From a80f55946d0f221517bdbe47aa2dc72aab3fc4ba Mon Sep 17 00:00:00 2001
From: Asumu Takikawa <asumu@ccs.neu.edu>
Date: Tue, 21 Apr 2015 15:38:32 -0400
Subject: [PATCH] Adjust error messages for : annotation form

Print better error messages for expression like
(: 2 Zero). Also fix and improve error messages for
multiple/missing types.

Closes PR 15044
---
 typed-racket-lib/typed-racket/base-env/colon.rkt | 11 ++++++-----
 typed-racket-test/unit-tests/prims-tests.rkt     | 10 ++++++++--
 2 files changed, 14 insertions(+), 7 deletions(-)

diff --git a/typed-racket-lib/typed-racket/base-env/colon.rkt b/typed-racket-lib/typed-racket/base-env/colon.rkt
index b14af4bc..a0be55f1 100644
--- a/typed-racket-lib/typed-racket/base-env/colon.rkt
+++ b/typed-racket-lib/typed-racket/base-env/colon.rkt
@@ -37,7 +37,8 @@
 
 (define-syntax (:-helper stx)
   (syntax-parse stx
-    [(_ _ top-level? i:id ty)
+    [(_ orig-stx top-level? i ty)
+     #:fail-unless (identifier? #'i) (err #'orig-stx "expected identifier" #'i)
      (unless (or (syntax-e #'top-level?)
                  (identifier-binding #'i))
        (tc-error/stx #'i
@@ -47,9 +48,9 @@
      (syntax-property (syntax/loc stx (begin (quote (:-internal i ty))
                                              (#%plain-app values)))
                       'disappeared-use #'i)]
-    [(_ orig-stx _ i:id x ...)
+    [(_ orig-stx _ i x ...)
+     #:fail-unless (identifier? #'i) (err #'orig-stx "expected identifier" #'i)
      (case (syntax-length #'(x ...))
-       [(1)  (err #'orig-stx "can only annotate identifiers with types" #'i)]
-       [(0)  (err #'orig-stx "missing type")]
-       [else (err #'orig-stx "bad syntax (multiple types after identifier)")])]))
+       [(0)  (err #'orig-stx "missing type after identifier")]
+       [else (err #'orig-stx "too many types after identifier")])]))
 
diff --git a/typed-racket-test/unit-tests/prims-tests.rkt b/typed-racket-test/unit-tests/prims-tests.rkt
index 500761fa..1576938c 100644
--- a/typed-racket-test/unit-tests/prims-tests.rkt
+++ b/typed-racket-test/unit-tests/prims-tests.rkt
@@ -20,10 +20,16 @@
 ;; and error checking in primitive macros
 (define tests
   (test-suite "Prims tests"
+    (check-bad (let () (: 2 Zero) 'dummy)
+               #rx"expected identifier")
+    (check-bad (let () (: x) 'dummy)
+               #rx"missing type")
+    (check-bad (let () (: x Listof Any) 'dummy)
+               #rx"too many types")
     (check-bad (let () (: x : Listof Any) 'dummy)
-               #rx"multiple types")
+               #rx"too many types")
     (check-bad (let () (: x : -> String String) 'dummy)
-               #rx"multiple types")
+               #rx"too many types")
     (check-ok (let () (: x : String -> String -> String)
                       (define x 0)
                       'dummy))))