Update TypeSpecifier.php

Author: staabm

src/Analyser/TypeSpecifier.php

@@ -1579,13 +1579,18 @@ private function getConditionalSpecifiedTypes(
 		if (!array_key_exists($parameterName, $argsMap)) {
 			return null;
 		}
+		$parameterExpr = $argsMap[$parameterName];
 
 		$targetType = $conditionalType->getTarget();
 		$ifType = $conditionalType->getIf();
 		$elseType = $conditionalType->getElse();
 
 		if (
-			$argsMap[$parameterName] instanceof Node\Scalar
+			(
+				$parameterExpr instanceof Node\Scalar
+				|| ($parameterExpr instanceof ConstFetch && in_array(strtolower($parameterExpr->name->toString()), ['true', 'false', 'null'], true))
+			)
+			&& !$targetType instanceof UnionType
 			&& $targetType->isConstantScalarValue()->yes()
 		) {
 			return null;
@@ -1600,7 +1605,7 @@ private function getConditionalSpecifiedTypes(
 		}
 
 		$specifiedTypes = $this->create(
-			$argsMap[$parameterName],
+			$parameterExpr,
 			$targetType,
 			$context,
 			$scope,
@@ -1611,7 +1616,7 @@ private function getConditionalSpecifiedTypes(
 				$context = $context->negate();
 			}
 
-			$specifiedTypes = $specifiedTypes->unionWith($this->specifyTypesInCondition($scope, $argsMap[$parameterName], $context));
+			$specifiedTypes = $specifiedTypes->unionWith($this->specifyTypesInCondition($scope, $parameterExpr, $context));
 		}
 
 		return $specifiedTypes;