From 5ed49c0c0374a605e0d50f03ae40e13c9e29f3e0 Mon Sep 17 00:00:00 2001
From: Brown <github@muglug.com>
Date: Wed, 26 Jun 2019 15:11:16 -0400
Subject: [PATCH] Fixed #1848 - allow static class strings to be compared

---
 .../Expression/Fetch/ConstFetchAnalyzer.php          |  8 +++++++-
 src/Psalm/Type/Reconciler.php                        |  9 +++++++--
 src/Psalm/Type/Union.php                             |  8 ++++++++
 tests/AnnotationTest.php                             |  2 +-
 tests/ClassStringTest.php                            | 12 ++++++++++++
 5 files changed, 35 insertions(+), 4 deletions(-)

diff --git a/src/Psalm/Internal/Analyzer/Statements/Expression/Fetch/ConstFetchAnalyzer.php b/src/Psalm/Internal/Analyzer/Statements/Expression/Fetch/ConstFetchAnalyzer.php
index f957fe10e..43eaac1b9 100644
--- a/src/Psalm/Internal/Analyzer/Statements/Expression/Fetch/ConstFetchAnalyzer.php
+++ b/src/Psalm/Internal/Analyzer/Statements/Expression/Fetch/ConstFetchAnalyzer.php
@@ -172,7 +172,13 @@ class ConstFetchAnalyzer
                         }
                     }
 
-                    $stmt->inferredType = Type::getLiteralClassString($fq_class_name);
+                    if ($first_part_lc === 'static') {
+                        $stmt->inferredType = new Type\Union([
+                            new Type\Atomic\TClassString($fq_class_name, new Type\Atomic\TNamedObject($fq_class_name))
+                        ]);
+                    } else {
+                        $stmt->inferredType = Type::getLiteralClassString($fq_class_name);
+                    }
 
                     if ($codebase->store_node_types) {
                         $codebase->analyzer->addNodeReference(
diff --git a/src/Psalm/Type/Reconciler.php b/src/Psalm/Type/Reconciler.php
index dd84e65ff..646168fa0 100644
--- a/src/Psalm/Type/Reconciler.php
+++ b/src/Psalm/Type/Reconciler.php
@@ -249,6 +249,7 @@ class Reconciler
                 && !$result_type->hasTemplate()
                 && !$result_type->hasType('iterable')
                 && (!$has_isset || substr($key, -1, 1) !== ']')
+                && !($statements_analyzer->getSource()->getSource() instanceof TraitAnalyzer)
             ) {
                 $reconcile_key = implode(
                     '&',
@@ -1307,6 +1308,9 @@ class Reconciler
                 && $new_type->getId() === $existing_var_type->getId()
                 && !$is_equality
                 && !$is_maybe_callable_array
+                && (!($statements_analyzer->getSource()->getSource() instanceof TraitAnalyzer)
+                    || ($key !== '$this'
+                        && !($existing_var_type->hasLiteralClassString() && $new_type->hasLiteralClassString())))
             ) {
                 self::triggerIssueForImpossible(
                     $existing_var_type,
@@ -1358,8 +1362,9 @@ class Reconciler
                             // fall through
                         }
                     }
-                } elseif ($key !== '$this'
-                    || !($statements_analyzer->getSource()->getSource() instanceof TraitAnalyzer)
+                } elseif (!($statements_analyzer->getSource()->getSource() instanceof TraitAnalyzer)
+                    || ($key !== '$this'
+                        && !($existing_var_type->hasLiteralClassString() && $new_type->hasLiteralClassString()))
                 ) {
                     if ($existing_var_type->from_docblock) {
                         if (IssueBuffer::accepts(
diff --git a/src/Psalm/Type/Union.php b/src/Psalm/Type/Union.php
index 01ca439b1..dd8ff9a7e 100644
--- a/src/Psalm/Type/Union.php
+++ b/src/Psalm/Type/Union.php
@@ -657,6 +657,14 @@ class Union
             || $this->typed_class_strings;
     }
 
+    /**
+     * @return bool
+     */
+    public function hasLiteralClassString()
+    {
+        return count($this->typed_class_strings) > 0;
+    }
+
     /**
      * @return bool
      */
diff --git a/tests/AnnotationTest.php b/tests/AnnotationTest.php
index c4e134032..a0e029f63 100644
--- a/tests/AnnotationTest.php
+++ b/tests/AnnotationTest.php
@@ -1591,7 +1591,7 @@ class AnnotationTest extends TestCase
                      */
                     function f($reference) {}',
                 'error_message' => 'MissingDocblockType'
-            ]
+            ],
         ];
     }
 }
diff --git a/tests/ClassStringTest.php b/tests/ClassStringTest.php
index 5531e6708..c4c9dc777 100644
--- a/tests/ClassStringTest.php
+++ b/tests/ClassStringTest.php
@@ -591,6 +591,18 @@ class ClassStringTest extends TestCase
                         }
                     }'
             ],
+            'allowComparisonToStaticClassString' => [
+                '<?php
+                    class A {
+                        const CLASSES = ["foobar" => B::class];
+
+                        function foo(): bool {
+                            return self::CLASSES["foobar"] === static::class;
+                        }
+                    }
+
+                    class B extends A {}'
+            ],
         ];
     }