From b770192dc5d0a54ae6f12de7409e6d476c1b0ea1 Mon Sep 17 00:00:00 2001
From: Markus Staab <maggus.staab@googlemail.com>
Date: Sat, 6 Aug 2022 10:46:40 +0200
Subject: [PATCH 1/3] implement LtrimFunctionReturnTypeExtension to support
 class-string

---
 conf/config.neon                              |  5 ++
 .../Php/LtrimFunctionReturnTypeExtension.php  | 50 +++++++++++++++++++
 .../Analyser/NodeScopeResolverTest.php        |  1 +
 tests/PHPStan/Analyser/data/bug-7483.php      | 17 +++++++
 4 files changed, 73 insertions(+)
 create mode 100644 src/Type/Php/LtrimFunctionReturnTypeExtension.php
 create mode 100644 tests/PHPStan/Analyser/data/bug-7483.php

diff --git a/conf/config.neon b/conf/config.neon
index 83a69fd93e..0f54599481 100644
--- a/conf/config.neon
+++ b/conf/config.neon
@@ -1418,6 +1418,11 @@ services:
 		tags:
 			- phpstan.broker.dynamicFunctionReturnTypeExtension
 
+	-
+		class: PHPStan\Type\Php\LtrimFunctionReturnTypeExtension
+		tags:
+			- phpstan.broker.dynamicFunctionReturnTypeExtension
+
 	-
 		class: PHPStan\Type\Php\MbFunctionsReturnTypeExtension
 		tags:
diff --git a/src/Type/Php/LtrimFunctionReturnTypeExtension.php b/src/Type/Php/LtrimFunctionReturnTypeExtension.php
new file mode 100644
index 0000000000..a1e86efed5
--- /dev/null
+++ b/src/Type/Php/LtrimFunctionReturnTypeExtension.php
@@ -0,0 +1,50 @@
+<?php declare(strict_types = 1);
+
+namespace PHPStan\Type\Php;
+
+use PhpParser\Node\Expr\FuncCall;
+use PHPStan\Analyser\Scope;
+use PHPStan\Php\PhpVersion;
+use PHPStan\Reflection\FunctionReflection;
+use PHPStan\Type\ClassStringType;
+use PHPStan\Type\Constant\ConstantStringType;
+use PHPStan\Type\DynamicFunctionReturnTypeExtension;
+use PHPStan\Type\Type;
+use function count;
+use function ltrim;
+
+class LtrimFunctionReturnTypeExtension implements DynamicFunctionReturnTypeExtension
+{
+
+	public function __construct(private PhpVersion $phpVersion)
+	{
+	}
+
+	public function isFunctionSupported(FunctionReflection $functionReflection): bool
+	{
+		return $functionReflection->getName() === 'ltrim';
+	}
+
+	public function getTypeFromFunctionCall(FunctionReflection $functionReflection, FuncCall $functionCall, Scope $scope): ?Type
+	{
+		if (count($functionCall->getArgs()) !== 2) {
+			return null;
+		}
+
+		$string = $scope->getType($functionCall->getArgs()[0]->value);
+		$trimChars = $scope->getType($functionCall->getArgs()[1]->value);
+
+		if ($trimChars instanceof ConstantStringType && $trimChars->getValue() === '\\') {
+			if ($string instanceof ConstantStringType && $string->isClassString()) {
+				return new ConstantStringType(ltrim($string->getValue(), $trimChars->getValue()), true);
+			}
+
+			if ($string instanceof ClassStringType) {
+				return new ClassStringType();
+			}
+		}
+
+		return null;
+	}
+
+}
diff --git a/tests/PHPStan/Analyser/NodeScopeResolverTest.php b/tests/PHPStan/Analyser/NodeScopeResolverTest.php
index 01b3febe36..6f91873dd7 100644
--- a/tests/PHPStan/Analyser/NodeScopeResolverTest.php
+++ b/tests/PHPStan/Analyser/NodeScopeResolverTest.php
@@ -964,6 +964,7 @@ public function dataFileAsserts(): iterable
 		yield from $this->gatherAssertTypes(__DIR__ . '/data/bug-5223.php');
 		yield from $this->gatherAssertTypes(__DIR__ . '/data/bug-7698.php');
 		yield from $this->gatherAssertTypes(__DIR__ . '/data/non-falsy-string.php');
+		yield from $this->gatherAssertTypes(__DIR__ . '/data/bug-7483.php');
 	}
 
