ReturnTypeHintSniff: Fixed false positive

Author: kukulich

SlevomatCodingStandard/Sniffs/TypeHints/ReturnTypeHintSniff.php

@@ -185,6 +185,7 @@ private function checkFunctionTypeHint(
 			$typeHints[] = AnnotationTypeHelper::getTypeHintFromOneType($returnTypeNode);
 
 		} elseif ($returnTypeNode instanceof UnionTypeNode || $returnTypeNode instanceof IntersectionTypeNode) {
+			$traversableTypeHints = [];
 			foreach ($returnTypeNode->types as $typeNode) {
 				if (!AnnotationTypeHelper::containsOneType($typeNode)) {
 					return;
@@ -193,7 +194,22 @@ private function checkFunctionTypeHint(
 				/** @var ArrayTypeNode|ArrayShapeNode|IdentifierTypeNode|ThisTypeNode|GenericTypeNode|CallableTypeNode $typeNode */
 				$typeNode = $typeNode;
 
-				$typeHints[] = AnnotationTypeHelper::getTypeHintFromOneType($typeNode);
+				$typeHint = AnnotationTypeHelper::getTypeHintFromOneType($typeNode);
+
+				if (
+					!$typeNode instanceof ArrayTypeNode
+					&& !$typeNode instanceof ArrayShapeNode
+					&& TypeHintHelper::isTraversableType(TypeHintHelper::getFullyQualifiedTypeHint($phpcsFile, $functionPointer, $typeHint), $this->getTraversableTypeHints())
+				) {
+					$traversableTypeHints[] = $typeHint;
+				}
+
+				$typeHints[] = $typeHint;
+			}
+
+			$traversableTypeHints = array_values(array_unique($traversableTypeHints));
+			if (count($traversableTypeHints) > 1) {
+				return;
 			}
 		}
 

tests/Sniffs/TypeHints/ReturnTypeHintSniffTest.php

@@ -22,7 +22,7 @@ public function testErrors(): void
 			'traversableTypeHints' => ['Traversable'],
 		]);
 
-		self::assertSame(30, $report->getErrorCount());
+		self::assertSame(31, $report->getErrorCount());
 
 		self::assertSniffError($report, 6, ReturnTypeHintSniff::CODE_MISSING_ANY_TYPE_HINT);
 		self::assertSniffError($report, 14, ReturnTypeHintSniff::CODE_MISSING_NATIVE_TYPE_HINT);
@@ -54,6 +54,7 @@ public function testErrors(): void
 		self::assertSniffError($report, 177, ReturnTypeHintSniff::CODE_MISSING_NATIVE_TYPE_HINT);
 		self::assertSniffError($report, 184, ReturnTypeHintSniff::CODE_MISSING_NATIVE_TYPE_HINT);
 		self::assertSniffError($report, 191, ReturnTypeHintSniff::CODE_MISSING_NATIVE_TYPE_HINT);
+		self::assertSniffError($report, 198, ReturnTypeHintSniff::CODE_MISSING_NATIVE_TYPE_HINT);
 
 		self::assertAllFixedInFile($report);
 	}

tests/Sniffs/TypeHints/data/returnTypeHintErrors.fixed.php

@@ -187,4 +187,11 @@ public function nullable(): ?int
 	{
 	}
 
+	/**
+	 * @return mixed[]|array
+	 */
+	public function traversableArray(): array
+	{
+	}
+
 }

tests/Sniffs/TypeHints/data/returnTypeHintErrors.php

@@ -192,4 +192,11 @@ public function nullable()
 	{
 	}
 
+	/**
+	 * @return mixed[]|array
+	 */
+	public function traversableArray()
+	{
+	}
+
 }

tests/Sniffs/TypeHints/data/returnTypeHintNoErrors.php

@@ -193,4 +193,11 @@ public function unionWithDifferentNullableBase($a)
 	{
 	}
 
+	/**
+	 * @return mixed[]|array|Traversable
+	 */
+	public function moreTraverasableTypes()
+	{
+	}
+
 }