Update NonNullabilityHelper.php

Author: staabm

src/Analyser/ExprHandler/Helper/NonNullabilityHelper.php

@@ -32,7 +32,10 @@ public function ensureShallowNonNullability(MutatingScope $scope, Scope $origina
 		// keep certainty
 		$certainty = TrinaryLogic::createYes();
 		$hasExpressionType = $originalScope->hasExpressionType($exprToSpecify);
-		if (!$hasExpressionType->no() || $exprToSpecify instanceof ArrayDimFetch) {
+		if (
+			!$hasExpressionType->no()
+			|| ($exprType->isArray()->yes() && $exprToSpecify instanceof ArrayDimFetch)
+		) {
 			$certainty = $hasExpressionType;
 		}