Add #[rustc_dump_generics] attribute

[addiesh]

View all comments

Added a rustc attribute to dump the generic parameters of a given item to the compiler output.

[rustbot]

Some changes occurred in compiler/rustc_attr_parsing

cc @jdonszelmann, @JonathanBrouwer

Some changes occurred in compiler/rustc_passes/src/check_attr.rs

cc @jdonszelmann, @JonathanBrouwer

Some changes occurred in compiler/rustc_hir/src/attrs

cc @jdonszelmann, @JonathanBrouwer

The rustc-dev-guide subtree was changed. If this PR only touches the dev guide consider submitting a PR directly to rust-lang/rustc-dev-guide otherwise thank you for updating the dev guide with your changes.

cc @BoxyUwU, @tshepang

[rustbot]

Thanks for the pull request, and welcome! The Rust team is excited to review your changes, and you should hear from @oli-obk (or someone else) some time within the next two weeks.

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[jdonszelmann]

I can review the attrs part!

[jdonszelmann]

You'll probably want a test using it on a trait some day, because I imagine the interaction can be a bit more involved for that. Im not quite sure how far along this is from proof of concept to done. You might want to initially not support traits if that test gives you trouble?

View changes since the review

[addiesh]

Just added a test for a trait, but it's definitely not exhaustive. Let me know your thoughts.

[oli-obk]

@bors r+ rollup

[rust-bors]

📌 Commit 7f0f6e0 has been approved by oli-obk

It is now in the queue for this repository.

[jhpratt]

@bors r-

#157726 (comment)

[rust-bors]

This pull request was unapproved.

This PR was contained in a rollup (#157726), which was unapproved.

View changes since this unapproval

[rustbot]

This PR was rebased onto a different main commit. Here's a range-diff highlighting what actually changed.

Rebasing is a normal part of keeping PRs up to date, so no action is needed—this note is just to help reviewers.

[mejrs]

@bors try jobs=i686-gnu-nopt-1

[rust-bors]

💔 Test for 87945f8 failed: CI. Failed job:

• try - i686-gnu-nopt-1 (web logs, enhanced plaintext logs)

[rust-log-analyzer]

The job i686-gnu-nopt-1 failed! Check out the build log: (web) (plain enhanced) (plain)

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

572           has_self: false,
573           has_late_bound_regions: None,

Note: some mismatched output was normalized before being compared
-               DefId(0:8 ~ dump_generics[c1f6]::NiceOfTheFoundation::U): 5,
-               DefId(0:7 ~ dump_generics[c1f6]::NiceOfTheFoundation::T): 4,
-               DefId(0:6 ~ dump_generics[c1f6]::NiceOfTheFoundation::N): 3,
-               DefId(0:5 ~ dump_generics[c1f6]::NiceOfTheFoundation::'_b): 2,
-               DefId(0:4 ~ dump_generics[c1f6]::NiceOfTheFoundation::'_a): 1,
-               DefId(0:3 ~ dump_generics[c1f6]::NiceOfTheFoundation): 0,
-               DefId(0:17 ~ dump_generics[c1f6]::IHopeItMadeLotsOfCode::'a): 1,
-               DefId(0:16 ~ dump_generics[c1f6]::IHopeItMadeLotsOfCode): 0,
-               DefId(0:21 ~ dump_generics[c1f6]::IHopeItMadeLotsOfCode::U): 5,
-               DefId(0:20 ~ dump_generics[c1f6]::IHopeItMadeLotsOfCode::T): 4,
-               DefId(0:19 ~ dump_generics[c1f6]::IHopeItMadeLotsOfCode::N): 3,
-               DefId(0:18 ~ dump_generics[c1f6]::IHopeItMadeLotsOfCode::'b): 2,
-               DefId(0:34 ~ dump_generics[c1f6]::HaveTakenOver::N): 2,
-               DefId(0:33 ~ dump_generics[c1f6]::HaveTakenOver::'b): 1,
-               DefId(0:32 ~ dump_generics[c1f6]::HaveTakenOver::'a): 0,
-               DefId(0:36 ~ dump_generics[c1f6]::HaveTakenOver::U): 4,
-               DefId(0:35 ~ dump_generics[c1f6]::HaveTakenOver::T): 3,
-               DefId(0:59 ~ dump_generics[c1f6]::i_dare_you::N): 1,
-               DefId(0:57 ~ dump_generics[c1f6]::i_dare_you::'a): 0,
-               DefId(0:61 ~ dump_generics[c1f6]::i_dare_you::U): 3,
-               DefId(0:60 ~ dump_generics[c1f6]::i_dare_you::T): 2,
+               DefId(..): 5,
+               DefId(..): 3,
+               DefId(..): 0,
+               DefId(..): 1,
+               DefId(..): 5,
+               DefId(..): 2,
+               DefId(..): 1,
+               DefId(..): 4,
+               DefId(..): 3,
+               DefId(..): 2,
+               DefId(..): 0,
+               DefId(..): 4,
+               DefId(..): 2,
+               DefId(..): 4,
+               DefId(..): 1,
+               DefId(..): 3,
+               DefId(..): 1,
+               DefId(..): 3,
+               DefId(..): 0,


