Implement arbitrary casts in custom mir - #160860
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maxdexh
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I am on vacation this week, so this will have to wait a bit. Or maybe @saethlin has time to look at it earlier. |
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This is not done yet anyway, I still gotta figure out how to unflatten the enum and write some tests. But thanks for letting me know :) |
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See zulip
Implement custom casts using an enum in
intrinsics::mirthat closely matches theCastKindenum in the compiler.We have 5 different ways to cast in custom MIR, 3 with functions (which hard code a cast kind), 1 implicit coerce (which only does subtyping i think), 1 with
as(which does a few more). They are all different and the error messages don't tell you what to do. Some are (i think) not possible at all.This came up while testing miri. We currently have to guess the casting syntax until we find the one that generates the MIR we want. This PR changes that by allowing you to just pick.
The
intrinsics::mir::CastKindis currently a flattened version of the compiler's. If nested enums are possible then I'd like to unflatten it.This is missing tests, still figuring out how those work.
r? RalfJung