Fix conditional types in array_map() return value

Author: rvanvelzen

src/Type/Php/ArrayMapFunctionReturnTypeExtension.php

@@ -2,9 +2,11 @@
 
 namespace PHPStan\Type\Php;
 
+use PhpParser\Node;
 use PhpParser\Node\Expr\FuncCall;
 use PHPStan\Analyser\Scope;
 use PHPStan\Reflection\FunctionReflection;
+use PHPStan\Reflection\ParametersAcceptorSelector;
 use PHPStan\Type\Accessory\AccessoryArrayListType;
 use PHPStan\Type\Accessory\NonEmptyArrayType;
 use PHPStan\Type\ArrayType;
@@ -13,10 +15,10 @@
 use PHPStan\Type\DynamicFunctionReturnTypeExtension;
 use PHPStan\Type\IntegerType;
 use PHPStan\Type\MixedType;
-use PHPStan\Type\NeverType;
 use PHPStan\Type\Type;
 use PHPStan\Type\TypeCombinator;
 use PHPStan\Type\TypeUtils;
+use function array_map;
 use function array_slice;
 use function count;
 
@@ -38,12 +40,18 @@ public function getTypeFromFunctionCall(FunctionReflection $functionReflection,
 		$callableType = $scope->getType($functionCall->getArgs()[0]->value);
 		$callableIsNull = $callableType->isNull()->yes();
 
+		$callableParametersAcceptors = null;
+
 		if ($callableType->isCallable()->yes()) {
-			$valueTypes = [new NeverType()];
-			foreach ($callableType->getCallableParametersAcceptors($scope) as $parametersAcceptor) {
-				$valueTypes[] = $parametersAcceptor->getReturnType();
-			}
-			$valueType = TypeCombinator::union(...$valueTypes);
+			$callableParametersAcceptors = $callableType->getCallableParametersAcceptors($scope);
+			$valueType = ParametersAcceptorSelector::selectFromTypes(
+				array_map(
+					static fn (Node\Arg $arg) => $scope->getType($arg->value)->getIterableValueType(),
+					array_slice($functionCall->getArgs(), 1),
+				),
+				$callableParametersAcceptors,
+				false,
+			)->getReturnType();
 		} elseif ($callableIsNull) {
 			$arrayBuilder = ConstantArrayTypeBuilder::createEmpty();
 			foreach (array_slice($functionCall->getArgs(), 1) as $index => $arg) {
@@ -70,10 +78,17 @@ public function getTypeFromFunctionCall(FunctionReflection $functionReflection,
 				if ($totalCount < ConstantArrayTypeBuilder::ARRAY_COUNT_LIMIT) {
 					foreach ($constantArrays as $constantArray) {
 						$returnedArrayBuilder = ConstantArrayTypeBuilder::createEmpty();
+						$valueTypes = $constantArray->getValueTypes();
 						foreach ($constantArray->getKeyTypes() as $i => $keyType) {
 							$returnedArrayBuilder->setOffsetValueType(
 								$keyType,
-								$valueType,
+								$callableParametersAcceptors !== null
+									? ParametersAcceptorSelector::selectFromTypes(
+										[$valueTypes[$i]],
+										$callableParametersAcceptors,
+										false,
+									)->getReturnType()
+									: $valueType,
 								$constantArray->isOptionalKey($i),
 							);
 						}

tests/PHPStan/Rules/Methods/ReturnTypeRuleTest.php

@@ -1049,4 +1049,9 @@ public function testBug11337(): void
 		$this->analyse([__DIR__ . '/data/bug-11337.php'], []);
 	}
 
+	public function testBug10715(): void
+	{
+		$this->analyse([__DIR__ . '/data/bug-10715.php'], []);
+	}
+
 }

tests/PHPStan/Rules/Methods/data/bug-10715.php

@@ -0,0 +1,30 @@
+<?php declare(strict_types = 1);
+
+namespace Bug10715;
+
+class Test
+{
+	/**
+	 * @param string|array<string> $word
+	 *
+	 * @return ($word is array<string> ? array<string> : string)
+	 */
+	public static function wgtrim(string|array $word): string|array
+	{
+		if (\is_array($word)) {
+			return array_map(static::wgtrim(...), $word);
+		}
+
+		return 'word';
+	}
+
+	/**
+	 * @param array{foo: array<string>, bar: string} $array
+	 *
+	 * @return array{foo: array<string>, bar: string}
+	 */
+	public static function example(array $array): array
+	{
+		return array_map(static::wgtrim(...), $array);
+	}
+}