The actual stderr differed from the expected stderr
To update references, rerun the tests and pass the `--bless` flag
To only update this specific test, also pass `--test-args attributes/dump_generics.rs`

error: 1 errors occurred comparing output.
status: exit status: 1
command: env -u RUSTC_LOG_COLOR RUSTC_ICE="0" RUST_BACKTRACE="short" "/checkout/obj/build/i686-unknown-linux-gnu/stage2/bin/rustc" "/checkout/tests/ui/attributes/dump_generics.rs" "-Zthreads=1" "-Zsimulate-remapped-rust-src-base=/rustc/FAKE_PREFIX" "-Ztranslate-remapped-path-to-local-path=no" "-Z" "ignore-directory-in-diagnostics-source-blocks=/cargo" "-Z" "ignore-directory-in-diagnostics-source-blocks=/checkout/vendor" "--sysroot" "/checkout/obj/build/i686-unknown-linux-gnu/stage2" "--target=i686-unknown-linux-gnu" "--check-cfg" "cfg(test,FALSE)" "--error-format" "json" "--json" "future-incompat" "-Ccodegen-units=1" "-Zui-testing" "-Zdeduplicate-diagnostics=no" "-Zwrite-long-types-to-disk=no" "-Cstrip=debuginfo" "--emit" "metadata" "-C" "prefer-dynamic" "--out-dir" "/checkout/obj/build/i686-unknown-linux-gnu/test/ui/attributes/dump_generics" "-A" "unused" "-W" "unused_attributes" "-A" "internal_features" "-A" "incomplete_features" "-A" "unused_parens" "-A" "unused_braces" "-Crpath" "-Cdebuginfo=0" "-Lnative=/checkout/obj/build/i686-unknown-linux-gnu/native/rust-test-helpers"
stdout: none
--- stderr -------------------------------
error: rustc_dump_generics: DefId(0:3 ~ dump_generics[c1f6]::NiceOfTheFoundation)
##[error]  --> /checkout/tests/ui/attributes/dump_generics.rs:8:1
   |
LL | trait NiceOfTheFoundation<'_a: '_a, '_b, const N: usize, T, U: Clone> {
   | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
   |
note: Generics {
          parent: None,
          parent_count: 0,
          own_params: [
              GenericParamDef {
                  name: "Self",
                  def_id: DefId(0:3 ~ dump_generics[c1f6]::NiceOfTheFoundation),
                  index: 0,
                  pure_wrt_drop: false,
                  kind: Type {
                      has_default: false,
                      synthetic: false,
                  },
              },
              GenericParamDef {
                  name: "'_a",
                  def_id: DefId(0:4 ~ dump_generics[c1f6]::NiceOfTheFoundation::'_a),
                  index: 1,
                  pure_wrt_drop: false,
                  kind: Lifetime,
              },
              GenericParamDef {
                  name: "'_b",
                  def_id: DefId(0:5 ~ dump_generics[c1f6]::NiceOfTheFoundation::'_b),
                  index: 2,
                  pure_wrt_drop: false,
                  kind: Lifetime,
              },
              GenericParamDef {
                  name: "N",
                  def_id: DefId(0:6 ~ dump_generics[c1f6]::NiceOfTheFoundation::N),
                  index: 3,
                  pure_wrt_drop: false,
                  kind: Const {
                      has_default: false,
                  },
              },
              GenericParamDef {
                  name: "T",
                  def_id: DefId(0:7 ~ dump_generics[c1f6]::NiceOfTheFoundation::T),
                  index: 4,
                  pure_wrt_drop: false,
                  kind: Type {
                      has_default: false,
                      synthetic: false,
                  },
              },
              GenericParamDef {
                  name: "U",
                  def_id: DefId(0:8 ~ dump_generics[c1f6]::NiceOfTheFoundation::U),
                  index: 5,
                  pure_wrt_drop: false,
                  kind: Type {
                      has_default: false,
                      synthetic: false,
                  },
              },
          ],
          param_def_id_to_index: {
              DefId(0:8 ~ dump_generics[c1f6]::NiceOfTheFoundation::U): 5,
              DefId(0:7 ~ dump_generics[c1f6]::NiceOfTheFoundation::T): 4,
              DefId(0:6 ~ dump_generics[c1f6]::NiceOfTheFoundation::N): 3,
              DefId(0:5 ~ dump_generics[c1f6]::NiceOfTheFoundation::'_b): 2,
              DefId(0:4 ~ dump_generics[c1f6]::NiceOfTheFoundation::'_a): 1,
              DefId(0:3 ~ dump_generics[c1f6]::NiceOfTheFoundation): 0,
          },
          has_self: true,
          has_late_bound_regions: None,
      }
  --> /checkout/tests/ui/attributes/dump_generics.rs:8:1
   |
LL | trait NiceOfTheFoundation<'_a: '_a, '_b, const N: usize, T, U: Clone> {
   | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^

