From @peschwa

15​:45 < psch> m​: say uniname -1
15​:45 <+camelia> rakudo-moar 20ffd3​: OUTPUT«should eventually
  be unreachable␤ in sub uniname at
  src/gen/m-CORE.setting​:8670␤ in block <unit>
  at /tmp/B_LbZ96Xk_​:1␤␤»
15​:46 < psch> eventually... :)
[...]
15​:55 < masak> psch​: that's an LTA error message. please submit
  rakudobug

The issue seems to be in Moar, where MVM_unicode_get_name calls into MVM_codepoint_to_row_index, where the latter of those throws an AdHoc exception when its codepoint argument is < 0. (MoarVM/src/strings/unicode.c lines 42970 and 42269 respectively.) Modifying MVM_codepoint_to_row_index to return -1 would be one approach to fix this.

From @jnthn

On Sun Mar 22 09​:04​:47 2015, peschwa@​gmail.com wrote​:

15​:45 < psch> m​: say uniname -1
15​:45 <+camelia> rakudo-moar 20ffd3​: OUTPUT«should eventually
be unreachable␤ in sub uniname at
src/gen/m-CORE.setting​:8670␤ in block <unit>
at /tmp/B_LbZ96Xk_​:1␤␤»
15​:46 < psch> eventually... :)
[...]
15​:55 < masak> psch​: that's an LTA error message. please submit
rakudobug

The issue seems to be in Moar, where MVM_unicode_get_name calls into
MVM_codepoint_to_row_index, where the latter of those throws an AdHoc
exception when its codepoint argument is < 0.
(MoarVM/src/strings/unicode.c lines 42970 and 42269 respectively.)
Modifying MVM_codepoint_to_row_index to return -1 would be one
approach to fix this.

Added ranged checks now, so​:

say uniname(-1)
<illegal>
say uniname(0x210000)
<unassigned>

Also added tests in S15-unicode-information/uniname.t.

The RT System itself - Status changed from 'new' to 'open'

@jnthn - Status changed from 'open' to 'resolved'