Propagate possibly-null issues onto fetched properties

src/Psalm/Internal/Analyzer/Statements/Expression/Fetch/PropertyFetchAnalyzer.php

@@ -297,7 +297,7 @@ class PropertyFetchAnalyzer
             $codebase->analyzer->incrementNonMixedCount($statements_analyzer->getRootFilePath());
         }
 
-        if ($stmt_var_type->isNullable() && !$stmt_var_type->ignore_nullable_issues && !$context->inside_isset) {
+        if ($stmt_var_type->isNullable() && !$context->inside_isset && !$stmt_var_type->ignore_nullable_issues) {
             if (IssueBuffer::accepts(
                 new PossiblyNullPropertyFetch(
                     'Cannot get property on possibly null variable ' . $stmt_var_id . ' of type ' . $stmt_var_type,
@@ -307,8 +307,6 @@ class PropertyFetchAnalyzer
             )) {
                 // fall through
             }
-
-            $stmt->inferredType = Type::getNull();
         }
 
         if (!$prop_name) {
@@ -798,6 +796,14 @@ class PropertyFetchAnalyzer
             }
         }
 
+        if ($stmt_var_type->isNullable() && !$context->inside_isset && $stmt->inferredType) {
+            $stmt->inferredType->addType(new TNull);
+
+            if ($stmt_var_type->ignore_nullable_issues) {
+                $stmt->inferredType->ignore_nullable_issues = true;
+            }
+        }
+
         if ($codebase->store_node_types
             && !$context->collect_initializations
             && !$context->collect_mutations

tests/PropertyTypeTest.php

@@ -1702,7 +1702,28 @@ class PropertyTypeTest extends TestCase
                         /** @var array<int, static> */
                         private $t2 = [];
                     }'
-            ]
+            ],
+            'propagateIgnoreNullableOnPropertyFetch' => [
+                '<?php
+                    class A {
+                        public string $s = "hey";
+                    }
+
+                    /**
+                     * @psalm-ignore-nullable-return
+                     */
+                    function foo() : ?A {
+                        return rand(0, 1) ? new A : null;
+                    }
+
+                    function takesString(string $_s) : void {}
+
+                    $foo = foo();
+
+                    if ($foo->s !== null) {}
+                    echo $foo->s ?? "bar";
+                    takesString($foo->s);',
+            ],
         ];
     }
 
@@ -2689,6 +2710,26 @@ class PropertyTypeTest extends TestCase
                     $a->bar = "goodbye";',
                 'error_message' => 'InaccessibleProperty',
             ],
+            'addNullToMixedAfterNullablePropertyFetch' => [
+                '<?php
+                    class A {
+                        /**
+                         * @var mixed
+                         */
+                        public $foo;
+                    }
+
+                    function takesString(string $s) : void {}
+
+                    function takesA(?A $a) : void {
+                        /**
+                         * @psalm-suppress PossiblyNullPropertyFetch
+                         * @psalm-suppress MixedArgument
+                         */
+                        takesString($a->foo);
+                    }',
+                'error_message' => 'PossiblyNullArgument',
+            ],
         ];
     }
 }