Fix #3532 - expand type alias types recursively

src/Psalm/Internal/Analyzer/CommentAnalyzer.php

@@ -264,7 +264,8 @@ class CommentAnalyzer
     public static function getTypeAliasesFromComment(
         PhpParser\Comment\Doc $comment,
         Aliases $aliases,
-        array $type_aliases = null
+        ?array $type_aliases,
+        ?string $self_fqcln
     ) {
         $parsed_docblock = DocComment::parsePreservingLength($comment);
 
@@ -275,7 +276,8 @@ class CommentAnalyzer
         return self::getTypeAliasesFromCommentLines(
             $parsed_docblock->tags['psalm-type'],
             $aliases,
-            $type_aliases
+            $type_aliases,
+            $self_fqcln
         );
     }
 
@@ -291,7 +293,8 @@ class CommentAnalyzer
     private static function getTypeAliasesFromCommentLines(
         array $type_alias_comment_lines,
         Aliases $aliases,
-        array $type_aliases = null
+        ?array $type_aliases,
+        ?string $self_fqcln
     ) {
         $type_alias_tokens = [];
 
@@ -344,7 +347,8 @@ class CommentAnalyzer
                     $type_string,
                     $aliases,
                     null,
-                    $type_alias_tokens + $type_aliases
+                    $type_alias_tokens + $type_aliases,
+                    $self_fqcln
                 );
             } catch (TypeParseTreeException $e) {
                 throw new DocblockParseException($type_string . ' is not a valid type');

src/Psalm/Internal/PhpVisitor/ReflectorVisitor.php

@@ -166,11 +166,17 @@ class ReflectorVisitor extends PhpParser\NodeVisitorAbstract implements PhpParse
     {
         foreach ($node->getComments() as $comment) {
             if ($comment instanceof PhpParser\Comment\Doc) {
+                $self_fqcln = $node instanceof PhpParser\Node\Stmt\ClassLike
+                    && $node->name !== null
+                    ? ($this->aliases->namespace ? $this->aliases->namespace . '\\' : '') . $node->name->name
+                    : null;
+
                 try {
                     $type_aliases = CommentAnalyzer::getTypeAliasesFromComment(
                         $comment,
                         $this->aliases,
-                        $this->type_aliases
+                        $this->type_aliases,
+                        $self_fqcln
                     );
 
                     foreach ($type_aliases as $type_alias) {

src/Psalm/Internal/Type/TypeExpander.php

@@ -288,7 +288,32 @@ class TypeExpander
                     $resolved_type_alias = $class_storage->type_aliases[$type_alias_name];
 
                     if ($resolved_type_alias->replacement_atomic_types) {
-                        return $resolved_type_alias->replacement_atomic_types;
+                        $replacement_atomic_types = $resolved_type_alias->replacement_atomic_types;
+
+                        $recursively_fleshed_out_types = [];
+
+                        foreach ($replacement_atomic_types as $replacement_atomic_type) {
+                            $recursively_fleshed_out_type = self::expandAtomic(
+                                $codebase,
+                                $replacement_atomic_type,
+                                $self_class,
+                                $static_class_type,
+                                $parent_class,
+                                $evaluate_class_constants,
+                                $evaluate_conditional_types
+                            );
+
+                            if (is_array($recursively_fleshed_out_type)) {
+                                $recursively_fleshed_out_types = array_merge(
+                                    $recursively_fleshed_out_type,
+                                    $recursively_fleshed_out_types
+                                );
+                            } else {
+                                $recursively_fleshed_out_types[] = $recursively_fleshed_out_type;
+                            }
+                        }
+
+                        return $recursively_fleshed_out_types;
                     }
                 }
             }

tests/TypeAnnotationTest.php

@@ -253,6 +253,42 @@ class TypeAnnotationTest extends TestCase
                     }
                 }'
             ],
+            'importTypeForParam' => [
+                '<?php
+                    /**
+                     * @psalm-type Type = self::NULL|self::BOOL|self::INT|self::STRING
+                     */
+                    interface I
+                    {
+                        public const NULL = 0;
+                        public const BOOL = 1;
+                        public const INT = 2;
+                        public const STRING = 3;
+
+                        /**
+                         * @psalm-param Type $type
+                         */
+                        public function a(int $type): void;
+                    }
+
+                    /**
+                     * @psalm-import-type Type from I as Type2
+                     */
+                    abstract class C implements I
+                    {
+                        public function a(int $type): void
+                        {
+                            $this->b($type);
+                        }
+
+                        /**
+                         * @psalm-param Type2 $type
+                         */
+                        private function b(int $type): void
+                        {
+                        }
+                    }'
+            ],
         ];
     }