error: rustc_dump_generics: DefId(0:16 ~ dump_generics[c1f6]::IHopeItMadeLotsOfCode)
##[error]  --> /checkout/tests/ui/attributes/dump_generics.rs:28:1
   |
LL | pub trait IHopeItMadeLotsOfCode<'a, 'b, const N: usize, T, U: Clone>
   | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
   |
note: Generics {
          parent: None,
          parent_count: 0,
          own_params: [
              GenericParamDef {
                  name: "Self",
                  def_id: DefId(0:16 ~ dump_generics[c1f6]::IHopeItMadeLotsOfCode),
                  index: 0,
                  pure_wrt_drop: false,
                  kind: Type {
                      has_default: false,
                      synthetic: false,
                  },
              },
              GenericParamDef {
                  name: "'a",
                  def_id: DefId(0:17 ~ dump_generics[c1f6]::IHopeItMadeLotsOfCode::'a),
                  index: 1,
                  pure_wrt_drop: false,
                  kind: Lifetime,
              },
              GenericParamDef {
                  name: "'b",
                  def_id: DefId(0:18 ~ dump_generics[c1f6]::IHopeItMadeLotsOfCode::'b),
                  index: 2,
                  pure_wrt_drop: false,
                  kind: Lifetime,
              },
              GenericParamDef {
                  name: "N",
                  def_id: DefId(0:19 ~ dump_generics[c1f6]::IHopeItMadeLotsOfCode::N),
                  index: 3,
                  pure_wrt_drop: false,
                  kind: Const {
                      has_default: false,
                  },
              },
              GenericParamDef {
                  name: "T",
                  def_id: DefId(0:20 ~ dump_generics[c1f6]::IHopeItMadeLotsOfCode::T),
                  index: 4,
                  pure_wrt_drop: false,
                  kind: Type {
                      has_default: false,
                      synthetic: false,
                  },
              },
              GenericParamDef {
                  name: "U",
                  def_id: DefId(0:21 ~ dump_generics[c1f6]::IHopeItMadeLotsOfCode::U),
                  index: 5,
                  pure_wrt_drop: false,
                  kind: Type {
                      has_default: false,
                      synthetic: false,
                  },
              },
          ],
          param_def_id_to_index: {
              DefId(0:17 ~ dump_generics[c1f6]::IHopeItMadeLotsOfCode::'a): 1,
              DefId(0:16 ~ dump_generics[c1f6]::IHopeItMadeLotsOfCode): 0,
              DefId(0:21 ~ dump_generics[c1f6]::IHopeItMadeLotsOfCode::U): 5,
              DefId(0:20 ~ dump_generics[c1f6]::IHopeItMadeLotsOfCode::T): 4,
              DefId(0:19 ~ dump_generics[c1f6]::IHopeItMadeLotsOfCode::N): 3,
              DefId(0:18 ~ dump_generics[c1f6]::IHopeItMadeLotsOfCode::'b): 2,
          },
          has_self: true,
          has_late_bound_regions: None,
      }
  --> /checkout/tests/ui/attributes/dump_generics.rs:28:1
   |
LL | pub trait IHopeItMadeLotsOfCode<'a, 'b, const N: usize, T, U: Clone>
   | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^

