Simplify the collecting of ? Trait bounds in where clause

[SparrowLii]

This PR fixes the FIXME about using less rightward drift and only one error reporting when collecting of ?Trait bounds in where clause.
Checking whether the path length of bound_ty is 1 can be replaced by whether unresolved_segments in the partial_res is 0.
Checking whether the param.kind is Type{...} can also be omitted. One Fx hash calculation will be done for Const or Lifetime param, but the impact on efficiency should be small IMO

[rust-highfive]

r? @wesleywiser

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[wesleywiser]

Thanks, LGTM!

Let's do a perf run just to be sure there isn't much of an impact.

@bors try @rust-timer queue

[rust-timer]

Awaiting bors try build completion.

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

[bors]

⌛ Trying commit 0f5bfc2 with merge 12fa27618837d6c2baa39ce6230ce51fab72cc8b...

[bors]

💔 Test failed - checks-actions

[rust-log-analyzer]

A job failed! Check out the build log: (web) (plain)

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

From https://github.com/rust-lang/miri
 * branch              062cf07d98822beb4c5b1132f47b4397275f403a -> FETCH_HEAD
 * branch              06758c48bd7a77bb5aa43fc50cf344540ba5afef -> FETCH_HEAD
 * branch              dd7f545a69e4b720407e458bf4ade0b207bbf9ee -> FETCH_HEAD
fatal: remote error: upload-pack: not our ref 9ad6e5b8f68ee4bcd85886e50b8b0a70cbb91a52
Errors during submodule fetch:
##[error]Process completed with exit code 1.
Post job cleanup.

[wesleywiser]

@bors try

[bors]

⌛ Trying commit 0f5bfc2 with merge 28412d0793bff25304c9c359ae4103c872fb090b...

[bors]

☀️ Try build successful - checks-actions
Build commit: 28412d0793bff25304c9c359ae4103c872fb090b (28412d0793bff25304c9c359ae4103c872fb090b)

[rust-timer]

Queued 28412d0793bff25304c9c359ae4103c872fb090b with parent e742158, future comparison URL.

[rust-timer]

Finished benchmarking try commit (28412d0793bff25304c9c359ae4103c872fb090b): comparison url.

Summary: This benchmark run did not return any significant changes.

If you disagree with this performance assessment, please file an issue in rust-lang/rustc-perf.

Benchmarking this pull request likely means that it is perf-sensitive, so we're automatically marking it as not fit for rolling up.

@bors rollup=never
@rustbot label: +S-waiting-on-review -S-waiting-on-perf -perf-regression

[SparrowLii]

Thanks for reviewing! I'm happy it is helpful

[wesleywiser]

@bors r+

[bors]

📌 Commit 0f5bfc2 has been approved by wesleywiser

[bors]

⌛ Testing commit 0f5bfc2 with merge d03456d...

[bors]

☀️ Test successful - checks-actions
Approved by: wesleywiser
Pushing d03456d to master...