diff --git a/hphp/compiler/parser/hphp.tab.cpp b/hphp/compiler/parser/hphp.tab.cpp
index cf151b88d..c38299e02 100644
--- a/hphp/compiler/parser/hphp.tab.cpp
+++ b/hphp/compiler/parser/hphp.tab.cpp
@@ -10376,7 +10376,7 @@ yyreduce:
                                         _p->onTypeList((yyvsp[(2) - (5)]), (yyvsp[(4) - (5)]));
                                         Token t; t.reset(); t.setText("array");
                                         _p->onTypeAnnotation((yyval), t, (yyvsp[(2) - (5)]));
-                                        _p->onTypeSpecialization((yyval), 's'); ;}
+                                        _p->onTypeSpecialization((yyval), 't'); ;}
     break;
 
   case 705:
diff --git a/hphp/test/slow/reflection_classes/1366.php b/hphp/test/slow/reflection_classes/1366.php
new file mode 100644
index 000000000..013ee2c5c
--- /dev/null
+++ b/hphp/test/slow/reflection_classes/1366.php
@@ -0,0 +1,140 @@
+<?hh
+function printFunc($rf) {
+  $rps = $rf->getParameters();
+  foreach($rps as $rp) {
+    var_dump($rp->getTypehintText());
+  }
+  var_dump($rf->getReturnTypehintText());
+}
+function printClass($rc) {
+  $rms = $rc->getMethods();
+  $meths = array();
+  foreach($rms as $rm) {
+    $meths[$rm->getName()] = $rm;
+  }
+  ksort($meths);
+  foreach($meths as $meth) {
+    printFunc($meth);
+  }
+  $rps = $rc->getProperties();
+  $props = array();
+  foreach($rps as $rp) {
+    $props[$rp->getName()] = $rp;
+  }
+  ksort($props);
+  foreach($props as $prop) {
+    var_dump($prop->getTypehintText());
+  }
+}
+function f() {
+}
+$rf = new ReflectionFunction('f');
+printFunc($rf);
+function f1(int $t) {
+}
+$rf = new ReflectionFunction('f1');
+printFunc($rf);
+function f2(@string $s) {
+}
+$rf = new ReflectionFunction('f2');
+printFunc($rf);
+function f3(?:xhp:hello $x) {
+}
+$rf = new ReflectionFunction('f3');
+printFunc($rf);
+function f100(): int {
+}
+$rf = new ReflectionFunction('f100');
+printFunc($rf);
+function f101(): string {
+}
+$rf = new ReflectionFunction('f101');
+printFunc($rf);
+function f102(): Vector<:xhp:element> {
+}
+$rf = new ReflectionFunction('f102');
+printFunc($rf);
+function f200((string, Template<A, B, ?C>, ?int, Vector<Map<C, B>>) $tuple): ?int {
+}
+$rf = new ReflectionFunction('f200');
+printFunc($rf);
+function f201((function (@int, Map<string, Map<int, Vector<string>>>):Vector<C>) $i): ClassA {
+}
+$rf = new ReflectionFunction('f201');
+printFunc($rf);
+function f202(:xhp:html-element $html): Map<string, Vector<:xhp:html-element>> {
+}
+$rf = new ReflectionFunction('f202');
+printFunc($rf);
+function f203((int, Vector<string>) $tupple): array<ClassA> {
+}
+$rf = new ReflectionFunction('f203');
+printFunc($rf);
+function f204((function (int): Vector<string>) $f): array<string, ClassA> {
+}
+$rf = new ReflectionFunction('f204');
+printFunc($rf);
+function f300<X, Y>(Y $y, ?double $d): X {
+}
+$rf = new ReflectionFunction('f300');
+printFunc($rf);
+function f301<X, Y>((function (): Vector<Y>) $f): array<string, X> {
+}
+$rf = new ReflectionFunction('f301');
+printFunc($rf);
+function f302<X, Y>((Y, X, double, string) $f): ?Y {
+}
+$rf = new ReflectionFunction('f302');
+printFunc($rf);
+class C {
+  public @int $a;
+  public ?string $b;
+  public Vector<C> $v;
+  public (string, (function(?int, (string, string)):void)) $c;
+  public function __construct(?int $i, (int, string) $c) {
+}
+  static public function m1() {
+}
+  public function m2(@double $d) : void {
+}
+  static public function m3(Vector<Map<int, Vector<?string>>> $v, :xhp:html $x) : @array<int, ?Vector<string>> {
+}
+  public function m4((function(@int, (string, string)): void) $v) : array<Map<string, :xhp:html>> {
+}
+}
+$rc = new ReflectionClass('C');
+printClass($rc);
+class CT<X, Y> {
