From 06bd5d36af88a99d2f76b65c073da21d63b5ee1f Mon Sep 17 00:00:00 2001
From: Asumu Takikawa <asumu@ccs.neu.edu>
Date: Thu, 1 May 2014 15:57:19 -0400
Subject: [PATCH] Don't track syntax with unknown source locations

Avoids recording original syntaxes with a source or position
of #f, since these are usually intermediate syntax pairs that
don't correspond to actual source syntax.

For example, in a (#%module-begin . rst) in a submodule, the
underlying pair may contain an identifier and a cdr that is a
syntax object. That cdr will have #f source and position and also
does not correspond to any source syntax.

Leaving such syntax objects in the table means there are spurious
hits later when a syntax object with an unknown source location
is looked up.

Closes PR 14389
---
 pkgs/typed-racket-pkgs/source-syntax/source-syntax.rkt |  7 ++++++-
 .../tests/typed-racket/fail/pr14389.rkt                | 10 ++++++++++
 2 files changed, 16 insertions(+), 1 deletion(-)
 create mode 100644 pkgs/typed-racket-pkgs/typed-racket-test/tests/typed-racket/fail/pr14389.rkt

diff --git a/pkgs/typed-racket-pkgs/source-syntax/source-syntax.rkt b/pkgs/typed-racket-pkgs/source-syntax/source-syntax.rkt
index 2dedd0dd5e..bb641cfef2 100644
--- a/pkgs/typed-racket-pkgs/source-syntax/source-syntax.rkt
+++ b/pkgs/typed-racket-pkgs/source-syntax/source-syntax.rkt
@@ -22,7 +22,12 @@
 
   ;; build `syntax-locs`
   (let loop ([stx orig])
-    (when (syntax? stx) (hash-set! syntax-locs (syntax-loc stx) stx))
+    (when (and (syntax? stx)
+               ;; avoid spurious hits in the table from syntaxes
+               ;; that have no useful source information
+               (and (syntax-source stx)
+                    (syntax-position stx)))
+      (hash-set! syntax-locs (syntax-loc stx) stx))
     (let ([stx (if (syntax? stx) (syntax-e stx) stx)])
       (when (pair? stx) (loop (car stx)) (loop (cdr stx)))))
 
diff --git a/pkgs/typed-racket-pkgs/typed-racket-test/tests/typed-racket/fail/pr14389.rkt b/pkgs/typed-racket-pkgs/typed-racket-test/tests/typed-racket/fail/pr14389.rkt
new file mode 100644
index 0000000000..bfb78b0792
--- /dev/null
+++ b/pkgs/typed-racket-pkgs/typed-racket-test/tests/typed-racket/fail/pr14389.rkt
@@ -0,0 +1,10 @@
+#;
+(exn-pred (regexp-quote "in: (for/flvector"))
+#lang typed/racket/base
+
+(require racket/flonum)
+(module+ test
+  (require typed/rackunit)
+  (define (from upto)
+    (for/flvector ([i (in-range from upto)])
+      0.0)))