Resolve missingType.callable and offsetAccess PHPStan errors

phpstan.neon

@@ -176,11 +176,6 @@ parameters:
             message: '#Cannot call method (.*?)\(\) on (.*?)\\ProcessPool\|null#'
             path: src/Parallel/Application/ParallelFileProcessor.php
 
-        -
-            identifier: missingType.callable
-            message: '#Method Rector\\Util\\ArrayParametersMerger\:\:mergeLeftToRightWithCallable\(\) has parameter \$mergeCallback with no signature specified for callable#'
-            path: src/Util/ArrayParametersMerger.php
-
         # required generics on interface array, not helpful
         -
             identifier: missingType.generics
@@ -205,12 +200,6 @@ parameters:
             identifier: offsetAccess.nonArray
             path: src/PhpParser/NodeTraverser/RectorNodeTraverser.php
 
-        # known non-empty class method
-        -
-            identifier: offsetAccess.notFound
-            message: '#Offset 0 might not exist on array<PhpParser\\Node\\Stmt>\|null#'
-            path: rules/DeadCode/Rector/ClassMethod/RemoveParentDelegatingConstructorRector.php
-
         -
             identifier: offsetAccess.notFound
             message: '#Offset float\|int\|string might not exist on string#'

rules/DeadCode/Rector/ClassMethod/RemoveParentDelegatingConstructorRector.php

@@ -209,6 +209,10 @@ private function matchParentConstructorCallArgs(Stmt $stmt): ?array
 
     private function isParameterAndArgCountAndOrderIdentical(ClassMethod $classMethod): bool
     {
+        if ($classMethod->stmts === null || ! isset($classMethod->stmts[0])) {
+            return false;
+        }
+
         $soleStmt = $classMethod->stmts[0];
 
         $parentCallArgs = $this->matchParentConstructorCallArgs($soleStmt);

src/Util/ArrayParametersMerger.php

@@ -32,6 +32,7 @@ public function merge(mixed $left, mixed $right): mixed
     /**
      * @param array<int|string, mixed> $left
      * @param array<int|string, mixed> $right
+     * @param callable(mixed, mixed): mixed $mergeCallback
      * @return mixed[]
      */
     private function mergeLeftToRightWithCallable(array $left, array $right, callable $mergeCallback): array