[ESS] Font lock bug?

[Kevin Wright]

My setup: Windows 2000, R 2.3.1, ESS 5.3.1

If you start R and type sqrt("a"), is "Error in" fontified in the output?

For me, neither "Error in" nor "Warning in" are properly fontified.
Only the "in" part is fontified as a keyword (in the usual face for
"in").

If I change ess-R-message-prefixes from:

(defvar ess-R-message-prefixes
  '("Error:" "Error in"
    "Warning:" "Warning in"
    "Warning messages"))

to

(defvar ess-R-message-prefixes
  '("Error" "Warning"))

then I do get fontification of "Error" in the output (and "in" has a
different display face). Interestingly enough, using
  '("Error" "Error:" "Error in"
doesn't seem to work for me.

Naive speculation:  I wonder if the fontification of "in" as a keyword
is interfering with fontification of "Error in".  Font-lock patterns
are scary things and since I have a working hack, I'm not going to dig
further.

Best,

Kevin Wright