Fix dead catch when iterating objects

Author: rajyan

src/Analyser/NodeScopeResolver.php

@@ -138,6 +138,7 @@
 use PHPStan\Type\UnionType;
 use PHPStan\Type\VoidType;
 use Throwable;
+use Traversable;
 use function array_fill_keys;
 use function array_filter;
 use function array_key_exists;
@@ -823,6 +824,9 @@ private function processStmtNode(
 			if (!$isIterableAtLeastOnce->no()) {
 				$throwPoints = array_merge($throwPoints, $finalScopeResult->getThrowPoints());
 			}
+			if (!(new ObjectType(Traversable::class))->isSuperTypeOf($scope->getType($stmt->expr))->no()) {
+				$throwPoints[] = ThrowPoint::createImplicit($scope, $stmt->expr);
+			}
 
 			return new StatementResult(
 				$finalScope,

tests/PHPStan/Rules/Exceptions/CatchWithUnthrownExceptionRuleTest.php

@@ -196,6 +196,20 @@ public function testFirstClassCallables(): void
 		]);
 	}
 
+	public function testBug5903(): void
+	{
+		$this->analyse([__DIR__ . '/data/bug-5903.php'], [
+			[
+				'Dead catch - Throwable is never thrown in the try block.',
+				47,
+			],
+			[
+				'Dead catch - Throwable is never thrown in the try block.',
+				54,
+			],
+		]);
+	}
+
 	public function testBug6262(): void
 	{
 		$this->analyse([__DIR__ . '/data/bug-6262.php'], []);

tests/PHPStan/Rules/Exceptions/data/bug-5903.php

@@ -0,0 +1,64 @@
+<?php
+
+namespace Bug5903;
+
+class Test
+{
+	/** @var \Traversable<string> */
+	protected $traversable;
+	/** @var \Iterator<string> */
+	protected $iterator;
+	/** @var iterable<string> */
+	protected $iterable;
+	/** @var array<string> */
+	protected $array;
+	/** @var array<string>|null */
+	protected $maybeArray;
+	/** @var \Iterator<string>|null */
+	protected $maybeIterable;
+
+	public function foo()
+	{
+		try {
+			foreach ($this->traversable as $val) {
+				echo $val;
+			}
+		} catch (\Throwable $e) {
+		}
+
+		try {
+			foreach ($this->iterator as $val) {
+				echo $val;
+			}
+		} catch (\Throwable $e) {
+		}
+
+		try {
+			foreach ($this->iterable as $val) {
+				echo $val;
+			}
+		} catch (\Throwable $e) {
+		}
+
+		try {
+			foreach ($this->array as $val) {
+				echo $val;
+			}
+		} catch (\Throwable $e) {
+		}
+
+		try {
+			foreach ($this->maybeArray as $val) {
+				echo $val;
+			}
+		} catch (\Throwable $e) {
+		}
+
+		try {
+			foreach ($this->maybeIterable as $val) {
+				echo $val;
+			}
+		} catch (\Throwable $e) {
+		}
+	}
+}