Fix phpstan/phpstan#14281: type narrowed too much after identical comparison

- Root cause: commit a063119 introduced parent constructor template inference
  that resolved TElement to *NEVER* from empty default array parameters
- When new TestCollection() was called without arguments, TElement was inferred
  as *NEVER* (from default []), causing get() to return null instead of mixed
- This made assert($data[1] === $collection->get(1)) resolve as assert(0 === null),
  narrowing $data to *NEVER* (dead code)
- Fix: skip NeverType when mapping parent constructor template types to child class
- New regression test in tests/PHPStan/Analyser/nsrt/bug-14281.php

Author: phpstan-bot

src/Analyser/ExprHandler/NewHandler.php

@@ -547,6 +547,10 @@ classReflection: $classReflection->withTypes($types)->asFinal(),
 					continue;
 				}
 
+				if ($type instanceof NeverType) {
+					continue;
+				}
+
 				if (!array_key_exists($ancestorType->getName(), $resolvedTypeMap)) {
 					$resolvedTypeMap[$ancestorType->getName()] = $type;
 					continue;

tests/PHPStan/Analyser/nsrt/bug-14281.php

@@ -0,0 +1,99 @@
+<?php declare(strict_types=1);
+
+namespace Bug14281;
+
+use function PHPStan\Testing\assertType;
+
+class CollectionTest
+{
+	public function testFromAssociative(): void
+	{
+		$data = [
+			null,
+			0,
+			'some-string',
+			new \stdClass(),
+			['some' => 'value'],
+		];
+
+		$collection = (new TestCollection())->assignRecursive($data);
+
+		assert(count($collection)===5);
+		assertType("array{null, 0, 'some-string', stdClass, array{some: 'value'}}", $data);
+
+		assert($data[0] === $collection->get(0));
+		assertType("array{null, 0, 'some-string', stdClass, array{some: 'value'}}", $data);
+		assert($data[1] === $collection->get(1));
+		assertType("array{null, 0, 'some-string', stdClass, array{some: 'value'}}", $data);
+		assert($data[2] === $collection->get(2));
+		assertType("array{null, 0, 'some-string', stdClass, array{some: 'value'}}", $data);
+		assert($data[3] === $collection->get(3));
+		assertType("array{null, 0, 'some-string', stdClass, array{some: 'value'}}", $data);
+		assert($data[4] === $collection->get(4));
+		assertType("array{null, 0, 'some-string', stdClass, array{some: 'value'}}", $data);
+	}
+}
+
+/**
+ * @template TElement
+ *
+ * @extends Collection<TElement>
+ */
+class TestCollection extends Collection
+{
+}
+
+/**
+ * @template TElement
+ *
+ * @implements \IteratorAggregate<array-key, TElement>
+ */
+abstract class Collection implements \IteratorAggregate, \Countable
+{
+	/**
+	 * @var array<array-key, TElement>
+	 */
+	protected array $elements = [];
+
+	/**
+	 * @param array<TElement> $elements
+	 */
+	public function __construct(array $elements = [])
+	{
+		$this->elements = $elements;
+	}
+
+	/**
+	 * @param array-key $key
+	 *
+	 * @return TElement|null
+	 */
+	public function get($key)
+	{
+		return $this->elements[$key] ?? null;
+	}
+
+	/**
+	 * @phpstan-impure
+	 */
+	#[\Override]
+	public function count(): int
+	{
+		return \count($this->elements);
+	}
+
+	/**
+	 * @return \Traversable<TElement>
+	 */
+	#[\Override]
+	public function getIterator(): \Traversable
+	{
+		yield from $this->elements;
+	}
+
+	/** @param array<mixed> $options */
+	public function assignRecursive(array $options): static
+	{
+		return $this;
+	}
+}