Facet values (like type values) can be copied around at runtime #5242
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Marked this as closing the leads question, as I think this is a potential answer and it's hinted at by the lowering test. |
Give them a value representation of copy, and allow conversions between two facet values of the same type to work. Convert was assuming that facet values are compile time constants, but thye can also be runtime values. In that case, we have no support for converting to a different facet value of a different facet type. But if the types are equal then it's all fine. In theory it seems that we should be able to convert if the target facet type can be found through the source value's FacetType. But currently that happens through impl lookup and it requires constant values. Adding a test for this.
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I think if you want this to close the leads issue, we should have a proper diagnostic for conversion of a runtime facet value rather than a Alternatively we can keep the TODO diagnostic and land this as-is (but without the "Closes #5241"), and update once the leads issue is closed. |
Got it, will leave it open. |
Give them a value representation of copy, and allow conversions between two facet values of the same type to work.
Convert was assuming that facet values are compile time constants, but thye can also be runtime values. In that case, we have no support for converting to a different facet value of a different facet type. But if the types are equal then it's all fine.
In theory it seems that we should be able to convert if the target facet type can be found through the source value's FacetType. But currently that happens through impl lookup and it requires constant values. Adding a test for this.
Related to #5241