Feat: Add NullableTypeDeclarationForDefaultNullValueFixer (part of #94)

Author: OndraM

Diff for: ecs.php

@@ -77,6 +77,7 @@
 use PhpCsFixer\Fixer\FunctionNotation\MethodArgumentSpaceFixer;
 use PhpCsFixer\Fixer\FunctionNotation\NoUnreachableDefaultArgumentValueFixer;
 use PhpCsFixer\Fixer\FunctionNotation\NoUselessSprintfFixer;
+use PhpCsFixer\Fixer\FunctionNotation\NullableTypeDeclarationForDefaultNullValueFixer;
 use PhpCsFixer\Fixer\FunctionNotation\PhpdocToParamTypeFixer;
 use PhpCsFixer\Fixer\FunctionNotation\PhpdocToPropertyTypeFixer;
 use PhpCsFixer\Fixer\FunctionNotation\PhpdocToReturnTypeFixer;
@@ -295,6 +296,8 @@
             NoUnreachableDefaultArgumentValueFixer::class,
             // There must be no `sprintf` calls with only the first argument.
             NoUselessSprintfFixer::class,
+            // Add `?` before single type declarations when parameters have a default null value.
+            NullableTypeDeclarationForDefaultNullValueFixer::class,
             // There must not be a space before colon in return type declarations.
             ReturnTypeDeclarationFixer::class,
             // Add `void` return type to functions with missing or empty return statements.

Diff for: tests/Integration/Fixtures/Basic.correct.php.inc

@@ -169,6 +169,10 @@ class Basic extends AbstractBasic implements InterfaceFromThisNamespace // Fully
         );
     }
 
-    // NullableTypeDeclarationFixer
-    public function withParameters(?string $nullableValue): void {}
+    public function withParameters(
+        // NullableTypeDeclarationFixer
+        ?string $nullableValue,
+        // NullableTypeDeclarationForDefaultNullValueFixer
+        ?string $anotherNullableValue = null,
+    ): void {}
 }

Diff for: tests/Integration/Fixtures/Basic.wrong.php.inc

@@ -166,7 +166,10 @@ but should be heredoc instead';
         );
     }
 
-    // NullableTypeDeclarationFixer
-    public function withParameters(null|string $nullableValue): void
-    {}
+    public function withParameters(
+        // NullableTypeDeclarationFixer
+        null|string $nullableValue,
+        // NullableTypeDeclarationForDefaultNullValueFixer
+        string $anotherNullableValue = null,
+    ): void {}
 }