[Php74] Skip non-nullable typed property on IfToNullCoalescingAssignRector

rules-tests/Php74/Rector/If_/IfToNullCoalescingAssignRector/Fixture/skip_typed_non_nullable_property.php.inc

@@ -0,0 +1,17 @@
+<?php
+
+namespace Rector\Tests\Php74\Rector\If_\IfToNullCoalescingAssignRector\Fixture;
+
+class SkipTypedNonNullableProperty
+{
+    private static array $parameters;
+
+    public function get(): array
+    {
+        if (! isset(self::$parameters)) {
+            self::$parameters = ['default'];
+        }
+
+        return self::$parameters;
+    }
+}

rules/Php74/Rector/If_/IfToNullCoalescingAssignRector.php

@@ -12,9 +12,13 @@
 use PhpParser\Node\Expr\BooleanNot;
 use PhpParser\Node\Expr\FuncCall;
 use PhpParser\Node\Expr\Isset_;
+use PhpParser\Node\Expr\PropertyFetch;
+use PhpParser\Node\Expr\StaticPropertyFetch;
 use PhpParser\Node\Stmt\Else_;
 use PhpParser\Node\Stmt\Expression;
 use PhpParser\Node\Stmt\If_;
+use PHPStan\Type\MixedType;
+use PHPStan\Type\TypeCombinator;
 use Rector\PhpParser\Node\BetterNodeFinder;
 use Rector\PhpParser\Node\Value\ValueResolver;
 use Rector\Rector\AbstractRector;
@@ -95,6 +99,11 @@ public function refactor(Node $node): ?Expression
             return null;
         }
 
+        // a typed non-nullable property can never be null on the left of ??=
+        if ($this->isNonNullableProperty($testedExpr)) {
+            return null;
+        }
+
         // the assigned value must not reference the target, e.g. $x = $x + 1
         $selfReference = $this->betterNodeFinder->findFirst(
             $assign->expr,
@@ -112,6 +121,20 @@ public function provideMinPhpVersion(): int
         return PhpVersionFeature::NULL_COALESCE_ASSIGN;
     }
 
+    private function isNonNullableProperty(Expr $expr): bool
+    {
+        if (! $expr instanceof PropertyFetch && ! $expr instanceof StaticPropertyFetch) {
+            return false;
+        }
+
+        $propertyType = $this->nodeTypeResolver->getType($expr);
+        if ($propertyType instanceof MixedType) {
+            return false;
+        }
+
+        return ! TypeCombinator::containsNull($propertyType);
+    }
+
     private function matchNullGuardedExpr(Expr $expr): ?Expr
     {
         // ! isset($value)