Constrain generic for regex values

Author: fredemmott

src/key-value-render/HackBuilderRegexRenderer.hack

@@ -13,7 +13,7 @@ use type Facebook\HackCodegen\{IHackBuilderValueRenderer, IHackCodegenConfig};
 
 use namespace HH\Lib\{Regex, Str};
 
-final class HackBuilderRegexRenderer<T>
+final class HackBuilderRegexRenderer<T as Regex\Match>
   implements IHackBuilderValueRenderer<Regex\Pattern<T>> {
 
   public function render(

src/key-value-render/HackBuilderValues.hack

@@ -33,7 +33,7 @@ abstract final class HackBuilderValues {
   /**
    * Render a regex literal, e.g. `re"/foo/"`.
    */
-  public static function regex<T>(
+  public static function regex<T as \HH\Lib\Regex\Match>(
   ): IHackBuilderValueRenderer<\HH\Lib\Regex\Pattern<T>> {
     return new _Private\HackBuilderRegexRenderer();
   }