In vi mode `:'<,'>s/^/;;/` leads to a crash.

[g-gundam]

Steps to Reproduce

1. M-x vi-mode
2. Select a range of lines using V
3. Hit : and then type s/^/;;/
   • The purpose of this regexp substitution is to put ";;" at the beginning of every line in the region.

Expectation

The lines in the region should have ";;" prepended to them.

Actual Result

Lem is unresponsive to input, and I saw this when I switched back to the terminal that I started Lem on.

Heap exhausted during garbage collection: 0 bytes available, 64 requested.
Gen  Boxed   Code    Raw  LgBox LgCode  LgRaw  Pin       Alloc     Waste        Trig      WP GCs Mem-age
 2   20760      0      0      0      0      0    5   339727520    404320   214536266       0   1  1.3998
 3   38774      1     73      0      0     24   68   636059232    819616     2000000   18797   0  0.4859
 4       0      0      0      0      0      0    0           0         0     2000000       0   0  0.0000
 5       0      0      0      0      0      0    0           0         0     2000000       0   0  0.0000
 6    3556     13   1762    350      0    222    0    94756640   1958112     2000000    5608   0  0.0000
           Total bytes allocated    =    1070543392
           Dynamic-space-size bytes =    1073741824
GC control variables:
   *GC-INHIBIT* = true
   *GC-PENDING* = true
   *STOP-FOR-GC-PENDING* = false
fatal error encountered in SBCL pid 2070099 tid 2070132:
Heap exhausted, game over.

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[Encryptoid]

Hi, this is now fixed with: #1725

For a brief overview, the editor was getting stuck in an infinite loop while trying to highlight regex that evaluated to an empty string, like "^". The same was true for other substitutions like "$", etc.

[g-gundam]

Nice. Thanks for fixing it.