Fix error message for env! when env var is not valid Unicode

[beetrees]

Currently (without this PR) the env! macro emits an environment variable `name` not defined at compile time error when the environment variable is defined, but not a valid Unicode string. This PR introduces a separate more accurate error message, and a test to verify this behaviour.

For reference, before this PR, the new test would have outputted:

error: environment variable `NON_UNICODE_VAR` not defined at compile time
 --> non_unicode_env.rs:2:13
  |
2 |     let _ = env!("NON_UNICODE_VAR");
  |             ^^^^^^^^^^^^^^^^^^^^^^^
  |
  = help: use `std::env::var("NON_UNICODE_VAR")` to read the variable at run time
  = note: this error originates in the macro `env` (in Nightly builds, run with -Z macro-backtrace for more info)

error: aborting due to 1 previous error

whereas with this PR, the test ouputs:

error: environment variable `NON_UNICODE_VAR` is not a valid Unicode string
 --> non_unicode_env.rs:2:13
  |
2 |     let _ = env!("NON_UNICODE_VAR");
  |             ^^^^^^^^^^^^^^^^^^^^^^^
  |
  = note: this error originates in the macro `env` (in Nightly builds, run with -Z macro-backtrace for more info)

error: aborting due to 1 previous error

[rustbot]

r? @TaKO8Ki

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[rustbot]

Some changes occurred in run-make tests.

cc @jieyouxu

[jieyouxu]

Is it possible to write this new run-make test in Rust instead?

[beetrees]

@jieyouxu Done

[rustbot]

The run-make-support library was changed

cc @jieyouxu

[bors]

☔ The latest upstream changes (presumably #122460) made this pull request unmergeable. Please resolve the merge conflicts.

[TaKO8Ki]

@beetrees Could you resolve a conflict? It looks good to me basically.

[TaKO8Ki]

@rustbot author

[beetrees]

@TaKO8Ki Rebased

@rustbot review

[TaKO8Ki]

Thanks! @bors r+ rollup

[bors]

📌 Commit 0bbaa25 has been approved by TaKO8Ki

It is now in the queue for this repository.

[bors]

⌛ Testing commit 0bbaa25 with merge 7f84ede...

[bors]

☀️ Test successful - checks-actions
Approved by: TaKO8Ki
Pushing 7f84ede to master...

[rust-timer]

Finished benchmarking commit (7f84ede): comparison URL.

Overall result: no relevant changes - no action needed

@rustbot label: -perf-regression

Instruction count

This benchmark run did not return any relevant results for this metric.

Max RSS (memory usage)

Results

This is a less reliable metric that may be of interest but was not used to determine the overall result at the top of this comment.

	mean	range	count
Regressions ❌ (primary)	0.6%	[0.6%, 0.6%]	1
Regressions ❌ (secondary)	-	-	0
Improvements ✅ (primary)	-	-	0
Improvements ✅ (secondary)	-	-	0
All ❌✅ (primary)	0.6%	[0.6%, 0.6%]	1

Cycles

Results

This is a less reliable metric that may be of interest but was not used to determine the overall result at the top of this comment.

	mean	range	count
Regressions ❌ (primary)	-	-	0
Regressions ❌ (secondary)	-	-	0
Improvements ✅ (primary)	-	-	0
Improvements ✅ (secondary)	-1.5%	[-1.5%, -1.5%]	1
All ❌✅ (primary)	-	-	0

Binary size

This benchmark run did not return any relevant results for this metric.

Bootstrap: 669.457s -> 667.101s (-0.35%)
Artifact size: 315.74 MiB -> 315.69 MiB (-0.02%)