Regression test for #1860

Author: ondrejmirtes

tests/PHPStan/Rules/Comparison/StrictComparisonOfDifferentTypesRuleTest.php

@@ -411,4 +411,19 @@ public function testBug2835(): void
 		$this->analyse([__DIR__ . '/data/bug-2835.php'], []);
 	}
 
+	public function testBug1860(): void
+	{
+		$this->checkAlwaysTrueStrictComparison = true;
+		$this->analyse([__DIR__ . '/data/bug-1860.php'], [
+			[
+				'Strict comparison using === between string and null will always evaluate to false.',
+				15,
+			],
+			[
+				'Strict comparison using !== between string and null will always evaluate to true.',
+				19,
+			],
+		]);
+	}
+
 }

tests/PHPStan/Rules/Comparison/data/bug-1860.php

@@ -0,0 +1,24 @@
+<?php
+
+namespace Bug1860;
+
+class Foo
+{
+
+	public function doFoo(): string
+	{
+
+	}
+
+	public function doBar(): void
+	{
+		if ($this->doFoo() === null) {
+			echo 'foo';
+		}
+
+		if ($this->doFoo() !== null) {
+			echo 'bar';
+		}
+	}
+
+}