Add support for checking DeprecatedTrait and DeprecatedConstant

assets/config_levels/3.xml

@@ -20,7 +20,9 @@
         <DeprecatedMethod errorLevel="info" />
         <DeprecatedProperty errorLevel="info" />
         <DeprecatedClass errorLevel="info" />
+        <DeprecatedConstant errorLevel="info" />
         <DeprecatedInterface errorLevel="info" />
+        <DeprecatedTrait errorLevel="info" />
 
         <MissingClosureReturnType errorLevel="info" />
         <MissingReturnType errorLevel="info" />

assets/config_levels/4.xml

@@ -20,7 +20,9 @@
         <DeprecatedMethod errorLevel="info" />
         <DeprecatedProperty errorLevel="info" />
         <DeprecatedClass errorLevel="info" />
+        <DeprecatedConstant errorLevel="info" />
         <DeprecatedInterface errorLevel="info" />
+        <DeprecatedTrait errorLevel="info" />
 
         <MissingClosureReturnType errorLevel="info" />
         <MissingReturnType errorLevel="info" />

assets/config_levels/5.xml

@@ -20,7 +20,9 @@
         <DeprecatedMethod errorLevel="info" />
         <DeprecatedProperty errorLevel="info" />
         <DeprecatedClass errorLevel="info" />
+        <DeprecatedConstant errorLevel="info" />
         <DeprecatedInterface errorLevel="info" />
+        <DeprecatedTrait errorLevel="info" />
 
         <MissingClosureReturnType errorLevel="info" />
         <MissingReturnType errorLevel="info" />

assets/config_levels/6.xml

@@ -20,7 +20,9 @@
         <DeprecatedMethod errorLevel="info" />
         <DeprecatedProperty errorLevel="info" />
         <DeprecatedClass errorLevel="info" />
+        <DeprecatedConstant errorLevel="info" />
         <DeprecatedInterface errorLevel="info" />
+        <DeprecatedTrait errorLevel="info" />
 
         <MissingClosureReturnType errorLevel="info" />
         <MissingReturnType errorLevel="info" />

assets/config_levels/7.xml

@@ -20,7 +20,9 @@
         <DeprecatedMethod errorLevel="info" />
         <DeprecatedProperty errorLevel="info" />
         <DeprecatedClass errorLevel="info" />
+        <DeprecatedConstant errorLevel="info" />
         <DeprecatedInterface errorLevel="info" />
+        <DeprecatedTrait errorLevel="info" />
 
         <MissingClosureReturnType errorLevel="info" />
         <MissingReturnType errorLevel="info" />

assets/config_levels/8.xml

@@ -20,7 +20,9 @@
         <DeprecatedMethod errorLevel="info" />
         <DeprecatedProperty errorLevel="info" />
         <DeprecatedClass errorLevel="info" />
+        <DeprecatedConstant errorLevel="info" />
         <DeprecatedInterface errorLevel="info" />
+        <DeprecatedTrait errorLevel="info" />
 
         <MissingClosureReturnType errorLevel="info" />
         <MissingReturnType errorLevel="info" />

config.xsd

@@ -117,9 +117,11 @@
             <xs:element name="ContinueOutsideLoop" type="IssueHandlerType" minOccurs="0" />
             <xs:element name="ConflictingReferenceConstraint" type="IssueHandlerType" minOccurs="0" />
             <xs:element name="DeprecatedClass" type="ClassIssueHandlerType" minOccurs="0" />
+            <xs:element name="DeprecatedConstant" type="ClassIssueHandlerType" minOccurs="0" />
             <xs:element name="DeprecatedInterface" type="IssueHandlerType" minOccurs="0" />
             <xs:element name="DeprecatedMethod" type="MethodIssueHandlerType" minOccurs="0" />
             <xs:element name="DeprecatedProperty" type="PropertyIssueHandlerType" minOccurs="0" />
+            <xs:element name="DeprecatedTrait" type="ClassIssueHandlerType" minOccurs="0" />
             <xs:element name="DocblockTypeContradiction" type="IssueHandlerType" minOccurs="0" />
             <xs:element name="DuplicateArrayKey" type="IssueHandlerType" minOccurs="0" />
             <xs:element name="DuplicateParam" type="IssueHandlerType" minOccurs="0" />

docs/issues.md

@@ -80,6 +80,19 @@ class A {}
 new A();
 ```
 
+### DeprecatedConstant
+
+Emitted when referring to a deprecated constant:
+
+```php
+class A {
+    /** @deprecated */
+    const FOO = 'foo';
+}
+
+echo A::FOO;
+```
+
 ### DeprecatedInterface
 
 Emitted when referring to a deprecated interface
@@ -118,6 +131,18 @@ class A {
 (new A())->foo = 5;
 ```
 
