diff --git a/src/Type/Php/CtypeDigitFunctionTypeSpecifyingExtension.php b/src/Type/Php/CtypeDigitFunctionTypeSpecifyingExtension.php
index ab1bd7aebd..ec4a59d5f3 100644
--- a/src/Type/Php/CtypeDigitFunctionTypeSpecifyingExtension.php
+++ b/src/Type/Php/CtypeDigitFunctionTypeSpecifyingExtension.php
@@ -2,6 +2,7 @@
 
 namespace PHPStan\Type\Php;
 
+use PhpParser\Node\Expr\Cast;
 use PhpParser\Node\Expr\FuncCall;
 use PHPStan\Analyser\Scope;
 use PHPStan\Analyser\SpecifiedTypes;
@@ -38,7 +39,8 @@ public function specifyTypes(FunctionReflection $functionReflection, FuncCall $n
 			throw new ShouldNotHappenException();
 		}
 
-		if ($context->true() && $scope->getType($node->getArgs()[0]->value)->isNumericString()->yes()) {
+		$exprArg = $node->getArgs()[0]->value;
+		if ($context->true() && $scope->getType($exprArg)->isNumericString()->yes()) {
 			return new SpecifiedTypes();
 		}
 
@@ -54,7 +56,16 @@ public function specifyTypes(FunctionReflection $functionReflection, FuncCall $n
 			]);
 		}
 
-		return $this->typeSpecifier->create($node->getArgs()[0]->value, TypeCombinator::union(...$types), $context, false, $scope);
+		$unionType = TypeCombinator::union(...$types);
+		$specifiedTypes = $this->typeSpecifier->create($exprArg, $unionType, $context, false, $scope);
+
+		if ($context->true() && $exprArg instanceof Cast) {
+			$specifiedTypes = $specifiedTypes->unionWith(
+				$this->typeSpecifier->create($exprArg->expr, $unionType, $context, false, $scope),
+			);
+		}
+
+		return $specifiedTypes;
 	}
 
 	public function setTypeSpecifier(TypeSpecifier $typeSpecifier): void
diff --git a/tests/PHPStan/Analyser/NodeScopeResolverTest.php b/tests/PHPStan/Analyser/NodeScopeResolverTest.php
index 6b8cbe3a03..49878908f4 100644
--- a/tests/PHPStan/Analyser/NodeScopeResolverTest.php
+++ b/tests/PHPStan/Analyser/NodeScopeResolverTest.php
@@ -1175,6 +1175,8 @@ public function dataFileAsserts(): iterable
 		yield from $this->gatherAssertTypes(__DIR__ . '/data/bug-8621.php');
 		yield from $this->gatherAssertTypes(__DIR__ . '/data/bug-8084.php');
 		yield from $this->gatherAssertTypes(__DIR__ . '/data/bug-3019.php');
+
+		yield from $this->gatherAssertTypes(__DIR__ . '/data/callsite-cast-narrowing.php');
 	}
 
 	/**
diff --git a/tests/PHPStan/Analyser/data/callsite-cast-narrowing.php b/tests/PHPStan/Analyser/data/callsite-cast-narrowing.php
new file mode 100644
index 0000000000..576409530e
--- /dev/null
+++ b/tests/PHPStan/Analyser/data/callsite-cast-narrowing.php
@@ -0,0 +1,54 @@
+<?php
+
+namespace CallsiteCastNarrowing;
+
+use function PHPStan\Testing\assertType;
+
+class HelloWorld
+{
+	public function sayHello($mixed, int $int, string $string): void
+	{
+		if (ctype_digit((string) $mixed)) {
+			assertType('int<48, 57>|int<256, max>|numeric-string', $mixed);
+		} else {
+			assertType('mixed', $mixed);
+		}
+		assertType('mixed', $mixed);
+
+		if (ctype_digit((int) $mixed)) {
+			assertType('int<48, 57>|int<256, max>|numeric-string', $mixed);
+		} else {
+			assertType('mixed', $mixed);
+		}
+		assertType('mixed', $mixed);
+
+		if (ctype_digit((string) $int)) {
+			assertType('int', $int);
+		} else {
+			assertType('int', $int);
+		}
+		assertType('int', $int);
+
+		if (ctype_digit((int) $int)) {
+			assertType('int<48, 57>|int<256, max>', $int);
+		} else {
+			assertType('int', $int);
+		}
+		assertType('int', $int);
+
+		if (ctype_digit((string) $string)) {
+			assertType('numeric-string', $string);
+		} else {
+			assertType('string', $string);
+		}
+		assertType('string', $string);
+
+		if (ctype_digit((int) $string)) {
+			assertType('numeric-string', $string);
+		} else {
+			assertType('string', $string);
+		}
+		assertType('string', $string);
+	}
+
+}