Fix 15984 [REG2.071] Interface contracts retrieve garbage instead of parameters

[thewilsonator]

The LDC fix is essentially this (c.f. LDC's fix)

although I'm not too sure about parents and dealing with irs.

cc @rainers @WalterBright @FeepingCreature

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Bugzilla references

Auto-close	Bugzilla	Severity	Description
✓	15984	regression	[REG2.071] Interface contracts retrieve garbage instead of parameters

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[jacob-carlborg]

Nit, I would quote any "word" that references a symbol in the code, to avoid any confusion with a regular word that is misspelled.

[WalterBright]

Please use:

https://issues.dlang.org/show_bug.cgi?id=15984

instead of:

Bugzilla 15984

[Geod24]

Please use more descriptive commit title (and as a consequence, PR title).

[FeepingCreature]

Note that this does not actually fix 15984.

import core.stdc.stdio;
interface I {
    void foo(Object obj)
    in { printf("%p\n", obj); obj.toString; }
}
class C : I { override void foo(Object obj) in { } do { } }
void main()
{
    auto c = new C;
    c.foo(new Object);
}

still fails with the branch.

[thewilsonator]

I'm not expecting that to, given the CI is red ;), I'm not sure which FunctionDeclarations are which.

[thewilsonator]

@FeepingCreature In particular I'm not certain about the provenance of irs.getFunc() (c.f. gIR->func() and fd (c.f.dfnval->func)
everything else I'm pretty sure is correct.

[rainers]

Don't you have to fix the this pointer everywhere getEthis is called? So maybe move the fixup there?

[thewilsonator]

Thanks I'll try that.

[thewilsonator]

So, it turns out that it is already handled in getEthis, but obviously that doesn't work properly.