From d296c4bb9a87d277d881117906dfbf565870e099 Mon Sep 17 00:00:00 2001
From: Bruce Weirdan <weirdan@gmail.com>
Date: Thu, 21 Jan 2021 00:42:11 +0200
Subject: [PATCH] Add missing dataflow population in array spreads (#5059)

Fixes vimeo/psalm#5057
---
 .../Statements/Expression/ArrayAnalyzer.php   | 24 +++++++++++++++++++
 tests/UnusedVariableTest.php                  | 10 ++++++++
 2 files changed, 34 insertions(+)

diff --git a/src/Psalm/Internal/Analyzer/Statements/Expression/ArrayAnalyzer.php b/src/Psalm/Internal/Analyzer/Statements/Expression/ArrayAnalyzer.php
index 2323e144d..a87cfb4d7 100644
--- a/src/Psalm/Internal/Analyzer/Statements/Expression/ArrayAnalyzer.php
+++ b/src/Psalm/Internal/Analyzer/Statements/Expression/ArrayAnalyzer.php
@@ -241,6 +241,30 @@ class ArrayAnalyzer
                 $unpacked_array_type
             );
 
+            if (($data_flow_graph = $statements_analyzer->data_flow_graph)
+                && $data_flow_graph instanceof \Psalm\Internal\Codebase\VariableUseGraph
+                && $unpacked_array_type->parent_nodes
+            ) {
+                $var_location = new CodeLocation($statements_analyzer->getSource(), $item->value);
+
+                $new_parent_node = \Psalm\Internal\DataFlow\DataFlowNode::getForAssignment(
+                    'array',
+                    $var_location
+                );
+
+                $data_flow_graph->addNode($new_parent_node);
+
+                foreach ($unpacked_array_type->parent_nodes as $parent_node) {
+                    $data_flow_graph->addPath(
+                        $parent_node,
+                        $new_parent_node,
+                        'array-assignment'
+                    );
+                }
+
+                $array_creation_info->parent_taint_nodes += [$new_parent_node->id => $new_parent_node];
+            }
+
             return;
         }
 
diff --git a/tests/UnusedVariableTest.php b/tests/UnusedVariableTest.php
index bff38743c..af97c8991 100644
--- a/tests/UnusedVariableTest.php
+++ b/tests/UnusedVariableTest.php
@@ -2182,6 +2182,16 @@ class UnusedVariableTest extends TestCase
                         print_r(...$d);
                     }'
             ],
+            'explicitSpread' => [
+                '<?php
+                    function f(): array {
+                        $s = [1, 2, 3];
+                        $b = ["a", "b", "c"];
+
+                        $r = [...$s, ...$b];
+                        return $r;
+                    }'
+            ],
             'funcGetArgs' => [
                 '<?php
                     function validate(bool $b, bool $c) : void {