diff --git a/src/parser/PhutilTypeSpec.php b/src/parser/PhutilTypeSpec.php
index ee70460..dbf3b4f 100644
--- a/src/parser/PhutilTypeSpec.php
+++ b/src/parser/PhutilTypeSpec.php
@@ -1,1912 +1,1921 @@
 <?php
 
 /**
  * Perform type checks using a simple type grammar. The grammar supports the
  * following basic types:
  *
  *    int
  *    float
  *    bool
  *    string
  *    null
  *    callable
  *    regex
  *    wild
  *    AnyClassOrInterfaceName
  *
  * It supports the following complex types:
  *
  *    list<type>
  *    map<type, type>
  *    type|type
  *
  * A type may be marked as optional by suffixing it with "?" or prefixing it
  * with the word "optional":
  *
  *    int?
  *    optional int
  *
  * A type may have a human-readable comment in parentheses, at the end:
  *
  *    int (must be even)
  *
  * For example, these are valid type specifications:
  *
  *    int|string
  *    map<int, bool>
  *    list<list<wild>>
  *    optional int
  *    string (uppercase)
  *
  */
 final class PhutilTypeSpec extends Phobject {
 
   private $type;
   private $subtypes = array();
   private $optional;
   private $comment;
 
   private function __construct() {}
 
   public function getType() {
     return $this->type;
   }
 
   public function check($value, $name = null) {
     switch ($this->type) {
       case 'int':
         if (!is_int($value)) {
           throw new PhutilTypeCheckException($this, $value, $name);
         }
         break;
       case 'float':
         if (!is_float($value)) {
           throw new PhutilTypeCheckException($this, $value, $name);
         }
         break;
       case 'bool':
         if (!is_bool($value)) {
           throw new PhutilTypeCheckException($this, $value, $name);
         }
         break;
       case 'string':
         if (!is_string($value)) {
           throw new PhutilTypeCheckException($this, $value, $name);
         }
         break;
       case 'regex':
         $trap = new PhutilErrorTrap();
           $ok = @preg_match($value, '');
           $err = $trap->getErrorsAsString();
         $trap->destroy();
 
         if ($ok === false) {
           throw new PhutilTypeCheckException($this, $value, $name, $err);
         }
         break;
       case 'null':
         if (!is_null($value)) {
           throw new PhutilTypeCheckException($this, $value, $name);
         }
         break;
       case 'list':
         if (!is_array($value)) {
           throw new PhutilTypeCheckException($this, $value, $name);
         }
         if ($value && (array_keys($value) !== range(0, count($value) - 1))) {
           throw new PhutilTypeCheckException($this, $value, $name);
         }
         try {
           foreach ($value as $v) {
             $this->subtypes[0]->check($v);
           }
         } catch (PhutilTypeCheckException $ex) {
           throw new PhutilTypeCheckException($this, $value, $name);
         }
         break;
       case 'map':
         if (!is_array($value)) {
           throw new PhutilTypeCheckException($this, $value, $name);
         }
         try {
           foreach ($value as $k => $v) {
             $this->subtypes[0]->check($k);
             $this->subtypes[1]->check($v);
           }
         } catch (PhutilTypeCheckException $ex) {
           throw new PhutilTypeCheckException($this, $value, $name);
         }
         break;
       case 'or':
         foreach ($this->subtypes as $subtype) {
           try {
             $subtype->check($value);
             return;
           } catch (PhutilTypeCheckException $ex) {
             // Ignore.
           }
         }
         throw new PhutilTypeCheckException($this, $value, $name);
       case 'wild':
         return;
       default:
         if (class_exists($this->type, false)) {
           if ($value instanceof $this->type) {
             return;
           }
         } else if (interface_exists($this->type, false)) {
           if ($value instanceof $this->type) {
             return;
           }
         }
 
         throw new PhutilTypeCheckException($this, $value, $name);
     }
   }
 
   public static function checkMap(array $values, array $types) {
     $extra = array_diff_key($values, $types);
     if ($extra) {
       throw new PhutilTypeExtraParametersException($extra);
     }
 
     $missing = array();
     foreach ($types as $key => $type) {
       $types[$key] = self::newFromString($type);
       if (!array_key_exists($key, $values)) {
         if (!$types[$key]->optional) {
           $missing[] = $key;
         }
       }
     }
 
     if ($missing) {
       throw new PhutilTypeMissingParametersException($missing);
     }
 
     foreach ($types as $key => $type) {
       if (array_key_exists($key, $values)) {
         $type->check($values[$key], $key);
       }
     }
   }
 
   public static function getCommonParentClass($class_a, $class_b) {
+    // Make sure both classes are really classes.
+    try {
+      if (!class_exists($class_a) || !class_exists($class_b)) {
+        return null;
+      }
+    } catch (PhutilMissingSymbolException $ex) {
+      return null;
+    }
+
     $ancestors_a = array();
     do {
       $ancestors_a[] = $class_a;
     } while ($class_a = get_parent_class($class_a));
 
     $ancestors_b = array();
     do {
       $ancestors_b[] = $class_b;
     } while ($class_b = get_parent_class($class_b));
 
     return head(array_intersect($ancestors_a, $ancestors_b));
   }
 
   public static function getTypeOf($value) {
     if (is_int($value)) {
       return 'int';
     } else if (is_float($value)) {
       return 'float';
     } else if (is_bool($value)) {
       return 'bool';
     } else if (is_string($value)) {
       return 'string';
     } else if (is_null($value)) {
       return 'null';
     } else if (is_object($value)) {
       return get_class($value);
     } else if (is_array($value)) {
       $vtype = self::getTypeOfVector($value);
       if ($value && (array_keys($value) === range(0, count($value) - 1))) {
         return 'list<'.$vtype.'>';
       } else {
         $ktype = self::getTypeOfVector(array_keys($value));
         return "map<{$ktype}, {$vtype}>";
       }
     } else {
       return 'wild';
     }
   }
 
   private static function getTypeOfVector(array $vector) {
     if (!$vector) {
       return 'wild';
     }
 
