diff --git a/src/Type/Php/ReplaceFunctionsDynamicReturnTypeExtension.php b/src/Type/Php/ReplaceFunctionsDynamicReturnTypeExtension.php
index 0c527c1a5c1..401200f4c5a 100644
--- a/src/Type/Php/ReplaceFunctionsDynamicReturnTypeExtension.php
+++ b/src/Type/Php/ReplaceFunctionsDynamicReturnTypeExtension.php
@@ -7,6 +7,7 @@
 use PHPStan\Reflection\FunctionReflection;
 use PHPStan\Reflection\ParametersAcceptorSelector;
 use PHPStan\Type\Accessory\AccessoryNonEmptyStringType;
+use PHPStan\Type\Accessory\AccessoryNonFalsyStringType;
 use PHPStan\Type\ArrayType;
 use PHPStan\Type\DynamicFunctionReturnTypeExtension;
 use PHPStan\Type\IntersectionType;
@@ -84,6 +85,9 @@ private function getPreliminarilyResolvedTypeFromFunctionCall(
 			if (count($functionCall->getArgs()) > $replaceArgumentPosition) {
 				$replaceArgumentType = $scope->getType($functionCall->getArgs()[$replaceArgumentPosition]->value);
 
+				if ($replaceArgumentType->isNonFalsyString()->yes()) {
+					return new IntersectionType([new StringType(), new AccessoryNonFalsyStringType()]);
+				}
 				if ($replaceArgumentType->isNonEmptyString()->yes()) {
 					return new IntersectionType([new StringType(), new AccessoryNonEmptyStringType()]);
 				}
diff --git a/tests/PHPStan/Analyser/LegacyNodeScopeResolverTest.php b/tests/PHPStan/Analyser/LegacyNodeScopeResolverTest.php
index cdc6492de97..b88b4f0fcd2 100644
--- a/tests/PHPStan/Analyser/LegacyNodeScopeResolverTest.php
+++ b/tests/PHPStan/Analyser/LegacyNodeScopeResolverTest.php
@@ -7344,7 +7344,7 @@ public function dataReplaceFunctions(): array
 	{
 		return [
 			[
-				'non-empty-string',
+				'non-falsy-string',
 				'$expectedString',
 			],
 			[
@@ -7352,7 +7352,7 @@ public function dataReplaceFunctions(): array
 				'$expectedString2',
 			],
 			[
-				'non-empty-string|null',
+				'non-falsy-string|null',
 				'$anotherExpectedString',
 			],
 			[