Remove unnecessary Symbol stringification in clippy

[camelid]

This should (slightly) improve performance and enhance code quality.

[rust-highfive]

Some changes occurred in src/tools/clippy.

cc @rust-lang/clippy

[rust-highfive]

r? @lcnr

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[camelid]

@bors try @rust-timer queue

[rust-timer]

Awaiting bors try build completion.

@rustbot label: +S-waiting-on-perf

[bors]

⌛ Trying commit e427d340bdb803ed5e4de98b7172790daf0389ff with merge ea957266538b17f07990ca8ba2aa4c18ce94e397...

[camelid]

Hmm, it seems like the rustc version is actually hard to get rid of. It also seems to only be used in an error path. So I removed that change.

[camelid]

r? @flip1995

[rust-log-analyzer]

The job mingw-check failed! Check out the build log: (web) (plain)

Click to see the possible cause of the failure (guessed by this bot)

    Checking cargo_metadata v0.14.0
    Checking rustfix v0.5.1
    Checking rustc-workspace-hack v1.0.0 (/checkout/src/tools/rustc-workspace-hack)
    Checking clippy_lints v0.1.60 (/checkout/src/tools/clippy/clippy_lints)
error[E0425]: cannot find value `Underscore` in module `sym`
    |
964 |                     let mut ident_bind_name = sym::Underscore;
    |                                                    ^^^^^^^^^^ not found in `sym`
    |
---
1   | use rustc_ast::ExprKind::Underscore;
    |
1   | use rustc_hir::LifetimeName::Underscore;
    |
1   | use rustc_span::symbol::kw::Underscore;

For more information about this error, try `rustc --explain E0425`.
error: could not compile `clippy_lints` due to previous error
Build completed unsuccessfully in 0:03:40

[rust-log-analyzer]

The job dist-x86_64-linux failed! Check out the build log: (web) (plain)

Click to see the possible cause of the failure (guessed by this bot)

[RUSTC-TIMING] rustc_codegen_ssa test:false 46.570
   Compiling rustc_typeck v0.0.0 (/checkout/compiler/rustc_typeck)
[RUSTC-TIMING] rustc_plugin_impl test:false 5.140
   Compiling rustc_borrowck v0.0.0 (/checkout/compiler/rustc_borrowck)
error[E0277]: a value of type `HashSet<std::string::String, BuildHasherDefault<FxHasher>>` cannot be built from an iterator over elements of type `Symbol`
     |
     |
540  |             .collect::<FxHashSet<String>>();
     |              ^^^^^^^ value of type `HashSet<std::string::String, BuildHasherDefault<FxHasher>>` cannot be built from `std::iter::Iterator<Item=Symbol>`
     |
     = help: the trait `FromIterator<Symbol>` is not implemented for `HashSet<std::string::String, BuildHasherDefault<FxHasher>>`
note: required by a bound in `collect`
For more information about this error, try `rustc --explain E0277`.
[RUSTC-TIMING] rustc_typeck test:false 6.038
error: could not compile `rustc_typeck` due to previous error
warning: build failed, waiting for other jobs to finish...

[matthiaskrgr]

Hm, afaik the rust benchmarking does not touch clippy at all.. 🤔

[Manishearth]

Yeah clippy isn't perf tested. Are you sure you want to land this PR here? It'll land faster on the clippy repo. We could also rollup, of course

[flip1995]

I'm good with landing it here or in Clippy. Since this is a NFC it doesn't have to go through the Clippy repo and the sync process.

But there's still an error:

error[E0425]: cannot find value `Underscore` in module `sym`
   --> src/tools/clippy/clippy_lints/src/matches.rs:964:52
    |
964 |                     let mut ident_bind_name = sym::Underscore;
    |                                                    ^^^^^^^^^^ not found in `sym`
    |
help: consider importing one of these items
    |
1   | use crate::matches::hir::LifetimeName::Underscore;
    |
1   | use rustc_ast::ExprKind::Underscore;
    |
1   | use rustc_hir::LifetimeName::Underscore;
    |
1   | use rustc_span::symbol::kw::Underscore;
    |

[camelid]

What does NFC mean btw?

Also: It seemed to work in rust-analyzer sigh

I'll close this and reopen against the clippy repo (this PR originally changed rustc too, which is why I filed it here).

[camsteffen]

NFC = non-functional change. I think you need kw::Underscore.

[camelid]

Ok, I've opened rust-lang/rust-clippy#8310. Closing this PR then!