branch coverage complete

// ============================================================================
// VERIFIED REGRESSION TEST - DO NOT MODIFY WITHOUT DISCUSSION
// ============================================================================
// Test 501: Complete branch coverage validation
// Tests that shape checker validates all branches are handled
// Demonstrates: Multi-branch event with complete coverage

~import std/io

// Event with two possible outcomes
~event divide { a: i32, b: i32 }
| ok i32
| err []const u8

~proc divide|zig {
    if (b == 0) {
        return .{ .err = "Division by zero" };
    }
    return .{ .ok = @divTrunc(a, b) };
}

// Test: Valid division - should take ok branch
~divide(a: 10, b: 2)
| ok _ |> std/io:print.ln("Success: divided")
| err _ |> std/io:print.ln("Error")

// Test: Division by zero - should take err branch
~divide(a: 10, b: 0)
| ok _ |> std/io:print.ln("Success")
| err _ |> std/io:print.ln("Error: division by zero")