling stackalloc expressions as initializing values for pointer-typed or inferred local variables. He approached this by updating both the language specification and compiler implementation, ensuring the changes were clear, testable, and reduced ambiguity around stackalloc scenarios. Neal used ANTLR for language specification work and applied his compiler development expertise to deliver end-to-end improvements, including comprehensive documentation updates. His work addressed evolving C# 8+ language capabilities, resulting in a more flexible and consistent developer experience. The depth of his contribution is reflected in the integrated code and documentation changes.