[perl #127367] [BUG] multimethod calls with subsets as type constraints fail when called the second time

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Consider the following code:

use v6.c;

subset T of List where *[0] eqv 1;

class R {
    multi method f(T:D $xs) { self.f(42) }
    multi method f(Any:D $xs) { say $xs }
}

R.f([1, 2]);
R.f([2, 2]);

It fails with the following output:

42
Type check failed in binding $xs; expected T but got Array
  in method f at /tmp/foo.pm6 line 6
  in block <unit> at /tmp/foo.pm6 line 11

However, when the R.f([1, 2]) call is removed, the program succeeds.

Thanks to masak++ for helping minimizing the example.

Rakudo version:

> This is Rakudo version 2015.12 built on MoarVM version 2015.12 implementing 
> Perl 6.c.