error: rustc_dump_generics: DefId(0:22 ~ dump_generics[c1f6]::LookItsFromCorro)
##[error]  --> /checkout/tests/ui/attributes/dump_generics.rs:33:1
   |
LL | struct LookItsFromCorro<'a, 'b, const N: usize, T, U: Clone> {
   | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
   |
note: Generics {
          parent: None,
          parent_count: 0,
          own_params: [
              GenericParamDef {
                  name: "'a",
                  def_id: DefId(0:23 ~ dump_generics[c1f6]::LookItsFromCorro::'a),
                  index: 0,
                  pure_wrt_drop: false,
                  kind: Lifetime,
              },
              GenericParamDef {
                  name: "'b",
                  def_id: DefId(0:24 ~ dump_generics[c1f6]::LookItsFromCorro::'b),
                  index: 1,
                  pure_wrt_drop: false,
                  kind: Lifetime,
              },
              GenericParamDef {
                  name: "N",
                  def_id: DefId(0:25 ~ dump_generics[c1f6]::LookItsFromCorro::N),
                  index: 2,
                  pure_wrt_drop: false,
                  kind: Const {
                      has_default: false,
                  },
              },
              GenericParamDef {
                  name: "T",
                  def_id: DefId(0:26 ~ dump_generics[c1f6]::LookItsFromCorro::T),
                  index: 3,
                  pure_wrt_drop: false,
                  kind: Type {
                      has_default: false,
                      synthetic: false,
                  },
              },
              GenericParamDef {
                  name: "U",
                  def_id: DefId(0:27 ~ dump_generics[c1f6]::LookItsFromCorro::U),
                  index: 4,
                  pure_wrt_drop: false,
                  kind: Type {
                      has_default: false,
                      synthetic: false,
                  },
              },
          ],
          param_def_id_to_index: {
              DefId(0:25 ~ dump_generics[c1f6]::LookItsFromCorro::N): 2,
              DefId(0:24 ~ dump_generics[c1f6]::LookItsFromCorro::'b): 1,
              DefId(0:23 ~ dump_generics[c1f6]::LookItsFromCorro::'a): 0,
              DefId(0:27 ~ dump_generics[c1f6]::LookItsFromCorro::U): 4,
              DefId(0:26 ~ dump_generics[c1f6]::LookItsFromCorro::T): 3,
          },
          has_self: false,
          has_late_bound_regions: None,
      }
  --> /checkout/tests/ui/attributes/dump_generics.rs:33:1
   |
LL | struct LookItsFromCorro<'a, 'b, const N: usize, T, U: Clone> {
   | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^

