From ae5b8bf668062acb19feb46b79bf37b2ab5d0350 Mon Sep 17 00:00:00 2001
From: "github-actions[bot]"
 <41898282+github-actions[bot]@users.noreply.github.com>
Date: Mon, 9 Mar 2026 17:23:30 +0000
Subject: [PATCH 1/3] Fix false positive unresolvable template type on optional
 variadic params

- When a template type is only used on a variadic parameter and no arguments are passed, it was incorrectly reported as unresolvable
- Fixed by inferring NeverType for variadic parameters with no arguments in GenericParametersAcceptorResolver, since an empty variadic means the element type is never
- Added regression tests in both rule test and NSRT format

Closes https://github.com/phpstan/phpstan/issues/2572
---
 .../GenericParametersAcceptorResolver.php     |  3 +++
 tests/PHPStan/Analyser/nsrt/bug-2572.php      | 27 +++++++++++++++++++
 .../CallToFunctionParametersRuleTest.php      |  5 ++++
 .../PHPStan/Rules/Functions/data/bug-2572.php | 25 +++++++++++++++++
 4 files changed, 60 insertions(+)
 create mode 100644 tests/PHPStan/Analyser/nsrt/bug-2572.php
 create mode 100644 tests/PHPStan/Rules/Functions/data/bug-2572.php

diff --git a/src/Reflection/GenericParametersAcceptorResolver.php b/src/Reflection/GenericParametersAcceptorResolver.php
index d9b75bf3e0e..5111b5d3fb7 100644
--- a/src/Reflection/GenericParametersAcceptorResolver.php
+++ b/src/Reflection/GenericParametersAcceptorResolver.php
@@ -10,6 +10,7 @@
 use PHPStan\Type\Generic\TemplateTypeMap;
 use PHPStan\Type\Generic\TemplateTypeVarianceMap;
 use PHPStan\Type\MixedType;
+use PHPStan\Type\NeverType;
 use PHPStan\Type\Type;
 use PHPStan\Type\TypeCombinator;
 use function array_key_exists;
@@ -61,6 +62,8 @@ public static function resolve(array $argTypes, ParametersAcceptor $parametersAc
 				$argType = $namedArgTypes[$param->getName()];
 			} elseif ($param->getDefaultValue() !== null) {
 				$argType = $param->getDefaultValue();
+			} elseif ($param->isVariadic()) {
+				$argType = new NeverType();
 			} else {
 				continue;
 			}
diff --git a/tests/PHPStan/Analyser/nsrt/bug-2572.php b/tests/PHPStan/Analyser/nsrt/bug-2572.php
new file mode 100644
index 00000000000..a1f332e4921
--- /dev/null
+++ b/tests/PHPStan/Analyser/nsrt/bug-2572.php
@@ -0,0 +1,27 @@
+<?php declare(strict_types = 1);
+
+namespace Bug2572Nsrt;
+
+use function PHPStan\Testing\assertType;
+
+/**
+ * @template TE
+ * @template TR
+ *
+ * @param TE $elt
+ * @param TR ...$elts
+ *
+ * @return TE|TR
+ */
+function collect($elt, ...$elts) {
+	$ret = $elt;
+	foreach ($elts as $item) {
+		if (rand(0, 1)) {
+			$ret = $item;
+		}
+	}
+	return $ret;
+}
+
+assertType("'a'", collect("a"));
+assertType("'a'|'b'|'c'", collect("a", "b", "c"));
diff --git a/tests/PHPStan/Rules/Functions/CallToFunctionParametersRuleTest.php b/tests/PHPStan/Rules/Functions/CallToFunctionParametersRuleTest.php
index 58faaefd2e6..666d80f5be8 100644
--- a/tests/PHPStan/Rules/Functions/CallToFunctionParametersRuleTest.php
+++ b/tests/PHPStan/Rules/Functions/CallToFunctionParametersRuleTest.php
@@ -2691,6 +2691,11 @@ public function testBug8936(): void
 		$this->analyse([__DIR__ . '/data/bug-8936.php'], []);
 	}
 
+	public function testBug2572(): void
+	{
+		$this->analyse([__DIR__ . '/data/bug-2572.php'], []);
+	}
+
 	public function testDumpFunctions(): void
 	{
 		$this->analyse([__DIR__ . '/data/dump-functions.php'], [
diff --git a/tests/PHPStan/Rules/Functions/data/bug-2572.php b/tests/PHPStan/Rules/Functions/data/bug-2572.php
new file mode 100644
index 00000000000..e56c50f8372
--- /dev/null
+++ b/tests/PHPStan/Rules/Functions/data/bug-2572.php
@@ -0,0 +1,25 @@
+<?php declare(strict_types = 1);
+
+namespace Bug2572;
+
+/**
+ * @template TE
+ * @template TR
+ *
+ * @param TE $elt
+ * @param TR ...$elts
+ *
+ * @return TE|TR
+ */
+function collect($elt, ...$elts) {
+	$ret = $elt;
+	foreach ($elts as $item) {
+		if (rand(0, 1)) {
+			$ret = $item;
+		}
+	}
+	return $ret;
+}
+
+echo collect("a");
+echo collect("a", "b", "c");

