diff --git a/.travis.yml b/.travis.yml
index 9405c5e..53abfb7 100644
--- a/.travis.yml
+++ b/.travis.yml
@@ -2,7 +2,7 @@ sudo: required
 language: generic
 services: docker
 env:
-- HHVM_VERSION=4.8-latest
+- HHVM_VERSION=4.14-latest
 - HHVM_VERSION=latest
 - HHVM_VERSION=nightly
 install:
diff --git a/composer.json b/composer.json
index 2ec19cf..0b91831 100644
--- a/composer.json
+++ b/composer.json
@@ -3,12 +3,12 @@
   "bin": [ "bin/hh-apidoc", "bin/hh-apidoc.hack" ],
   "license": "MIT",
   "require": {
-    "hhvm": "^4.8",
+    "hhvm": "^4.14",
     "hhvm/hsl": "^4.0",
     "facebook/fbmarkdown": "^1.0",
     "facebook/hh-clilib": "^2.1.0",
     "facebook/definition-finder": "^2.0.0",
-    "hhvm/hhast": "^4.8"
+    "hhvm/hhast": "^4.14"
   },
   "require-dev": {
     "hhvm/hhvm-autoload": "^2.0"
diff --git a/src/MarkdownExt/AutoLinkifyFilter.hack b/src/MarkdownExt/AutoLinkifyFilter.hack
index 2fa9834..a4d8cd2 100644
--- a/src/MarkdownExt/AutoLinkifyFilter.hack
+++ b/src/MarkdownExt/AutoLinkifyFilter.hack
@@ -35,7 +35,7 @@ final class AutoLinkifyFilter extends Markdown\RenderFilter {
     Markdown\RenderContext $context,
     Markdown\ASTNode $node,
   ): vec<Markdown\ASTNode> {
-    if (!$node instanceof CodeSpan) {
+    if (!$node is CodeSpan) {
       return vec[$node];
     }
 
@@ -55,7 +55,7 @@ final class AutoLinkifyFilter extends Markdown\RenderFilter {
     }
 
     invariant(
-      $context instanceof RenderContext,
+      $context is RenderContext,
       'Expected render context to be a %s',
       RenderContext::class,
     );
@@ -129,7 +129,7 @@ final class AutoLinkifyFilter extends Markdown\RenderFilter {
     }
 
     $def = $context->getDocumentable()['definition'];
-    if ($def instanceof ScannedClassish) {
+    if ($def is ScannedClassish) {
       $path = self::getPathForMethod($context, $def->getName(), $search);
       if ($path !== null) {
         return $path;
diff --git a/src/MarkdownExt/SyntaxHighlightingFilter.hack b/src/MarkdownExt/SyntaxHighlightingFilter.hack
index 1bc8b9a..e762bc5 100644
--- a/src/MarkdownExt/SyntaxHighlightingFilter.hack
+++ b/src/MarkdownExt/SyntaxHighlightingFilter.hack
@@ -33,10 +33,10 @@ final class SyntaxHighlightingFilter extends Markdown\RenderFilter {
     Markdown\RenderContext $context,
     Markdown\ASTNode $node,
   ): vec<Markdown\ASTNode> {
-    if (!$node instanceof CodeBlock) {
+    if (!$node is CodeBlock) {
       return vec[$node];
     }
-    if ($context instanceof namespace\RenderContext) {
+    if ($context is namespace\RenderContext) {
       if ($context->getOutputFormat() !== OutputFormat::HTML) {
         return vec[$node];
       }
@@ -65,10 +65,6 @@ final class SyntaxHighlightingFilter extends Markdown\RenderFilter {
 
   /** Convert an HHAST FFP AST node into an HTML string. */
   protected static function getHTML(HHAST\Node $node): string {
-    if ($node instanceof HHAST\Missing) {
-      return '';
-    }
-
     if ($node->isTrivia() || $node->isToken()) {
       $inner = \htmlspecialchars($node->getCode());
     } else {
@@ -77,7 +73,7 @@ final class SyntaxHighlightingFilter extends Markdown\RenderFilter {
         |> Str\join($$, '');
     }
 
