Fix false-positive: Method never returns XX so it can be removed from the return type

src/Rules/TooWideTypehints/TooWideTypeCheck.php

@@ -98,6 +98,13 @@ public function checkFunction(
 
 		$returnType = TypeCombinator::union(...$returnTypes);
 
+		if (
+			$returnType->isConstantScalarValue()->yes()
+			&& $functionReturnType->isConstantScalarValue()->yes()
+		) {
+			return [];
+		}
+
 		// Do not require to have @return null/true/false in descendant classes
 		if (
 			$checkDescendantClass

tests/PHPStan/Rules/TooWideTypehints/TooWideClosureReturnTypehintRuleTest.php

@@ -18,6 +18,11 @@ protected function getRule(): Rule
 		);
 	}
 
+	public function testBug10312e(): void
+	{
+		$this->analyse([__DIR__ . '/data/bug-10312e.php'], []);
+	}
+
 	public function testRule(): void
 	{
 		$this->analyse([__DIR__ . '/data/tooWideClosureReturnType.php'], [

tests/PHPStan/Rules/TooWideTypehints/TooWideFunctionReturnTypehintRuleTest.php

@@ -61,4 +61,9 @@ public function testBug11980(): void
 		]);
 	}
 
+	public function testBug10312a(): void
+	{
+		$this->analyse([__DIR__ . '/data/bug-10312a.php'], []);
+	}
+
 }

tests/PHPStan/Rules/TooWideTypehints/TooWideMethodReturnTypehintRuleTest.php

@@ -88,12 +88,7 @@ public function testPublicProtectedWithInheritance(): void
 
 	public function testBug5095(): void
 	{
-		$this->analyse([__DIR__ . '/data/bug-5095.php'], [
-			[
-				'Method Bug5095\Parser::unaryOperatorFor() never returns \'not\' so it can be removed from the return type.',
-				21,
-			],
-		]);
+		$this->analyse([__DIR__ . '/data/bug-5095.php'], []);
 	}
 
 	#[RequiresPhp('>= 8.0')]
@@ -199,4 +194,28 @@ public function testBug11980(): void
 		]);
 	}
 
+	public function testBug10312(): void
+	{
+		$this->checkProtectedAndPublicMethods = true;
+		$this->analyse([__DIR__ . '/data/bug-10312.php'], []);
+	}
+
+	public function testBug10312b(): void
+	{
+		$this->checkProtectedAndPublicMethods = true;
+		$this->analyse([__DIR__ . '/data/bug-10312b.php'], []);
+	}
+
+	public function testBug10312c(): void
+	{
+		$this->checkProtectedAndPublicMethods = true;
+		$this->analyse([__DIR__ . '/data/bug-10312c.php'], []);
+	}
+
+	public function testBug10312d(): void
+	{
+		$this->checkProtectedAndPublicMethods = true;
+		$this->analyse([__DIR__ . '/data/bug-10312d.php'], []);
+	}
+
 }

tests/PHPStan/Rules/TooWideTypehints/data/bug-10312.php

@@ -0,0 +1,48 @@
+<?php
+
+namespace Bug10312;
+
+class Cmsissue
+{
+	public const LANE_BACKLOG = 'Backlog';
+
+	public const LANE_READY_FOR_IMPL = 'Bereit zur Entwicklung';
+
+	public const LANE_IN_IMPL = 'In Entwicklung';
+
+	public const LANE_READY_FOR_UAT = 'Bereit zur Abnahme';
+
+	public const LANE_READY_FOR_UAT_KANBAN = 'Test';
+
+	public const LANE_PROJECT_BACKLOG = 'Backlog';
+
+	public const LANE_PROJECT_IN_IMPL = 'Projekt in Umsetzung';
+
+	public const LANE_SKIP = '';
+}
+
+
+final class Mapper
+{
+
+	/**
+	 * @return Cmsissue::LANE_*
+	 */
+	public function mapIssueStatus(): string
+	{
+		if (rand(0,1) === 0) {
+			return Cmsissue::LANE_BACKLOG;
+		}
+		if (rand(0,1) === 0) {
+			return Cmsissue::LANE_READY_FOR_IMPL;
+		}
+		if (rand(0,1) === 0) {
+			return Cmsissue::LANE_IN_IMPL;
+		}
+		if (rand(0,1) === 0) {
+			return Cmsissue::LANE_READY_FOR_UAT;
+		}
+
+		return Cmsissue::LANE_SKIP;
+	}
+}

tests/PHPStan/Rules/TooWideTypehints/data/bug-10312a.php

@@ -0,0 +1,45 @@
+<?php
+
+namespace Bug10312a;
+
+class Cmsissue
+{
+	public const LANE_BACKLOG = 'Backlog';
+
+	public const LANE_READY_FOR_IMPL = 'Bereit zur Entwicklung';
+
+	public const LANE_IN_IMPL = 'In Entwicklung';
+
+	public const LANE_READY_FOR_UAT = 'Bereit zur Abnahme';
+
+	public const LANE_READY_FOR_UAT_KANBAN = 'Test';
+
+	public const LANE_PROJECT_BACKLOG = 'Backlog';
+
+	public const LANE_PROJECT_IN_IMPL = 'Projekt in Umsetzung';
+
+	public const LANE_SKIP = '';
+}
+
+
+/**
+ * @return Cmsissue::LANE_*
+ */
+function mapIssueStatus(): string
+{
+	if (rand(0,1) === 0) {
+		return Cmsissue::LANE_BACKLOG;
+	}
+	if (rand(0,1) === 0) {
+		return Cmsissue::LANE_READY_FOR_IMPL;
+	}
+	if (rand(0,1) === 0) {
+		return Cmsissue::LANE_IN_IMPL;
+	}
+	if (rand(0,1) === 0) {
+		return Cmsissue::LANE_READY_FOR_UAT;
+	}
+
+	return Cmsissue::LANE_SKIP;
+}
+

