Cannot parse an anonymous sigilless parameter with a trait

[Kaiepi]

The Problem

Given sigilless variables are being looked at, a trait may be applied to an anonymous scalar parameter:

LAPTOP-7I9RCT0C:~% raku -e 'sub ($ is readonly) { }(1)'
LAPTOP-7I9RCT0C:~%

But not an anonymous term:

LAPTOP-7I9RCT0C:~% raku -e 'sub (\ is readonly) { }(1)'

Expected Behavior

Should just return like the anonymous scalar case.

Actual Behavior

Throws:

===SORRY!=== Error while compiling -e
Invalid typename 'is' in parameter declaration.
at -e:1
------> sub (\ is⏏ readonly) { }(1)

Steps to Reproduce

Run the given golf.

Environment

• Operating system:

Linux LAPTOP-7I9RCT0C 5.10.16.3-microsoft-standard-WSL2 #1 SMP Fri Apr 2 22:23:49 UTC 2021 x86_64 GNU/Linux

• Compiler version (perl6 -v or raku -v):

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