Fix #4976 - improve type narrowing

src/Psalm/Internal/PhpVisitor/AssignmentMapVisitor.php

@@ -6,6 +6,11 @@ use Psalm\Internal\Analyzer\Statements\Expression\ExpressionIdentifier;
 
 /**
  * @internal
+ *
+ * This produces a graph of probably assignments inside a loop
+ *
+ * With this map we can calculate how many times the loop analysis must
+ * be run before all variables have the correct types
  */
 class AssignmentMapVisitor extends PhpParser\NodeVisitorAbstract
 {

src/Psalm/Type/Atomic/TArray.php

@@ -83,6 +83,8 @@ class TArray extends \Psalm\Type\Atomic
 
     public function getAssertionString(): string
     {
-        return $this->getKey();
+        return 'array<'
+            . $this->type_params[0]->getAssertionString() . ', ' . $this->type_params[1]->getAssertionString()
+            . '>' ;
     }
 }

src/Psalm/Type/Atomic/TList.php

@@ -192,7 +192,7 @@ class TList extends \Psalm\Type\Atomic
 
     public function getAssertionString(): string
     {
-        return 'list';
+        return 'list<' . $this->type_param->getAssertionString() . '>';
     }
 
     public function getChildNodes() : array

tests/TypeReconciliation/ValueTest.php

@@ -836,6 +836,24 @@ class ValueTest extends \Psalm\Tests\TestCase
                         if (!in_array(A::ACTION_ONE, $case_actions, true)) {}
                     }'
             ],
+            'checkIdenticalArray' => [
+                '<?php
+                    /** @psalm-suppress MixedAssignment */
+                    $array = json_decode(file_get_contents(\'php://stdin\'));
+
+                    if (is_array($array)) {
+                        $filtered = array_filter($array, fn ($value) => \is_string($value));
+
+                        if ($array === $filtered) {
+                            foreach ($array as $obj) {
+                                echo strlen($obj);
+                            }
+                        }
+                    }',
+                [],
+                [],
+                '7.4'
+            ],
         ];
     }