Merge the two conditional purity parameter mergers into one class

MergedPureUnlessCallableIsImpureParameters and
MergedPureUnlessParameterPassedParameters were identical apart from which
getter they read off each method reflection. MergedConditionalPurityParameters
keeps that merge once and exposes one entry point per tag.

Co-authored-by: Claude Opus 5 <noreply@anthropic.com>

Author: zonuexe

src/Reflection/Type/IntersectionTypeMethodReflection.php

@@ -216,12 +216,12 @@ public function isPure(): TrinaryLogic
 
 	public function getPureUnlessCallableIsImpureParameters(): array
 	{
-		return MergedPureUnlessCallableIsImpureParameters::merge($this->methods);
+		return MergedConditionalPurityParameters::mergePureUnlessCallableIsImpure($this->methods);
 	}
 
 	public function getPureUnlessParameterPassedParameters(): array
 	{
-		return MergedPureUnlessParameterPassedParameters::merge($this->methods);
+		return MergedConditionalPurityParameters::mergePureUnlessParameterPassed($this->methods);
 	}
 
 	public function getDocComment(): ?string

src/Reflection/Type/MergedConditionalPurityParameters.php

@@ -0,0 +1,77 @@
+<?php declare(strict_types = 1);
+
+namespace PHPStan\Reflection\Type;
+
+use PHPStan\Reflection\ExtendedMethodReflection;
+use PHPStan\TrinaryLogic;
+use function array_keys;
+use function array_map;
+
+/**
+ * Merges the per-parameter conditional purity flags of several method reflections
+ * (union/intersection members). A parameter that is flagged differently across the
+ * members - or present in some and absent in others - resolves to Maybe.
+ */
+final class MergedConditionalPurityParameters
+{
+
+	/**
+	 * @param ExtendedMethodReflection[] $methods
+	 * @return array<string, TrinaryLogic>
+	 */
+	public static function mergePureUnlessCallableIsImpure(array $methods): array
+	{
+		return self::merge(array_map(
+			static fn (ExtendedMethodReflection $method) => $method->getPureUnlessCallableIsImpureParameters(),
+			$methods,
+		));
+	}
+
+	/**
+	 * @param ExtendedMethodReflection[] $methods
+	 * @return array<string, TrinaryLogic>
+	 */
+	public static function mergePureUnlessParameterPassed(array $methods): array
+	{
+		return self::merge(array_map(
+			static fn (ExtendedMethodReflection $method) => $method->getPureUnlessParameterPassedParameters(),
+			$methods,
+		));
+	}
+
+	/**
+	 * @param array<array<string, TrinaryLogic>> $maps
+	 * @return array<string, TrinaryLogic>
+	 */
+	private static function merge(array $maps): array
+	{
+		$parameterNames = [];
+		foreach ($maps as $map) {
+			foreach (array_keys($map) as $name) {
+				$parameterNames[$name] = true;
+			}
+		}
+
+		$merged = [];
+		foreach (array_keys($parameterNames) as $name) {
+			$value = null;
+			foreach ($maps as $map) {
+				$current = $map[$name] ?? TrinaryLogic::createNo();
+				if ($value === null) {
+					$value = $current;
+					continue;
+				}
+				$value = $value->equals($current) ? $value : TrinaryLogic::createMaybe();
+			}
+
+			if ($value === null) {
+				continue;
+			}
+
+			$merged[$name] = $value;
+		}
+
+		return $merged;
+	}
+
+}

src/Reflection/Type/MergedPureUnlessCallableIsImpureParameters.php

@@ -173,12 +173,12 @@ public function isPure(): TrinaryLogic
 
 	public function getPureUnlessCallableIsImpureParameters(): array
 	{
-		return MergedPureUnlessCallableIsImpureParameters::merge($this->methods);
+		return MergedConditionalPurityParameters::mergePureUnlessCallableIsImpure($this->methods);
 	}
 
 	public function getPureUnlessParameterPassedParameters(): array
 	{
-		return MergedPureUnlessParameterPassedParameters::merge($this->methods);
+		return MergedConditionalPurityParameters::mergePureUnlessParameterPassed($this->methods);
 	}
 
 	public function getDocComment(): ?string