Add separate rule for testing unused traits.

Author: ianef

.gitignore

@@ -7,6 +7,7 @@
 
 # PHPUnit
 /phpunit.xml
+/.phpunit.result.cache
 
 # Build data
 /build/

.phpunit.result.cache

@@ -1,7 +1,8 @@
 # A collection of PHPStan extensions
 
 This repo contains some useful PHPStan extension for detecting errors in your code. The currently list of rules is:
-  - ==UnusedClassRule==
+## `UnusedClassRule`
+## `UnusedTraitRule`
 
 ## Install
 
@@ -23,17 +24,16 @@ include:
 ```
 
 ## Rules
-### UnusedClassRule
-This rule scans for class and trait declarations and use statements. If a class or trait is declared but not used within the scanned source files, an error is generated.
+### `UnusedClassRule`
+This rule scans for class declarations and use statements. If a class is declared but not used within the scanned source files, an error is generated.
 
 ### Disabling the rule
-You can disable scanning classes and traits as follows:
+You can disable scanning classes as follows:
 ```yaml
 # phpstan.neon
 parameters:
     unused_classes:
         classes: false
-        traits: false
 ```
 
 #### Excluding files
@@ -47,3 +47,18 @@ parameters:
             - 'src/Controller'
             - 'src/MyUnusedClass.php'
 ```
+
+### `UnusedTraitRule`
+This rule scans for trait declarations and use statements. If a trait is declared but not used within the scanned source files, an error is generated.
+
+### Disabling the rule
+You can disable scanning traits as follows:
+```yaml
+# phpstan.neon
+parameters:
+    unused_classes:
+        traits: false
+```
+
+#### Excluding files
+You can exclude directories and individual files from being scanned by this rule using the excludePaths parameter as shown above/

README.md

@@ -31,10 +31,6 @@ services:
         class: Xact\PHPStan\Collectors\DeclareClassCollector
         tags:
             - phpstan.collector
-    -
-        class: Xact\PHPStan\Collectors\DeclareTraitCollector
-        tags:
-            - phpstan.collector
 
 rules:
     - Xact\PHPStan\Rules\UnusedClassRule

config/extension.neon

@@ -20,7 +20,6 @@
     <testsuites>
         <testsuite name="Project Test Suite">
             <directory>tests</directory>
-            <exclude>tests/UnusedClass/</exclude>
         </testsuite>
     </testsuites>
 

phpunit.xml.dist

@@ -12,7 +12,6 @@
 use Xact\PHPStan\Collectors\ClassGroupUseCollector;
 use Xact\PHPStan\Collectors\ClassUseCollector;
 use Xact\PHPStan\Collectors\DeclareClassCollector;
-use Xact\PHPStan\Collectors\DeclareTraitCollector;
 use Xact\PHPStan\Exception\InvalidNodeTypeException;
 
 class UnusedClassRule implements Rule
@@ -36,7 +35,6 @@ public function processNode(Node $node, Scope $scope): array
         }
 
         $classDeclarationData = $node->get(DeclareClassCollector::class);
-        $traitDeclarationData = $node->get(DeclareTraitCollector::class);
         $groupUses = $node->get(ClassGroupUseCollector::class);
         $normalUses = $node->get(ClassUseCollector::class);
 
@@ -71,20 +69,6 @@ public function processNode(Node $node, Scope $scope): array
                 }
             }
         }
-        foreach ($traitDeclarationData as $file => $declarations) {
-            /**
-             * @var string $className
-             * @var int $line
-             */
-            foreach ($declarations as [$className, $line]) {
-                if (!array_key_exists($className, $usedClasses)) {
-                    $errors[] = RuleErrorBuilder::message("Trait {$className} is never used.")
-                        ->file($file)
-                        ->line($line)
-                        ->build();
-                }
-            }
-        }
 
         return $errors;
     }

src/Rules/UnusedClassRule.php

@@ -0,0 +1,66 @@
+<?php
+
+declare(strict_types=1);
+
+namespace Xact\PHPStan\Rules;
+
+use PhpParser\Node;
+use PHPStan\Analyser\Scope;
+use PHPStan\Node\CollectedDataNode;
+use PHPStan\Rules\Rule;
+use PHPStan\Rules\RuleErrorBuilder;
+use PHPStan\Rules\Traits\TraitDeclarationCollector;
+use PHPStan\Rules\Traits\TraitUseCollector;
+use Xact\PHPStan\Exception\InvalidNodeTypeException;
+
+class UnusedTraitRule implements Rule
+{
+    /**
+     * @inheritDoc
+     */
+    public function getNodeType(): string
+    {
+        return CollectedDataNode::class;
+    }
+
+    /**
+     * @inheritDoc
+     */
+    // phpcs:ignore SlevomatCodingStandard.Functions.UnusedParameter.UnusedParameter
+    public function processNode(Node $node, Scope $scope): array
+    {
+        if (!$node instanceof CollectedDataNode) {
+            throw InvalidNodeTypeException::create($node, CollectedDataNode::class);
+        }
+
+        $traitDeclarationData = $node->get(TraitDeclarationCollector::class);
+        $traitUses = $node->get(TraitUseCollector::class);
+
+        $usedTraits = [];
+        foreach ($traitUses as $fileUses) {
+            foreach ((array)$fileUses as $traitUse) {
+                foreach ((array)$traitUse as $trait) {
+                    $usedTraits[$trait] = $trait;
+                }
+            }
+        }
+
+        $errors = [];
+        foreach ($traitDeclarationData as $file => $declarations) {
+            /**
+             * @var string $className
+             * @var int $line
+             */
+            foreach ($declarations as [$className, $line]) {
+                if (!array_key_exists($className, $usedTraits)) {
+                    $errors[] = RuleErrorBuilder::message("Trait {$className} is never used.")
+                        ->file($file)
+                        ->line($line)
+                        ->build();
+                }
+            }
+        }
+
+        return $errors;
+    }
+}

src/Rules/UnusedTraitRule.php

@@ -4,6 +4,14 @@
 
 namespace Xact\PHPStan\Tests\UnusedClass;
 
+use Xact\PHPStan\Tests\UnusedClass\TraitA;
+
 class ClassA
 {
+    use TraitA;
+
+    public function __construct()
+    {
+        $this->testA();
+    }
 }

tests/UnusedClass/ClassA.php

@@ -0,0 +1,13 @@
+<?php
+
+declare(strict_types=1);
+
+namespace Xact\PHPStan\Tests\UnusedClass;
+
+trait TraitA
+{
+    public function testA(): int
+    {
+        return 1;
+    }
+}

tests/UnusedClass/TraitA.php

@@ -0,0 +1,9 @@
+<?php
+
+declare(strict_types=1);
+
+namespace Xact\PHPStan\Tests\UnusedClass;
+
+trait TraitB
+{
+}