Collection Expressions

Collection expressions, added in C# 12, give you a single literal shape, [a, b, c], that works for arrays, lists, spans, immutable arrays, and any collection type that opts in. This lesson zooms in on the language feature itself: how target typing drives the construction, what the spread operator compiles into, what conversions the compiler is willing to make, and where the feature stops. The focus is on the rules the compiler follows and how to migrate older code safely.