+### DeprecatedTrait
+
+Emitted when referring to a deprecated trait:
+
+```php
+/** @deprecated */
+trait T {}
+class A {
+    use T;
+}
+```
+
 ### DocblockTypeContradiction
 
 Emitted when conditional doesn't make sense given the docblock types supplied.

src/Psalm/Checker/ClassChecker.php

@@ -10,6 +10,7 @@ use Psalm\Config;
 use Psalm\Context;
 use Psalm\Issue\DeprecatedClass;
 use Psalm\Issue\DeprecatedInterface;
+use Psalm\Issue\DeprecatedTrait;
 use Psalm\Issue\InaccessibleMethod;
 use Psalm\Issue\MissingConstructor;
 use Psalm\Issue\MissingPropertyType;
@@ -687,6 +688,20 @@ class ClassChecker extends ClassLikeChecker
                     continue;
                 }
 
+                $trait_storage = $codebase->classlike_storage_provider->get($fq_trait_name);
+
+                if ($trait_storage->deprecated) {
+                    if (IssueBuffer::accepts(
+                        new DeprecatedTrait(
+                            'Trait ' . $fq_trait_name . ' is deprecated',
+                            new CodeLocation($this, $trait_name)
+                        ),
+                        array_merge($storage->suppressed_issues, $this->getSuppressedIssues())
+                    )) {
+                        return false;
+                    }
+                }
+
                 $trait_file_checker = $project_checker->getFileCheckerForClassLike($fq_trait_name);
                 $trait_node = $codebase->classlikes->getTraitNode($fq_trait_name);
                 $trait_aliases = $codebase->classlikes->getTraitAliases($fq_trait_name);

src/Psalm/Checker/Statements/Expression/Fetch/ConstFetchChecker.php

@@ -9,6 +9,7 @@ use Psalm\Checker\TraitChecker;
 use Psalm\Codebase;
 use Psalm\CodeLocation;
 use Psalm\Context;
+use Psalm\Issue\DeprecatedConstant;
 use Psalm\Issue\InaccessibleClassConstant;
 use Psalm\Issue\ParentNotFound;
 use Psalm\Issue\UndefinedConstant;
@@ -204,6 +205,20 @@ class ConstFetchChecker
                 return false;
             }
 
+            $class_const_storage = $codebase->classlike_storage_provider->get($fq_class_name);
+
+            if (isset($class_const_storage->deprecated_constants[$stmt->name->name])) {
+                if (IssueBuffer::accepts(
+                    new DeprecatedConstant(
+                        'Constant ' . $const_id . ' is deprecated',
+                        new CodeLocation($statements_checker->getSource(), $stmt)
+                    ),
+                    $statements_checker->getSuppressedIssues()
+                )) {
+                    // fall through
+                }
+            }
+
             if (isset($class_constants[$stmt->name->name]) && $first_part_lc !== 'static') {
                 $stmt->inferredType = clone $class_constants[$stmt->name->name];
             } else {

src/Psalm/Issue/DeprecatedConstant.php

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

src/Psalm/Issue/DeprecatedTrait.php

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

src/Psalm/Storage/ClassLikeStorage.php

@@ -70,6 +70,11 @@ class ClassLikeStorage
      */
     public $deprecated = false;
 
+    /**
+     * @var array<string, bool>
+     */
+    public $deprecated_constants = [];
+
     /**
      * @var bool
      */

src/Psalm/Visitor/DependencyFinderVisitor.php

@@ -1766,6 +1766,18 @@ class DependencyFinderVisitor extends PhpParser\NodeVisitorAbstract implements P
             + $storage->private_class_constants
             + $storage->public_class_constants;
 
+        $comment = $stmt->getDocComment();
+        $deprecated = false;
+        $config = $this->config;
+
+        if ($comment && $comment->getText() && ($config->use_docblock_types || $config->use_docblock_property_types)) {
+            $comments = CommentChecker::parseDocComment($comment->getText(), 0);
+
+            if (isset($comments['specials']['deprecated'])) {
+                $deprecated = true;
+            }
+        }
+
         foreach ($stmt->consts as $const) {
             $const_type = StatementsChecker::getSimpleType(
                 $this->codebase,
@@ -1797,6 +1809,10 @@ class DependencyFinderVisitor extends PhpParser\NodeVisitorAbstract implements P
 
                 $storage->aliases = $this->aliases;
             }
+
+            if ($deprecated) {
+                $storage->deprecated_constants[$const->name->name] = true;
+            }
         }
     }