From 388d60e7075b74c35f97fdea95e89ce388f3aade Mon Sep 17 00:00:00 2001
From: phpstan-bot <ondrej+phpstanbot@mirtes.cz>
Date: Thu, 26 Mar 2026 09:52:22 +0000
Subject: [PATCH 2/3] Address review: deduplicate test file and fix NeverType
 to be explicit

- Reuse tests/PHPStan/Analyser/nsrt/bug-2572.php in rule test instead of
  duplicating the file in tests/PHPStan/Rules/Functions/data/
- Use explicit NeverType(true) for empty variadic params so the
  UnresolvableTypeHelper doesn't treat it as unresolvable
- Add staabm's reproducer (value() with Closure|TValue union) as
  additional test coverage

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>
---
 .../GenericParametersAcceptorResolver.php     |  2 +-
 tests/PHPStan/Analyser/nsrt/bug-2572.php      | 22 ++++++++++++++++
 .../CallToFunctionParametersRuleTest.php      |  2 +-
 .../PHPStan/Rules/Functions/data/bug-2572.php | 25 -------------------
 4 files changed, 24 insertions(+), 27 deletions(-)
 delete mode 100644 tests/PHPStan/Rules/Functions/data/bug-2572.php

diff --git a/src/Reflection/GenericParametersAcceptorResolver.php b/src/Reflection/GenericParametersAcceptorResolver.php
index 5111b5d3fb7..c72afeedbb5 100644
--- a/src/Reflection/GenericParametersAcceptorResolver.php
+++ b/src/Reflection/GenericParametersAcceptorResolver.php
@@ -63,7 +63,7 @@ public static function resolve(array $argTypes, ParametersAcceptor $parametersAc
 			} elseif ($param->getDefaultValue() !== null) {
 				$argType = $param->getDefaultValue();
 			} elseif ($param->isVariadic()) {
-				$argType = new NeverType();
+				$argType = new NeverType(true);
 			} else {
 				continue;
 			}
diff --git a/tests/PHPStan/Analyser/nsrt/bug-2572.php b/tests/PHPStan/Analyser/nsrt/bug-2572.php
index a1f332e4921..43720afb199 100644
--- a/tests/PHPStan/Analyser/nsrt/bug-2572.php
+++ b/tests/PHPStan/Analyser/nsrt/bug-2572.php
@@ -25,3 +25,25 @@ function collect($elt, ...$elts) {
 
 assertType("'a'", collect("a"));
 assertType("'a'|'b'|'c'", collect("a", "b", "c"));
+
+/**
+ * @template TValue
+ * @template TArgs
+ *
+ * @param  TValue|\Closure(TArgs): TValue  $value
+ * @param  TArgs  ...$args
+ * @return TValue
+ */
+function value($value, ...$args)
+{
+	return $value instanceof \Closure ? $value(...$args) : $value;
+}
+
+assertType("'foo'", value('foo'));
+assertType("'foo'", value('foo', 42));
+assertType('42', value(fn () => 42));
+assertType('42', value(function ($foo) {
+	assertType('true', $foo);
+
+	return 42;
+}, true));
diff --git a/tests/PHPStan/Rules/Functions/CallToFunctionParametersRuleTest.php b/tests/PHPStan/Rules/Functions/CallToFunctionParametersRuleTest.php
index 666d80f5be8..373e6902918 100644
--- a/tests/PHPStan/Rules/Functions/CallToFunctionParametersRuleTest.php
+++ b/tests/PHPStan/Rules/Functions/CallToFunctionParametersRuleTest.php
@@ -2693,7 +2693,7 @@ public function testBug8936(): void
 
 	public function testBug2572(): void
 	{
-		$this->analyse([__DIR__ . '/data/bug-2572.php'], []);
+		$this->analyse([__DIR__ . '/../../Analyser/nsrt/bug-2572.php'], []);
 	}
 
 	public function testDumpFunctions(): void
diff --git a/tests/PHPStan/Rules/Functions/data/bug-2572.php b/tests/PHPStan/Rules/Functions/data/bug-2572.php
deleted file mode 100644
index e56c50f8372..00000000000
--- a/tests/PHPStan/Rules/Functions/data/bug-2572.php
+++ /dev/null
@@ -1,25 +0,0 @@
-<?php declare(strict_types = 1);
-
-namespace Bug2572;
-
-/**
- * @template TE
- * @template TR
- *
- * @param TE $elt
- * @param TR ...$elts
- *
- * @return TE|TR
- */
-function collect($elt, ...$elts) {
-	$ret = $elt;
-	foreach ($elts as $item) {
-		if (rand(0, 1)) {
-			$ret = $item;
-		}
-	}
-	return $ret;
-}
-
-echo collect("a");
-echo collect("a", "b", "c");

