Fix IntegerRangeType count narrowing for falsey context with unbounded max

When the range has no upper bound (e.g. int<1, max>), the falsey context
should not narrow using the min value, as this incorrectly eliminates
arrays that could satisfy the condition for some (but not all) values
in the range. Only set sizeType when the context is truthy and min is
available, or when falsey and max is available.

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

Author: phpstan-bot

src/Analyser/TypeSpecifier.php

@@ -280,6 +280,7 @@ public function specifyTypesInCondition(
 			) {
 				$argType = $scope->getType($expr->right->getArgs()[0]->value);
 
+				$sizeType = null;
 				if ($leftType instanceof ConstantIntegerType) {
 					if ($orEqual) {
 						$sizeType = IntegerRangeType::createAllGreaterThanOrEqualTo($leftType->getValue());
@@ -293,22 +294,22 @@ public function specifyTypesInCondition(
 						} else {
 							$sizeType = IntegerRangeType::createAllGreaterThan($leftType->getMax());
 						}
-					} elseif ($leftType->getMin() !== null) {
+					} elseif ($context->truthy() && $leftType->getMin() !== null) {
 						if ($orEqual) {
 							$sizeType = IntegerRangeType::createAllGreaterThanOrEqualTo($leftType->getMin());
 						} else {
 							$sizeType = IntegerRangeType::createAllGreaterThan($leftType->getMin());
 						}
-					} else {
-						$sizeType = $leftType->shift($offset);
 					}
 				} else {
 					$sizeType = $leftType;
 				}
 
-				$specifiedTypes = $this->specifyTypesForCountFuncCall($expr->right, $argType, $sizeType, $context, $scope, $expr);
-				if ($specifiedTypes !== null) {
-					$result = $result->unionWith($specifiedTypes);
+				if ($sizeType !== null) {
+					$specifiedTypes = $this->specifyTypesForCountFuncCall($expr->right, $argType, $sizeType, $context, $scope, $expr);
+					if ($specifiedTypes !== null) {
+						$result = $result->unionWith($specifiedTypes);
+					}
 				}
 
 				if (

tests/PHPStan/Analyser/nsrt/bug-4700.php

@@ -21,8 +21,8 @@ function(array $array, int $count): void {
 		assertType('int<1, 5>', count($a));
 		assertType('list{0: mixed~null, 1?: mixed~null, 2?: mixed~null, 3?: mixed~null, 4?: mixed~null}', $a);
 	} else {
-		assertType('0', count($a));
-		assertType('array{}', $a);
+		assertType('int<0, 5>', count($a));
+		assertType('array{}|list{0: mixed~null, 1?: mixed~null, 2?: mixed~null, 3?: mixed~null, 4?: mixed~null}', $a);
 	}
 };