From b701f8cf7857399851855eaca6a49f8a6a0654e7 Mon Sep 17 00:00:00 2001
From: Richard van Velzen <richard@frank.nl>
Date: Fri, 17 Jun 2022 10:56:12 +0200
Subject: [PATCH] Improve parenthesization for union types

---
 src/Type/UnionType.php                        |  4 +++-
 src/Type/VerbosityLevel.php                   |  5 ++++
 .../Rules/Generators/YieldTypeRuleTest.php    | 10 ++++++++
 .../Rules/Generators/data/bug-7484.php        | 23 +++++++++++++++++++
 4 files changed, 41 insertions(+), 1 deletion(-)
 create mode 100644 tests/PHPStan/Rules/Generators/data/bug-7484.php

diff --git a/src/Type/UnionType.php b/src/Type/UnionType.php
index 3e7f5a1935..46dd193b45 100644
--- a/src/Type/UnionType.php
+++ b/src/Type/UnionType.php
@@ -203,9 +203,11 @@ public function describe(VerbosityLevel $level): string
 	{
 		$joinTypes = static function (array $types) use ($level): string {
 			$typeNames = [];
-			foreach ($types as $type) {
+			foreach ($types as $i => $type) {
 				if ($type instanceof ClosureType || $type instanceof CallableType || $type instanceof TemplateUnionType) {
 					$typeNames[] = sprintf('(%s)', $type->describe($level));
+				} elseif ($type instanceof TemplateType && $i < (count($types) - 1) && ($level->isTypeOnly() || $level->isValue())) {
+					$typeNames[] = sprintf('(%s)', $type->describe($level));
 				} elseif ($type instanceof IntersectionType) {
 					$intersectionDescription = $type->describe($level);
 					if (strpos($intersectionDescription, '&') !== false) {
diff --git a/src/Type/VerbosityLevel.php b/src/Type/VerbosityLevel.php
index fe3bfc0610..304f8c1de3 100644
--- a/src/Type/VerbosityLevel.php
+++ b/src/Type/VerbosityLevel.php
@@ -60,6 +60,11 @@ public function isTypeOnly(): bool
 		return $this->value === self::TYPE_ONLY;
 	}
 
+	public function isValue(): bool
+	{
+		return $this->value === self::VALUE;
+	}
+
 	/** @api */
 	public static function getRecommendedLevelByType(Type $acceptingType, ?Type $acceptedType = null): self
 	{
diff --git a/tests/PHPStan/Rules/Generators/YieldTypeRuleTest.php b/tests/PHPStan/Rules/Generators/YieldTypeRuleTest.php
index 15a07d334c..ce02212878 100644
--- a/tests/PHPStan/Rules/Generators/YieldTypeRuleTest.php
+++ b/tests/PHPStan/Rules/Generators/YieldTypeRuleTest.php
@@ -59,4 +59,14 @@ public function testRule(): void
 		]);
 	}
 
+	public function testBug7484(): void
+	{
+		$this->analyse([__DIR__ . '/data/bug-7484.php'], [
+			[
+				'Generator expects key type K of int|string, (K of int)|string given.',
+				21,
+			],
+		]);
+	}
+
 }
diff --git a/tests/PHPStan/Rules/Generators/data/bug-7484.php b/tests/PHPStan/Rules/Generators/data/bug-7484.php
new file mode 100644
index 0000000000..a0d8889a9c
--- /dev/null
+++ b/tests/PHPStan/Rules/Generators/data/bug-7484.php
@@ -0,0 +1,23 @@
+<?php
+
+namespace Bug7484;
+
+/**
+ * @template K of int|string
+ * @template V
+ * @param iterable<K, V> $iterable
+ * @return iterable<K, V>
+ */
+function changeKeyCase(
+	iterable $iterable,
+	int $case = CASE_LOWER
+): iterable {
+	$callable = $case === CASE_LOWER ? 'strtolower' : 'strtoupper';
+	foreach ($iterable as $key => $value) {
+		if (is_string($key)) {
+			$key = $callable($key);
+		}
+
+		yield $key => $value;
+	}
+}