From f0153721a458a42972676483c6dc8da46646f1ee Mon Sep 17 00:00:00 2001
From: adrew <klimichkartorgnusov@gmail.com>
Date: Sat, 15 Apr 2023 18:46:22 +0300
Subject: [PATCH] Fix list template replacement

---
 psalm-baseline.xml                    |  1 -
 src/Psalm/Type/Atomic/TKeyedArray.php | 48 ++++++++++++++++++++++++---
 tests/FunctionCallTest.php            | 29 ++++++++++++++++
 3 files changed, 72 insertions(+), 6 deletions(-)

diff --git a/psalm-baseline.xml b/psalm-baseline.xml
index e53cd8c1c17..965b3127e18 100644
--- a/psalm-baseline.xml
+++ b/psalm-baseline.xml
@@ -549,7 +549,6 @@
     <PossiblyUndefinedIntArrayOffset>
       <code><![CDATA[$this->properties[0]]]></code>
       <code><![CDATA[$this->properties[0]]]></code>
-      <code><![CDATA[$this->properties[0]]]></code>
     </PossiblyUndefinedIntArrayOffset>
     <PossiblyUnusedMethod>
       <code>getList</code>
diff --git a/src/Psalm/Type/Atomic/TKeyedArray.php b/src/Psalm/Type/Atomic/TKeyedArray.php
index f2814a8a115..966cfbb1116 100644
--- a/src/Psalm/Type/Atomic/TKeyedArray.php
+++ b/src/Psalm/Type/Atomic/TKeyedArray.php
@@ -149,15 +149,24 @@ public function isSealed(): bool
         return $this->fallback_params === null;
     }
 
+    /**
+     * @psalm-assert-if-true list{Union} $this->properties
+     * @psalm-assert-if-true list{Union, Union} $this->fallback_params
+     */
+    public function isGenericList(): bool
+    {
+        return $this->is_list
+            && count($this->properties) === 1
+            && $this->fallback_params
+            && $this->properties[0]->equals($this->fallback_params[1], true, true, false);
+    }
+
     public function getId(bool $exact = true, bool $nested = false): string
     {
         $property_strings = [];
 
         if ($this->is_list) {
-            if (count($this->properties) === 1
-                && $this->fallback_params
-                && $this->properties[0]->equals($this->fallback_params[1], true, true, false)
-            ) {
+            if ($this->isGenericList()) {
                 $t = $this->properties[0]->possibly_undefined ? 'list' : 'non-empty-list';
                 return "$t<".$this->fallback_params[1]->getId($exact).'>';
             }
@@ -415,7 +424,7 @@ public function getGenericArrayType(bool $allow_non_empty = true, ?string $list_
 
     public function isNonEmpty(): bool
     {
-        if ($this->is_list) {
+        if ($this->isGenericList()) {
             return !$this->properties[0]->possibly_undefined;
         }
         foreach ($this->properties as $property) {
@@ -503,6 +512,35 @@ public function replaceTemplateTypesWithStandins(
         bool $add_lower_bound = false,
         int $depth = 0
     ): self {
+        if ($input_type instanceof TKeyedArray
+            && $input_type->is_list
+            && $input_type->isSealed()
+            && $this->isGenericList()
+        ) {
+            $replaced_list_type = $this
+                ->getGenericArrayType()
+                ->replaceTemplateTypesWithStandins(
+                    $template_result,
+                    $codebase,
+                    $statements_analyzer,
+                    $input_type->getGenericArrayType(),
+                    $input_arg_offset,
+                    $calling_class,
+                    $calling_function,
+                    $replace,
+                    $add_lower_bound,
+                    $depth,
+                )
+                ->type_params[1]
+                ->setPossiblyUndefined(!$this->isNonEmpty());
+
+            $cloned = clone $this;
+            $cloned->properties = [$replaced_list_type];
+            $cloned->fallback_params = [$this->fallback_params[1], $replaced_list_type];
+
+            return $cloned;
+        }
+
         $properties = $this->properties;
 
         foreach ($properties as $offset => $property) {
diff --git a/tests/FunctionCallTest.php b/tests/FunctionCallTest.php
index d6c4f86b232..7905ac3378b 100644
--- a/tests/FunctionCallTest.php
+++ b/tests/FunctionCallTest.php
@@ -17,6 +17,35 @@ class FunctionCallTest extends TestCase
     public function providerValidCodeParse(): iterable
     {
         return [
+            'inferGenericListFromTuple' => [
+                'code' => '<?php
+                    /**
+                     * @template A
+                     * @param list<A> $list
+                     * @return list<A>
+                     */
+                    function testList(array $list): array { return $list; }
+                    /**
+                     * @template A
+                     * @param non-empty-list<A> $list
+                     * @return non-empty-list<A>
+                     */
+                    function testNonEmptyList(array $list): array { return $list; }
+                    /**
+                     * @template A of list<mixed>
+                     * @param A $list
+                     * @return A
+                     */
+                    function testGenericList(array $list): array { return $list; }
+                    $list = testList([1, 2, 3]);
+                    $nonEmptyList = testNonEmptyList([1, 2, 3]);
+                    $genericList = testGenericList([1, 2, 3]);',
+                'assertions' => [
+                    '$list===' => 'list<1|2|3>',
+                    '$nonEmptyList===' => 'non-empty-list<1|2|3>',
+                    '$genericList===' => 'list{1, 2, 3}',
+                ],
+            ],
             'countShapedArrays' => [
                 'code' => '<?php
                     /** @var array{a?: int} */