Remember function_exists() from constructor

Author: staabm

Diff for: src/Analyser/MutatingScope.php

@@ -306,7 +306,7 @@ private function rememberConstructorExpressions(array $currentExpressionTypes):
 			if ($expr instanceof FuncCall) {
 				if (
 					!$expr->name instanceof Name
-					|| !in_array($expr->name->name, ['class_exists'], true)
+					|| !in_array($expr->name->name, ['class_exists', 'function_exists'], true)
 				) {
 					continue;
 				}

Diff for: tests/PHPStan/Rules/Functions/CallToNonExistentFunctionRuleTest.php

@@ -258,4 +258,9 @@ public function testBug10003(): void
 		]);
 	}
 
+	public function testRememberFunctionExistsFromConstructor(): void
+	{
+		$this->analyse([__DIR__ . '/data/remember-function-exists-from-constructor.php'], []);
+	}
+
 }

Diff for: tests/PHPStan/Rules/Functions/data/remember-function-exists-from-constructor.php

@@ -0,0 +1,19 @@
+<?php // lint >= 7.4
+
+namespace RememberFunctionExistsFromConstructor;
+
+class User
+{
+	public function __construct(
+	) {
+		if (!function_exists('some_unknown_function')) {
+			throw new \LogicException();
+		}
+	}
+
+	public function doFoo(): void
+	{
+		some_unknown_function();
+	}
+
+}