diff --git a/resources/functionMap.php b/resources/functionMap.php
index fade07b20c..16b8e6bf6d 100644
--- a/resources/functionMap.php
+++ b/resources/functionMap.php
@@ -5695,6 +5695,7 @@
 'jobqueue_license_info' => ['array'],
 'join' => ['string', 'glue'=>'string', 'pieces'=>'array'],
 'join\'1' => ['string', 'pieces'=>'array'],
+'join\'2' => ['string', 'pieces'=>'array', 'glue'=>'string'],
 'jpeg2wbmp' => ['bool', 'jpegname'=>'string', 'wbmpname'=>'string', 'dest_height'=>'int', 'dest_width'=>'int', 'threshold'=>'int'],
 'json_decode' => ['mixed', 'json'=>'string', 'assoc='=>'bool|null', 'depth='=>'positive-int', 'options='=>'int'],
 'json_encode' => ['non-empty-string|false', 'data'=>'mixed', 'options='=>'int', 'depth='=>'positive-int'],
diff --git a/resources/functionMap_php74delta.php b/resources/functionMap_php74delta.php
index 9b187510c8..86bc99ef80 100644
--- a/resources/functionMap_php74delta.php
+++ b/resources/functionMap_php74delta.php
@@ -60,5 +60,6 @@
 	],
 	'old' => [
 		'implode\'2' => ['string', 'pieces'=>'array', 'glue'=>'string'],
+		'join\'2' => ['string', 'pieces'=>'array', 'glue'=>'string'],
 	],
 ];
diff --git a/src/Parser/ImplodeArgVisitor.php b/src/Parser/ImplodeArgVisitor.php
new file mode 100644
index 0000000000..36e0201b83
--- /dev/null
+++ b/src/Parser/ImplodeArgVisitor.php
@@ -0,0 +1,32 @@
+<?php declare(strict_types = 1);
+
+namespace PHPStan\Parser;
+
+use Override;
+use PhpParser\Node;
+use PhpParser\NodeVisitorAbstract;
+use PHPStan\DependencyInjection\AutowiredService;
+use function in_array;
+
+#[AutowiredService]
+final class ImplodeArgVisitor extends NodeVisitorAbstract
+{
+
+	public const ATTRIBUTE_NAME = 'isImplodeArg';
+
+	#[Override]
+	public function enterNode(Node $node): ?Node
+	{
+		if ($node instanceof Node\Expr\FuncCall && $node->name instanceof Node\Name) {
+			$functionName = $node->name->toLowerString();
+			if (in_array($functionName, ['implode', 'join'], true)) {
+				$args = $node->getRawArgs();
+				if (isset($args[0])) {
+					$args[0]->setAttribute(self::ATTRIBUTE_NAME, true);
+				}
+			}
+		}
+		return null;
+	}
+
+}
diff --git a/src/Reflection/ParametersAcceptorSelector.php b/src/Reflection/ParametersAcceptorSelector.php
index 81bc3a2a99..a2986b2fbc 100644
--- a/src/Reflection/ParametersAcceptorSelector.php
+++ b/src/Reflection/ParametersAcceptorSelector.php
@@ -15,6 +15,7 @@
 use PHPStan\Parser\ClosureBindArgVisitor;
 use PHPStan\Parser\ClosureBindToVarVisitor;
 use PHPStan\Parser\CurlSetOptArgVisitor;
+use PHPStan\Parser\ImplodeArgVisitor;
 use PHPStan\Reflection\Callables\CallableParametersAcceptor;
 use PHPStan\Reflection\Native\NativeParameterReflection;
 use PHPStan\Reflection\Php\DummyParameter;
@@ -203,6 +204,32 @@ public static function selectFromArgs(
 				];
 			}
 
+			if (count($args) <= 2 && (bool) $args[0]->getAttribute(ImplodeArgVisitor::ATTRIBUTE_NAME)) {
+				$acceptor = $namedArgumentsVariants[0] ?? $parametersAcceptors[0];
+				$parameters = $acceptor->getParameters();
+				if (isset($args[1]) || ($args[0]->name !== null && $args[0]->name->name === 'array')) {
+					$parameters = [
+						new NativeParameterReflection($parameters[0]->getName(), false, new StringType(), PassedByReference::createNo(), false, null),
+						new NativeParameterReflection($parameters[1]->getName(), false, new ArrayType(new MixedType(), new MixedType()), PassedByReference::createNo(), false, null),
