Fix unparseable string representation of CallableTypeParameterNode

Author: ondrejmirtes

src/Ast/Type/CallableTypeParameterNode.php

@@ -41,8 +41,8 @@ public function __toString(): string
 		$type = "{$this->type} ";
 		$isReference = $this->isReference ? '&' : '';
 		$isVariadic = $this->isVariadic ? '...' : '';
-		$default = $this->isOptional ? ' = default' : '';
-		return trim("{$type}{$isReference}{$isVariadic}{$this->parameterName}") . $default;
+		$isOptional = $this->isOptional ? '=' : '';
+		return trim("{$type}{$isReference}{$isVariadic}{$this->parameterName}") . $isOptional;
 	}
 
 }

tests/PHPStan/Ast/ToString/TypeToStringTest.php

@@ -102,7 +102,7 @@ public static function provideCallableCases(): Generator
 				], new IdentifierTypeNode('void')),
 			],
 			[
-				'callable(int = default, int $foo = default): void',
+				'callable(int=, int $foo=): void',
 				new CallableTypeNode(new IdentifierTypeNode('callable'), [
 					new CallableTypeParameterNode(new IdentifierTypeNode('int'), false, false, '', true),
 					new CallableTypeParameterNode(new IdentifierTypeNode('int'), false, false, '$foo', true),