Improve implode signature

Author: VincentLanglet

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;
+	}
+
+}

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 +204,31 @@ public static function selectFromArgs(
 				];
 			}
 
+			if (isset($args[0]) && (bool) $args[0]->getAttribute(ImplodeArgVisitor::ATTRIBUTE_NAME)) {
+				if (isset($args[1])) {
+					$parameters = [
+						new NativeParameterReflection('separator', false, new StringType(), PassedByReference::createNo(), false, null),
+						new NativeParameterReflection('array', false, new ArrayType(new MixedType(), new MixedType()), PassedByReference::createNo(), false, null),
+					];
+				} else {
+					$parameters = [
+						new NativeParameterReflection('array', false, new ArrayType(new MixedType(), new MixedType()), PassedByReference::createNo(), false, null),
+					];
+				}
+
+				$acceptor = $parametersAcceptors[0];
+				$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),

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,
 				],
 			];
@@ -2192,6 +2200,46 @@ public function testBug13065(): void
 		$this->analyse([__DIR__ . '/data/bug-13065.php'], $errors);
 	}
 
+	public function testBug5760(): void
+	{
+		$this->checkExplicitMixed = true;
+		$this->checkImplicitMixed = true;
+		$this->analyse([__DIR__ . '/data/bug-5760.php'], [
+			[
+				'Parameter #2 $pieces of function join expects array, list<int>|null given.',
+				10,
+			],
+			[
+				'Parameter #1 $glue of function join expects array, list<int>|null given.',
+				11,
+			],
+			[
+				'Parameter #2 $array of function implode expects array, list<int>|null given.',
+				13,
+			],
+			[
+				'Parameter #1 $separator of function implode expects array, list<int>|null given.',
+				14,
+			],
+			[
+				'Parameter #2 $pieces of function join expects array, array<string>|string given.',
+				22,
+			],
+			[
+				'Parameter #1 $glue of function join expects array, array<string>|string given.',
+				23,
+			],
+			[
+				'Parameter #2 $array of function implode expects array, array<string>|string given.',
+				25,
+			],
+			[
+				'Parameter #1 $separator of function implode expects array, array<string>|string given.',
+				26,
+			],
+		]);
+	}
+
 	#[RequiresPhp('>= 8.0')]
 	public function testBug12317(): void
 	{

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(['']);
+}