This issue tracks the work for implementing Mono support for InlineArrayAttribute #61135 and the related C# features such as params ReadOnlySpan, safe fixed size buffers, stackalloc of reference types, etc.

Required work: Completed in .NET8

• Implement struct layout support for InlineArrayAttribute
  This should work for the JIT/interp and also for the AOT compiler
• Implement GC descriptor for boxed structs with InlineArrayAttribute
• [mono][debugger] Implement Mono debugger support for structs with InlineArrayAttribute #84071
• JS Interop generator: Disallow marshaling structs with InlineArrayAttribute in JSImport/JSExport

Nice to have: Future Release.

• Implement support for fast well-known custom attribute lookup in Mono.
  (This isn't strictly necessary, but we already have a number of custom attributes that we check for on every class, and it would be nice to have a single fast lookup function (CoreCLR uses perfect hashing for this))