11 wrong base type reverse

// Database module with Connection and Transaction as IDENTICAL struct layout
// Both have phantom states with the SAME NAME
// The ONLY difference is the semantic TYPE NAME

const std = @import("std");

// BOTH are structurally identical - just an i32 handle!
const Connection = struct { handle: i32 };
const Transaction = struct { handle: i32 };  // Same layout as Connection!

// connect: produces *Connection[active!]
~pub event connect { host: []const u8 }
| ok { conn: *Connection[active!] }
| err { msg: []const u8 }

~proc connect {
    const c = std.heap.page_allocator.create(Connection) catch unreachable;
    c.* = Connection{ .handle = 42 };
    return .{ .ok = .{ .conn = c } };
}

// begin: consumes *Connection[!active], produces *Transaction[active!]
// NOTE: Transaction also has [active!] - same state name as Connection!
~pub event begin { conn: *Connection[!active] }
| ok { tx: *Transaction[active!] }
| err { msg: []const u8 }

~proc begin {
    const tx = std.heap.page_allocator.create(Transaction) catch unreachable;
    tx.* = Transaction{ .handle = conn.handle };
    std.heap.page_allocator.destroy(conn);
    return .{ .ok = .{ .tx = tx } };
}

// close: consumes *Connection[!active]
// This should ONLY accept Connection, NOT Transaction!
~[!]pub event close { conn: *Connection[!active] }

~proc close {
    std.debug.print("Connection closed (handle={})\n", .{conn.handle});
    std.heap.page_allocator.destroy(conn);
}

// commit: consumes *Transaction[!active]
// This should ONLY accept Transaction, NOT Connection!
~[!]pub event commit { tx: *Transaction[!active] }

~proc commit {
    std.debug.print("COMMIT (handle={})\n", .{tx.handle});
    std.heap.page_allocator.destroy(tx);
}