diff --git a/src/model/parts/TypePart.php b/src/model/parts/TypePart.php
index 881221a..84159c9 100644
--- a/src/model/parts/TypePart.php
+++ b/src/model/parts/TypePart.php
@@ -71,7 +71,7 @@ public function getTypeDescription(): ?string {
 	 * 
 	 * @return bool
 	 */
-	public function getNullable(): bool {
+	public function getNullable(): ?bool {
 		return $this->typeNullable;
 	}
 
diff --git a/tests/generator/ParameterGeneratorTest.php b/tests/generator/ParameterGeneratorTest.php
index ab7bb0d..3b69c84 100644
--- a/tests/generator/ParameterGeneratorTest.php
+++ b/tests/generator/ParameterGeneratorTest.php
@@ -103,6 +103,13 @@ public function testPhp73Nullable() {
 	    $this->assertEquals('?float $foo', $generator->generate($param));
 	}
 
+	public function testPhp73NullableDefaultsToFalseWhenUnset() {
+	    $generator = new ModelGenerator(['generateScalarTypeHints' => true, 'generateNullableTypes' => true]);
+
+	    $param = PhpParameter::create('foo')->setType('float');
+	    $this->assertEquals('float $foo', $generator->generate($param));
+	}
+
 	public function testValues() {
 		$generator = new ModelGenerator();