From @masak

<masak> perl6​: say "5 breads" + "2 fish"
<p6eval> pugs​: OUTPUT«7␤»
<p6eval> ..niecza v15-6-gefda208​: OUTPUT«Unhandled exception​: Cannot
parse number​: 5 breads [...]
<p6eval> ..rakudo a4c78f​: OUTPUT«Cannot call 'Numeric'; none of these
signatures match​:␤​:(Mu​:U \$v, Mu %_!)␤␤ in method Numeric at
src/gen/CORE.setting​:644␤ in sub infix​:<+> at
src/gen/CORE.setting​:2284 [...]
<masak> perl6​: say "5" + "2"
<p6eval> pugs, rakudo a4c78f, niecza v15-6-gefda208​: OUTPUT«7␤»
<masak> Rakudo's error message leaves something to be desired, IMO.
<colomon> +1
* masak submits rakudobug

I'm guessing Rakudo and Niecza fail both for the same reason here​: the
strings can't be numified properly. But Rakudo's error message is not
clear that this is the cause.

From @moritz

Now says

./perl6 -e 'say "5 foo" + 8'
Cannot convert string to number​: trailing characters after number in '5⏏
foo' (indicated by the ⏏ symbol)
  in method Numeric at src/gen/CORE.setting​:8109
  in sub infix​:<+> at src/gen/CORE.setting​:2284
  in sub infix​:<+> at src/gen/CORE.setting​:2284
  in block <anon> at -e​:1

Tested in S32-exceptions/misc.t

@moritz - Status changed from 'new' to 'resolved'