     $type = null;
     foreach ($vector as $value) {
       $vtype = self::getTypeOf($value);
       if ($type === null) {
         $type = $vtype;
       } else if ($type === $vtype) {
         continue;
       } else {
         $parent = self::getCommonParentClass($type, $vtype);
         if ($parent) {
           $type = $parent;
         } else {
           return 'wild';
         }
       }
     }
 
     return $type;
   }
 
   public function toString() {
     $sub = array();
     foreach ($this->subtypes as $subtype) {
       $sub[] = $subtype->toString();
     }
 
     switch ($this->type) {
       case 'map':
         $string = 'map<'.$sub[0].', '.$sub[1].'>';
         break;
       case 'list':
         $string = 'list<'.$sub[0].'>';
         break;
       case 'or':
         $string = implode('|', $sub);
         break;
       default:
         $string = $this->type;
         break;
     }
 
     if ($this->optional) {
       $string = 'optional '.$string;
     }
 
     if ($this->comment) {
       $string .= ' ('.$this->comment.')';
     }
 
     return $string;
   }
 
   public static function newFromString($string) {
     $lexer = self::getLexer();
     $tokens = $lexer->getTokens($string);
 
     // Strip whitespace tokens.
     foreach ($tokens as $key => $token) {
       $type = $token[0];
       if ($type == ' ') {
         unset($tokens[$key]);
       }
     }
 
     $tokens = array_values($tokens);
     $callback = array(__CLASS__, 'didReduceTokens');
     return self::parseTokens($tokens, $callback);
   }
 
   public static function didReduceTokens($rule, $production, array $tokens) {
     switch ($rule) {
       case 'start':
       case 'some_type':
       case 'not_or_type':
         return $tokens[0];
       case 'type':
         if ($production == 'yes') {
           $tokens[0]->optional = true;
         }
         return $tokens[0];
       case 'basic_type':
         $obj = new PhutilTypeSpec();
         $obj->type = $tokens[0][1];
         return $obj;
       case 'or_type':
         $l = $tokens[0];
         $r = $tokens[2];
 
         if ($l->type == 'or') {
           if ($r->type == 'or') {
             foreach ($r->subtypes as $subtype) {
               $l->subtypes[] = $subtype;
             }
           } else {
             $l->subtypes[] = $r;
           }
           return $l;
         } else if ($r->type == 'or') {
           $r->subtypes[] = $l;
           return $r;
         } else {
           $obj = new PhutilTypeSpec();
           $obj->type = 'or';
           $obj->subtypes[] = $l;
           $obj->subtypes[] = $r;
           return $obj;
         }
         break;
       case 'map_type':
         $obj = new PhutilTypeSpec();
         $obj->type = 'map';
         $obj->subtypes[] = $tokens[2];
         $obj->subtypes[] = $tokens[4];
         return $obj;
       case 'list_type':
         $obj = new PhutilTypeSpec();
         $obj->type = 'list';
         $obj->subtypes[] = $tokens[2];
         return $obj;
       case 'maybe_optional':
         if ($production == 'yes') {
           $tokens[1]->optional = true;
           return $tokens[1];
         } else {
           return $tokens[0];
         }
         break;
       case 'maybe_comment':
         if ($production == 'yes') {
           $tokens[0]->comment = $tokens[1];
         }
         return $tokens[0];
       case 'comment':
         return $tokens[1];
       case 'comment_text':
         $result = '';
         foreach ($tokens as $token) {
           if (is_array($token)) {
             $result .= $token[1];
           } else {
             $result .= $token;
           }
         }
         return $result;
       default:
         throw new Exception(pht("Unhandled parser rule '%s'!", $rule));
     }
   }
 
   private static function getLexer() {
     static $lexer;
     if (!$lexer) {
       $lexer = new PhutilTypeLexer();
     }
     return $lexer;
   }
 
   private static function parseTokens(array $tokens, $callback) {
     // NOTE: This is automatically generated by the script
     // `support/parser/generate-type-parser.php`.
 