tests/PHPStan/Rules/TooWideTypehints/data/bug-10312b.php

@@ -0,0 +1,40 @@
+<?php
+
+namespace Bug10312b;
+
+interface MinPhpVersionInterface
+{
+	/**
+	 * @return PhpVersion::*
+	 */
+	public function provideMinPhpVersion() : int;
+}
+
+final class PhpVersion
+{
+	/**
+	 * @var int
+	 */
+	public const PHP_52 = 50200;
+	/**
+	 * @var int
+	 */
+	public const PHP_53 = 50300;
+	/**
+	 * @var int
+	 */
+	public const PHP_54 = 50400;
+	/**
+	 * @var int
+	 */
+	public const PHP_55 = 50500;
+}
+
+final class TypedPropertyFromStrictConstructorReadonlyClassRector implements MinPhpVersionInterface
+{
+	public function provideMinPhpVersion(): int
+	{
+		return PhpVersion::PHP_55;
+	}
+
+}

tests/PHPStan/Rules/TooWideTypehints/data/bug-10312c.php

@@ -0,0 +1,44 @@
+<?php // lint >= 8.1
+
+declare(strict_types = 1);
+
+namespace Bug10312c;
+
+enum Foo: int
+{
+	case BAR = 1;
+	case BAZ = 2;
+}
+
+interface ReturnsFoo
+{
+	/** @return value-of<Foo> */
+	public function returnsFooValue(): int;
+}
+
+class ReturnsBar implements ReturnsFoo
+{
+	#[\Override]
+	public function returnsFooValue(): int
+	{
+		return Foo::BAR->value;
+	}
+}
+
+class ReturnsBarWithFinalMethod implements ReturnsFoo
+{
+	#[\Override]
+	final public function returnsFooValue(): int
+	{
+		return Foo::BAR->value;
+	}
+}
+
+final class ReturnsBaz implements ReturnsFoo
+{
+	#[\Override]
+	public function returnsFooValue(): int
+	{
+		return Foo::BAZ->value;
+	}
+}

tests/PHPStan/Rules/TooWideTypehints/data/bug-10312d.php

@@ -0,0 +1,41 @@
+<?php // lint >= 8.1
+
+declare(strict_types = 1);
+
+namespace Bug10312d;
+
+enum Foo: int
+{
+	case BAR = 1;
+	case BAZ = 2;
+}
+
+class FooBar {
+	public ?Foo $foo = null;
+}
+
+interface ReturnsFoo
+{
+	/** @return value-of<Foo> */
+	public function returnsFooValue(): int;
+
+	/** @return value-of<Foo>|null */
+	public function returnsFooOrNullValue(): ?int;
+}
+
+final class ReturnsNullsafeBaz implements ReturnsFoo
+{
+	#[\Override]
+	public function returnsFooValue(): int
+	{
+		$f = new FooBar();
+		return $f->foo?->value;
+	}
+
+	#[\Override]
+	public function returnsFooOrNullValue(): ?int
+	{
+		$f = new FooBar();
+		return $f->foo?->value;
+	}
+}

tests/PHPStan/Rules/TooWideTypehints/data/bug-10312e.php

@@ -0,0 +1,44 @@
+<?php
+
+namespace Bug10312e;
+
+class Cmsissue
+{
+	public const LANE_BACKLOG = 'Backlog';
+
+	public const LANE_READY_FOR_IMPL = 'Bereit zur Entwicklung';
+
+	public const LANE_IN_IMPL = 'In Entwicklung';
+
+	public const LANE_READY_FOR_UAT = 'Bereit zur Abnahme';
+
+	public const LANE_READY_FOR_UAT_KANBAN = 'Test';
+
+	public const LANE_PROJECT_BACKLOG = 'Backlog';
+
+	public const LANE_PROJECT_IN_IMPL = 'Projekt in Umsetzung';
+
+	public const LANE_SKIP = '';
+}
+
+
+/**
+ * @return Cmsissue::LANE_*
+ */
+$x = function(): string
+{
+	if (rand(0,1) === 0) {
+		return Cmsissue::LANE_BACKLOG;
+	}
+	if (rand(0,1) === 0) {
+		return Cmsissue::LANE_READY_FOR_IMPL;
+	}
+	if (rand(0,1) === 0) {
+		return Cmsissue::LANE_IN_IMPL;
+	}
+	if (rand(0,1) === 0) {
+		return Cmsissue::LANE_READY_FOR_UAT;
+	}
+
+	return Cmsissue::LANE_SKIP;
+};