Why Substring cannot make a reference to the original data instead of a copy?

[jjxtra]

referencesource/mscorlib/system/string.cs

Line 1302 in dae1427

unsafe string InternalSubString(int startIndex, int length) {

Why can't Substring just have a reference to the original unmanaged memory? Is there something with GC that would prevent a string referencing another string?

[svick]

This repo is not very active, so it's not a great place to ask questions like this. A better choice would be the repo for the modern .Net runtime: dotnet/runtime.

That being said, what you're saying would require changing the structure of the string type, which is a pretty fundamental part of the runtime. Instead, .Net decided to add the Span<T> type, which can represent any memory sequence, which means the equivalent operation to Substring, called Slice, works exactly the way you want there.