StrictComparisonOfDifferentTypesRule - tip for always true comparison between enums

Author: ondrejmirtes

src/Rules/Comparison/StrictComparisonOfDifferentTypesRule.php

@@ -79,7 +79,11 @@ public function processNode(Node $node, Scope $scope): array
 				$rightType->describe(VerbosityLevel::value()),
 			)));
 			if ($isLast === false && !$this->reportAlwaysTrueInLastCondition) {
-				$errorBuilder->tip('Remove remaining cases below this one and this error will disappear too.');
+				$errorBuilder->addTip('Remove remaining cases below this one and this error will disappear too.');
+			}
+
+			if ($leftType->isEnum()->yes() && $rightType->isEnum()->yes()) {
+				$errorBuilder->addTip('Use match expression instead. PHPStan will report unhandled enum cases.');
 			}
 
 			return [

tests/PHPStan/Rules/Comparison/StrictComparisonOfDifferentTypesRuleTest.php

@@ -637,6 +637,7 @@ public function testBug8485(): void
 			[
 				'Strict comparison using === between Bug8485\E::c and Bug8485\E::c will always evaluate to true.',
 				19,
+				'Use match expression instead. PHPStan will report unhandled enum cases.',
 			],
 			[
 				'Strict comparison using === between Bug8485\F::c and Bug8485\E::c will always evaluate to false.',
@@ -657,12 +658,12 @@ public function testBug8485(): void
 			[
 				'Strict comparison using === between Bug8485\FooEnum::C and Bug8485\FooEnum::C will always evaluate to true.',
 				67,
-				'Remove remaining cases below this one and this error will disappear too.',
+				"• Remove remaining cases below this one and this error will disappear too.\n• Use match expression instead. PHPStan will report unhandled enum cases.",
 			],
 			[
 				'Strict comparison using === between Bug8485\FooEnum::C and Bug8485\FooEnum::C will always evaluate to true.',
 				74,
-				'Remove remaining cases below this one and this error will disappear too.',
+				"• Remove remaining cases below this one and this error will disappear too.\n• Use match expression instead. PHPStan will report unhandled enum cases.",
 			],
 		]);
 	}
@@ -936,4 +937,25 @@ public function testBug9104(): void
 		]);
 	}
 
+	public function testEnumTips(): void
+	{
+		if (PHP_VERSION_ID < 80100) {
+			$this->markTestSkipped('Test requires PHP 8.1.');
+		}
+
+		$this->checkAlwaysTrueStrictComparison = true;
+		$this->analyse([__DIR__ . '/data/strict-comparison-enum-tips.php'], [
+			[
+				'Strict comparison using === between $this(StrictComparisonEnumTips\SomeEnum)&StrictComparisonEnumTips\SomeEnum::Two and StrictComparisonEnumTips\SomeEnum::Two will always evaluate to true.',
+				15,
+				"• Remove remaining cases below this one and this error will disappear too.\n• Use match expression instead. PHPStan will report unhandled enum cases.",
+			],
+			[
+				'Strict comparison using === between $this(StrictComparisonEnumTips\SomeEnum)&StrictComparisonEnumTips\SomeEnum::Two and StrictComparisonEnumTips\SomeEnum::Two will always evaluate to true.',
+				29,
+				'Use match expression instead. PHPStan will report unhandled enum cases.',
+			],
+		]);
+	}
+
 }

tests/PHPStan/Rules/Comparison/data/strict-comparison-enum-tips.php

@@ -0,0 +1,36 @@
+<?php // lint >= 8.1
+
+namespace StrictComparisonEnumTips;
+
+enum SomeEnum
+{
+
+	case One;
+	case Two;
+
+	public function exhaustiveWithSafetyCheck(): int
+	{
+		if ($this === self::One) {
+			return -1;
+		} elseif ($this === self::Two) {
+			return 0;
+		} else {
+			throw new \LogicException('New case added, handling missing');
+		}
+	}
+
+
+	public function exhaustiveWithSafetyCheck2(): int
+	{
+		if ($this === self::One) {
+			return -1;
+		}
+
+		if ($this === self::Two) {
+			return 0;
+		}
+
+		throw new \LogicException('New case added, handling missing');
+	}
+
+}