fix: treat enum variants as generic item on their own

[lowr]

Fixup for #13335

It turns out I tried to merge two procedures into one utility function without noticing the incompatibility.

This time I did run analysis-stats on the four crates and confirmed it doesn't crash and this patch doesn't cause regression.

[Veykril]

@bors r+

[bors]

📌 Commit e0a161b has been approved by Veykril

It is now in the queue for this repository.

[bors]

⌛ Testing commit e0a161b with merge 974caaf...

[bors]

☀️ Test successful - checks-actions
Approved by: Veykril
Pushing 974caaf to master...

[Veykril]

Looks like there is still something wrong after this fix, analysis-stats works fine on r-a, but not on the std library it seems?

Run target/x86_64-unknown-linux-gnu/release/rust-analyzer analysis-stats --with-deps $(rustc --print sysroot)/lib/rustlib/src/rust/library/std
Failed to create perf counter: Operation not permitted (os error 1)
Failed to create perf counter: Operation not permitted (os error 1)
Database loaded:     19.00s (metadata 1.38s; build 17.51s)
Failed to create perf counter: Operation not permitted (os error 1)
  crates: 35, mods: 1252, decls: 39416, fns: 26420
Item Collection:     7.95s
Failed to create perf counter: Operation not permitted (os error 1)
thread 'main' panicked at 'called `Option::unwrap()` on a `None` value', /github/home/.cargo/registry/src/github.com-1ecc6299db9ec823/chalk-ir-0.84.0/src/lib.rs:1457:33
stack backtrace:
   0: rust_begin_unwind
             at /rustc/a55dd71d5fb0ec5a6a3a9e8c27b2127ba491ce52/library/std/src/panicking.rs:584:5
   1: core::panicking::panic_fmt
             at /rustc/a55dd71d5fb0ec5a6a3a9e8c27b2127ba491ce52/library/core/src/panicking.rs:142:14
   2: core::panicking::panic
             at /rustc/a55dd71d5fb0ec5a6a3a9e8c27b2127ba491ce52/library/core/src/panicking.rs:48:5
   3: <&chalk_ir::SubstFolder<I,A> as chalk_ir::fold::TypeFolder<I>>::fold_free_var_const
   4: <chalk_ir::Const<I> as chalk_ir::fold::TypeSuperFoldable<I>>::super_fold_with
   5: chalk_ir::fold::boring_impls::<impl chalk_ir::fold::TypeFoldable<I> for chalk_ir::GenericArg<I>>::fold_with
   6: <smallvec::SmallVec<A> as core::iter::traits::collect::Extend<<A as smallvec::Array>::Item>>::extend
   7: <hir_ty::interner::Interner as chalk_ir::interner::Interner>::intern_substitution
   8: chalk_ir::fold::boring_impls::<impl chalk_ir::fold::TypeFoldable<I> for chalk_ir::Substitution<I>>::fold_with
   9: <chalk_ir::Ty<I> as chalk_ir::fold::TypeSuperFoldable<I>>::super_fold_with
  10: chalk_ir::fold::boring_impls::<impl chalk_ir::fold::TypeFoldable<I> for chalk_ir::GenericArg<I>>::fold_with
  11: <smallvec::SmallVec<A> as core::iter::traits::collect::Extend<<A as smallvec::Array>::Item>>::extend
  12: <hir_ty::interner::Interner as chalk_ir::interner::Interner>::intern_substitution
  13: chalk_ir::fold::boring_impls::<impl chalk_ir::fold::TypeFoldable<I> for chalk_ir::Substitution<I>>::fold_with
  14: hir_ty::lower::named_associated_type_shorthand_candidates::{{closure}}
  15: hir_ty::lower::TyLoweringContext::lower_ty_relative_path
  16: hir_ty::lower::TyLoweringContext::lower_partly_resolved_path
  17: hir_ty::lower::TyLoweringContext::lower_ty_ext
  18: <smallvec::SmallVec<A> as core::iter::traits::collect::Extend<<A as smallvec::Array>::Item>>::extend
  19: core::iter::adapters::try_process
  20: hir_ty::lower::TyLoweringContext::lower_ty_ext
  21: hir_ty::lower::TyLoweringContext::substs_from_path_segment
  22: hir_ty::lower::TyLoweringContext::lower_trait_ref_from_path
  23: hir_ty::lower::TyLoweringContext::lower_type_bound
  24: hir_ty::lower::TyLoweringContext::lower_where_predicate
  25: hir_ty::lower::trait_environment_query
  26: salsa::runtime::Runtime::execute_query_implementation
  27: salsa::derived::slot::Slot<Q,MP>::read_upgrade
  28: salsa::derived::slot::Slot<Q,MP>::read
  29: <salsa::derived::DerivedStorage<Q,MP> as salsa::plumbing::QueryStorageOps<Q>>::try_fetch
  30: <DB as hir_ty::db::HirDatabase>::trait_environment::__shim
  31: <DB as hir_ty::db::HirDatabase>::trait_environment
  32: hir_ty::infer::infer_query
  33: salsa::runtime::Runtime::execute_query_implementation
  34: salsa::derived::slot::Slot<Q,MP>::read_upgrade
  35: salsa::derived::slot::Slot<Q,MP>::read
  36: <salsa::derived::DerivedStorage<Q,MP> as salsa::plumbing::QueryStorageOps<Q>>::try_fetch
  37: <DB as hir_ty::db::HirDatabase>::infer_query::__shim
  38: <DB as hir_ty::db::HirDatabase>::infer_query
  39: hir_ty::db::infer_wait
  40: rust_analyzer::cli::analysis_stats::<impl rust_analyzer::cli::flags::AnalysisStats>::run_inference
  41: rust_analyzer::cli::analysis_stats::<impl rust_analyzer::cli::flags::AnalysisStats>::run
  42: rust_analyzer::main
note: Some details are omitted, run with `RUST_BACKTRACE=full` for a verbose backtrace.

[lowr]

@Veykril Thanks for notifying, I'm working on the fix.