-    if ($node instanceof HHAST\NodeList ) {
+    if ($node is HHAST\NodeList<_> ) {
       return $inner;
     }
 
diff --git a/src/PageSections/FunctionishParameters.hack b/src/PageSections/FunctionishParameters.hack
index 0403e18..ba3e276 100644
--- a/src/PageSections/FunctionishParameters.hack
+++ b/src/PageSections/FunctionishParameters.hack
@@ -21,7 +21,7 @@ final class FunctionishParameters extends PageSection {
   <<__Override>>
   public function getMarkdown(): ?string {
     $f = $this->definition;
-    if (!$f instanceof ScannedFunctionish) {
+    if (!$f is ScannedFunctionish) {
       return null;
     }
 
diff --git a/src/PageSections/FunctionishReturnValues.hack b/src/PageSections/FunctionishReturnValues.hack
index 0bd7ee6..f2041a9 100644
--- a/src/PageSections/FunctionishReturnValues.hack
+++ b/src/PageSections/FunctionishReturnValues.hack
@@ -19,7 +19,7 @@ final class FunctionishReturnValues extends PageSection {
   <<__Override>>
   public function getMarkdown(): ?string {
     $f = $this->definition;
-    if (!$f instanceof ScannedFunctionish) {
+    if (!$f is ScannedFunctionish) {
       return null;
     }
 
diff --git a/src/PageSections/FunctionishSignature.hack b/src/PageSections/FunctionishSignature.hack
index 3b2daba..eb1b5da 100644
--- a/src/PageSections/FunctionishSignature.hack
+++ b/src/PageSections/FunctionishSignature.hack
@@ -16,7 +16,7 @@ final class FunctionishSignature extends PageSection {
   <<__Override>>
   public function getMarkdown(): ?string {
     $f = $this->definition;
-    if (!$f instanceof ScannedFunctionish) {
+    if (!$f is ScannedFunctionish) {
       return null;
     }
 
diff --git a/src/PageSections/InterfaceSynopsis.hack b/src/PageSections/InterfaceSynopsis.hack
index 265aa58..23f8a4d 100644
--- a/src/PageSections/InterfaceSynopsis.hack
+++ b/src/PageSections/InterfaceSynopsis.hack
@@ -24,7 +24,7 @@ final class InterfaceSynopsis extends PageSection {
   <<__Override>>
   public function getMarkdown(): ?string {
     $c = $this->definition;
-    if (!$c instanceof ScannedClassish) {
+    if (!$c is ScannedClassish) {
       return null;
     }
 
@@ -104,13 +104,13 @@ final class InterfaceSynopsis extends PageSection {
     ScannedMethod $m,
   ): ?string {
     $pp = $this->context->getPathProvider();
-    if ($c instanceof ScannedClass) {
+    if ($c is ScannedClass) {
       return $pp->getPathForClassMethod($c->getName(), $m->getName());
     }
-    if ($c instanceof ScannedInterface) {
+    if ($c is ScannedInterface) {
       return $pp->getPathForInterfaceMethod($c->getName(), $m->getName());
     }
-    if ($c instanceof ScannedTrait) {
+    if ($c is ScannedTrait) {
       return $pp->getPathForTraitMethod($c->getName(), $m->getName());
     }
     invariant_violation("Don't know how to handle type %s", \get_class($c));
@@ -131,11 +131,11 @@ final class InterfaceSynopsis extends PageSection {
       $ret .= 'final ';
     }
 
-    if ($c instanceof ScannedClass) {
+    if ($c is ScannedClass) {
       $ret .= 'class ';
-    } else if ($c instanceof ScannedInterface) {
+    } else if ($c is ScannedInterface) {
       $ret .= 'interface ';
-    } else if ($c instanceof ScannedTrait) {
+    } else if ($c is ScannedTrait) {
       $ret .= 'trait ';
     } else {
       invariant_violation("Don't know what a %s is.", \get_class($c));
diff --git a/src/PageSections/NameHeading.hack b/src/PageSections/NameHeading.hack
index 66451db..b31077a 100644
--- a/src/PageSections/NameHeading.hack
+++ b/src/PageSections/NameHeading.hack
@@ -23,7 +23,7 @@ final class NameHeading extends PageSection {
     $def = $this->definition;
     $md .= $def->getName();
 
