Fix for Closure returns

src/Analyser/MutatingScope.php

@@ -1231,7 +1231,9 @@ private function resolveType(string $exprString, Expr $node): Type
 						new VoidType(),
 					]);
 				} else {
-					$returnType = $arrowScope->getType($node->expr);
+					$expr = clone $node->expr;
+					$expr->setAttribute('keepVoid', true);
+					$returnType = $arrowScope->getType($expr);
 					if ($node->returnType !== null) {
 						$returnType = TypehintHelper::decideType($this->getFunctionType($node->returnType, false, false), $returnType);
 					}

tests/PHPStan/Rules/Methods/ReturnTypeRuleTest.php

@@ -974,4 +974,14 @@ public function testWrongListTip(): void
 		]);
 	}
 
+	public function testArrowFunctionReturningVoidClosure(): void
+	{
+		if (PHP_VERSION_ID < 70400) {
+			$this->markTestSkipped('Test requires PHP 7.4.');
+		}
+
+		$this->checkExplicitMixed = true;
+		$this->analyse([__DIR__ . '/data/arrow-function-returning-void-closure.php'], []);
+	}
+
 }

tests/PHPStan/Rules/Methods/data/arrow-function-returning-void-closure.php

@@ -0,0 +1,19 @@
+<?php
+
+namespace ArrowFunctionReturningVoidClosure;
+
+class ArrowFunctionReturningVoidClosure
+{
+	/**
+	 * @return \Closure(): void
+	 */
+	public function getClosure(): \Closure
+	{
+		return fn () => $this->returnVoid();
+	}
+
+	public function returnVoid(): void
+	{
+
+	}
+}