[DO NOT MERGE] have tag be explicit debug_assert! argument

[krasimirgg]

No functional changes intended.

We've got a custom rustc build. After 2b8d27b we're seeing a new build error while building rustc_middle:

error: there is no argument named `tag`
    --> <rust>/compiler/rustc_middle/src/ty/mod.rs:1505:1
     |
1505 | / impl_tag! {
1506 | |     impl Tag for ParamTag;
1507 | |     ParamTag { reveal: traits::Reveal::UserFacing, constness: hir::Constness::NotConst },
1508 | |     ParamTag { reveal: traits::Reveal::All,        constness: hir::Constness::NotConst },
1509 | |     ParamTag { reveal: traits::Reveal::UserFacing, constness: hir::Constness::Const    },
1510 | |     ParamTag { reveal: traits::Reveal::All,        constness: hir::Constness::Const    },
1511 | | }
     | |_^
     |
     = note: did you intend to capture a variable `tag` from the surrounding scope?
     = note: to avoid ambiguity, `format_args!` cannot capture variables when the format string is expanded from a macro
     = note: this error originates in the macro `impl_tag` (in Nightly builds, run with -Z macro-backtrace for more info)

This patch fixes it. I'm not sure why this doesn't fire with x.py, hence the DO NOT MERGE. I suspect our custom build is a bit more strict than what x.py's. Maybe we're missing come rustc flags that silence this error?

[rustbot]

r? @petrochenkov

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[krasimirgg]

r? @WaffleLapkin

[krasimirgg]

Hey @WaffleLapkin, could you please take a look and see if there's something suspicious about the new impl_tag behaviour? Do you know which rustc flags/features may be related to this kind of error?

[Noratrieb]

uh, something is wrong with your bootstrap compiler.. this should compile just fine

[Noratrieb]

the specific error may be related to #106505, a rustc bug I fixed recently. But there's something wrong with your build setup. How are you building the compiler and with what bootstrap compiler version? @krasimirgg

[krasimirgg]

Thank you! I noticed I was using a different beta (bdd077d5d 2023-03-19) as the bootstrap compiler, suspect that's why.

[Noratrieb]

That was probably it. Only the exact beta in src/stage0.json is supported.

[WaffleLapkin]

@krasimirgg closing this, since this doesn't seem like a bug in the rust codebase, but rather a problem with invalid toolchain on your side. Feel free to reach out/reopen this PR in case you still have the problem.