     return PhutilParserGenerator::parseTokensWithTables(
       array(
         0 => array(
           'opt' => array(
             0 => 'S',
             1 => 3,
           ),
           'k' => array(
             0 => 'S',
             1 => 20,
           ),
           'map' => array(
             0 => 'S',
             1 => 21,
           ),
           'list' => array(
             0 => 'S',
             1 => 71,
           ),
         ),
         1 => array(
           '(end-of-file)' => array(
             0 => 'A',
           ),
         ),
         2 => array(
           '(end-of-file)' => array(
             0 => 'R',
             1 => array(
               0 => 'start',
               1 => 0,
               2 => 1,
             ),
           ),
         ),
         3 => array(
           'k' => array(
             0 => 'S',
             1 => 20,
           ),
           'map' => array(
             0 => 'S',
             1 => 21,
           ),
           'list' => array(
             0 => 'S',
             1 => 71,
           ),
         ),
         4 => array(
           '(end-of-file)' => array(
             0 => 'R',
             1 => array(
               0 => 'maybe_optional',
               1 => 'yes',
               2 => 2,
             ),
           ),
         ),
         5 => array(
           '(end-of-file)' => array(
             0 => 'R',
             1 => array(
               0 => 'maybe_comment',
               1 => 'no',
               2 => 1,
             ),
           ),
           '(' => array(
             0 => 'S',
             1 => 7,
           ),
         ),
         6 => array(
           '(end-of-file)' => array(
             0 => 'R',
             1 => array(
               0 => 'maybe_comment',
               1 => 'yes',
               2 => 2,
             ),
           ),
         ),
         7 => array(
           'cm' => array(
             0 => 'S',
             1 => 11,
           ),
         ),
         8 => array(
           ')' => array(
             0 => 'S',
             1 => 9,
           ),
           'cm' => array(
             0 => 'S',
             1 => 10,
           ),
         ),
         9 => array(
           '(end-of-file)' => array(
             0 => 'R',
             1 => array(
               0 => 'comment',
               1 => 0,
               2 => 3,
             ),
           ),
         ),
         10 => array(
           ')' => array(
             0 => 'R',
             1 => array(
               0 => 'comment_text',
               1 => 0,
               2 => 2,
             ),
           ),
           'cm' => array(
             0 => 'R',
             1 => array(
               0 => 'comment_text',
               1 => 0,
               2 => 2,
             ),
           ),
         ),
         11 => array(
           ')' => array(
             0 => 'R',
             1 => array(
               0 => 'comment_text',
               1 => 1,
               2 => 1,
             ),
           ),
           'cm' => array(
             0 => 'R',
             1 => array(
               0 => 'comment_text',
               1 => 1,
               2 => 1,
             ),
           ),
         ),
         12 => array(
           '(' => array(
             0 => 'R',
             1 => array(
               0 => 'type',
               1 => 'no',
               2 => 1,
             ),
           ),
           '(end-of-file)' => array(
             0 => 'R',
             1 => array(
               0 => 'type',
               1 => 'no',
               2 => 1,
             ),
           ),
           '?' => array(
             0 => 'S',
             1 => 13,
           ),
         ),
         13 => array(
           '(' => array(
             0 => 'R',
             1 => array(
               0 => 'type',
               1 => 'yes',
               2 => 2,
             ),
           ),
           '(end-of-file)' => array(
             0 => 'R',
             1 => array(
               0 => 'type',
               1 => 'yes',
               2 => 2,
             ),
           ),
         ),
         14 => array(
           '?' => array(
             0 => 'R',
             1 => array(
               0 => 'some_type',
               1 => 0,
               2 => 1,
             ),
           ),
           '(' => array(
             0 => 'R',
             1 => array(
               0 => 'some_type',
               1 => 0,
               2 => 1,
             ),
           ),
           '(end-of-file)' => array(
             0 => 'R',
             1 => array(
               0 => 'some_type',
               1 => 0,
               2 => 1,
             ),
           ),
           '|' => array(
             0 => 'S',
             1 => 15,
           ),
         ),
         15 => array(
           'k' => array(
             0 => 'S',
             1 => 20,
           ),
           'map' => array(
             0 => 'S',
             1 => 21,
           ),
           'list' => array(
             0 => 'S',
             1 => 71,
           ),
         ),
         16 => array(
           '?' => array(
             0 => 'R',
             1 => array(
               0 => 'or_type',
               1 => 0,
               2 => 3,
             ),
           ),
           '(' => array(
             0 => 'R',
             1 => array(
               0 => 'or_type',
               1 => 0,
               2 => 3,
             ),
           ),
           '(end-of-file)' => array(
             0 => 'R',
             1 => array(
               0 => 'or_type',
               1 => 0,
               2 => 3,
             ),
           ),
           '|' => array(
             0 => 'R',
             1 => array(
               0 => 'or_type',
               1 => 0,
               2 => 3,
             ),
           ),
         ),
         17 => array(
           '?' => array(
             0 => 'R',
             1 => array(
               0 => 'not_or_type',
               1 => 0,
               2 => 1,
             ),
           ),
           '(' => array(
             0 => 'R',
             1 => array(
               0 => 'not_or_type',
               1 => 0,
               2 => 1,
             ),
           ),
           '(end-of-file)' => array(
             0 => 'R',
             1 => array(
               0 => 'not_or_type',
               1 => 0,
               2 => 1,
             ),
           ),
           '|' => array(
             0 => 'R',
             1 => array(
               0 => 'not_or_type',
               1 => 0,
               2 => 1,
             ),
           ),
         ),
         18 => array(
           '?' => array(
             0 => 'R',
             1 => array(
               0 => 'not_or_type',
               1 => 1,
               2 => 1,
             ),
           ),
           '(' => array(
             0 => 'R',
             1 => array(
               0 => 'not_or_type',
               1 => 1,
               2 => 1,
             ),
           ),
           '(end-of-file)' => array(
             0 => 'R',
             1 => array(
               0 => 'not_or_type',
               1 => 1,
               2 => 1,
             ),
           ),
           '|' => array(
             0 => 'R',
             1 => array(
               0 => 'not_or_type',
               1 => 1,
               2 => 1,
             ),
           ),
         ),
         19 => array(
           '?' => array(
             0 => 'R',
             1 => array(
               0 => 'not_or_type',
               1 => 2,
               2 => 1,
             ),
           ),
           '(' => array(
             0 => 'R',
             1 => array(
               0 => 'not_or_type',
               1 => 2,
               2 => 1,
             ),
           ),
           '(end-of-file)' => array(
             0 => 'R',
             1 => array(
               0 => 'not_or_type',
               1 => 2,
               2 => 1,
             ),
           ),
           '|' => array(
             0 => 'R',
             1 => array(
               0 => 'not_or_type',
               1 => 2,
               2 => 1,
             ),
           ),
         ),
         20 => array(
           '?' => array(
             0 => 'R',
             1 => array(
               0 => 'basic_type',
               1 => 0,
               2 => 1,
             ),
           ),
           '(' => array(
             0 => 'R',
             1 => array(
               0 => 'basic_type',
               1 => 0,
               2 => 1,
