julia

726c816b - Prohibit `import`ing or `using` Main during incremental compilation (#57426)

Prohibit `import`ing or `using` Main during incremental compilation (#57426) An upcoming optimization will skip most binding validation if no binding replacement has taken place in (sysimage, pkgimage) modules. However, as a special case, we would like to treat `Main` as a non-sysimage module because the addition of new bindings in `Main` is common and we would like this to not ruin the optimization. To make this legal, we have to prohibit `import`ing or `using` any `Main` bindings in pkgimages. I don't think anybody actually does this, particularly, since `Main` is not considered loading during precompile (so you have to use the main binding via (Core|Base|).Main), and I can't think of any good semantic reason to want to do this, but regardless, it does add additional restrictions to `using`/`import`, so I wanted to break it out into its own PR.