+  public @int $a;
+  public ?string $b;
+  public Vector<X> $v;
+  public (string, (function(?int, (X, Y)):void)) $c;
+  public function __construct(?int $i, (int, X) $c) {
+}
+  static public function m1() {
+}
+  public function m2(@Y $d) : void {
+}
+  static public function m3(Vector<Map<int, Vector<?X>>> $v, :xhp:html $x) : @array<Y, ?Vector<string>> {
+}
+  public function m4((function(@int, (X, string)): void) $v) : array<Map<Y, :xhp:html>> {
+}
+}
+$rc = new ReflectionClass('CT');
+printClass($rc);
+trait T {
+  static public function m1() {
+}
+  public function m2(@int $d) : void {
+}
+  static public function m3(Vector<Map<int, Vector<?C>>> $v, :xhp:html $x) : @array<C, ?Vector<string>> {
+}
+  public function m4((function(@int, (double, string)): void) $v) : array<Map<CT<int, string>, :xhp:html>> {
+}
+}
+class TC {
+  use T;
+}
+$rc = new ReflectionClass('TC');
+printClass($rc);
+
diff --git a/hphp/test/slow/reflection_classes/1366.php.expect b/hphp/test/slow/reflection_classes/1366.php.expect
new file mode 100644
index 000000000..60f73dfdc
--- /dev/null
+++ b/hphp/test/slow/reflection_classes/1366.php.expect
@@ -0,0 +1,65 @@
+bool(false)
+string(3) "int"
+bool(false)
+string(7) "@string"
+bool(false)
+string(11) "?:xhp:hello"
+bool(false)
+string(3) "int"
+string(6) "string"
+string(20) "Vector<:xhp:element>"
+string(53) "(string, Template<A, B, ?C>, ?int, Vector<Map<C, B>>)"
+string(4) "?int"
+string(67) "(function (@int, Map<string, Map<int, Vector<string>>>): Vector<C>)"
+string(6) "ClassA"
+string(17) ":xhp:html-element"
+string(38) "Map<string, Vector<:xhp:html-element>>"
+string(21) "(int, Vector<string>)"
+string(13) "array<ClassA>"
+string(32) "(function (int): Vector<string>)"
+string(21) "array<string, ClassA>"
+string(1) "Y"
+string(7) "?double"
+string(1) "X"
+string(24) "(function (): Vector<Y>)"
+string(16) "array<string, X>"
+string(22) "(Y, X, double, string)"
+string(2) "?Y"
+string(4) "?int"
+string(13) "(int, string)"
+bool(false)
+bool(false)
+string(7) "@double"
+string(4) "void"
+string(33) "Vector<Map<int, Vector<?string>>>"
+string(9) ":xhp:html"
+string(28) "@array<int, ?Vector<string>>"
+string(41) "(function (@int, (string, string)): void)"
+string(29) "array<Map<string, :xhp:html>>"
+string(4) "@int"
+string(7) "?string"
+string(51) "(string, (function (?int, (string, string)): void))"
+string(9) "Vector<C>"
+string(4) "?int"
+string(8) "(int, X)"
+bool(false)
+bool(false)
+string(2) "@Y"
+string(4) "void"
+string(28) "Vector<Map<int, Vector<?X>>>"
+string(9) ":xhp:html"
+string(26) "@array<Y, ?Vector<string>>"
+string(36) "(function (@int, (X, string)): void)"
+string(24) "array<Map<Y, :xhp:html>>"
+string(4) "@int"
+string(7) "?string"
+string(41) "(string, (function (?int, (X, Y)): void))"
+string(9) "Vector<X>"
+bool(false)
+string(4) "@int"
+string(4) "void"
+string(28) "Vector<Map<int, Vector<?C>>>"
+string(9) ":xhp:html"
+string(26) "@array<C, ?Vector<string>>"
+string(41) "(function (@int, (double, string)): void)"
+string(38) "array<Map<CT<int, string>, :xhp:html>>"
diff --git a/hphp/util/parser/test/hphp.tab.cpp b/hphp/util/parser/test/hphp.tab.cpp
index 92dce225d..b9f980563 100644
--- a/hphp/util/parser/test/hphp.tab.cpp
+++ b/hphp/util/parser/test/hphp.tab.cpp
@@ -10372,7 +10372,7 @@ yyreduce:
                                         _p->onTypeList((yyvsp[(2) - (5)]), (yyvsp[(4) - (5)]));
                                         Token t; t.reset(); t.setText("array");
                                         _p->onTypeAnnotation((yyval), t, (yyvsp[(2) - (5)]));
-                                        _p->onTypeSpecialization((yyval), 's'); ;}
+                                        _p->onTypeSpecialization((yyval), 't'); ;}
     break;
 
   case 705: