From @zoffixznet

Trying to smartmatch against S/// gives a compile time warning​:

  'Smartmatch with S/// can never succeed because the string it returns will fail to match' [...]

First, that warning is inaccurate, because if S/// doesn't match the string, it'll return the original string, which will smartmatch as True.

Also, the second part of the error is misleading​:

  [...] 'You can use given instead of ~~.'

It's perfectly understandable if a new Perl 6 programmer will take that to mean "change ~~ to `given`". And if they do so, they'll get another confusing (to a beginner) error, since there's no .match method in their code​:

  Method 'match' not found for invocant of class 'Any'

Thus, I propose the error message to be changed to the following​:

  'Smartmatch with S/// is not useful. You can use given instead​: S/// given $foo'

From @zoffixznet

PR to resolve this​: rakudo/rakudo#789

From @zoffixznet

Resolved in commit rakudo/rakudo@449a2e7

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