Improve dead code detection, reducing false positives for params

assets/config_levels/4.xml

@@ -39,6 +39,5 @@
         <PossiblyNullPropertyFetch errorLevel="info" />
         <PossiblyNullReference errorLevel="info" />
         <PossiblyUndefinedVariable errorLevel="info" />
-        <PossiblyUnusedVariable errorLevel="info" />
     </issueHandlers>
 </psalm>

assets/config_levels/5.xml

@@ -39,7 +39,6 @@
         <PossiblyNullPropertyFetch errorLevel="info" />
         <PossiblyNullReference errorLevel="info" />
         <PossiblyUndefinedVariable errorLevel="info" />
-        <PossiblyUnusedVariable errorLevel="info" />
 
         <!-- level 5 issues - should be avoided at mosts costs... -->
 

config.xsd

@@ -188,8 +188,8 @@
             <xs:element name="PossiblyUndefinedMethod" type="IssueHandlerType" minOccurs="0" />
             <xs:element name="PossiblyUndefinedGlobalVariable" type="IssueHandlerType" minOccurs="0" />
             <xs:element name="PossiblyUndefinedVariable" type="IssueHandlerType" minOccurs="0" />
-            <xs:element name="PossiblyUnusedVariable" type="IssueHandlerType" minOccurs="0" />
             <xs:element name="PossiblyUnusedMethod" type="IssueHandlerType" minOccurs="0" />
+            <xs:element name="PossiblyUnusedParam" type="IssueHandlerType" minOccurs="0" />
             <xs:element name="PropertyNotSetInConstructor" type="IssueHandlerType" minOccurs="0" />
             <xs:element name="RawObjectIteration" type="IssueHandlerType" minOccurs="0" />
             <xs:element name="RedundantCondition" type="IssueHandlerType" minOccurs="0" />
@@ -219,6 +219,7 @@
             <xs:element name="UnresolvableInclude" type="IssueHandlerType" minOccurs="0" />
             <xs:element name="UnevaluatedCode" type="IssueHandlerType" minOccurs="0" />
             <xs:element name="UnusedVariable" type="IssueHandlerType" minOccurs="0" />
+            <xs:element name="UnusedParam" type="IssueHandlerType" minOccurs="0" />
             <xs:element name="UnusedClass" type="IssueHandlerType" minOccurs="0" />
             <xs:element name="UnusedMethod" type="IssueHandlerType" minOccurs="0" />
         </xs:choice>

psalm.xml

@@ -25,12 +25,19 @@
         <MissingConstructor errorLevel="suppress" />
         <DeprecatedProperty errorLevel="suppress" />
 
-        <PossiblyUnusedVariable>
+        <UnusedParam>
             <errorLevel type="suppress">
                 <file name="src/Psalm/Plugin.php" />
                 <directory name="examples" />
             </errorLevel>
-        </PossiblyUnusedVariable>
+        </UnusedParam>
+
+        <PossiblyUnusedParam>
+            <errorLevel type="suppress">
+                <file name="src/Psalm/Plugin.php" />
+                <directory name="examples" />
+            </errorLevel>
+        </PossiblyUnusedParam>
 
         <UnusedVariable>
             <errorLevel type="suppress">
@@ -55,6 +62,9 @@
             <errorLevel type="suppress">
                 <directory name="tests" />
                 <directory name="examples" />
+                <file name="src/Psalm/Type/Atomic/GenericTrait.php" />
+                <file name="src/Psalm/TraitSource.php" />
+                <file name="src/Psalm/FileManipulation/FileManipulationBuffer.php" />
             </errorLevel>
         </PossiblyUnusedMethod>
 

src/Psalm/Checker/ClassLikeChecker.php

@@ -1378,33 +1378,6 @@ abstract class ClassLikeChecker extends SourceChecker implements StatementsSourc
         }
     }
 
-    /**
-     * @param  string $class_name
-     * @param  mixed  $visibility
-     *
-     * @return array<string, PropertyStorage>
-     */
-    public static function getPropertiesForClass(ProjectChecker $project_checker, $class_name, $visibility)
-    {
-        $storage = $project_checker->classlike_storage_provider->get($class_name);
-
-        $properties = [];
-
-        foreach ($storage->properties as $property_name => $property) {
-            if (!$property->is_static) {
-                if ($visibility === ReflectionProperty::IS_PRIVATE ||
-                    $property->visibility === ClassLikeChecker::VISIBILITY_PUBLIC ||
-                    ($property->visibility === ClassLikeChecker::VISIBILITY_PROTECTED &&
-                        $visibility === ReflectionProperty::IS_PROTECTED)
-                ) {
-                    $properties[$property_name] = $property;
-                }
-            }
-        }
-
-        return $properties;
-    }
-
     /**
      * Gets the Psalm type from a particular value
      *

