Function runDemoAssertions

examples/demo.php:5227–6197

()

// Run: php examples/demo.php

function runDemoAssertions(): void
{
    // ── Body Return Type Inference ──────────────────────────────────────
    $factory = new ScaffoldingUntypedFactory();
    $pen = $factory->createPen();
    assert($pen instanceof Pen, 'createPen() must return Pen (inferred from body)');
    $tool = $factory->createTool(true);
    assert($tool instanceof Pen || $tool instanceof Pencil, 'createTool() must return Pen|Pencil');

    // ── Return Type: static ─────────────────────────────────────────────
    $pen = Pen::make();
    assert($pen instanceof Pen, 'Pen::make() must return Pen');

    $marker = Marker::make();
    assert($marker instanceof Marker, 'Marker::make() must return Marker (not Pen)');

    $fluent = $marker->rename('Bold');
    assert($fluent instanceof Marker, 'Marker::rename() returns static, must stay Marker');

    // ── Return Type: function ───────────────────────────────────────────
    $created = makePen();
    assert($created instanceof Pen, 'makePen() must return Pen');

    $union = pickPenOrPencil();
    assert($union instanceof Pen || $union instanceof Pencil, 'pickPenOrPencil() must return Pen|Pencil');

    $rock = pickRockOrBanana();
    assert($rock instanceof Rock || $rock instanceof Banana, 'pickRockOrBanana() must return Rock|Banana');

    $user = createUser('Alice', 'alice@example.com');
    assert($user instanceof User, 'createUser() must return User');

    // ── Chaining ────────────────────────────────────────────────────────
    $brush = new Brush();
    $sized = $brush->setSize('large');
    assert($sized instanceof Brush, 'Brush::setSize() returns static, must stay Brush');
    $styled = $sized->setStyle('pointed');
    assert($styled instanceof Brush, 'Brush::setStyle() returns static, must stay Brush');

    $canvas = $brush->getCanvas();
    assert($canvas instanceof Canvas, 'Brush::getCanvas() must return Canvas');

    $backToBrush = $canvas->getBrush();
    assert($backToBrush instanceof Brush, 'Canvas::getBrush() must return Brush');

    $easel = $canvas->easel;
    assert($easel instanceof Easel, 'Canvas::$easel must be Easel');

    // ── Fluent Model chains (static return) ─────────────────────────────
    $userObj = new User('Bob', 'bob@example.com');
    $renamed = $userObj->setName('Robert');
    assert($renamed instanceof User, 'User::setName() returns static, must stay User');

    $timestamped = $userObj->setCreatedAt('2024-01-01');
    assert($timestamped instanceof User, 'HasTimestamps::setCreatedAt() returns static, must stay User');

    // ── User method return types ────────────────────────────────────────
    $profile = $userObj->getProfile();