             ),
           ),
           '(end-of-file)' => array(
             0 => 'R',
             1 => array(
               0 => 'basic_type',
               1 => 0,
               2 => 1,
             ),
           ),
           '|' => array(
             0 => 'R',
             1 => array(
               0 => 'basic_type',
               1 => 0,
               2 => 1,
             ),
           ),
         ),
         21 => array(
           '<' => array(
             0 => 'S',
             1 => 22,
           ),
         ),
         22 => array(
           'k' => array(
             0 => 'S',
             1 => 57,
           ),
           'map' => array(
             0 => 'S',
             1 => 58,
           ),
           'list' => array(
             0 => 'S',
             1 => 67,
           ),
         ),
         23 => array(
           ',' => array(
             0 => 'S',
             1 => 24,
           ),
         ),
         24 => array(
           'k' => array(
             0 => 'S',
             1 => 35,
           ),
           'map' => array(
             0 => 'S',
             1 => 36,
           ),
           'list' => array(
             0 => 'S',
             1 => 45,
           ),
         ),
         25 => array(
           '>' => array(
             0 => 'S',
             1 => 26,
           ),
         ),
         26 => array(
           '?' => array(
             0 => 'R',
             1 => array(
               0 => 'map_type',
               1 => 0,
               2 => 6,
             ),
           ),
           '(' => array(
             0 => 'R',
             1 => array(
               0 => 'map_type',
               1 => 0,
               2 => 6,
             ),
           ),
           '(end-of-file)' => array(
             0 => 'R',
             1 => array(
               0 => 'map_type',
               1 => 0,
               2 => 6,
             ),
           ),
           '|' => array(
             0 => 'R',
             1 => array(
               0 => 'map_type',
               1 => 0,
               2 => 6,
             ),
           ),
         ),
         27 => array(
           '>' => array(
             0 => 'R',
             1 => array(
               0 => 'type',
               1 => 'no',
               2 => 1,
             ),
           ),
           '?' => array(
             0 => 'S',
             1 => 28,
           ),
         ),
         28 => array(
           '>' => array(
             0 => 'R',
             1 => array(
               0 => 'type',
               1 => 'yes',
               2 => 2,
             ),
           ),
         ),
         29 => array(
           '?' => array(
             0 => 'R',
             1 => array(
               0 => 'some_type',
               1 => 0,
               2 => 1,
             ),
           ),
           '>' => array(
             0 => 'R',
             1 => array(
               0 => 'some_type',
               1 => 0,
               2 => 1,
             ),
           ),
           '|' => array(
             0 => 'S',
             1 => 30,
           ),
         ),
         30 => array(
           'k' => array(
             0 => 'S',
             1 => 35,
           ),
           'map' => array(
             0 => 'S',
             1 => 36,
           ),
           'list' => array(
             0 => 'S',
             1 => 45,
           ),
         ),
         31 => array(
           '?' => array(
             0 => 'R',
             1 => array(
               0 => 'or_type',
               1 => 0,
               2 => 3,
             ),
           ),
           '>' => array(
             0 => 'R',
             1 => array(
               0 => 'or_type',
               1 => 0,
               2 => 3,
             ),
           ),
           '|' => array(
             0 => 'R',
             1 => array(
               0 => 'or_type',
               1 => 0,
               2 => 3,
             ),
           ),
         ),
         32 => array(
           '?' => array(
             0 => 'R',
             1 => array(
               0 => 'not_or_type',
               1 => 0,
               2 => 1,
             ),
           ),
           '>' => array(
             0 => 'R',
             1 => array(
               0 => 'not_or_type',
               1 => 0,
               2 => 1,
             ),
           ),
           '|' => array(
             0 => 'R',
             1 => array(
               0 => 'not_or_type',
               1 => 0,
               2 => 1,
             ),
           ),
         ),
         33 => array(
           '?' => array(
             0 => 'R',
             1 => array(
               0 => 'not_or_type',
               1 => 1,
               2 => 1,
             ),
           ),
           '>' => array(
             0 => 'R',
             1 => array(
               0 => 'not_or_type',
               1 => 1,
               2 => 1,
             ),
           ),
           '|' => array(
             0 => 'R',
             1 => array(
               0 => 'not_or_type',
               1 => 1,
               2 => 1,
             ),
           ),
         ),
         34 => array(
           '?' => array(
             0 => 'R',
             1 => array(
               0 => 'not_or_type',
               1 => 2,
               2 => 1,
             ),
           ),
           '>' => array(
             0 => 'R',
             1 => array(
               0 => 'not_or_type',
               1 => 2,
               2 => 1,
             ),
           ),
           '|' => array(
             0 => 'R',
             1 => array(
               0 => 'not_or_type',
               1 => 2,
               2 => 1,
             ),
           ),
         ),
         35 => array(
           '?' => array(
             0 => 'R',
             1 => array(
               0 => 'basic_type',
               1 => 0,
               2 => 1,
             ),
           ),
           '>' => array(
             0 => 'R',
             1 => array(
               0 => 'basic_type',
               1 => 0,
               2 => 1,
             ),
           ),
           '|' => array(
             0 => 'R',
             1 => array(
               0 => 'basic_type',
               1 => 0,
               2 => 1,
             ),
           ),
         ),
         36 => array(
           '<' => array(
             0 => 'S',
             1 => 37,
           ),
         ),
         37 => array(
           'k' => array(
             0 => 'S',
             1 => 57,
           ),
           'map' => array(
             0 => 'S',
             1 => 58,
           ),
           'list' => array(
             0 => 'S',
             1 => 67,
           ),
         ),
         38 => array(
           ',' => array(
             0 => 'S',
             1 => 39,
           ),
         ),
         39 => array(
           'k' => array(
             0 => 'S',
             1 => 35,
           ),
           'map' => array(
             0 => 'S',
             1 => 36,
           ),
           'list' => array(
             0 => 'S',
             1 => 45,
           ),
         ),
         40 => array(
           '>' => array(
             0 => 'S',
             1 => 41,
           ),
         ),
         41 => array(
           '?' => array(
             0 => 'R',
             1 => array(
               0 => 'map_type',
               1 => 0,
               2 => 6,
             ),
           ),
           '>' => array(
             0 => 'R',
             1 => array(
               0 => 'map_type',
               1 => 0,
               2 => 6,
             ),
           ),
           '|' => array(
             0 => 'R',
             1 => array(
               0 => 'map_type',
               1 => 0,
               2 => 6,
             ),
           ),
         ),
         42 => array(
           '?' => array(
             0 => 'R',
             1 => array(
               0 => 'some_type',
               1 => 1,
               2 => 1,
             ),
           ),
           '>' => array(
             0 => 'R',
             1 => array(
               0 => 'some_type',
               1 => 1,
               2 => 1,
             ),
           ),
           '|' => array(
             0 => 'S',
             1 => 43,
           ),
         ),
         43 => array(
           'k' => array(
             0 => 'S',
             1 => 35,
           ),
           'map' => array(
             0 => 'S',
             1 => 36,
           ),
           'list' => array(
