Allow iterating over generator with void send() type

Author: danog

src/Psalm/Internal/Analyzer/Statements/Block/ForeachAnalyzer.php

@@ -69,6 +69,7 @@
 use function in_array;
 use function is_string;
 use function reset;
+use function stripos;
 use function strtolower;
 
 /**
@@ -702,15 +703,19 @@ public static function checkIteratorType(
             if ($has_valid_iterator) {
                 IssueBuffer::maybeAdd(
                     new PossiblyInvalidIterator(
-                        'Cannot iterate over ' . $invalid_iterator_types[0],
+                        stripos($invalid_iterator_types[0], 'generator<') === 0
+                            ? 'Cannot iterate over generator with non-null send() type ' . $invalid_iterator_types[0]
+                            : 'Cannot iterate over ' . $invalid_iterator_types[0],
                         new CodeLocation($statements_analyzer->getSource(), $expr),
                     ),
                     $statements_analyzer->getSuppressedIssues(),
                 );
             } else {
                 IssueBuffer::maybeAdd(
                     new InvalidIterator(
-                        'Cannot iterate over ' . $invalid_iterator_types[0],
+                        stripos($invalid_iterator_types[0], 'generator<') === 0
+                            ? 'Cannot iterate over generator with non-null send() type ' . $invalid_iterator_types[0]
+                            : 'Cannot iterate over ' . $invalid_iterator_types[0],
                         new CodeLocation($statements_analyzer->getSource(), $expr),
                     ),
                     $statements_analyzer->getSuppressedIssues(),
@@ -901,7 +906,11 @@ public static function handleIterable(
                     && strtolower($iterator_atomic_type->value) === 'generator'
                 ) {
                     $type_params = $iterator_atomic_type->type_params;
-                    if (isset($type_params[2]) && !$type_params[2]->isNullable() && !$type_params[2]->isMixed()) {
+                    if (isset($type_params[2])
+                        && !$type_params[2]->isNullable()
+                        && !$type_params[2]->isVoid()
+                        && !$type_params[2]->isMixed()
+                    ) {
                         $invalid_iterator_types[] = $iterator_atomic_type->getKey();
                     } else {
                         $has_valid_iterator = true;

tests/Loop/ForeachTest.php

@@ -1193,6 +1193,21 @@ function gen() : Generator {
                     foreach ($gen as $i) {}
                 PHP,
             ],
+            'generatorWithVoidSend' => [
+                'code' => <<<'PHP'
+                    <?php
+
+                    /**
+                     * @return Generator<string, int, void, void>
+                     */
+                    function test(): Generator {
+                        yield 'test' => 1;
+                    }
+
+                    foreach (test() as $_) {
+                    }
+                PHP,
+            ],
             'nullableGenerator' => [
                 'code' => <<<'PHP'
                     <?php