Bad printing of const-eval queries

[RalfJung]

Evaluating of promoteds currently looks very confusing in the query stack:

query stack during panic:
#0 [const_eval_raw] const-evaluating `main`
#1 [const_eval_validated] const-evaluating + checking `main`
#2 [const_eval_validated] const-evaluating + checking `main`
#3 [normalize_generic_arg_after_erasing_regions] normalizing `main::promoted[2]`
#4 [optimized_mir] optimizing MIR for `main`
#5 [collect_and_partition_mono_items] collect_and_partition_mono_items

main is not a const, so "const-evaluating main" is just nonsense.

I presume that this is easy to fix but only @oli-obk would know how. ;)

[RalfJung]

Also see #75445 (comment)

[ThibsG]

Let's give a try 😉

[ThibsG]

@rustbot claim

[RalfJung]

@ThibsG awesome. :) Let us know if you need any help.

I am not very familiar with that specific code, but can still help with more general questions, and I hope @oli-obk can help with the specifics. :D