Fix 23168 - return scope wrongly rewritten for structs with no indirections

[dkorpel]

Stripping scope off a parameter is covered by FuncDeclaration semantic, VarDeclaration semantic, and TypeFunction semantic. Only TypeFunction considers return scope, so remove the check in FuncDeclaration semantic and add return scope stripping to VarDeclaration.

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Bugzilla references

Auto-close	Bugzilla	Severity	Description
✓	23168	normal	[DIP1000] return scope wrongly rewritten for structs with no indirections

Testing this PR locally

If you don't have a local development environment setup, you can use Digger to test this PR:

dub run digger -- build "master + dmd#14232"

[thewilsonator]

I don't think the test failure is related, but I'm not sure. cc @9il

[dkorpel]

It is related, I can reproduce it locally. Looking at it now.

[dkorpel]

Okay, so the problem is a forward reference error:

struct S 
{
    alias _get_value this; // Error: undefined identifier `_get_value`

    static if (true)
        int _get_value() {return 3;}
    else
        int _get_value() {return 4;}
}

But here comes the magic trick: add a scope function before it and it will call hasPointers() on itself which will look forwards, and then it can find it:

struct S 
{
    void f() scope {}
    alias _get_value this; // works now!

    static if (true)
        int _get_value() {return 3;}
    else
        int _get_value() {return 4;}
}

Since this PR removes the scope check in FuncDeclaration semantic, it now misses the forward reference. Of course, other times eagerly calling hasPointers causes problems: Issue 21667 - scope parameter causes 'no size because of forward references'

[thewilsonator]

Please add the forward reference issue to the test case.