Return false from range() for an invalid step on PHP 7

Before PHP 8.0 an invalid step was reported by a warning and a false
return value instead of a ValueError.

Author: zonuexe

src/Type/Php/RangeFunctionReturnTypeExtension.php

@@ -14,6 +14,7 @@
 use PHPStan\Type\ArrayType;
 use PHPStan\Type\BenevolentUnionType;
 use PHPStan\Type\Constant\ConstantArrayTypeBuilder;
+use PHPStan\Type\Constant\ConstantBooleanType;
 use PHPStan\Type\Constant\ConstantFloatType;
 use PHPStan\Type\Constant\ConstantIntegerType;
 use PHPStan\Type\Constant\ConstantStringType;
@@ -30,7 +31,6 @@
 use ValueError;
 use function abs;
 use function count;
-use function is_array;
 use function is_finite;
 use function is_float;
 use function is_string;
@@ -93,14 +93,18 @@ public function getTypeFromFunctionCall(FunctionReflection $functionReflection,
 					try {
 						$rangeValues = @range($startConstant->getValue(), $endConstant->getValue(), $stepConstant->getValue());
 					} catch (ValueError) {
-						if ($this->throwsOnAnalysedVersion($startConstant->getValue(), $endConstant->getValue(), $stepConstant->getValue())) {
-							$throwingCombinations++;
-						}
-						continue;
+						$rangeValues = false;
 					}
 
-					// @phpstan-ignore function.alreadyNarrowedType
-					if (!is_array($rangeValues)) {
+					// PHP 7 reports an invalid step by returning false instead of throwing a ValueError
+					if ($rangeValues === false) {
+						if ($this->failsOnAnalysedVersion($startConstant->getValue(), $endConstant->getValue(), $stepConstant->getValue())) {
+							if ($this->phpVersion->throwsValueErrorForInternalFunctions()) {
+								$throwingCombinations++;
+							} else {
+								$constantReturnTypes[] = new ConstantBooleanType(false);
+							}
+						}
 						continue;
 					}
 
@@ -193,15 +197,11 @@ public function getTypeFromFunctionCall(FunctionReflection $functionReflection,
 
 	/**
 	 * The constant arguments are folded by calling range() on the PHP version PHPStan
-	 * itself runs on, so a ValueError only says that the runtime rejects the step.
-	 * The analysed PHP version is consulted separately before it is turned into never.
+	 * itself runs on, so a failure only says that the runtime rejects the step.
+	 * This checks whether the analysed PHP version rejects it as well.
 	 */
-	private function throwsOnAnalysedVersion(int|float|string $start, int|float|string $end, int|float $step): bool
+	private function failsOnAnalysedVersion(int|float|string $start, int|float|string $end, int|float $step): bool
 	{
-		if (!$this->phpVersion->throwsValueErrorForInternalFunctions()) {
-			return false;
-		}
-
 		if ($this->phpVersion->hasStricterRangeFunction()) {
 			return true;
 		}

tests/PHPStan/Analyser/RangePhp74Test.php

@@ -0,0 +1,36 @@
+<?php declare(strict_types = 1);
+
+namespace PHPStan\Analyser;
+
+use PHPStan\Testing\TypeInferenceTestCase;
+use PHPUnit\Framework\Attributes\DataProvider;
+
+class RangePhp74Test extends TypeInferenceTestCase
+{
+
+	public static function dataFileAsserts(): iterable
+	{
+		yield from self::gatherAssertTypes(__DIR__ . '/data/range-php74.php');
+	}
+
+	/**
+	 * @param mixed ...$args
+	 */
+	#[DataProvider('dataFileAsserts')]
+	public function testFileAsserts(
+		string $assertType,
+		string $file,
+		...$args,
+	): void
+	{
+		$this->assertFileAsserts($assertType, $file, ...$args);
+	}
+
+	public static function getAdditionalConfigFiles(): array
+	{
+		return [
+			__DIR__ . '/nodeScopeResolverPhp7.neon',
+		];
+	}
+
+}

tests/PHPStan/Analyser/data/range-php74.php

@@ -0,0 +1,15 @@
+<?php
+
+namespace RangePhp74;
+
+use function PHPStan\Testing\assertType;
+
+// PHP 7 reports an invalid step with a warning and returns false instead of throwing a ValueError
+assertType('false', range(1, 10, INF));
+assertType('false', range(2, 5, 0));
+assertType('false', range(5, 6, 3));
+
+function maybeInvalidStep(bool $flag): void
+{
+	assertType('array{6}|false', range($flag ? 5 : 6, 6, 3));
+}