Make it work?

Author: rvanvelzen

Diff for: src/Reflection/ParametersAcceptorSelector.php

@@ -17,6 +17,7 @@
 use PHPStan\Type\NullType;
 use PHPStan\Type\Type;
 use PHPStan\Type\TypeCombinator;
+use PHPStan\Type\TypeUtils;
 use PHPStan\Type\UnionType;
 use function array_key_last;
 use function array_slice;
@@ -32,7 +33,7 @@ class ParametersAcceptorSelector
 	/**
 	 * @template T of ParametersAcceptor
 	 * @param T[] $parametersAcceptors
-	 * @return T
+	 * @return T|SingleParametersAcceptor
 	 */
 	public static function selectSingle(
 		array $parametersAcceptors,
@@ -48,7 +49,12 @@ public static function selectSingle(
 			throw new ShouldNotHappenException('Multiple variants - use selectFromArgs() instead.');
 		}
 
-		return new SingleParametersAcceptor($parametersAcceptors[0]);
+		$parametersAcceptor = $parametersAcceptors[0];
+		if (TypeUtils::containsConditional($parametersAcceptor->getReturnType())) {
+			return new SingleParametersAcceptor($parametersAcceptor);
+		}
+
+		return $parametersAcceptor;
 	}
 
 	/**

Diff for: src/Reflection/SingleParametersAcceptor.php

@@ -11,6 +11,8 @@
 class SingleParametersAcceptor implements ParametersAcceptor
 {
 
+	private ?Type $returnType = null;
+
 	public function __construct(private ParametersAcceptor $acceptor)
 	{
 	}
@@ -40,13 +42,17 @@ public function isVariadic(): bool
 
 	public function getReturnType(): Type
 	{
-		return TypeTraverser::map($this->acceptor->getReturnType(), static function (Type $type, callable $traverse) {
-			while ($type instanceof ConditionalType || $type instanceof ConditionalTypeForParameter) {
-				$type = $type->getResult();
-			}
+		if ($this->returnType === null) {
+			return $this->returnType = TypeTraverser::map($this->acceptor->getReturnType(), static function (Type $type, callable $traverse) {
+				while ($type instanceof ConditionalType || $type instanceof ConditionalTypeForParameter) {
+					$type = $type->getResult();
+				}
+
+				return $traverse($type);
+			});
+		}
 
-			return $traverse($type);
-		});
+		return $this->returnType;
 	}
 
 }

Diff for: src/Type/TypeUtils.php

@@ -328,4 +328,22 @@ public static function containsCallable(Type $type): bool
 		return false;
 	}
 
+	public static function containsConditional(Type $type): bool
+	{
+		if ($type instanceof ConditionalType || $type instanceof ConditionalTypeForParameter) {
+			return true;
+		}
+
+		$contains = false;
+		TypeTraverser::map($type, static function (Type $type, callable $traverse) use (&$contains): Type {
+			if ($type instanceof ConditionalType || $type instanceof ConditionalTypeForParameter) {
+				$contains = true;
+			}
+
+			return !$contains ? $traverse($type) : $type;
+		});
+
+		return $contains;
+	}
+
 }

Diff for: tests/PHPStan/Analyser/AnalyserIntegrationTest.php

@@ -622,7 +622,7 @@ public function testBug6896(): void
 		}
 
 		$errors = $this->runAnalyse(__DIR__ . '/data/bug-6896.php');
-		$this->assertCount(4, $errors);
+		$this->assertCount(2, $errors);
 	}
 
 	public function testBug6940(): void