From 15cb7e2c73ad2e37f31542ccd55796d0eafd6f2b Mon Sep 17 00:00:00 2001
From: phpstan-bot <ondrej+phpstanbot@mirtes.cz>
Date: Thu, 26 Mar 2026 11:03:05 +0000
Subject: [PATCH 3/3] Add regression tests for phpstan/phpstan#7704 and
 phpstan/phpstan#9360

Both issues report the same underlying bug: unresolvable template type
errors when calling functions with variadic template parameters without
providing any variadic arguments.

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>
---
 tests/PHPStan/Analyser/nsrt/bug-7704.php      | 30 +++++++++++++++++++
 tests/PHPStan/Analyser/nsrt/bug-9360.php      | 24 +++++++++++++++
 .../CallToFunctionParametersRuleTest.php      | 10 +++++++
 3 files changed, 64 insertions(+)
 create mode 100644 tests/PHPStan/Analyser/nsrt/bug-7704.php
 create mode 100644 tests/PHPStan/Analyser/nsrt/bug-9360.php

diff --git a/tests/PHPStan/Analyser/nsrt/bug-7704.php b/tests/PHPStan/Analyser/nsrt/bug-7704.php
new file mode 100644
index 00000000000..45bb92fb969
--- /dev/null
+++ b/tests/PHPStan/Analyser/nsrt/bug-7704.php
@@ -0,0 +1,30 @@
+<?php declare(strict_types = 1);
+
+namespace Bug7704;
+
+use function PHPStan\Testing\assertType;
+
+/**
+ * @template T
+ * @template TRest
+ *
+ * @param T $first
+ * @param TRest ...$rest
+ *
+ * @return T|TRest
+ */
+function intersection($first, ...$rest)
+{
+	$ret = $first;
+	foreach ($rest as $item) {
+		if (rand(0, 1)) {
+			$ret = $item;
+		}
+	}
+	return $ret;
+}
+
+assertType("'a'", intersection("a"));
+assertType("'a'|'b'|'c'", intersection("a", "b", "c"));
+assertType('1', intersection(1));
+assertType('1|2|3', intersection(1, 2, 3));
diff --git a/tests/PHPStan/Analyser/nsrt/bug-9360.php b/tests/PHPStan/Analyser/nsrt/bug-9360.php
new file mode 100644
index 00000000000..668affdb43d
--- /dev/null
+++ b/tests/PHPStan/Analyser/nsrt/bug-9360.php
@@ -0,0 +1,24 @@
+<?php declare(strict_types = 1);
+
+namespace Bug9360;
+
+use function PHPStan\Testing\assertType;
+
+/**
+ * @template T of string|bool
+ *
+ * @param T ...$args
+ *
+ * @return (T is string ? string : bool)
+ */
+function environment(string|bool ...$args): string|bool
+{
+	if (count($args) === 0) {
+		return true;
+	}
+	return (string) $args[0];
+}
+
+assertType('string', environment());
+assertType('string', environment('APP_ENV'));
+assertType('string', environment('APP_ENV', 'production'));
diff --git a/tests/PHPStan/Rules/Functions/CallToFunctionParametersRuleTest.php b/tests/PHPStan/Rules/Functions/CallToFunctionParametersRuleTest.php
index 373e6902918..70f72187d7b 100644
--- a/tests/PHPStan/Rules/Functions/CallToFunctionParametersRuleTest.php
+++ b/tests/PHPStan/Rules/Functions/CallToFunctionParametersRuleTest.php
@@ -2696,6 +2696,16 @@ public function testBug2572(): void
 		$this->analyse([__DIR__ . '/../../Analyser/nsrt/bug-2572.php'], []);
 	}
 
+	public function testBug7704(): void
+	{
+		$this->analyse([__DIR__ . '/../../Analyser/nsrt/bug-7704.php'], []);
+	}
+
+	public function testBug9360(): void
+	{
+		$this->analyse([__DIR__ . '/../../Analyser/nsrt/bug-9360.php'], []);
+	}
+
 	public function testDumpFunctions(): void
 	{
 		$this->analyse([__DIR__ . '/data/dump-functions.php'], [