Update CLAUDE.md current status

https://claude.ai/code/session_01Q5xT68N3RbaPCXJxKShnwC

Author: claude

CLAUDE.md

@@ -86,7 +86,7 @@ These differ from older Zig versions and are critical to get right:
 
 ## Current Status
 
-Full pipeline working: Source → Lex → Parse → Naming → Resolve → TypeCheck → Lower → CodegenC → zig cc. Functions, let/var, assignments, if/else, for loops, literals, binary/unary ops, and calls all compile and run. Type checking validates variable/assignment/return type mismatches, function argument counts and types, ordering comparison operands, and naming conventions. Diagnostics use Rust-style rich format with source context, caret annotations, notes/help/hints, "did you mean?" suggestions, and error count summaries. Missing in lower.zig: for-in, switch, structs, defer, closures, channels, error handling.
+Full pipeline working: Source → Lex → Parse → Naming → Resolve → TypeCheck → Lower → CodegenC → zig cc. Implemented end to end: functions (with parameters), let/var, assignments, if/else, all loop forms (`for cond`, `for i in a..b`, `for x in slice`, `for i, v in slice`, break/continue), switch (multi-pattern arms, wildcard, string subjects, `.ok`/`.err` on error unions), structs with Go-style methods (&T/@T/value receivers), non-capturing closures and function values, error unions (`!T`, bare `!`, `try` propagation, `errors.new`), slices (alloc/append/len/index with runtime bounds checks), channels and `run` spawning (user main runs as a green thread). Memory safety: epoch-based generational references with quarantined free lists — stale references always fail their check deterministically; checked dereference costs ~3 ns. Constructs without a lowering (sum types, interfaces, maps, nullable, anonymous structs, capturing closures) produce compile errors instead of miscompiling. Diagnostics use Rust-style rich format with source context, caret annotations, notes/help/hints, "did you mean?" suggestions, and error count summaries.
 
 ## Self-Improvement