fix for throw is expression

Author: fey

src/Rules/Expression/DisallowUnusedExpressionRule.php

@@ -4,6 +4,7 @@
 
 use PhpParser\Node;
 use PhpParser\Node\Stmt\Expression;
+use PhpParser\Node\Expr\Throw_;
 use PHPStan\Analyser\Scope;
 use PHPStan\Rules\Rule;
 use PHPStan\Rules\RuleErrorBuilder;
@@ -38,6 +39,10 @@ public function processNode(Node $node, Scope $scope): array
             return [];
         }
 
+        if ($node->expr instanceof Throw_) {
+            return [];
+        }
+
         return [
             RuleErrorBuilder::message('Enforce that an expression gets used')
                 ->identifier('phpstanFunctionalProgramming.disallowUnusedExpression')

tests/Rules/Expression/data/expressions.php

@@ -32,3 +32,10 @@ function example()
 
 for ($i = 0; 2 + 5; $i++) {
 }
+
+function getFileData(string $filepath): void
+{
+    if (!file_exists($filepath)) {
+        throw new \Exception("File '$filepath' does not exist");
+    }
+}