Fix #2380 - prevent string docblock for callable param

src/Psalm/Config.php

@@ -1031,11 +1031,14 @@ class Config
     {
         $codebase = $project_analyzer->getCodebase();
 
+        $project_analyzer->progress->debug('Initializing plugins...' . PHP_EOL);
+
         $socket = new PluginRegistrationSocket($this, $codebase);
         // initialize plugin classes earlier to let them hook into subsequent load process
         foreach ($this->plugin_classes as $plugin_class_entry) {
             $plugin_class_name = $plugin_class_entry['class'];
             $plugin_config = $plugin_class_entry['config'];
+
             try {
                 // Below will attempt to load plugins from the project directory first.
                 // Failing that, it will use registered autoload chain, which will load
@@ -1045,6 +1048,10 @@ class Config
                 if ($this->composer_class_loader
                     && ($plugin_class_path = $this->composer_class_loader->findFile($plugin_class_name))
                 ) {
+                    $project_analyzer->progress->debug(
+                        'Loading plugin ' . $plugin_class_name . ' via require'. PHP_EOL
+                    );
+
                     /** @psalm-suppress UnresolvableInclude */
                     require_once($plugin_class_path);
                 } else {
@@ -1063,6 +1070,8 @@ class Config
             } catch (\Throwable $e) {
                 throw new ConfigException('Failed to load plugin ' . $plugin_class_name, 0, $e);
             }
+
+            $project_analyzer->progress->debug('Loaded plugin ' . $plugin_class_name . ' successfully'. PHP_EOL);
         }
 
         foreach ($this->filetype_scanner_paths as $extension => $path) {

src/Psalm/Internal/Analyzer/TypeAnalyzer.php

@@ -1374,7 +1374,7 @@ class TypeAnalyzer
 
         if ($container_type_part instanceof TCallable &&
             (
-                $input_type_part instanceof TString
+                $input_type_part instanceof TLiteralString
                 || $input_type_part instanceof TArray
                 || $input_type_part instanceof ObjectLike
                 || $input_type_part instanceof TList

tests/CallableTest.php

@@ -1574,6 +1574,16 @@ class CallableTest extends TestCase
                     new Func("f", ["Foo", "bar"]);',
                 'error_message' => 'InvalidArgument'
             ],
+            'preventStringDocblockType' => [
+                '<?php
+                    /**
+                     * @param string $mapper
+                     */
+                    function map2(callable $mapper): void {}
+
+                    map2("foo");',
+                'error_message' => 'MismatchingDocblockParamType',
+            ],
         ];
     }
 }