-    if ($def instanceof ScannedFunctionish) {
+    if ($def is ScannedFunctionish) {
       $md .= '()';
     }
 
diff --git a/src/PageSections/ShapeFields.hack b/src/PageSections/ShapeFields.hack
index e7887ba..1c142a9 100644
--- a/src/PageSections/ShapeFields.hack
+++ b/src/PageSections/ShapeFields.hack
@@ -19,7 +19,7 @@ final class ShapeFields extends PageSection {
   public function getMarkdown(): ?string {
     $t = $this->definition;
     // Intentionally not documenting opaque type aliases
-    if (!$t instanceof ScannedType) {
+    if (!$t is ScannedType) {
       return null;
     }
     $t = $t->getAliasedType();
diff --git a/src/PageSections/TypeDeclaration.hack b/src/PageSections/TypeDeclaration.hack
index 9a45550..70155f6 100644
--- a/src/PageSections/TypeDeclaration.hack
+++ b/src/PageSections/TypeDeclaration.hack
@@ -20,7 +20,7 @@ final class TypeDeclaration extends PageSection {
   <<__Override>>
   public function getMarkdown(): ?string {
     $t = $this->definition;
-    if (!$t instanceof ScannedTypeish) {
+    if (!$t is ScannedTypeish) {
       return null;
     }
     return $this->getTypeDeclaration($t);
@@ -34,7 +34,7 @@ final class TypeDeclaration extends PageSection {
       $code .= 'namespace '.$ns.";\n\n";
     }
 
-    if ($t instanceof ScannedType) {
+    if ($t is ScannedType) {
       $code .= 'type ';
     } else {
       $code .= 'newtype ';
@@ -42,7 +42,7 @@ final class TypeDeclaration extends PageSection {
 
     $code .= _Private\ns_normalize_type($ns, $t->getName());
 
-    if ($t instanceof ScannedType) {
+    if ($t is ScannedType) {
       $code .= ' = '.
         _Private\stringify_typehint(
           $t->getNamespaceName(),
diff --git a/src/PageSections/_Private/stringify_functionish_signature.hack b/src/PageSections/_Private/stringify_functionish_signature.hack
index d80e05c..6f6644a 100644
--- a/src/PageSections/_Private/stringify_functionish_signature.hack
+++ b/src/PageSections/_Private/stringify_functionish_signature.hack
@@ -29,7 +29,7 @@ function stringify_functionish_signature(
     $name = $function->getName();
   }
 
-  if ($function instanceof ScannedMethod) {
+  if ($function is ScannedMethod) {
     if ($function->isAbstract()) {
       $ret .= 'abstract ';
     }
diff --git a/src/create_index.hack b/src/create_index.hack
index 2695572..d2b3c18 100644
--- a/src/create_index.hack
+++ b/src/create_index.hack
@@ -38,31 +38,31 @@ function create_index(
     $def = $what['definition'];
     $name = $def->getName();
 
-    if ($def instanceof ScannedFunction) {
+    if ($def is ScannedFunction) {
       $index['functions'][] = $name;
       continue;
     }
-    if ($def instanceof ScannedType) {
+    if ($def is ScannedType) {
       $index['types'][] = $name;
       continue;
     }
-    if ($def instanceof ScannedNewtype) {
+    if ($def is ScannedNewtype) {
       $index['newtypes'][] = $name;
       continue;
     }
-    if ($def instanceof ScannedClass) {
+    if ($def is ScannedClass) {
       if (!C\contains_key($index['classes'], $name)) {
         $index['classes'][$def->getName()] = keyset[];
       }
       continue;
     }
-    if ($def instanceof ScannedInterface) {
+    if ($def is ScannedInterface) {
       if (!C\contains_key($index['interfaces'], $name)) {
         $index['interfaces'][$def->getName()] = keyset[];
       }
       continue;
     }
-    if ($def instanceof ScannedTrait) {
+    if ($def is ScannedTrait) {
       if (!C\contains_key($index['traits'], $name)) {
         $index['traits'][$def->getName()] = keyset[];
       }
@@ -70,7 +70,7 @@ function create_index(
     }
 