             0 => 'S',
             1 => 45,
           ),
         ),
         44 => array(
           '?' => array(
             0 => 'R',
             1 => array(
               0 => 'or_type',
               1 => 1,
               2 => 3,
             ),
           ),
           '>' => array(
             0 => 'R',
             1 => array(
               0 => 'or_type',
               1 => 1,
               2 => 3,
             ),
           ),
           '|' => array(
             0 => 'R',
             1 => array(
               0 => 'or_type',
               1 => 1,
               2 => 3,
             ),
           ),
         ),
         45 => array(
           '<' => array(
             0 => 'S',
             1 => 46,
           ),
         ),
         46 => array(
           'k' => array(
             0 => 'S',
             1 => 35,
           ),
           'map' => array(
             0 => 'S',
             1 => 36,
           ),
           'list' => array(
             0 => 'S',
             1 => 45,
           ),
         ),
         47 => array(
           '>' => array(
             0 => 'S',
             1 => 48,
           ),
         ),
         48 => array(
           '?' => array(
             0 => 'R',
             1 => array(
               0 => 'list_type',
               1 => 0,
               2 => 4,
             ),
           ),
           '>' => array(
             0 => 'R',
             1 => array(
               0 => 'list_type',
               1 => 0,
               2 => 4,
             ),
           ),
           '|' => array(
             0 => 'R',
             1 => array(
               0 => 'list_type',
               1 => 0,
               2 => 4,
             ),
           ),
         ),
         49 => array(
           ',' => array(
             0 => 'R',
             1 => array(
               0 => 'type',
               1 => 'no',
               2 => 1,
             ),
           ),
           '?' => array(
             0 => 'S',
             1 => 50,
           ),
         ),
         50 => array(
           ',' => array(
             0 => 'R',
             1 => array(
               0 => 'type',
               1 => 'yes',
               2 => 2,
             ),
           ),
         ),
         51 => array(
           '?' => array(
             0 => 'R',
             1 => array(
               0 => 'some_type',
               1 => 0,
               2 => 1,
             ),
           ),
           ',' => array(
             0 => 'R',
             1 => array(
               0 => 'some_type',
               1 => 0,
               2 => 1,
             ),
           ),
           '|' => array(
             0 => 'S',
             1 => 52,
           ),
         ),
         52 => array(
           'k' => array(
             0 => 'S',
             1 => 57,
           ),
           'map' => array(
             0 => 'S',
             1 => 58,
           ),
           'list' => array(
             0 => 'S',
             1 => 67,
           ),
         ),
         53 => array(
           '?' => array(
             0 => 'R',
             1 => array(
               0 => 'or_type',
               1 => 0,
               2 => 3,
             ),
           ),
           ',' => array(
             0 => 'R',
             1 => array(
               0 => 'or_type',
               1 => 0,
               2 => 3,
             ),
           ),
           '|' => array(
             0 => 'R',
             1 => array(
               0 => 'or_type',
               1 => 0,
               2 => 3,
             ),
           ),
         ),
         54 => array(
           '?' => array(
             0 => 'R',
             1 => array(
               0 => 'not_or_type',
               1 => 0,
               2 => 1,
             ),
           ),
           ',' => array(
             0 => 'R',
             1 => array(
               0 => 'not_or_type',
               1 => 0,
               2 => 1,
             ),
           ),
           '|' => array(
             0 => 'R',
             1 => array(
               0 => 'not_or_type',
               1 => 0,
               2 => 1,
             ),
           ),
         ),
         55 => array(
           '?' => array(
             0 => 'R',
             1 => array(
               0 => 'not_or_type',
               1 => 1,
               2 => 1,
             ),
           ),
           ',' => array(
             0 => 'R',
             1 => array(
               0 => 'not_or_type',
               1 => 1,
               2 => 1,
             ),
           ),
           '|' => array(
             0 => 'R',
             1 => array(
               0 => 'not_or_type',
               1 => 1,
               2 => 1,
             ),
           ),
         ),
         56 => array(
           '?' => array(
             0 => 'R',
             1 => array(
               0 => 'not_or_type',
               1 => 2,
               2 => 1,
             ),
           ),
           ',' => array(
             0 => 'R',
             1 => array(
               0 => 'not_or_type',
               1 => 2,
               2 => 1,
             ),
           ),
           '|' => array(
             0 => 'R',
             1 => array(
               0 => 'not_or_type',
               1 => 2,
               2 => 1,
             ),
           ),
         ),
         57 => array(
           '?' => array(
             0 => 'R',
             1 => array(
               0 => 'basic_type',
               1 => 0,
               2 => 1,
             ),
           ),
           ',' => array(
             0 => 'R',
             1 => array(
               0 => 'basic_type',
               1 => 0,
               2 => 1,
             ),
           ),
           '|' => array(
             0 => 'R',
             1 => array(
               0 => 'basic_type',
               1 => 0,
               2 => 1,
             ),
           ),
         ),
         58 => array(
           '<' => array(
             0 => 'S',
             1 => 59,
           ),
         ),
         59 => array(
           'k' => array(
             0 => 'S',
             1 => 57,
           ),
           'map' => array(
             0 => 'S',
             1 => 58,
           ),
           'list' => array(
             0 => 'S',
             1 => 67,
           ),
         ),
         60 => array(
           ',' => array(
             0 => 'S',
             1 => 61,
           ),
         ),
         61 => array(
           'k' => array(
             0 => 'S',
             1 => 35,
           ),
           'map' => array(
             0 => 'S',
             1 => 36,
           ),
           'list' => array(
             0 => 'S',
             1 => 45,
           ),
         ),
         62 => array(
           '>' => array(
             0 => 'S',
             1 => 63,
           ),
         ),
         63 => array(
           '?' => array(
             0 => 'R',
             1 => array(
               0 => 'map_type',
               1 => 0,
               2 => 6,
             ),
           ),
           ',' => array(
             0 => 'R',
             1 => array(
               0 => 'map_type',
               1 => 0,
               2 => 6,
             ),
           ),
           '|' => array(
             0 => 'R',
             1 => array(
               0 => 'map_type',
               1 => 0,
               2 => 6,
             ),
           ),
         ),
         64 => array(
           '?' => array(
             0 => 'R',
             1 => array(
               0 => 'some_type',
               1 => 1,
               2 => 1,
             ),
           ),
           ',' => array(
             0 => 'R',
             1 => array(
               0 => 'some_type',
               1 => 1,
               2 => 1,
             ),
           ),
           '|' => array(
             0 => 'S',
             1 => 65,
           ),
         ),
         65 => array(
           'k' => array(
             0 => 'S',
             1 => 57,
           ),
           'map' => array(
             0 => 'S',
             1 => 58,
           ),
           'list' => array(
             0 => 'S',
             1 => 67,
           ),
         ),
         66 => array(
           '?' => array(
             0 => 'R',
             1 => array(
               0 => 'or_type',
               1 => 1,
               2 => 3,
             ),
           ),
           ',' => array(
             0 => 'R',
             1 => array(
               0 => 'or_type',
