Collection expressions with arguments in C# 15

C# 15 extends collection expressions, introduced in C# 12, with the ability to pass arguments to the underlying collection constructor or builder method using a new 'with(...)' syntax as the first element in the collection expression. This enables scenarios previously impossible with collection expression syntax, such as specifying an initial list capacity or passing a custom comparer to immutable collection builders like ImmutableHashSet.Create. The feature is still in preview as part of .NET 11 preview 7 and requires setting LangVersion to preview; it may change before the November release.

Source: https://www.damirscorner.com/blog/posts/20260904-CollectionExpressionsWithArgumentsInCs15.html. 8 Sync News only summarizes and links out; content copyright belongs to the authors and original sources.