     invariant(
-      $def instanceof ScannedMethod,
+      $def is ScannedMethod,
       "Can't handle class %s",
       \get_class($def),
     );
@@ -78,21 +78,21 @@ function create_index(
     $p = $what['parent'];
     invariant($p !== null, 'got a method with null parent');
     $pn = $p->getName();
-    if ($p instanceof ScannedClass) {
+    if ($p is ScannedClass) {
       if (!C\contains_key($index['classes'], $pn)) {
         $index['classes'][$pn] = keyset[];
       }
       $index['classes'][$pn][] = $name;
       continue;
     }
-    if ($p instanceof ScannedInterface) {
+    if ($p is ScannedInterface) {
       if (!C\contains_key($index['interfaces'], $pn)) {
         $index['interfaces'][$pn] = keyset[];
       }
       $index['interfaces'][$pn][] = $name;
       continue;
     }
-    if ($p instanceof ScannedTrait) {
+    if ($p is ScannedTrait) {
       if (!C\contains_key($index['traits'], $pn)) {
         $index['traits'][$pn] = keyset[];
       }
diff --git a/src/from_parser.hack b/src/from_parser.hack
index 91fba16..01ed1e9 100644
--- a/src/from_parser.hack
+++ b/src/from_parser.hack
@@ -41,7 +41,7 @@ function from_parser(BaseParser $parser): vec<Documentable> {
     $top_level,
     $data ==>  {
       $class = $data['definition'];
-      if (!$class instanceof ScannedClassish) {
+      if (!$class is ScannedClassish) {
         return vec[];
       }
 
diff --git a/src/get_path_for_documentable.hack b/src/get_path_for_documentable.hack
index 1819cf4..97f935a 100644
--- a/src/get_path_for_documentable.hack
+++ b/src/get_path_for_documentable.hack
@@ -24,34 +24,34 @@ function get_path_for_documentable(
   Documentable $what,
 ): ?string {
   $def = $what['definition'];
-  if ($def instanceof ScannedClass) {
+  if ($def is ScannedClass) {
     return $provider->getPathForClass($def->getName());
   }
-  if ($def instanceof ScannedInterface) {
+  if ($def is ScannedInterface) {
     return $provider->getPathForInterface($def->getName());
   }
-  if ($def instanceof ScannedTrait) {
+  if ($def is ScannedTrait) {
     return $provider->getPathForTrait($def->getName());
   }
-  if ($def instanceof ScannedFunction) {
+  if ($def is ScannedFunction) {
     return $provider->getPathForFunction($def->getName());
   }
-  if ($def instanceof ScannedType) {
+  if ($def is ScannedType) {
     return $provider->getPathForTransparentTypeAlias($def->getName());
   }
-  if ($def instanceof ScannedNewtype) {
+  if ($def is ScannedNewtype) {
     return $provider->getPathForOpaqueTypeAlias($def->getName());
   }
-  if ($def instanceof ScannedMethod) {
+  if ($def is ScannedMethod) {
     $p = $what['parent'];
-    if ($p instanceof ScannedClass) {
+    if ($p is ScannedClass) {
       return $provider->getPathForClassMethod($p->getName(), $def->getName());
     }
-    if ($p instanceof ScannedInterface) {
+    if ($p is ScannedInterface) {
       return
         $provider->getPathForInterfaceMethod($p->getName(), $def->getName());
     }
-    if ($p instanceof ScannedTrait) {
+    if ($p is ScannedTrait) {
       return $provider->getPathForTraitMethod($p->getName(), $def->getName());
     }
   }