Improve loose comparison on constant types

Author: staabm

src/Type/Constant/ConstantArrayType.php

@@ -418,9 +418,25 @@ public function isSuperTypeOf(Type $type): IsSuperTypeOfResult
 
 	public function looseCompare(Type $type, PhpVersion $phpVersion): BooleanType
 	{
-		if ($this->isIterableAtLeastOnce()->no() && count($type->getConstantScalarValues()) === 1) {
-			// @phpstan-ignore equal.invalid, equal.notAllowed
-			return new ConstantBooleanType($type->getConstantScalarValues()[0] == []); // phpcs:ignore
+		if ($type->isInteger()->yes()) {
+			return new ConstantBooleanType(false);
+		}
+
+		if ($this->isIterableAtLeastOnce()->no()) {
+			if ($type->isIterableAtLeastOnce()->yes()) {
+				return new ConstantBooleanType(false);
+			}
+
+			$constantScalarValues = $type->getConstantScalarValues();
+			if (count($constantScalarValues) > 0) {
+				$results = [];
+				foreach ($constantScalarValues as $constantScalarValue) {
+					// @phpstan-ignore equal.invalid, equal.notAllowed
+					$results[] = TrinaryLogic::createFromBoolean($constantScalarValue == []); // phpcs:ignore
+				}
+
+				return TrinaryLogic::extremeIdentity(...$results)->toBooleanType();
+			}
 		}
 
 		return new BooleanType();

tests/PHPStan/Analyser/nsrt/loose-comparisons.php

@@ -4,6 +4,7 @@
 
 namespace LooseSemantics;
 
+use SelfOut\a;
 use function PHPStan\Testing\assertType;
 
 class HelloWorld
@@ -633,6 +634,8 @@ public function sayInt(
 		array $array,
 		int $int,
 		int $intRange,
+		string $emptyStr,
+		string $phpStr,
 	): void
 	{
 		assertType('bool', $int == $true);
@@ -651,17 +654,35 @@ public function sayInt(
 		assertType('false', $intRange == $emptyArr);
 		assertType('false', $intRange == $array);
 
+		assertType('false', 5 == $emptyArr);
+		assertType('false', $emptyArr == 5);
+		assertType('false', 5 == $array);
+		assertType('false', $array == 5);
+		assertType('false', [] == 5);
+		assertType('false', 5 == []);
+
+		assertType('false', 5 == $emptyStr);
+		assertType('false', 5 == $phpStr);
+		assertType('false', 5 == 'a');
+
+		assertType('false', $emptyStr == 5);
+		assertType('false', $phpStr == 5);
+		assertType('false', 'a' == 5);
 	}
 
 	/**
 	 * @param true|1|"1" $looseOne
 	 * @param false|0|"0" $looseZero
 	 * @param false|1 $constMix
+	 * @param array{abc: string, num?: int, nullable: ?string} $arrShape
+	 * @param array{} $emptyArr
 	 */
 	public function sayConstUnion(
 		$looseOne,
 		$looseZero,
-		$constMix
+		$constMix,
+		array $arrShape,
+		array $emptyArr
 	): void
 	{
 		assertType('true', $looseOne == 1);
@@ -696,13 +717,22 @@ public function sayConstUnion(
 		assertType('bool', $constMix == $looseOne);
 		assertType('bool', $looseZero == $constMix);
 		assertType('bool', $constMix == $looseZero);
+
+		assertType('false', $emptyArr == $looseOne);
+		assertType('bool', $emptyArr == $constMix);
+		assertType('bool', $emptyArr == $looseZero);
+
+		assertType('bool', $arrShape == $looseOne);
+		assertType('bool', $arrShape == $constMix);
+		assertType('bool', $arrShape == $looseZero);
 	}
 
 	/**
 	 * @param uppercase-string $upper
 	 * @param lowercase-string $lower
 	 * @param array{} $emptyArr
 	 * @param non-empty-array $nonEmptyArr
+	 * @param array{abc: string, num?: int, nullable: ?string} $arrShape
 	 * @param int<10, 20> $intRange
 	 */
 	public function sayIntersection(
@@ -712,6 +742,7 @@ public function sayIntersection(
 		array $emptyArr,
 		array $nonEmptyArr,
 		array $arr,
+		array $arrShape,
 		int $i,
 		int $intRange,
 	): void
@@ -743,11 +774,24 @@ public function sayIntersection(
 		assertType('false', $nonEmptyArr == $i);
 		assertType('false', $arr == $intRange);
 		assertType('false', $nonEmptyArr == $intRange);
-		assertType('bool', $emptyArr == $nonEmptyArr); // should be false
+		assertType('false', $emptyArr == $nonEmptyArr);
 		assertType('false', $nonEmptyArr == $emptyArr);
 		assertType('bool', $arr == $nonEmptyArr);
 		assertType('bool', $nonEmptyArr == $arr);
 
+		assertType('false', 5 == $arr);
+		assertType('false', $arr == 5);
+		assertType('false', 5 == $emptyArr);
+		assertType('false', $emptyArr == 5);
+		assertType('false', 5 == $nonEmptyArr);
+		assertType('false', $nonEmptyArr == 5);
+		assertType('false', 5 == $arrShape);
+		assertType('false', $arrShape == 5);
+		if (count($arr) > 0) {
+			assertType('false', 5 == $arr);
+			assertType('false', $arr == 5);
+		}
+
 		assertType('bool', '' == $lower);
 		if ($lower != '') {
 			assertType('false', '' == $lower);