From dfa885435474d41498e211a78b69132a3bf0d367 Mon Sep 17 00:00:00 2001
From: Matt Brown <github@muglug.com>
Date: Mon, 12 Oct 2020 14:45:11 -0400
Subject: [PATCH] Fix #4310 - prevent literal class check on union

---
 .../Expression/Call/ArgumentAnalyzer.php      |  2 +-
 tests/Template/ConditionalReturnTypeTest.php  | 33 +++++++++++++++++++
 2 files changed, 34 insertions(+), 1 deletion(-)

diff --git a/src/Psalm/Internal/Analyzer/Statements/Expression/Call/ArgumentAnalyzer.php b/src/Psalm/Internal/Analyzer/Statements/Expression/Call/ArgumentAnalyzer.php
index 608b8f4a852..918855609fd 100644
--- a/src/Psalm/Internal/Analyzer/Statements/Expression/Call/ArgumentAnalyzer.php
+++ b/src/Psalm/Internal/Analyzer/Statements/Expression/Call/ArgumentAnalyzer.php
@@ -851,7 +851,7 @@ public static function verifyType(
             foreach ($param_type->getAtomicTypes() as $param_type_part) {
                 if ($param_type_part instanceof TClassString
                     && $input_expr instanceof PhpParser\Node\Scalar\String_
-                    && !$param_type->getLiteralStrings()
+                    && $param_type->isSingle()
                 ) {
                     if (ClassLikeAnalyzer::checkFullyQualifiedClassLikeName(
                         $statements_analyzer,
diff --git a/tests/Template/ConditionalReturnTypeTest.php b/tests/Template/ConditionalReturnTypeTest.php
index 02a6db973d5..aa5f781ad1b 100644
--- a/tests/Template/ConditionalReturnTypeTest.php
+++ b/tests/Template/ConditionalReturnTypeTest.php
@@ -621,6 +621,39 @@ public function get_liste_tdm_by_cod_s(bool $id_only = false): array {
                         }
                     }'
             ],
+            'stringOrClassStringT' => [
+                '<?php
+                    class A {}
+
+                    /**
+                     * @template T
+                     * @param string|class-string<T> $name
+                     * @return ($name is class-string ? T : mixed)
+                     */
+                    function get(string $name) {
+                        return;
+                    }
+
+                    $lowercase_a = "a";
+
+                    /** @var class-string $class_string */
+                    $class_string = "b";
+
+                    /** @psalm-suppress MixedAssignment */
+                    $expect_mixed = get($lowercase_a);
+                    $expect_object = get($class_string);
+
+                    $expect_a_object = get(A::class);
+
+                    /** @psalm-suppress MixedAssignment */
+                    $expect_mixed_from_literal = get("LiteralDirect");',
+                [
+                    '$expect_mixed' => 'mixed',
+                    '$expect_object' => 'object',
+                    '$expect_a_object' => 'A',
+                    '$expect_mixed_from_literal' => 'mixed',
+                ]
+            ],
         ];
     }
 }