Fix type aliases in method-level template types

src/Type/FileTypeMapper.php

@@ -304,11 +304,12 @@ function (Node $node) use ($fileName, $lookForTrait, &$traitFound, $traitMethodA
 				if ($node instanceof Node\Stmt\ClassLike || $node instanceof Node\Stmt\ClassMethod || $node instanceof Node\Stmt\Function_) {
 					$phpDocString = GetLastDocComment::forNode($node);
 					if ($phpDocString !== null) {
-						$typeMapStack[] = function () use ($namespace, $uses, $className, $functionName, $phpDocString, $typeMapStack, $constUses): TemplateTypeMap {
+						$typeMapStack[] = function () use ($namespace, $uses, $className, $functionName, $phpDocString, $typeMapStack, $typeAliasStack, $constUses): TemplateTypeMap {
 							$phpDocNode = $this->resolvePhpDocStringToDocNode($phpDocString);
 							$typeMapCb = $typeMapStack[count($typeMapStack) - 1] ?? null;
 							$currentTypeMap = $typeMapCb !== null ? $typeMapCb() : null;
-							$nameScope = new NameScope($namespace, $uses, $className, $functionName, $currentTypeMap, [], false, $constUses);
+							$typeAliasesMap = $typeAliasStack[count($typeAliasStack) - 1] ?? [];
+							$nameScope = new NameScope($namespace, $uses, $className, $functionName, $currentTypeMap, $typeAliasesMap, false, $constUses);
 							$templateTags = $this->phpDocNodeResolver->resolveTemplateTags($phpDocNode, $nameScope);
 							$templateTypeScope = $nameScope->getTemplateTypeScope();
 							if ($templateTypeScope === null) {

tests/PHPStan/Analyser/AnalyserIntegrationTest.php

@@ -1164,6 +1164,12 @@ public function testBug8983(): void
 		$this->assertNoErrors($errors);
 	}
 
+	public function testBug9008(): void
+	{
+		$errors = $this->runAnalyse(__DIR__ . '/data/bug-9008.php');
+		$this->assertNoErrors($errors);
+	}
+
 	/**
 	 * @param string[]|null $allAnalysedFiles
 	 * @return Error[]

tests/PHPStan/Analyser/data/bug-9008.php

@@ -0,0 +1,69 @@
+<?php
+
+namespace Bug9008;
+
+use function PHPStan\Testing\assertType;
+
+class A {}
+class B {}
+class C {}
+
+/** @phpstan-type Alpha A|B|C */
+class Example
+{
+	/**
+	 * @template TypeAlpha of Alpha
+	 * @param TypeAlpha $alpha
+	 * @phpstan-return TypeAlpha
+	 */
+	public function shouldWorkOne(object $alpha): object
+	{
+		assertType('TypeAlpha of Bug9008\A|Bug9008\B|Bug9008\C (method Bug9008\Example::shouldWorkOne(), argument)', $alpha);
+		return $alpha;
+	}
+
+	/**
+	 * @template TypeAlpha of Alpha
+	 * @param TypeAlpha $alpha
+	 * @phpstan-return TypeAlpha
+	 */
+	public function shouldWorkTwo(object $alpha): object
+	{
+		assertType('TypeAlpha of Bug9008\A|Bug9008\B|Bug9008\C (method Bug9008\Example::shouldWorkTwo(), argument)', $alpha);
+		return $alpha;
+	}
+
+	/**
+	 * @template TypeAlpha of A|B|C
+	 * @param TypeAlpha $alpha
+	 * @phpstan-return TypeAlpha
+	 */
+	public function worksButExtraVerboseOne(object $alpha): object
+	{
+		assertType('TypeAlpha of Bug9008\A|Bug9008\B|Bug9008\C (method Bug9008\Example::worksButExtraVerboseOne(), argument)', $alpha);
+		return $alpha;
+	}
+
+	/**
+	 * @template TypeAlpha of A|B|C
+	 * @param TypeAlpha $alpha
+	 * @phpstan-return TypeAlpha
+	 */
+	public function worksButExtraVerboseTwo(object $alpha): object
+	{
+		assertType('TypeAlpha of Bug9008\A|Bug9008\B|Bug9008\C (method Bug9008\Example::worksButExtraVerboseTwo(), argument)', $alpha);
+		return $alpha;
+	}
+
+	/**
+	 * @param Alpha $alpha
+	 */
+	public function test(object $alpha): void
+	{
+		assertType('Bug9008\\A|Bug9008\\B|Bug9008\\C', $alpha);
+		assertType('Bug9008\\A|Bug9008\\B|Bug9008\\C', $this->shouldWorkOne($alpha));
+		assertType('Bug9008\\A|Bug9008\\B|Bug9008\\C', $this->shouldWorkTwo($alpha));
+		assertType('Bug9008\\A|Bug9008\\B|Bug9008\\C', $this->worksButExtraVerboseOne($alpha));
+		assertType('Bug9008\\A|Bug9008\\B|Bug9008\\C', $this->worksButExtraVerboseTwo($alpha));
+	}
+}