New Rule Idea: Do not use collection initializers with `ImmutableArray`

[Tim-Pohlmann]

Using a collection initializer with the ImmutableArray type, causes a NullReferenceException.

_ = new ImmutableArray<string> { "init" }; // NRE

SharpLab

[jilles-sg]

This NRE is a special case of the fact that the parameterless constructor of ImmutableArray<T> results in an object that throws on most access. Perhaps the new rule can trigger on uses of that constructor instead. If a "null" value of ImmutableArray<T> is needed, I'd say the developer should be explicit and write default.