samth/test-bugs — Issue #142: DrRacket misses `#lang' highlights
Author: racket-bug-submit
Created: 2012-03-09 03:08:20+00:00
State: open
Labels: anon-submit, gnats-migrated

###### Originally submitted by Eli Barzilay on: Wed Oct 05 14:16:01 -0400 2011

```racket
Start with an empty buffer, and make it have this at the top

#lang at-exp racket

Now insert a space before the `#lang', then insert "t" at the end
and see the "#lang at-exp" turn red. Now delete the "t", and the
red highlight stays.

The same happens with:

;
#lang at-exp racket

with no spaces.

It does not happen without the `at-exp' language.

*But*, with a `#lang s-exp' prefix there are no red highlights when
the language is wrong. (The online checker does give an indication
that it is wrong or right, but no color changes.)
```

##### Release:

```
5.1.3.11--2011-10-04(9b3f242/a)
```

##### Environment:

```
unix "Linux winooski.ccs.neu.edu 2.6.35.14-95.fc14.x86_64 #1 SMP Tue Aug 16 21:01:58 UTC
2011 x86_64 x86_64 x86_64 GNU/Linux" (x86_64-linux/3m) (get-display-depth) = 32
Human Language: english
(current-memory-use) 282682288
Links: (links) = (); (links #:user? #f) = (); (links #:root? #t) = (); (links #:user? #f
#:root? #t) = ()

Collections:
("/home/eli/.racket/5.1.3.11/collects"
(non-existent-path))
("/home/scheme/plt/collects"
("syntax" "planet" "errortrace" "xml" "scribblings" "file" "htdp" "s-exp" "schemeunit"
"handin-server" "eopl" "slatex" "syntax-color" "hierlist" "deinprogramm" "tests" "make"
"gui-debugger" "guibuilder" "picturing-programs" "unstable" "sirmail" "slideshow"
"info-domain" "openssl" "honu" "version" "parser-tools" "combinator-parser" "r6rs"
"defaults" "rnrs" "scriblib" "dynext" "r5rs" "rackunit" "string-constants" "lazy"
"launcher" "readline" "mysterx" "mrlib" "browser" "mzcom" "typed-racket" "lang"
"embedded-gui" "framework" "at-exp" "graphics" "test-box-recovery" "mred" "datalog"
"games" "compiler" "profile" "web-server" "icons" "frtime" "handin-client" "teachpack"
"raco" "wxme" "typed-scheme" "trace" "texpict" "ffi" "algol60" "racket" "meta" "setup"
"scribble" "plot" "drracket" "drscheme" "typed" "scheme" "racklog" "data" "html"
"tex2page" "xrepl" "stepper" "db" "srfi" "mzscheme" "macro-debugger" "net" "test-engine"
"repo-time-stamp" "config" "sgl" "mzlib" "help" "swindle" !
"plai" "reader" "redex" "2htdp" "preprocessor"))

Computer Language: (("Determine language from source") (#(#t print mixed-fraction-e #f #t
test-coverage) (default) #() "#lang racket\n" #f #t))
```

###### This bug was converted from Gnats bug [12260](http://bugs.racket-lang.org/old/12260).

[anon-submit eli AT barzilay.org]