[Mpdreamz]

C# 14 extension blocks were read as the compiler's lowering: a nested <G>$… type nobody can name and a set of static methods. They are now first-class.

Reading and writing.

• A new ApiExtension member holds the receiver, type parameters and members of each block.
• The file writes a block as the source declares it, extension<T>(List<T> list) where T : struct, with its members indented under it.
• The static implementation methods are left out. A receiver that only static members use has no name, extension(string).
• The parser reads blocks back to the same model.

Comparing. Each block member is paired with its receiver.

• A member that moves to another block over the same type is a receiver change on that member, not a removal and an addition.
• Rewriting static int A(this string s) as a block member, or back, reports no change: callers compile and run against the same method.

An older bug. Reading System.Private.CoreLib (whose Vector128 and others have blocks with no parameter rows) turned up a crash in ReadParameters: a parameter without a row got a default CustomAttributeHandleCollection, which has no reader.

Verified:

• The Roslyn oracle compares blocks, receivers and their members, and skips the implementation methods. It agrees on CoreLib and the other framework assemblies.
• The library generator now writes blocks: instance and static members, generic blocks with constraints, ref receivers and unnamed receivers. All properties pass: compile, oracle, round trip, split files, self-comparison, mirror.
• New writer sample and six comparison scenarios.
• Mutations caught:
  • block identity ignoring its member, in both equality and hash;
  • no flattening of blocks;
  • keeping the implementation methods.
• mise run ci is green locally.

🤖 Generated with Claude Code