fix(codegen): rebuild variadic aggregation array per statement

src/Generator/CallArgumentGenerator.php

@@ -305,7 +305,16 @@ protected function parseNativeCallArgs(
                     }
                 }
 
-                $variadicVar ??= $this->addTmpVar(Type::ARRAY);
+                if ($variadicVar === null) {
+                    // Keep the aggregation array in the function preamble
+                    // (addTmpVar) so a forward goto can never jump across a
+                    // call-site C++ local declaration, and reset it instead.
+                    // The reset runs on every evaluation of the call site, so a
+                    // call inside a loop aggregates into an empty array every
+                    // iteration instead of accumulating arguments.
+                    $variadicVar = $this->addTmpVar(Type::ARRAY);
+                    $this->context->beforeStmtLines[] = $variadicVar . '.unset();';
+                }
                 if ($arg->unpack) {
                     $method = $argInfo->byRef ? 'mergeReferences' : 'merge';
                     $this->context->beforeStmtLines[] = $variadicVar . '.' . $method

tests/compiler/variadic/loop-accumulation.phpt

@@ -0,0 +1,47 @@
+--TEST--
+Variadic arguments reset on every loop iteration instead of accumulating
+--FILE--
+<?php
+class Leaf {}
+class Box {
+    /** @var array<int, Leaf> */
+    public array $k = [];
+    public function add(...$els): void {
+        foreach ($els as $e) { $this->k[] = $e; }
+    }
+    public function cnt(): int { return count($this->k); }
+}
+
+function main()
+{
+    $b = new Box();
+
+    // Positional variadic inside a for loop: 3 iterations x 2 args = 6.
+    for ($i = 0; $i < 3; $i++) {
+        $b->add(new Leaf(), new Leaf());
+    }
+
+    // Positional variadic inside a while loop: 2 iterations x 1 arg = 2.
+    $i = 0;
+    while ($i < 2) {
+        $b->add(new Leaf());
+        $i++;
+    }
+
+    // Unpacked variadic inside a for loop: 2 iterations x 2 args = 4.
+    $arr = [new Leaf(), new Leaf()];
+    for ($i = 0; $i < 2; $i++) {
+        $b->add(...$arr);
+    }
+
+    // Mixed positional + unpacked variadic enters the aggregation path
+    // (the single-unpack fast path does not): 2 iterations x 3 args = 6.
+    for ($i = 0; $i < 2; $i++) {
+        $b->add(new Leaf(), ...$arr);
+    }
+
+    var_dump($b->cnt());
+}
+?>
+--EXPECT--
+int(18)

tests/compiler/variadic/variadic-goto-skip.phpt

@@ -0,0 +1,19 @@
+--TEST--
+A forward goto may skip a by-value variadic call without crossing an initialization
+--FILE--
+<?php
+function count_values(...$values): int {
+    return count($values);
+}
+
+function main(): void {
+    if (time() > 0) {
+        goto finished;
+    }
+    count_values(1, 2);
+    finished:
+    echo "done\n";
+}
+?>
+--EXPECT--
+done