From 64996f464e6e992bd5de06c1ba155520708d5508 Mon Sep 17 00:00:00 2001
From: Brown <github@muglug.com>
Date: Wed, 6 Nov 2019 16:59:08 -0500
Subject: [PATCH] Prevent empty array workaround to #2308

---
 src/Psalm/Internal/Analyzer/TypeAnalyzer.php |  5 ++++-
 tests/Template/ClassTemplateExtendsTest.php  | 18 +++++++++++++++---
 tests/Template/ClassTemplateTest.php         | 19 ++++++++++++++++++-
 3 files changed, 37 insertions(+), 5 deletions(-)

diff --git a/src/Psalm/Internal/Analyzer/TypeAnalyzer.php b/src/Psalm/Internal/Analyzer/TypeAnalyzer.php
index d88f9f77b..50f562f05 100644
--- a/src/Psalm/Internal/Analyzer/TypeAnalyzer.php
+++ b/src/Psalm/Internal/Analyzer/TypeAnalyzer.php
@@ -814,7 +814,10 @@ class TypeAnalyzer
                     $allow_float_int_equality,
                     $atomic_comparison_result
                 )) {
-                    if ($allow_interface_equality || $input_type_part instanceof TArray) {
+                    if ($allow_interface_equality
+                        || ($input_type_part instanceof TArray
+                            && !$input_type_part->type_params[1]->isEmpty())
+                    ) {
                         return true;
                     }
                 }
diff --git a/tests/Template/ClassTemplateExtendsTest.php b/tests/Template/ClassTemplateExtendsTest.php
index 62bbb596b..b6ee7a298 100644
--- a/tests/Template/ClassTemplateExtendsTest.php
+++ b/tests/Template/ClassTemplateExtendsTest.php
@@ -677,9 +677,21 @@ class ClassTemplateExtendsTest extends TestCase
 
                     class Collection3 extends Collection2{}
 
-                    $a = new Collection1(["a" => "b"]);
-                    $a = new Collection2(["a" => "b"]);
-                    $a = new Collection3(["a" => "b"]);',
+                    foreach ((new Collection1(["a" => "b"])) as $a) {}
+
+                    /** @psalm-suppress MixedAssignment */
+                    foreach ((new Collection2(["a" => "b"])) as $a) {}
+
+                    /** @psalm-suppress MixedAssignment */
+                    foreach ((new Collection3(["a" => "b"])) as $a) {}
+
+                    foreach ((new Collection1([])) as $i) {}
+
+                    /** @psalm-suppress MixedAssignment */
+                    foreach ((new Collection2([])) as $i) {}
+
+                    /** @psalm-suppress MixedAssignment */
+                    foreach ((new Collection3([])) as $i) {}',
             ],
             'iterateOverExtendedArrayObjectWithoutParam' => [
                 '<?php
diff --git a/tests/Template/ClassTemplateTest.php b/tests/Template/ClassTemplateTest.php
index c9a5dab0e..4e5a9d440 100644
--- a/tests/Template/ClassTemplateTest.php
+++ b/tests/Template/ClassTemplateTest.php
@@ -2397,7 +2397,7 @@ class ClassTemplateTest extends TestCase
                     function expectsShape($_): void {}',
                 'error_message' => 'MixedArgumentTypeCoercion'
             ],
-            'preventUseWithMoreSpecificParam' => [
+            'preventUseWithMoreSpecificParamInt' => [
                 '<?php
                     /** @template T */
                     abstract class Collection {
@@ -2414,6 +2414,23 @@ class ClassTemplateTest extends TestCase
                     }',
                 'error_message' => 'InvalidArgument'
             ],
+            'preventUseWithMoreSpecificParamEmptyArray' => [
+                '<?php
+                    /** @template T */
+                    abstract class Collection {
+                        /** @param T $elem */
+                        public function add($elem): void {}
+                    }
+
+                    /**
+                     * @template T
+                     * @param Collection<T> $col
+                     */
+                    function usesCollection(Collection $col): void {
+                        $col->add([]);
+                    }',
+                'error_message' => 'InvalidArgument'
+            ],
         ];
     }
 }