src/Psalm/Checker/FunctionLikeChecker.php

@@ -26,8 +26,9 @@ use Psalm\Issue\MixedInferredReturnType;
 use Psalm\Issue\MoreSpecificImplementedReturnType;
 use Psalm\Issue\MoreSpecificReturnType;
 use Psalm\Issue\OverriddenMethodAccess;
-use Psalm\Issue\PossiblyUnusedVariable;
+use Psalm\Issue\PossiblyUnusedParam;
 use Psalm\Issue\UntypedParam;
+use Psalm\Issue\UnusedParam;
 use Psalm\Issue\UnusedVariable;
 use Psalm\IssueBuffer;
 use Psalm\StatementsSource;
@@ -129,6 +130,10 @@ abstract class FunctionLikeChecker extends SourceChecker implements StatementsSo
 
         $implemented_docblock_param_types = [];
 
+        $project_checker = $this->file_checker->project_checker;
+
+        $classlike_storage_provider = $project_checker->classlike_storage_provider;
+
         if ($this->function instanceof ClassMethod) {
             $real_method_id = (string)$this->getMethodId();
 
@@ -162,10 +167,6 @@ abstract class FunctionLikeChecker extends SourceChecker implements StatementsSo
 
             $fq_class_name = (string)$context->self;
 
-            $project_checker = $this->file_checker->project_checker;
-
-            $classlike_storage_provider = $project_checker->classlike_storage_provider;
-
             $class_storage = $classlike_storage_provider->get($fq_class_name);
 
             $storage = MethodChecker::getStorage($project_checker, $declaring_method_id);
@@ -473,10 +474,7 @@ abstract class FunctionLikeChecker extends SourceChecker implements StatementsSo
                     $original_location = $statements_checker->getFirstAppearance($var_name);
 
                     if (!isset($context->referenced_var_ids[$var_name]) && $original_location) {
-                        if (!isset($storage->param_types[substr($var_name, 1)]) ||
+                        if (!array_key_exists(substr($var_name, 1), $storage->param_types)) {
-                            !$storage instanceof MethodStorage ||
-                            $storage->visibility === ClassLikeChecker::VISIBILITY_PRIVATE
-                        ) {
                             if (IssueBuffer::accepts(
                                 new UnusedVariable(
                                     'Variable ' . $var_name . ' is never referenced',
@@ -486,10 +484,40 @@ abstract class FunctionLikeChecker extends SourceChecker implements StatementsSo
                             )) {
                                 // fall through
                             }
-                        } else {
+                        } elseif (!$storage instanceof MethodStorage
+                            || $storage->visibility === ClassLikeChecker::VISIBILITY_PRIVATE
+                        ) {
                             if (IssueBuffer::accepts(
-                                new PossiblyUnusedVariable(
+                                new UnusedParam(
-                                    'Variable ' . $var_name . ' is never referenced in this method',
+                                    'Param ' . $var_name . ' is never referenced in this method',
+                                    $original_location
+                                ),
+                                $this->getSuppressedIssues()
+                            )) {
+                                // fall through
+                            }
+                        } else {
+                            if (!$class_storage || $storage->abstract) {
+                                continue;
+                            }
+
+                            /** @var ClassMethod $this->function */
+                            $method_name_lc = strtolower((string)$this->function->name);
+                            $parent_method_id = end($class_storage->overridden_method_ids[$method_name_lc]);
+
+                            if ($parent_method_id) {
+                                list($parent_fq_class_name) = explode('::', $parent_method_id);
+
+                                $parent_method_class_storage = $classlike_storage_provider->get($parent_fq_class_name);
+
+                                if (!$parent_method_class_storage->abstract) {
+                                    continue;
+                                }
+                            }
+
+                            if (IssueBuffer::accepts(
+                                new PossiblyUnusedParam(
+                                    'Param ' . $var_name . ' is never referenced in this method',
                                     $original_location
                                 ),
                                 $this->getSuppressedIssues()

src/Psalm/Checker/ProjectChecker.php

@@ -920,6 +920,8 @@ class ProjectChecker
              * @param string $file_path
              *
              * @return void
+             *
+             * @psalm-suppress UnusedParam
              */
             function ($i, $file_path) use ($filetype_handlers) {
                 $file_checker = $this->getFile($file_path, $filetype_handlers, true);
@@ -1117,11 +1119,9 @@ class ProjectChecker
     }
 
