Fix naming in the lint API

[nnethercote]

Methods for emit lints are named very inconsistently. This PR fixes that up.

r? @compiler-errors

[rustbot]

Some changes might have occurred in exhaustiveness checking

cc @Nadrieril

rustc_macros::diagnostics was changed

cc @davidtwco, @compiler-errors, @TaKO8Ki

Some changes occurred in src/tools/clippy

cc @rust-lang/clippy

Some changes might have occurred in exhaustiveness checking

cc @Nadrieril

Some changes occurred to MIR optimizations

cc @rust-lang/wg-mir-opt

Some changes occurred to the CTFE / Miri engine

cc @rust-lang/miri

[nnethercote]

Here is the table I worked from.

old name               args                                     new name
------                 -----------------------------------      --------
LintContext
- lint                 lint,               msg, decorate        // lint (unchanged)
- struct_span_lint     lint,         span, msg, decorate        // span_lint
- lookup_with_diags    lint,         span, msg, decorate, diags // span_lint_with_diags
- lookup               lint,     opt_span, msg, decorate        // opt_span_lint
- emit_lint            lint,                    decorator       // emit_lint (unchanged)
- emit_spanned_lint    lint,         span,      decorator       // emit_span_lint

LintLevelsBuilder (missing plain `lint`)
- struct_lint          lint,     opt_span, msg, decorate        // opt_span_lint
- emit_lint            lint,                    decorator       // emit_lint (unchanged)
- emit_spanned_lint    lint,         span,      decorator       // emit_span_lint

TyCtxt
- struct_lint_node     lint, hir_id,       msg, decorate        // node_lint
- struct_span_lint_hir lint, hir_id, span, msg, decorate        // node_span_lint
- emit_lint            lint, hir_id,            decorator       // emit_node_lint
- emit_spanned_lint    lint, hir_id, span,      decorator       // emit_node_span_lint

(top-level)
- struct_lint_level    lint,lvl,src, span, msg, decorate        // lint_level

Improvements:

• Remove misleading struct_ prefixes. These functions don't return
  diagnostics, they emit!
• Use span instead of spanned, for consistency with normal diagnostics.
• Retain emit_ prefix for newer cases using decorator: DecorateLint, and
  use no prefix for older cases using decorate, similar to how it's done for
  normal diagnostics.
• Use node consistently for the TyCtxt ones, not a mix of node and hir.
• Replace lookup, which is so vague that it's meaningless.
• Make the equivalent functions across the different types have the same name.

Now I can look at a method name and have a pretty good chance of understanding how to use it. That was not the case before!

[oli-obk]

the node part of the TyCtxt methods seems not useful to me. We could just leave it off, even if it then has the same name as LintContext methods.

[nnethercote]

We could just leave it off, even if it then has the same name as LintContext methods.

That's exactly why I want a different name, because it has an extra argument. Different signature, different name.

[bors]

☔ The latest upstream changes (presumably #120025) made this pull request unmergeable. Please resolve the merge conflicts.

[compiler-errors]

r=me after rebasing

[nnethercote]

I rebased.

@bors r=compiler-errors

[bors]

📌 Commit 0a03a9f has been approved by compiler-errors

It is now in the queue for this repository.

[oli-obk]

@bors r- conflicts

[nnethercote]

I rebased again. Bumping priority because this is conflict-prone.

@bors r=oli-obk p=1

[bors]

📌 Commit 15a4c4f has been approved by oli-obk

It is now in the queue for this repository.

[bors]

⌛ Testing commit 15a4c4f with merge 0011fac...

[bors]

☀️ Test successful - checks-actions
Approved by: oli-obk
Pushing 0011fac to master...

[rust-timer]

Finished benchmarking commit (0011fac): 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)	2.8%	[2.5%, 3.0%]	2
Regressions ❌ (secondary)	-	-	0
Improvements ✅ (primary)	-	-	0
Improvements ✅ (secondary)	-	-	0
All ❌✅ (primary)	2.8%	[2.5%, 3.0%]	2

Cycles

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

Binary size

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

Bootstrap: 663.509s -> 662.56s (-0.14%)
Artifact size: 308.32 MiB -> 308.33 MiB (0.00%)