Fun fact, one of the original Perl6 implementations was done in Haskell (the parrot VM I think).
Before all that happened, though, there was Pugs, which is the Perl-6-on-Haskell thingy that you are thinking of. A fair portion of the current Perl 6 test suite comes from the Pugs project, at least originally. And, IIUC, it was the success of Pugs that revived the Perl 6 efforts and led to the Rakudo project (Perl 6 implemented in Perl 6) which is what we still use today.
So yeah, it is definitely the case that Haskell had a big influence on Perl 6 both from a language design and a more raw "inspiration" in the sense that it literally might not have happened without it -- the original wave of Perl 6 development had largely failed and there was some serious burnout happening. Pugs, Haskell, and Audrey Tang managed to put the ship back on course.
A lot of history happens in 16 years, and I make no claim to know the truth of any of it. There are more than a few rants floating around out there that will give you a picture of what happened when, albeit from a ranty perspective. Hopefully one day it will all be collected in a more comprehensive historical document.
Note that depending on your point of view, Rakudo actually predates Pugs: It's just that Parrot and Perl6-on-Parrot used to be developed in a single repository, and it wasn't yet called 'Rakudo'.
edit: However, NQP (the basis for the current Rakudo architecture) does indeed postdate Pugs (according to the ChangeLog, it first appeared in Parrot release 0.4.15 in 2007).
I think this is misleading; one of the original goals for Parrot was language interoperability, especially between Perl and P6.
However, I am talking about the focus shift that made Perl 6 just one among many of "client languages" (for lack of a better word). This was a distinct moment, at least as far as I remember it.
Not only by logical extension! One of Larry's primary goals was to "let any language use the CPAN", through Parrot. Running Perl and P6 on the same VM, in process, without embedding libperl.so was the plan as far back as I can remember.
I am talking about the focus shift that made Perl 6 just one among many of "client languages"
That's been a common, though unrealistic, criticism of Parrot for the past several years. Various contributors never had (or lost) interest in P6 but wanted to work on an multi-language VM. Expecting that all volunteers to a project have the same primary goal in mind is ridiculous and ignores decades of F/OSS contributions; it's easy to look at the Linux kernel and recognize that multiple competing business and personal interests can be shepherded into a technically useful result that meets a lot of those needs despite their competing interests.
People implementing `invokedynamic` didn't somehow make Java a second-class citizen on the JVM, for example.
You can certainly argue that we handled some of those competing interests poorly (I've argued this), but the "focus shift" argument rests on some questionable assumptions and ignores other, more important, concerns.
Now, I think you are also being a bit disingenuous. The Parrot team shifted focus. You can say all you want that the original vision was always all dynamic languages (which I already said, by the way). But to frame the original Parrot efforts as anything less than building a foundation for Perl 6 clashes with my own memory of the timeline.
If the JVM and the Java teams essentially stopped talking to each other, I would definitely consider that to be some form of collective decision making representing an overall shift in focus for the projects. That's more akin to what I remember of the Parrot/P6 split. Even your post hints at it when you say "Various contributors never had (or lost) interest in P6". But again, I was only "involved" from the sidelines and am limited to the available materials, including yours, and synthesizing them from individual rants into some semblance of a balanced picture.
That's the story certain people have been telling for quite a while, but it never happened while I was involved in either project. If you look at the use.perl.org archives, you can see that both Allison and I (as the architect of Parrot and a lead developer, respectively) were collaborating closely with Rakudo developers on the weekly P6 design calls.
I understand that, from the outside, there's a natural tendency to take all of the perspectives and comments and assume that the truth lies somewhere in the middle, but the historical record is out there and available. I've certainly referred to it directly when posting my opinions about what happened and when.