diff --git a/src/Psalm/Internal/Analyzer/FunctionLikeAnalyzer.php b/src/Psalm/Internal/Analyzer/FunctionLikeAnalyzer.php
index 413138075..9689fb33f 100644
--- a/src/Psalm/Internal/Analyzer/FunctionLikeAnalyzer.php
+++ b/src/Psalm/Internal/Analyzer/FunctionLikeAnalyzer.php
@@ -321,7 +321,10 @@ abstract class FunctionLikeAnalyzer extends SourceAnalyzer
             }
         } elseif ($this->function instanceof Function_) {
             $cased_method_id = $this->function->name->name;
-            $context->calling_function_id = strtolower($cased_method_id);
+            $namespace_prefix = $this->getNamespace();
+            $context->calling_function_id = strtolower(
+                ($namespace_prefix !== null ? $namespace_prefix . '\\' : '') . $cased_method_id
+            );
         } else { // Closure
             if ($storage->return_type) {
                 $closure_return_type = ExpressionAnalyzer::fleshOutType(
diff --git a/tests/Template/FunctionTemplateTest.php b/tests/Template/FunctionTemplateTest.php
index 13f23b915..eb6b2196c 100644
--- a/tests/Template/FunctionTemplateTest.php
+++ b/tests/Template/FunctionTemplateTest.php
@@ -969,6 +969,42 @@ class FunctionTemplateTest extends TestCase
                         echo (string) $key;
                     }'
             ],
+            'uksortNoNamespace' => [
+                '<?php
+                    /**
+                     * @template Tk of array-key
+                     * @template Tv
+                     *
+                     * @param array<Tk, Tv> $result
+                     * @param (callable(Tk, Tk): int) $comparator
+                     *
+                     * @preturn array<Tk, Tv>
+                     */
+                    function sort_by_key(array $result, callable $comparator): array
+                    {
+                        \uksort($result, $comparator);
+                        return $result;
+                    }'
+            ],
+            'uksortNamespaced' => [
+                '<?php
+                    namespace Psl\Arr;
+
+                    /**
+                     * @template Tk of array-key
+                     * @template Tv
+                     *
+                     * @param array<Tk, Tv> $result
+                     * @param (callable(Tk, Tk): int) $comparator
+                     *
+                     * @preturn array<Tk, Tv>
+                     */
+                    function sort_by_key(array $result, callable $comparator): array
+                    {
+                        \uksort($result, $comparator);
+                        return $result;
+                    }'
+            ],
         ];
     }