diff --git a/src/Analyser/TypeSpecifier.php b/src/Analyser/TypeSpecifier.php
index 3df7d26fb67..f56c3379e6a 100644
--- a/src/Analyser/TypeSpecifier.php
+++ b/src/Analyser/TypeSpecifier.php
@@ -251,15 +251,18 @@ public function specifyTypesInCondition(
 					&& isset($exprNode->getArgs()[0])
 					&& $constantType instanceof ConstantStringType
 					&& $constantType->getValue() !== ''
-					&& $scope->getType($exprNode->getArgs()[0]->value)->isString()->yes()
 				) {
-					return $this->create(
-						$exprNode->getArgs()[0]->value,
-						TypeCombinator::intersect($scope->getType($exprNode->getArgs()[0]->value), new AccessoryNonEmptyStringType()),
-						$context,
-						false,
-						$scope
-					);
+					$argType = $scope->getType($exprNode->getArgs()[0]->value);
+
+					if ($argType->isString()->yes() && !$argType->isNonEmptyString()->yes()) {
+						return $this->create(
+							$exprNode->getArgs()[0]->value,
+							TypeCombinator::intersect($argType, new AccessoryNonEmptyStringType()),
+							$context,
+							false,
+							$scope,
+						);
+					}
 				}
 			}