+					];
+				} else {
+					$parameters = [
+						new NativeParameterReflection($parameters[0]->getName(), false, new ArrayType(new MixedType(), new MixedType()), PassedByReference::createNo(), false, null),
+					];
+				}
+
+				$parametersAcceptors = [
+					new FunctionVariant(
+						$acceptor->getTemplateTypeMap(),
+						$acceptor->getResolvedTemplateTypeMap(),
+						$parameters,
+						$acceptor->isVariadic(),
+						$acceptor->getReturnType(),
+						$acceptor instanceof ExtendedParametersAcceptor ? $acceptor->getCallSiteVarianceMap() : TemplateTypeVarianceMap::createEmpty(),
+					),
+				];
+			}
+
 			if (isset($args[0]) && (bool) $args[0]->getAttribute(ArrayWalkArgVisitor::ATTRIBUTE_NAME)) {
 				$arrayWalkParameters = [
 					new DummyParameter('item', $scope->getIterableValueType($scope->getType($args[0]->value)), false, PassedByReference::createReadsArgument(), false, null),
diff --git a/tests/PHPStan/Levels/data/acceptTypes-5.json b/tests/PHPStan/Levels/data/acceptTypes-5.json
index 76aac5c080..4bb076e055 100644
--- a/tests/PHPStan/Levels/data/acceptTypes-5.json
+++ b/tests/PHPStan/Levels/data/acceptTypes-5.json
@@ -185,7 +185,7 @@
         "ignorable": true
     },
     {
-        "message": "Parameter #2 $array of function implode expects array|null, int given.",
+        "message": "Parameter #2 $array of function implode expects array, int given.",
         "line": 763,
         "ignorable": true
     }
diff --git a/tests/PHPStan/Levels/data/acceptTypes-7.json b/tests/PHPStan/Levels/data/acceptTypes-7.json
index ba67e6a9d6..216fad8987 100644
--- a/tests/PHPStan/Levels/data/acceptTypes-7.json
+++ b/tests/PHPStan/Levels/data/acceptTypes-7.json
@@ -165,7 +165,7 @@
         "ignorable": true
     },
     {
-        "message": "Parameter #2 $array of function implode expects array|null, array|int|string given.",
+        "message": "Parameter #2 $array of function implode expects array, array|int|string given.",
         "line": 756,
         "ignorable": true
     }
diff --git a/tests/PHPStan/Rules/Functions/CallToFunctionParametersRuleTest.php b/tests/PHPStan/Rules/Functions/CallToFunctionParametersRuleTest.php
index 385fab83b5..69207e94f3 100644
--- a/tests/PHPStan/Rules/Functions/CallToFunctionParametersRuleTest.php
+++ b/tests/PHPStan/Rules/Functions/CallToFunctionParametersRuleTest.php
@@ -322,7 +322,11 @@ public function testImplodeOnPhp74(): void
 		if (PHP_VERSION_ID >= 80000) {
 			$errors = [
 				[
-					'Parameter #2 $array of function implode expects array|null, string given.',
+					'Parameter #1 $separator of function implode expects string, array given.',
+					8,
+				],
+				[
+					'Parameter #2 $array of function implode expects array, string given.',
 					8,
 				],
 			];
@@ -336,7 +340,11 @@ public function testImplodeOnLessThanPhp74(): void
 		if (PHP_VERSION_ID >= 80000) {
 			$errors = [
 				[
-					'Parameter #2 $array of function implode expects array|null, string given.',
+					'Parameter #1 $separator of function implode expects string, array given.',
+					8,
+				],
+				[
+					'Parameter #2 $array of function implode expects array, string given.',
 					8,
 				],
 			];
@@ -356,6 +364,21 @@ public function testImplodeOnLessThanPhp74(): void
 		$this->analyse([__DIR__ . '/data/implode-74.php'], $errors);
 	}
 
+	#[RequiresPhp('>= 8.0')]