               1 => 1,
               2 => 3,
             ),
           ),
           '|' => array(
             0 => 'R',
             1 => array(
               0 => 'or_type',
               1 => 1,
               2 => 3,
             ),
           ),
         ),
         67 => array(
           '<' => array(
             0 => 'S',
             1 => 68,
           ),
         ),
         68 => array(
           'k' => array(
             0 => 'S',
             1 => 35,
           ),
           'map' => array(
             0 => 'S',
             1 => 36,
           ),
           'list' => array(
             0 => 'S',
             1 => 45,
           ),
         ),
         69 => array(
           '>' => array(
             0 => 'S',
             1 => 70,
           ),
         ),
         70 => array(
           '?' => array(
             0 => 'R',
             1 => array(
               0 => 'list_type',
               1 => 0,
               2 => 4,
             ),
           ),
           ',' => array(
             0 => 'R',
             1 => array(
               0 => 'list_type',
               1 => 0,
               2 => 4,
             ),
           ),
           '|' => array(
             0 => 'R',
             1 => array(
               0 => 'list_type',
               1 => 0,
               2 => 4,
             ),
           ),
         ),
         71 => array(
           '<' => array(
             0 => 'S',
             1 => 72,
           ),
         ),
         72 => array(
           'k' => array(
             0 => 'S',
             1 => 35,
           ),
           'map' => array(
             0 => 'S',
             1 => 36,
           ),
           'list' => array(
             0 => 'S',
             1 => 45,
           ),
         ),
         73 => array(
           '>' => array(
             0 => 'S',
             1 => 74,
           ),
         ),
         74 => array(
           '?' => array(
             0 => 'R',
             1 => array(
               0 => 'list_type',
               1 => 0,
               2 => 4,
             ),
           ),
           '(' => array(
             0 => 'R',
             1 => array(
               0 => 'list_type',
               1 => 0,
               2 => 4,
             ),
           ),
           '(end-of-file)' => array(
             0 => 'R',
             1 => array(
               0 => 'list_type',
               1 => 0,
               2 => 4,
             ),
           ),
           '|' => array(
             0 => 'R',
             1 => array(
               0 => 'list_type',
               1 => 0,
               2 => 4,
             ),
           ),
         ),
         75 => array(
           '?' => array(
             0 => 'R',
             1 => array(
               0 => 'some_type',
               1 => 1,
               2 => 1,
             ),
           ),
           '(' => array(
             0 => 'R',
             1 => array(
               0 => 'some_type',
               1 => 1,
               2 => 1,
             ),
           ),
           '(end-of-file)' => array(
             0 => 'R',
             1 => array(
               0 => 'some_type',
               1 => 1,
               2 => 1,
             ),
           ),
           '|' => array(
             0 => 'S',
             1 => 76,
           ),
         ),
         76 => array(
           'k' => array(
             0 => 'S',
             1 => 20,
           ),
           'map' => array(
             0 => 'S',
             1 => 21,
           ),
           'list' => array(
             0 => 'S',
             1 => 71,
           ),
         ),
         77 => array(
           '?' => array(
             0 => 'R',
             1 => array(
               0 => 'or_type',
               1 => 1,
               2 => 3,
             ),
           ),
           '(' => array(
             0 => 'R',
             1 => array(
               0 => 'or_type',
               1 => 1,
               2 => 3,
             ),
           ),
           '(end-of-file)' => array(
             0 => 'R',
             1 => array(
               0 => 'or_type',
               1 => 1,
               2 => 3,
             ),
           ),
           '|' => array(
             0 => 'R',
             1 => array(
               0 => 'or_type',
               1 => 1,
               2 => 3,
             ),
           ),
         ),
         78 => array(
           '(end-of-file)' => array(
             0 => 'R',
             1 => array(
               0 => 'maybe_optional',
               1 => 'no',
               2 => 1,
             ),
           ),
         ),
       ),
       array(
         0 => array(
           'start' => 1,
           'maybe_optional' => 2,
           'maybe_comment' => 78,
           'type' => 5,
           'some_type' => 12,
           'or_type' => 14,
           'not_or_type' => 75,
           'basic_type' => 17,
           'map_type' => 18,
           'list_type' => 19,
         ),
         3 => array(
           'maybe_comment' => 4,
           'type' => 5,
           'some_type' => 12,
           'or_type' => 14,
           'not_or_type' => 75,
           'basic_type' => 17,
           'map_type' => 18,
           'list_type' => 19,
         ),
         5 => array(
           'comment' => 6,
         ),
         7 => array(
           'comment_text' => 8,
         ),
         15 => array(
           'not_or_type' => 16,
           'basic_type' => 17,
           'map_type' => 18,
           'list_type' => 19,
         ),
         22 => array(
           'type' => 23,
           'some_type' => 49,
           'or_type' => 51,
           'not_or_type' => 64,
           'basic_type' => 54,
           'map_type' => 55,
           'list_type' => 56,
         ),
         24 => array(
           'type' => 25,
           'some_type' => 27,
           'or_type' => 29,
           'not_or_type' => 42,
           'basic_type' => 32,
           'map_type' => 33,
           'list_type' => 34,
         ),
         30 => array(
           'not_or_type' => 31,
           'basic_type' => 32,
           'map_type' => 33,
           'list_type' => 34,
         ),
         37 => array(
           'type' => 38,
           'some_type' => 49,
           'or_type' => 51,
           'not_or_type' => 64,
           'basic_type' => 54,
           'map_type' => 55,
           'list_type' => 56,
         ),
         39 => array(
           'type' => 40,
           'some_type' => 27,
           'or_type' => 29,
           'not_or_type' => 42,
           'basic_type' => 32,
           'map_type' => 33,
           'list_type' => 34,
         ),
         43 => array(
           'not_or_type' => 44,
           'basic_type' => 32,
           'map_type' => 33,
           'list_type' => 34,
         ),
         46 => array(
           'type' => 47,
           'some_type' => 27,
           'or_type' => 29,
           'not_or_type' => 42,
           'basic_type' => 32,
           'map_type' => 33,
           'list_type' => 34,
         ),
         52 => array(
           'not_or_type' => 53,
           'basic_type' => 54,
           'map_type' => 55,
           'list_type' => 56,
         ),
         59 => array(
           'type' => 60,
           'some_type' => 49,
           'or_type' => 51,
           'not_or_type' => 64,
           'basic_type' => 54,
           'map_type' => 55,
           'list_type' => 56,
         ),
         61 => array(
           'type' => 62,
           'some_type' => 27,
           'or_type' => 29,
           'not_or_type' => 42,
           'basic_type' => 32,
           'map_type' => 33,
           'list_type' => 34,
         ),
         65 => array(
           'not_or_type' => 66,
           'basic_type' => 54,
           'map_type' => 55,
           'list_type' => 56,
         ),
         68 => array(
           'type' => 69,
           'some_type' => 27,
           'or_type' => 29,
           'not_or_type' => 42,
           'basic_type' => 32,
           'map_type' => 33,
           'list_type' => 34,
         ),
         72 => array(
           'type' => 73,
           'some_type' => 27,
           'or_type' => 29,
           'not_or_type' => 42,
           'basic_type' => 32,
           'map_type' => 33,
           'list_type' => 34,
         ),
         76 => array(
           'not_or_type' => 77,
           'basic_type' => 17,
           'map_type' => 18,
           'list_type' => 19,
         ),
       ),
       '(end-of-file)',
       $tokens,
       $callback);
   }
 
