From 4627065d1fbc429b234c0891e30ee8b1587b1e9f Mon Sep 17 00:00:00 2001
From: Matt Brown <github@muglug.com>
Date: Tue, 26 Jan 2021 14:06:43 -0500
Subject: [PATCH] Fix #5108 - prevent crash on 0 type

---
 src/Psalm/Internal/Codebase/Analyzer.php |  6 +++---
 tests/LanguageServer/CompletionTest.php  | 17 +++++++++++++++++
 2 files changed, 20 insertions(+), 3 deletions(-)

diff --git a/src/Psalm/Internal/Codebase/Analyzer.php b/src/Psalm/Internal/Codebase/Analyzer.php
index 9ac2464c0..276dff853 100644
--- a/src/Psalm/Internal/Codebase/Analyzer.php
+++ b/src/Psalm/Internal/Codebase/Analyzer.php
@@ -1144,7 +1144,7 @@ class Analyzer
         string $node_type,
         PhpParser\Node $parent_node = null
     ): void {
-        if (!$node_type) {
+        if ($node_type === '') {
             throw new \UnexpectedValueException('non-empty node_type expected');
         }
 
@@ -1161,8 +1161,8 @@ class Analyzer
         string $reference,
         int $argument_number
     ): void {
-        if (!$reference) {
-            throw new \UnexpectedValueException('non-empty node_type expected');
+        if ($reference === '') {
+            throw new \UnexpectedValueException('non-empty reference expected');
         }
 
         $this->argument_map[$file_path][$start_position] = [
diff --git a/tests/LanguageServer/CompletionTest.php b/tests/LanguageServer/CompletionTest.php
index 3b5a80d49..a99046f09 100644
--- a/tests/LanguageServer/CompletionTest.php
+++ b/tests/LanguageServer/CompletionTest.php
@@ -798,4 +798,21 @@ class CompletionTest extends \Psalm\Tests\TestCase
         $completion_items = $codebase->getCompletionItemsForClassishThing($completion_data[0], $completion_data[1]);
         $this->assertCount(2, $completion_items);
     }
+
+    public function testNoCrashOnLoopId(): void
+    {
+        $codebase = $this->project_analyzer->getCodebase();
+        $config = $codebase->config;
+        $config->throw_exception = false;
+
+        $this->addFile(
+            'somefile.php',
+            '<?php
+                for ($x = 0; $x <= 10; $x++) {}'
+        );
+
+        $codebase->file_provider->openFile('somefile.php');
+        $codebase->scanFiles();
+        $this->analyzeFile('somefile.php', new Context());
+    }
 }