     /**
-     * @param  \Psalm\Storage\ClassLikeStorage  $classlike_storage
-     *
      * @return void
      */
-    protected static function checkMethodReferences($classlike_storage)
+    protected static function checkMethodReferences(\Psalm\Storage\ClassLikeStorage $classlike_storage)
     {
         foreach ($classlike_storage->methods as $method_name => $method_storage) {
             if (($method_storage->referencing_locations === null
@@ -1137,7 +1137,8 @@ class ProjectChecker
                         new PossiblyUnusedMethod(
                             'Cannot find public calls to method ' . $method_id,
                             $method_storage->location
-                        )
+                        ),
+                        $method_storage->suppressed_issues
                     )) {
                         // fall through
                     }

src/Psalm/Issue/CodeIssue.php

@@ -61,6 +61,8 @@ abstract class CodeIssue
 
     /**
      * @return string
+     *
+     * @psalm-suppress PossiblyUnusedMethod for convenience
      */
     public function getFileName()
     {

src/Psalm/Issue/PossiblyUnusedParam.php

@@ -0,0 +1,6 @@
+<?php
+namespace Psalm\Issue;
+
+class PossiblyUnusedParam extends CodeError
+{
+}

src/Psalm/Issue/PossiblyUnusedVariable.php

@@ -1,6 +0,0 @@
-<?php
-namespace Psalm\Issue;
-
-class PossiblyUnusedVariable extends CodeError
-{
-}

src/Psalm/Issue/UnusedParam.php

@@ -0,0 +1,6 @@
+<?php
+namespace Psalm\Issue;
+
+class UnusedParam extends CodeError
+{
+}

src/Psalm/Provider/Cache/NoParserCacheProvider.php

@@ -6,14 +6,13 @@ use PhpParser;
 class NoParserCacheProvider extends \Psalm\Provider\ParserCacheProvider
 {
     /**
-     * @param  string   $file_path
      * @param  string   $file_content_hash
      * @param  string   $file_cache_key
      * @param mixed $file_modified_time
      *
      * @return array<int, PhpParser\Node\Stmt>|null
      */
-    public function loadStatementsFromCache($file_path, $file_modified_time, $file_content_hash, $file_cache_key)
+    public function loadStatementsFromCache($file_modified_time, $file_content_hash, $file_cache_key)
     {
         return null;
     }

src/Psalm/Provider/ParserCacheProvider.php

@@ -26,7 +26,6 @@ class ParserCacheProvider
     public $use_igbinary = false;
 
     /**
-     * @param  string   $file_path
      * @param  string   $file_content_hash
      * @param  string   $file_cache_key
      * @param mixed $file_modified_time
@@ -35,7 +34,7 @@ class ParserCacheProvider
      *
      * @psalm-suppress UndefinedFunction
      */
-    public function loadStatementsFromCache($file_path, $file_modified_time, $file_content_hash, $file_cache_key)
+    public function loadStatementsFromCache($file_modified_time, $file_content_hash, $file_cache_key)
     {
         $root_cache_directory = Config::getInstance()->getCacheDirectory();
 

src/Psalm/Provider/StatementsProvider.php

@@ -35,7 +35,6 @@ class StatementsProvider
         $file_cache_key = $cache_provider->getParserCacheKey($file_path);
 
         $stmts = $cache_provider->loadStatementsFromCache(
-            $file_path,
             $modified_time,
             $file_content_hash,
             $file_cache_key

src/Psalm/Type/Union.php

@@ -165,14 +165,6 @@ class Union
         return isset($this->types['array']);
     }
 
-    /**
-     * @return bool
-     */
-    public function hasObjectLike()
-    {
-        return isset($this->types['array']) && $this->types['array'] instanceof Atomic\ObjectLike;
-    }
-
     /**
      * @return bool
      */
@@ -301,18 +293,6 @@ class Union
         return isset($this->types['empty']);
     }
 
-    /**
-     * @return void
-     */
-    public function removeObjects()
-    {
-        foreach ($this->types as $key => $type) {
-            if ($type instanceof Atomic\TNamedObject) {
-                unset($this->types[$key]);
-            }
-        }
-    }
-
     /**
      * @return void
      */

tests/Provider/FakeParserCacheProvider.php

@@ -6,14 +6,13 @@ use PhpParser;
 class FakeParserCacheProvider extends \Psalm\Provider\ParserCacheProvider
 {
     /**
-     * @param  string   $file_path
      * @param  string   $file_content_hash
      * @param  string   $file_cache_key
      * @param mixed $file_modified_time
      *
      * @return array<int, PhpParser\Node\Stmt>|null
      */
-    public function loadStatementsFromCache($file_path, $file_modified_time, $file_content_hash, $file_cache_key)
+    public function loadStatementsFromCache($file_modified_time, $file_content_hash, $file_cache_key)
     {
         return null;
     }