 }
diff --git a/src/parser/__tests__/PhutilTypeSpecTestCase.php b/src/parser/__tests__/PhutilTypeSpecTestCase.php
index 9c833ae..2863c52 100644
--- a/src/parser/__tests__/PhutilTypeSpecTestCase.php
+++ b/src/parser/__tests__/PhutilTypeSpecTestCase.php
@@ -1,291 +1,312 @@
 <?php
 
 final class PhutilTypeSpecTestCase extends PhutilTestCase {
 
   public function testTypeSpecParse() {
     $good = array(
       'int',
       'int|null',
       'string',
       'SomeClass',
       'map<string, string>',
       'int  | null',
       'list  < string   >',
       'int (must be even)',
       'optional int',
       'int?',
       'int|null?',
       'optional int? (minimum 300)',
       'list<wild>',
       'list<list<list<map<string, string>>>> (easy)',
     );
 
     $bad = array(
       '<list>',
       'list<>',
       'list<string, string>',
       'map|map',
       'int optional',
       '(derp)',
       'list<string (capital letters), string>',
       'int?|string',
     );
 
     $good = array_fill_keys($good, true);
     $bad = array_fill_keys($bad, false);
 
     foreach ($good + $bad as $input => $expect) {
       $caught = null;
       try {
         PhutilTypeSpec::newFromString($input);
       } catch (Exception $ex) {
         $caught = $ex;
       }
 
       $this->assertEqual(
         $expect,
         ($caught === null),
         $input);
     }
   }
 
   public function testTypeSpecStringify() {
     $types = array(
       'int',
       'list<int>',
       'map<int, int>',
       'list<list<string>>',
       'map<string, map<int, string>>',
       'int|null',
       'int|string|null',
       'list<int|string>',
       'list<SomeObject>',
       'optional int',
       'int (even)',
     );
 
     foreach ($types as $type) {
       $this->assertEqual(
         $type,
         PhutilTypeSpec::newFromString($type)->toString());
     }
   }
 
   public function testCanonicalize() {
     $tests = array(
       'int?'        => 'optional int',
       'int  | null' => 'int|null',
       'list  < map <  int , string > >  ?' => 'optional list<map<int, string>>',
       'int   (  x  )' => 'int (  x  )',
     );
 
     foreach ($tests as $input => $expect) {
       $this->assertEqual(
         $expect,
         PhutilTypeSpec::newFromString($input)->toString(),
         $input);
     }
   }
 
   public function testGetCommonParentClass() {
     $map = array(
       'stdClass'  => array(
         array('stdClass', 'stdClass'),
       ),
       false       => array(
         array('Exception', 'stdClass'),
       ),
       'Exception' => array(
         array('Exception', 'RuntimeException'),
         array('LogicException', 'RuntimeException'),
         array('BadMethodCallException', 'OutOfBoundsException'),
       ),
     );
 
     foreach ($map as $expect => $tests) {
       if (is_int($expect)) {
         $expect = (bool)$expect;
       }
 
       foreach ($tests as $input) {
         list($class_a, $class_b) = $input;
 
