Add flattening optimization for deep BooleanAnd chains in truthy context

Unlike `BooleanOr` which already had `specifyTypesForFlattenedBooleanOr`,
`BooleanAnd` chains had no flattening — each level recursed through
`specifyTypesInCondition` and `filterByTruthyValue`, creating O(N²)
scope operations. This was slow even at the original
`BOOLEAN_EXPRESSION_MAX_PROCESS_DEPTH = 4`.

Add `specifyTypesForFlattenedBooleanAnd` that flattens the chain,
processes each arm independently in the original scope, and batches
the type union construction to avoid incremental O(N²) growth.

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

Author: ondrejmirtes

src/Analyser/TypeSpecifier.php

@@ -714,6 +714,17 @@ public function specifyTypesInCondition(
 			if (!$scope instanceof MutatingScope) {
 				throw new ShouldNotHappenException();
 			}
+
+			// For deep BooleanAnd chains in truthy context, flatten and
+			// process all arms at once to avoid O(N²) recursive
+			// filterByTruthyValue calls.
+			if (
+				$context->true()
+				&& BooleanAndHandler::getBooleanExpressionDepth($expr) > self::BOOLEAN_EXPRESSION_MAX_PROCESS_DEPTH
+			) {
+				return $this->specifyTypesForFlattenedBooleanAnd($scope, $expr, $context);
+			}
+
 			$leftTypes = $this->specifyTypesInCondition($scope, $expr->left, $context)->setRootExpr($expr);
 			$rightScope = $scope->filterByTruthyValue($expr->left);
 			$rightTypes = $this->specifyTypesInCondition($rightScope, $expr->right, $context)->setRootExpr($expr);
@@ -2075,6 +2086,56 @@ private function specifyTypesForFlattenedBooleanOr(
 		return $result->setRootExpr($expr);
 	}
 
+	/**
+	 * @param BooleanAnd|LogicalAnd $expr
+	 */
+	private function specifyTypesForFlattenedBooleanAnd(
+		MutatingScope $scope,
+		Expr $expr,
+		TypeSpecifierContext $context,
+	): SpecifiedTypes
+	{
+		$arms = [];
+		$current = $expr;
+		while ($current instanceof BooleanAnd || $current instanceof LogicalAnd) {
+			$arms[] = $current->right;
+			$current = $current->left;
+		}
+		$arms[] = $current;
+		$arms = array_reverse($arms);
+
+		// Truthy: all arms are true → union all SpecifiedTypes.
+		// Collect per-expression types first, then build unions once
+		// to avoid O(N²) from incremental growth.
+		/** @var array<string, array{Expr, list<Type>}> $sureTypesPerExpr */
+		$sureTypesPerExpr = [];
+		/** @var array<string, array{Expr, list<Type>}> $sureNotTypesPerExpr */
+		$sureNotTypesPerExpr = [];
+
+		foreach ($arms as $arm) {
+			$armTypes = $this->specifyTypesInCondition($scope, $arm, $context);
+			foreach ($armTypes->getSureTypes() as $exprString => [$exprNode, $type]) {
+				$sureTypesPerExpr[$exprString][0] = $exprNode;
+				$sureTypesPerExpr[$exprString][1][] = $type;
+			}
+			foreach ($armTypes->getSureNotTypes() as $exprString => [$exprNode, $type]) {
+				$sureNotTypesPerExpr[$exprString][0] = $exprNode;
+				$sureNotTypesPerExpr[$exprString][1][] = $type;
+			}
+		}
+
+		$sureTypes = [];
+		foreach ($sureTypesPerExpr as $exprString => [$exprNode, $types]) {
+			$sureTypes[$exprString] = [$exprNode, TypeCombinator::union(...$types)];
+		}
+		$sureNotTypes = [];
+		foreach ($sureNotTypesPerExpr as $exprString => [$exprNode, $types]) {
+			$sureNotTypes[$exprString] = [$exprNode, TypeCombinator::union(...$types)];
+		}
+
+		return (new SpecifiedTypes($sureTypes, $sureNotTypes))->setRootExpr($expr);
+	}
+
 	/**
 	 * @return array<string, ConditionalExpressionHolder[]>
 	 */

tests/bench/data/and-chain-truthy-blowup.php

@@ -0,0 +1,15 @@
+<?php declare(strict_types = 1);
+
+namespace BenchAndChainTruthyBlowup;
+
+/**
+ * Regression test for O(N²) in deep BooleanAnd chains.
+ * Without the flattening optimization, each level recursed through
+ * specifyTypesInCondition and filterByTruthyValue, creating O(N²) scope operations.
+ * Slow at the original BOOLEAN_EXPRESSION_MAX_PROCESS_DEPTH = 4.
+ */
+function test(string $x): void {
+	if ($x !== "val_1" && $x !== "val_2" && $x !== "val_3" && $x !== "val_4" && $x !== "val_5" && $x !== "val_6" && $x !== "val_7" && $x !== "val_8" && $x !== "val_9" && $x !== "val_10" && $x !== "val_11" && $x !== "val_12" && $x !== "val_13" && $x !== "val_14" && $x !== "val_15" && $x !== "val_16" && $x !== "val_17" && $x !== "val_18" && $x !== "val_19" && $x !== "val_20" && $x !== "val_21" && $x !== "val_22" && $x !== "val_23" && $x !== "val_24" && $x !== "val_25" && $x !== "val_26" && $x !== "val_27" && $x !== "val_28" && $x !== "val_29" && $x !== "val_30" && $x !== "val_31" && $x !== "val_32" && $x !== "val_33" && $x !== "val_34" && $x !== "val_35" && $x !== "val_36" && $x !== "val_37" && $x !== "val_38" && $x !== "val_39" && $x !== "val_40" && $x !== "val_41" && $x !== "val_42" && $x !== "val_43" && $x !== "val_44" && $x !== "val_45" && $x !== "val_46" && $x !== "val_47" && $x !== "val_48" && $x !== "val_49" && $x !== "val_50" && $x !== "val_51" && $x !== "val_52" && $x !== "val_53" && $x !== "val_54" && $x !== "val_55" && $x !== "val_56" && $x !== "val_57" && $x !== "val_58" && $x !== "val_59" && $x !== "val_60" && $x !== "val_61" && $x !== "val_62" && $x !== "val_63" && $x !== "val_64" && $x !== "val_65" && $x !== "val_66" && $x !== "val_67" && $x !== "val_68" && $x !== "val_69" && $x !== "val_70" && $x !== "val_71" && $x !== "val_72" && $x !== "val_73" && $x !== "val_74" && $x !== "val_75" && $x !== "val_76" && $x !== "val_77" && $x !== "val_78" && $x !== "val_79" && $x !== "val_80" && $x !== "val_81" && $x !== "val_82" && $x !== "val_83" && $x !== "val_84" && $x !== "val_85" && $x !== "val_86" && $x !== "val_87" && $x !== "val_88" && $x !== "val_89" && $x !== "val_90" && $x !== "val_91" && $x !== "val_92" && $x !== "val_93" && $x !== "val_94" && $x !== "val_95" && $x !== "val_96" && $x !== "val_97" && $x !== "val_98" && $x !== "val_99" && $x !== "val_100") {
+		echo $x;
+	}
+}