Check XP core for nullable support and change assertions

Fixes issue #103

Author: thekid

ChangeLog.md

@@ -3,6 +3,8 @@ XP Compiler ChangeLog
 
 ## ?.?.? / ????-??-??
 
+* Fixed issue #103: Nullable types - @thekid
+
 ## 6.1.0 / 2021-01-04
 
 * Included languages and emitters in `xp compile` output - @thekid

src/test/php/lang/ast/unittest/emit/NullableSupport.class.php

@@ -0,0 +1,13 @@
+<?php namespace lang\ast\unittest\emit;
+
+use lang\{Nullable, Type};
+
+trait NullableSupport {
+
+  /** Creates a nullable type if XP core supports it */
+  private function nullable(Type $t): Type {
+    static $support= null;
+
+    return ($support ?? $support= class_exists(Nullable::class)) ? new Nullable($t) : $t;
+  }
+}

src/test/php/lang/ast/unittest/emit/ParameterTest.class.php

@@ -5,6 +5,7 @@
 use unittest\{Assert, Test, Values, Action};
 
 class ParameterTest extends EmittingTest {
+  use NullableSupport;
 
   /**
    * Helper to declare a type and return a parameter reflection object
@@ -49,12 +50,12 @@ public function value_typed() {
 
   #[Test]
   public function value_type_with_null() {
-    Assert::equals(new XPClass(Value::class), $this->param('Value $param= null')->getType());
+    Assert::equals($this->nullable(new XPClass(Value::class)), $this->param('Value $param= null')->getType());
   }
 
   #[Test]
   public function nullable_value_type() {
-    Assert::equals(new XPClass(Value::class), $this->param('?Value $param')->getType());
+    Assert::equals($this->nullable(new XPClass(Value::class)), $this->param('?Value $param')->getType());
   }
 
   #[Test]
@@ -64,17 +65,17 @@ public function string_typed() {
 
   #[Test]
   public function string_typed_with_null() {
-    Assert::equals(Primitive::$STRING, $this->param('string $param= null')->getType());
+    Assert::equals($this->nullable(Primitive::$STRING), $this->param('string $param= null')->getType());
   }
 
   #[Test]
   public function nullable_string_type() {
-    Assert::equals(Primitive::$STRING, $this->param('?string $param')->getType());
+    Assert::equals($this->nullable(Primitive::$STRING), $this->param('?string $param')->getType());
   }
 
   #[Test, Action(eval: 'new RuntimeVersion(">=7.1")')]
   public function nullable_string_type_restriction() {
-    Assert::equals(Primitive::$STRING, $this->param('?string $param')->getTypeRestriction());
+    Assert::equals($this->nullable(Primitive::$STRING), $this->param('?string $param')->getTypeRestriction());
   }
 
   #[Test]