Auto merge of #70452 - eddyb:repeat-expr-correct-generics-parent, r=nikomatsakis

typeck: always expose repeat count `AnonConst`s' parent in `generics_of`.

This should reduce some of the confusion around #43408, although, if you look at the changed test outputs (for the last commit), they all hit #68436, so nothing new will start compiling.

We can let counts of "repeat expressions" (`N` in `[x; N]`) always have the correct generics parenting, because they're always in a body, so nothing in the `where` clauses or `impl` trait/type of the parent can use it, and therefore no query cycles can occur.

<hr/>

Other potential candidates we might want to apply the same approach to, are:
* ~~(easy) `enum` discriminants (see also #70453)~~ opened #70825
* (trickier) array *type* (not *expression*) lengths nested in:
  * bodies
  * types of (associated or not) `const`/`static`
  * RHS of `type` aliases and associated `type`s
  * `fn` signatures

We should've done so from the start, the only reason we haven't is because I was squeamish about blacklisting some of the cases, but if we whitelist instead we should be fine.
Also, lazy normalization is taking forever :disappointed:.

<hr/>

There's also 5 other commits here:
* "typeck: track any errors injected during writeback and taint tables appropriately." - fixes #66706, as the next commit would otherwise trigger an ICE again
* "typeck: workaround WF hole in `to_const`." - its purpose is to emulate most of #70107's direct effect, at least in the case of repeat expressions, where the count always goes through `to_const`
  * this is the reason no new code can really compile, as the WF checks require #68436 to bypass
  * however, this has more test changes than I hoped, so it should be reviewed separately, and maybe even landed separately (as #70107 might take a while, as it's blocked on a few of my PRs)
* "ty: erase lifetimes early in `ty::Const::eval`." - first attempt at fixing #70773
  * still useful, I believe the new approach is less likely to cause issues long-term
  * I could take this out or move it into another PR if desired or someone else could take over (cc @skinny121)
* "traits/query/normalize: add some `debug!` logging for the result." - debugging aid for #70773
* "borrow_check/type_check: normalize `Aggregate` and `Call` operands." - actually fixes #70773

r? @nikomatsakis cc @pnkfelix @varkor @yodaldevoid @oli-obk @estebank

0 files changed, 0 insertions, 0 deletions