diff --git a/info.rkt b/info.rkt
index 70b64f7..a782684 100644
--- a/info.rkt
+++ b/info.rkt
@@ -4,7 +4,7 @@
 (define deps '("base" "errortrace-lib" "rackunit-lib"
                "syntax-color-lib" "compiler-lib"))
 (define build-deps
-  '("racket-doc" "scribble-lib" "typed-racket-doc"))
+  '("racket-doc" "scribble-lib" "typed-racket-doc" "htdp-lib"))
 
 (define raco-commands
   '(("cover" (submod cover/raco main) "a code coverage tool" 30)))
diff --git a/private/format-utils.rkt b/private/format-utils.rkt
index babc726..a43c587 100644
--- a/private/format-utils.rkt
+++ b/private/format-utils.rkt
@@ -41,7 +41,11 @@
   (with-input-from-file f
     (thunk
      (define lexer
-       ((read-language) 'color-lexer racket-lexer))
+       (with-handlers ([exn:fail:read? (const racket-lexer)])
+         (define f (read-language))
+         (if f
+             (f 'color-lexer racket-lexer)
+             racket-lexer)))
      (define irrelevant? (make-irrelevant? lexer f))
      (define file-length (string-length (file->string f)))
      (define cache
diff --git a/private/html.rkt b/private/html.rkt
index f6f02ea..aaebd32 100644
--- a/private/html.rkt
+++ b/private/html.rkt
@@ -238,7 +238,9 @@
   (define (is-covered? e)
     ;; we don't need to look at the span because the coverage is expression based
     (define p (syntax-position e))
-    (covered? p #:byte? #t))
+    (if p
+        (covered? p #:byte? #t)
+        'missing))
 
   (define e
     (with-module-reading-parameterization
diff --git a/tests/do-reader.rkt b/tests/do-reader.rkt
new file mode 100644
index 0000000..1734890
--- /dev/null
+++ b/tests/do-reader.rkt
@@ -0,0 +1,10 @@
+#lang racket
+(require racket/runtime-path "../main.rkt" rackunit "../private/shared.rkt")
+(define-runtime-path reader.rkt "reader.rkt")
+(parameterize ([verbose #t])
+  (check-not-exn
+   (thunk
+    (define r (path->string reader.rkt))
+    (test-files! r)
+    (define c (make-covered? (hash-ref (get-test-coverage) r) r))
+    (c 10))))
diff --git a/tests/reader.rkt b/tests/reader.rkt
new file mode 100644
index 0000000..225485a
--- /dev/null
+++ b/tests/reader.rkt
@@ -0,0 +1,4 @@
+;; The first three lines of this file were inserted by DrRacket. They record metadata
+;; about the language level of this file in a form that our tools can easily process.
+#reader(lib "htdp-intermediate-lambda-reader.ss" "lang")((modname ex) (read-case-sensitive #t) (teachpacks ()) (htdp-settings #(#t constructor repeating-decimal #f #t none #f ())))
+10