Optimize discarded trailing return values

phpunit/code/multi-return-tuple.php

@@ -10,6 +10,14 @@ function phpunit_multi_consumer(): void
 {
     [$first, $second] = phpunit_multi_values();
     $array = phpunit_multi_values();
+
+    [$partialFirst, $partialSecond] = phpunit_multi_three_values();
+    [$overflowFirst, $overflowSecond, $overflowThird] = phpunit_multi_values();
+}
+
+function phpunit_multi_three_values(): array
+{
+    return [1, 2, 3];
 }
 
 function phpunit_multi_side_effect(): array

phpunit/src/MultiReturnTest.php

@@ -32,6 +32,14 @@ final class MultiReturnTest extends TestCase
             'array = php_phpunit_multi_values()',
             $code,
         );
+        $this->assertStringContainsString(
+            'std::tie(partialFirst, partialSecond, std::ignore) = typephp::detail::php_phpunit_multi_three_values()',
+            $code,
+        );
+        $this->assertStringNotContainsString(
+            'std::tie(overflowFirst, overflowSecond, overflowThird)',
+            $code,
+        );
         $this->assertStringNotContainsString(
             'typephp::detail::php_phpunit_multi_side_effect',
             $code,

src/Parser/AssignOpTrait.php

@@ -123,7 +123,7 @@ trait AssignOpTrait
         }
         $functionDef = $this->getFunction($nativeFunc);
         if (!$functionDef->hasMultiReturn()
-            || $functionDef->multiReturnCount !== count($left->items)
+            || $functionDef->multiReturnCount < count($left->items)
             || $this->shouldUseDynamicCallForNativeArgs($nativeFunc, $right->args)) {
             return null;
         }
@@ -146,8 +146,12 @@ trait AssignOpTrait
                 $this->addLocalVar($name, Type::VAR);
             }
         }
+        $tieItems = array_merge(
+            $variables,
+            array_fill(0, $functionDef->multiReturnCount - count($variables), 'std::ignore'),
+        );
         $right->setAttribute(self::ATTR_MULTI_RETURN_IMPL, true);
-        return 'std::tie(' . implode(', ', $variables) . ') = ' . $this->parseFuncCall($right);
+        return 'std::tie(' . implode(', ', $tieItems) . ') = ' . $this->parseFuncCall($right);
     }
 
     protected function parseAssignToList(Expr $left, Expr $right): string

tests/compiler/array/multi-return-discard-tail.phpt

@@ -0,0 +1,18 @@
+--TEST--
+Tuple multi-return fast path can discard trailing values
+--FILE--
+<?php
+function multi_return_three_values(): array
+{
+    return [1, 2, 3];
+}
+
+function main(): void
+{
+    [$first, $second] = multi_return_three_values();
+    var_dump($first, $second);
+}
+?>
+--EXPECT--
+int(1)
+int(2)