Fix #2642 - merging two explicit lists is still a list

vimeo · Jan 17, 2020 · 24e1d54 · 24e1d54
1 parent adf230e
commit 24e1d54
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Showing 2 changed files with 23 additions and 3 deletions.
diff --git a/src/Psalm/Internal/Provider/ReturnTypeProvider/ArrayMergeReturnTypeProvider.php b/src/Psalm/Internal/Provider/ReturnTypeProvider/ArrayMergeReturnTypeProvider.php
@@ -78,6 +78,10 @@ public static function getFunctionReturnType(
                                 );
                             }
 
+                            if (!$unpacked_type_part->is_list) {
+                                $all_nonempty_lists = false;
+                            }
+
                             $unpacked_type_part = $unpacked_type_part->getGenericArrayType();
                         } elseif ($unpacked_type_part instanceof Type\Atomic\TList) {
                             $generic_properties = null;
@@ -99,6 +103,7 @@ public static function getFunctionReturnType(
                         }
                     } elseif (!$unpacked_type_part->type_params[0]->isEmpty()) {
                         $generic_properties = null;
+                        $all_nonempty_lists = false;
                     }
 
                     if ($unpacked_type_part instanceof Type\Atomic\TArray) {
@@ -128,9 +133,13 @@ public static function getFunctionReturnType(
         }
 
         if ($generic_properties) {
-            return new Type\Union([
-                new Type\Atomic\ObjectLike($generic_properties),
-            ]);
+            $objectlike = new Type\Atomic\ObjectLike($generic_properties);
+
+            if ($all_nonempty_lists) {
+                $objectlike->is_list = true;
+            }
+
+            return new Type\Union([$objectlike]);
         }
 
         if ($inner_value_types) {

diff --git a/tests/FunctionCallTest.php b/tests/FunctionCallTest.php
@@ -2475,6 +2475,17 @@ function($x) {
                     '$b' => 'array<int, B>',
                 ],
             ],
+            'arrayMergeTwoExplicitLists' => [
+                '<?php
+                    /**
+                     * @param list<int> $foo
+                     */
+                    function foo(array $foo) : void {}
+
+                    $foo1 = [1, 2, 3];
+                    $foo2 = [1, 4, 5];
+                    foo(array_merge($foo1, $foo2));'
+            ],
         ];
     }