Don’t crash when encountering empty @throws

src/Psalm/Internal/Analyzer/CommentAnalyzer.php

@@ -386,7 +386,13 @@ class CommentAnalyzer
 
         if (isset($comments['specials']['throws'])) {
             foreach ($comments['specials']['throws'] as $throws_entry) {
-                $info->throws[] = preg_split('/[\s]+/', $throws_entry)[0];
+                $throws_class = preg_split('/[\s]+/', $throws_entry)[0];
+
+                if (!$throws_class) {
+                    throw new IncorrectDocblockException('Unexpectedly empty @throws');
+                }
+
+                $info->throws[] = $throws_class;
             }
         }
 

tests/ThrowsAnnotationTest.php

@@ -302,6 +302,30 @@ class ThrowsAnnotationTest extends TestCase
         $this->analyzeFile('somefile.php', $context);
     }
 
+    /**
+     * @expectedException        \Psalm\Exception\CodeException
+     * @expectedExceptionMessage MissingDocblockType
+     *
+     * @return                   void
+     */
+    public function testEmptyThrows()
+    {
+        Config::getInstance()->check_for_throws_docblock = true;
+
+        $this->addFile(
+            'somefile.php',
+            '<?php
+                /**
+                 * @throws
+                 */
+                function foo(int $x, int $y) : int {}'
+        );
+
+        $context = new Context();
+
+        $this->analyzeFile('somefile.php', $context);
+    }
+
     /**
      * @return void
      */