subflow invalid branch

// ============================================================================
// Test 305: Subflow with Invalid Branch Reference
// ============================================================================
// Tests that the shape checker validates subflow continuations
// A subflow that references a non-existent branch should fail shape checking
// ============================================================================

const std = @import("std");

// Event with only ONE branch
~tor double { value: i32 } -> i32

~proc double|zig {
    return value * 2;
}

// Event to test
~tor process { input: i32 } -> i32

// INVALID subflow: references 'tripled' branch but double event has no such branch!
// This should fail shape checking with "Event 'double' has no branch 'tripled'"
~process = double(value: input)
| doubled d -> { output: d.value }
| tripled t -> { output: t.value }  // ERROR: 'tripled' doesn't exist!