 	/**
diff --git a/tests/PHPStan/Analyser/data/bug-7483.php b/tests/PHPStan/Analyser/data/bug-7483.php
new file mode 100644
index 0000000000..d5d3fe9943
--- /dev/null
+++ b/tests/PHPStan/Analyser/data/bug-7483.php
@@ -0,0 +1,17 @@
+<?php declare(strict_types=1);
+
+namespace Bug7483;
+
+use function PHPStan\Testing\assertType;
+
+class A {}
+
+/**
+ * @param class-string $class
+ * @return class-string
+ */
+function foo($class): string
+{
+	assertType('class-string', ltrim($class, '\\'));
+	assertType("'Bug7483\\\\A'", ltrim(A::class, '\\'));
+}

From 9c45e292e9f5fa02f9f3dd247ece9ee6fb08da09 Mon Sep 17 00:00:00 2001
From: Markus Staab <maggus.staab@googlemail.com>
Date: Sat, 6 Aug 2022 11:02:02 +0200
Subject: [PATCH 2/3] cover generic class string

---
 src/Type/Php/LtrimFunctionReturnTypeExtension.php | 3 +--
 tests/PHPStan/Analyser/data/bug-7483.php          | 8 ++++++++
 2 files changed, 9 insertions(+), 2 deletions(-)

diff --git a/src/Type/Php/LtrimFunctionReturnTypeExtension.php b/src/Type/Php/LtrimFunctionReturnTypeExtension.php
index a1e86efed5..f9d1537c09 100644
--- a/src/Type/Php/LtrimFunctionReturnTypeExtension.php
+++ b/src/Type/Php/LtrimFunctionReturnTypeExtension.php
@@ -4,7 +4,6 @@
 
 use PhpParser\Node\Expr\FuncCall;
 use PHPStan\Analyser\Scope;
-use PHPStan\Php\PhpVersion;
 use PHPStan\Reflection\FunctionReflection;
 use PHPStan\Type\ClassStringType;
 use PHPStan\Type\Constant\ConstantStringType;
@@ -16,7 +15,7 @@
 class LtrimFunctionReturnTypeExtension implements DynamicFunctionReturnTypeExtension
 {
 
-	public function __construct(private PhpVersion $phpVersion)
+	public function __construct()
 	{
 	}
 
diff --git a/tests/PHPStan/Analyser/data/bug-7483.php b/tests/PHPStan/Analyser/data/bug-7483.php
index d5d3fe9943..c6fe12d899 100644
--- a/tests/PHPStan/Analyser/data/bug-7483.php
+++ b/tests/PHPStan/Analyser/data/bug-7483.php
@@ -6,6 +6,14 @@
 
 class A {}
 
+/**
+ * @param class-string<A> $class
+ */
+function bar($class): string
+{
+	assertType('class-string', ltrim($class, '\\'));
+}
+
 /**
  * @param class-string $class
  * @return class-string

From 2a14dd44c9b6f2b98094c7f924fa5df89ff83149 Mon Sep 17 00:00:00 2001
From: Markus Staab <maggus.staab@googlemail.com>
Date: Sat, 6 Aug 2022 13:42:17 +0200
Subject: [PATCH 3/3] Remove construct()

---
 src/Type/Php/LtrimFunctionReturnTypeExtension.php | 4 ----
 1 file changed, 4 deletions(-)

diff --git a/src/Type/Php/LtrimFunctionReturnTypeExtension.php b/src/Type/Php/LtrimFunctionReturnTypeExtension.php
index f9d1537c09..a70f736661 100644
--- a/src/Type/Php/LtrimFunctionReturnTypeExtension.php
+++ b/src/Type/Php/LtrimFunctionReturnTypeExtension.php
@@ -15,10 +15,6 @@
 class LtrimFunctionReturnTypeExtension implements DynamicFunctionReturnTypeExtension
 {
 
-	public function __construct()
-	{
-	}
-
 	public function isFunctionSupported(FunctionReflection $functionReflection): bool
 	{
 		return $functionReflection->getName() === 'ltrim';