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Java’s type erasure means that generic type information is not available at runtime. C# lambdas: although non-capturing lambdas do not allocate, capturing lamb

Java’s type erasure means that generic type information is not available at runtime. C# lambdas: although non-capturing lambdas do not allocate, capturing lambdas do. "calls through them are virtual" is due to the underlying implementation of delegates in .NET.

neonsunset 2y ago
Well, yes, but delegates as a term is not often used in other languages so I did not mention them for simplicity's sake. For what it's worth - the real issue in C# is not even the virtual calls but the way Roslyn caches lazily allocated non-capturing lambda instances. It does so in a compiler-unfriendly way due to questionable design decisions inside Roslyn. Luckily, this has a high chance of changing in .NET 10. Ideally, by the time it releases hopefully the compiler will both understand the Roslyn's pattern of caching better and be able to stack-allocate non-escaping lambda closure instances. Lambdas capturing 'this' inside instance methods of the object they refer to do not allocate either.