Infer more duplicated array keys

Author: VincentLanglet

src/Rules/Arrays/DuplicateKeysInLiteralArraysRule.php

@@ -8,10 +8,12 @@
 use PHPStan\Node\Printer\ExprPrinter;
 use PHPStan\Rules\Rule;
 use PHPStan\Rules\RuleErrorBuilder;
+use PHPStan\Type\Constant\ConstantIntegerType;
 use PHPStan\Type\ConstantScalarType;
 use function array_keys;
 use function count;
 use function implode;
+use function max;
 use function sprintf;
 use function var_export;
 
@@ -38,25 +40,55 @@ public function processNode(Node $node, Scope $scope): array
 		$duplicateKeys = [];
 		$printedValues = [];
 		$valueLines = [];
+
+		/**
+		 * @var int|false|null $autoGeneratedIndex
+		 * - An int value represent the biggest integer used as array key.
+		 *   When no key is provided this value + 1 will be used.
+		 * - Null is used as initializer instead of 0 to avoid issue with negative keys.
+		 * - False means a non-scalar value was encountered and we cannot be sure of the next keys.
+		 */
+		$autoGeneratedIndex = null;
 		foreach ($node->getItemNodes() as $itemNode) {
 			$item = $itemNode->getArrayItem();
 			if ($item === null) {
-				continue;
-			}
-			if ($item->key === null) {
+				$autoGeneratedIndex = false;
 				continue;
 			}
 
 			$key = $item->key;
-			$keyType = $itemNode->getScope()->getType($key);
-			if (
-				!$keyType instanceof ConstantScalarType
-			) {
+			if ($key === null) {
+				if ($autoGeneratedIndex === false) {
+					continue;
+				}
+
+				if ($autoGeneratedIndex === null) {
+					$autoGeneratedIndex = 0;
+					$keyType = new ConstantIntegerType(0);
+				} else {
+					$keyType = new ConstantIntegerType(++$autoGeneratedIndex);
+				}
+			} else {
+				$keyType = $itemNode->getScope()->getType($key);
+
+				$arrayKeyValue = $keyType->toArrayKey();
+				if ($arrayKeyValue instanceof ConstantIntegerType) {
+					$autoGeneratedIndex = $autoGeneratedIndex === null
+						? $arrayKeyValue->getValue()
+						: max($autoGeneratedIndex, $arrayKeyValue->getValue());
+				}
+			}
+
+			if (!$keyType instanceof ConstantScalarType) {
+				$autoGeneratedIndex = false;
 				continue;
 			}
 
-			$printedValue = $this->exprPrinter->printExpr($key);
 			$value = $keyType->getValue();
+			$printedValue = $key !== null
+				? $this->exprPrinter->printExpr($key)
+				: $value;
+
 			$printedValues[$value][] = $printedValue;
 
 			if (!isset($valueLines[$value])) {

tests/PHPStan/Rules/Arrays/DuplicateKeysInLiteralArraysRuleTest.php

@@ -45,6 +45,22 @@ public function testDuplicateKeys(): void
 				'Array has 2 duplicate keys with value 2 ($idx, $idx).',
 				55,
 			],
+			[
+				'Array has 2 duplicate keys with value 0 (0, 0).',
+				63,
+			],
+			[
+				'Array has 2 duplicate keys with value 101 (101, 101).',
+				67,
+			],
+			[
+				'Array has 2 duplicate keys with value 102 (102, 102).',
+				69,
+			],
+			[
+				'Array has 2 duplicate keys with value -41 (-41, -41).',
+				76,
+			],
 		]);
 	}
 

tests/PHPStan/Rules/Arrays/data/duplicate-keys.php

@@ -57,4 +57,39 @@ public function doIncrement2()
 		];
 	}
 
+	public function doWithoutKeys(int $int)
+	{
+		$foo = [
+			1, // Key is 0
+			0 => 2,
+			100 => 3,
+			'This key is ignored' => 42,
+			4, // Key is 101
+			10 => 5,
+			6, // Key is 102
+			101 => 7,
+			102 => 8,
+		];
+
+		$foo2 = [
+			'-42' => 1,
+			2, // The key is -41
+			0 => 3,
+			-41 => 4,
+		];
+
+		$foo3 = [
+			$int => 33,
+			0 => 1,
+			2, // Because of `$int` key, the key value cannot be known.
+			1 => 3,
+		];
+
+		$foo4 = [
+			1,
+			2,
+			3,
+		];
+	}
+
 }