         $this->assertEqual(
           $expect,
           PhutilTypeSpec::getCommonParentClass($class_a, $class_b),
           print_r($input, true));
       }
     }
   }
 
   public function testGetTypeOf() {
     $map = array(
       'int'                     => 1,
       'string'                  => 'asdf',
       'float'                   => 1.5,
       'bool'                    => true,
       'null'                    => null,
       'map<wild, wild>'         => array(),
       'list<string>'            => array('a', 'b'),
       'list<int>'               => array(1, 2, 3),
       'map<string, int>'        => array('x' => 3),
       'map<int, list<string>>'  => array(1 => array('x', 'y')),
       'stdClass'                => new stdClass(),
       'list<Exception>'         => array(
         new Exception(),
         new LogicException(),
         new RuntimeException(),
       ),
       'map<string, stdClass>'   => array('x' => new stdClass()),
     );
 
     foreach ($map as $expect => $input) {
       $this->assertEqual(
         $expect,
         PhutilTypeSpec::getTypeOf($input),
         print_r($input, true));
 
       PhutilTypeSpec::newFromString($expect)->check($input);
     }
   }
 
   public function testTypeCheckFailures() {
     $map = array(
       'int'                     => 'string',
       'string'                  => 32,
       'null'                    => true,
       'bool'                    => null,
       'map<wild, wild>'         => 16,
       'list<string>'            => array('y' => 'z'),
       'int|null'                => 'ducks',
       'stdClass'                => new Exception(),
       'list<RuntimeException>'  => array(new Exception()),
     );
 
     foreach ($map as $type => $value) {
       $caught = null;
       try {
         PhutilTypeSpec::newFromString($type)->check($value);
       } catch (PhutilTypeCheckException $ex) {
         $caught = $ex;
       }
 
-      $this->assertTrue($ex instanceof PhutilTypeCheckException);
+      $this->assertTrue($caught instanceof PhutilTypeCheckException);
     }
   }
 
   public function testCheckMap() {
     $spec = array(
       'count' => 'int',
       'color' => 'optional string',
     );
 
     // Valid
 
     PhutilTypeSpec::checkMap(
       array(
         'count' => 1,
       ),
       $spec);
 
     // Valid, with optional parameter.
 
     PhutilTypeSpec::checkMap(
       array(
         'count' => 3,
         'color' => 'red',
       ),
       $spec);
 
     // Parameter "count" is required but missing.
 
     $caught = null;
     try {
       PhutilTypeSpec::checkMap(
         array(),
         $spec);
     } catch (Exception $ex) {
       $caught = $ex;
     }
 
-    $this->assertTrue($ex instanceof PhutilTypeMissingParametersException);
+    $this->assertTrue($caught instanceof PhutilTypeMissingParametersException);
 
     // Parameter "size" is specified but does not exist.
 
     $caught = null;
     try {
       PhutilTypeSpec::checkMap(
         array(
           'count' => 4,
           'size' => 'large',
         ),
         $spec);
     } catch (Exception $ex) {
       $caught = $ex;
     }
 
-    $this->assertTrue($ex instanceof PhutilTypeExtraParametersException);
+    $this->assertTrue($caught instanceof PhutilTypeExtraParametersException);
   }
 
   public function testRegexValidation() {
     PhutilTypeSpec::checkMap(
       array(
         'regex' => '/.*/',
       ),
       array(
         'regex' => 'regex',
       ));
 
     $caught = null;
     try {
       PhutilTypeSpec::checkMap(
         array(
           'regex' => '.*',
         ),
         array(
           'regex' => 'regex',
         ));
     } catch (PhutilTypeCheckException $ex) {
       $caught = $ex;
     }
 
-    $this->assertTrue($ex instanceof PhutilTypeCheckException);
+    $this->assertTrue($caught instanceof PhutilTypeCheckException);
   }
 
   public function testScalarOrListRegexp() {
     PhutilTypeSpec::checkMap(
       array(
         'regex' => '/.*/',
       ),
       array(
         'regex' => 'regex | list<regex>',
       ));
 
     PhutilTypeSpec::checkMap(
       array(
         'regex' => array('/.*/'),
       ),
       array(
         'regex' => 'regex | list<regex>',
       ));
 
     PhutilTypeSpec::checkMap(
       array(
         'regex' => '/.*/',
       ),
       array(
         'regex' => 'list<regex> | regex',
       ));
 
     PhutilTypeSpec::checkMap(
       array(
         'regex' => array('/.*/'),
       ),
       array(
         'regex' => 'list<regex> | regex',
       ));
 
     $this->assertTrue(true);
   }
 
+  public function testMixedVector() {
+    // This is a test case for an issue where we would not infer the type
+    // of a vector containing a mixture of scalar and nonscalar elements
+    // correctly.
+
+    $caught = null;
+    try {
+      PhutilTypeSpec::checkMap(
+        array(
+          'key' => array('!', (object)array()),
+        ),
+        array(
+          'key' => 'list<X>',
+        ));
+    } catch (PhutilTypeCheckException $ex) {
+      $caught = $ex;
+    }
+
+    $this->assertTrue($caught instanceof PhutilTypeCheckException);
+  }
+
 }