Fixes for capture checking case class methods - #25278
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Needed so that we can call it from Setup as well.
These fell through the cracks before. There's still a hole: External global objects don't get their capture set implied by fields. So if they do not extend a Capability trait they are deemed pure, even if they contain capability fields. See console-use in pending tests. There are two ways to fix this: - Also do capturesImpliedByFields for global objects so that their capset is computed structurally. - Or, require that global objects with capability fields extend the appropriate capability class.
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Yes, ready for review |
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@Linyxus ping for review |
Linyxus
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Feb 25, 2026
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If a class extends a Capability, it will now get a LocalCap on creation. This solves the problem that ```scala class C extends Capability val a = C() val b: C = C() ``` did two different things: `a` was pure but `b` was impure. Now they are both impure. Based on #25278 Also, several other new rules around capture sets of `new`, outlined on the doc page.
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Fixes #23823.
We special treat primary constructors when we compute the result capture set. We need to do the same for case class
applyandcopymethods.The result type is patched when we instantiate one of these methods with arguments. I tried to do that as a transform of the info of these methods instead. That almost worked, but failed because of the unbox operation needed in
refineConctructorInstancewhich needs to know the actual arguments. This is a tricky bit. I added some comments torefineConctructorInstance.As part of this amandoned attempt to work on info transformers in Setup, I moved a lot of machinery needed by
refineConctructorInstancefromCheckCapturesintoCaptureOps. It's not strictly necessary to do that since in the final PR the only root call is fromCheckCaptures. But it might be needed later, so kept the refactoring.