phantom state mismatch

// Test 909: Phantom State Mismatch Detection
//
// Validates that the compiler REJECTS flows where phantom states don't match.
//
// This test deliberately creates a state mismatch:
// - open_file returns *File[open]
// - close_file expects *File[closed]
// - Trying to pass [open] to event expecting [closed] should FAIL

const std = @import("std");

~event open_file {}
| opened { file: *std.fs.File[open] }

~proc open_file {
    const allocator = std.heap.page_allocator;
    const f = allocator.create(std.fs.File) catch unreachable;
    return .{ .opened = .{ .file = f } };
}

~event close_file { file: *std.fs.File[closed] }
| done {}

~proc close_file {
    return .{ .done = .{} };
}

// This flow should FAIL: trying to pass [open] to event expecting [closed]
~open_file()
| opened o |> close_file(file: o.file)
    | done |> _