bug#13449: 24.3.50; Perl mode composed symbols not visible

[Richard Copley <rcopley@gmail.com>]

On 15 January 2013 16:21, Eli Zaretskii wrote:

> I cannot reproduce this on my XP SP3 box, with today's development
> sources.  Your Emacs is quite old (2 months ago), but I doubt that
> this problem is due to some bug we had at that time.

Sorry, I should have said: the bug is still present in 111524 (early
this morning); 110872 (two months ago) was the earliest build that I
happen to have hanging around that exhibits the bug.

> When you go to those "space characters" and type "C-u C-x =", what
> does Emacs say about these two characters in the buffer that it pops
> up?

The following (except that the "=>" is not visible in the Emacs buffer):

             position: 388 of 13355 (3%), column: 34
            character: = (displayed as =) (codepoint 61, #o75, #x3d)
    preferred charset: ascii (ASCII (ISO646 IRV))
code point in charset: 0x3D
               syntax: . 	which means: punctuation
             category: .:Base, a:ASCII, l:Latin, r:Roman
             to input: type "C-x 8 RET HEX-CODEPOINT" or "C-x 8 RET NAME"
          buffer code: #x3D
            file code: #x3D (encoded by coding system undecided-dos)
              display: composed to form "=>" (see below)

Composed with the following character(s) ">" by the rule:
	(?=>)
The component character(s) are displayed by these fonts (glyph codes):
 =>: uniscribe:-outline-Source Code
Pro-normal-normal-normal-mono-13-*-*-*-c-*-iso10646-1 (#x01)
See the variable `reference-point-alist' for the meaning of the rule.

Character code properties: customize what to show
  name: EQUALS SIGN
  general-category: Sm (Symbol, Math)
  decomposition: (61) ('=')

There are text properties here:
  composition          [Show]
  fontified            t