+	public function testImplodeNamedParameters(): void
+	{
+		$this->analyse([__DIR__ . '/data/implode-named-parameters.php'], [
+			[
+				'Missing parameter $separator (string) in call to function implode.',
+				6,
+			],
+			[
+				'Missing parameter $separator (string) in call to function join.',
+				7,
+			],
+		]);
+	}
+
 	public function testVariableIsNotNullAfterSeriesOfConditions(): void
 	{
 		require_once __DIR__ . '/data/variable-is-not-null-after-conditions.php';
@@ -2192,6 +2215,54 @@ public function testBug13065(): void
 		$this->analyse([__DIR__ . '/data/bug-13065.php'], $errors);
 	}
 
+	public function testBug5760(): void
+	{
+		if (PHP_VERSION_ID < 80000) {
+			$param1Name = '$glue';
+			$param2Name = '$pieces';
+		} else {
+			$param1Name = '$separator';
+			$param2Name = '$array';
+		}
+
+		$this->checkExplicitMixed = true;
+		$this->checkImplicitMixed = true;
+		$this->analyse([__DIR__ . '/data/bug-5760.php'], [
+			[
+				sprintf('Parameter #2 %s of function join expects array, list<int>|null given.', $param2Name),
+				10,
+			],
+			[
+				sprintf('Parameter #1 %s of function join expects array, list<int>|null given.', $param1Name),
+				11,
+			],
+			[
+				sprintf('Parameter #2 %s of function implode expects array, list<int>|null given.', $param2Name),
+				13,
+			],
+			[
+				sprintf('Parameter #1 %s of function implode expects array, list<int>|null given.', $param1Name),
+				14,
+			],
+			[
+				sprintf('Parameter #2 %s of function join expects array, array<string>|string given.', $param2Name),
+				22,
+			],
+			[
+				sprintf('Parameter #1 %s of function join expects array, array<string>|string given.', $param1Name),
+				23,
+			],
+			[
+				sprintf('Parameter #2 %s of function implode expects array, array<string>|string given.', $param2Name),
+				25,
+			],
+			[
+				sprintf('Parameter #1 %s of function implode expects array, array<string>|string given.', $param1Name),
+				26,
+			],
+		]);
+	}
+
 	#[RequiresPhp('>= 8.0')]
 	public function testBug12317(): void
 	{
diff --git a/tests/PHPStan/Rules/Functions/data/bug-5760.php b/tests/PHPStan/Rules/Functions/data/bug-5760.php
new file mode 100644
index 0000000000..f3ec36535f
--- /dev/null
+++ b/tests/PHPStan/Rules/Functions/data/bug-5760.php
@@ -0,0 +1,36 @@
+<?php declare(strict_types=1);
+
+namespace Bug5760;
+
+/**
+ * @param list<int>|null $arrayOrNull
+ */
+function doImplode(?array $arrayOrNull): void
+{
+	join(',', $arrayOrNull);
+	join($arrayOrNull);
+
+	implode(',', $arrayOrNull);
+	implode($arrayOrNull);
+}
+
+/**
+ * @param array<string>|string $union
+ */
+function more(array|string $union): void
+{
+	join(',', $union);
+	join($union);
+
+	implode(',', $union);
+	implode($union);
+}
+
+function success(): void
+{
+	join(',', ['']);
+	join(['']);
+
+	implode(',', ['']);
+	implode(['']);
+}
diff --git a/tests/PHPStan/Rules/Functions/data/implode-named-parameters.php b/tests/PHPStan/Rules/Functions/data/implode-named-parameters.php
new file mode 100644
index 0000000000..8e016b5157
--- /dev/null
+++ b/tests/PHPStan/Rules/Functions/data/implode-named-parameters.php
@@ -0,0 +1,10 @@
+<?php declare(strict_types = 1);
+
+namespace ImplodeNamedParameters;
+
+function (): void {
+	implode(array: ['']); // error
+	join(array: ['']); // error
+	implode(separator: '', array: ['']);
+	join(separator: '', array: ['']);
+};