error: rustc_dump_generics: DefId(0:31 ~ dump_generics[c1f6]::HaveTakenOver)
##[error]  --> /checkout/tests/ui/attributes/dump_generics.rs:40:1
   |
LL | enum HaveTakenOver<'a: 'a, 'b, const N: usize, T, U: Clone> {
   | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
   |
note: Generics {
          parent: None,
          parent_count: 0,
          own_params: [
              GenericParamDef {
                  name: "'a",
                  def_id: DefId(0:32 ~ dump_generics[c1f6]::HaveTakenOver::'a),
                  index: 0,
                  pure_wrt_drop: false,
                  kind: Lifetime,
              },
              GenericParamDef {
                  name: "'b",
                  def_id: DefId(0:33 ~ dump_generics[c1f6]::HaveTakenOver::'b),
                  index: 1,
                  pure_wrt_drop: false,
                  kind: Lifetime,
              },
              GenericParamDef {
                  name: "N",
                  def_id: DefId(0:34 ~ dump_generics[c1f6]::HaveTakenOver::N),
                  index: 2,
                  pure_wrt_drop: false,
                  kind: Const {
                      has_default: false,
                  },
              },
              GenericParamDef {
                  name: "T",
                  def_id: DefId(0:35 ~ dump_generics[c1f6]::HaveTakenOver::T),
                  index: 3,
                  pure_wrt_drop: false,
                  kind: Type {
                      has_default: false,
                      synthetic: false,
                  },
              },
              GenericParamDef {
                  name: "U",
                  def_id: DefId(0:36 ~ dump_generics[c1f6]::HaveTakenOver::U),
                  index: 4,
                  pure_wrt_drop: false,
                  kind: Type {
                      has_default: false,
                      synthetic: false,
                  },
              },
          ],
          param_def_id_to_index: {
              DefId(0:34 ~ dump_generics[c1f6]::HaveTakenOver::N): 2,
              DefId(0:33 ~ dump_generics[c1f6]::HaveTakenOver::'b): 1,
              DefId(0:32 ~ dump_generics[c1f6]::HaveTakenOver::'a): 0,
              DefId(0:36 ~ dump_generics[c1f6]::HaveTakenOver::U): 4,
              DefId(0:35 ~ dump_generics[c1f6]::HaveTakenOver::T): 3,
          },
          has_self: false,
          has_late_bound_regions: None,
      }
  --> /checkout/tests/ui/attributes/dump_generics.rs:40:1
   |
LL | enum HaveTakenOver<'a: 'a, 'b, const N: usize, T, U: Clone> {
   | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^

error: rustc_dump_generics: DefId(0:47 ~ dump_generics[c1f6]::TheFoundation)
##[error]  --> /checkout/tests/ui/attributes/dump_generics.rs:48:1
   |
LL | union TheFoundation<'a: 'a, 'b, const N: usize, T, U: Clone> {
   | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
   |
note: Generics {
          parent: None,
          parent_count: 0,
          own_params: [
              GenericParamDef {
                  name: "'a",
                  def_id: DefId(0:48 ~ dump_generics[c1f6]::TheFoundation::'a),
                  index: 0,
                  pure_wrt_drop: false,
                  kind: Lifetime,
              },
              GenericParamDef {
                  name: "'b",
                  def_id: DefId(0:49 ~ dump_generics[c1f6]::TheFoundation::'b),
                  index: 1,
                  pure_wrt_drop: false,
                  kind: Lifetime,
              },
              GenericParamDef {
                  name: "N",
                  def_id: DefId(0:50 ~ dump_generics[c1f6]::TheFoundation::N),
                  index: 2,
                  pure_wrt_drop: false,
                  kind: Const {
                      has_default: false,
                  },
              },
              GenericParamDef {
                  name: "T",
                  def_id: DefId(0:51 ~ dump_generics[c1f6]::TheFoundation::T),
                  index: 3,
                  pure_wrt_drop: false,
                  kind: Type {
                      has_default: false,
                      synthetic: false,
                  },
              },
              GenericParamDef {
                  name: "U",
                  def_id: DefId(0:52 ~ dump_generics[c1f6]::TheFoundation::U),
                  index: 4,
                  pure_wrt_drop: false,
                  kind: Type {
                      has_default: false,
                      synthetic: false,
                  },
              },
          ],
          param_def_id_to_index: {
              DefId(0:51 ~ dump_generics[c1f6]::TheFoundation::T): 3,
              DefId(0:50 ~ dump_generics[c1f6]::TheFoundation::N): 2,
              DefId(0:49 ~ dump_generics[c1f6]::TheFoundation::'b): 1,
              DefId(0:48 ~ dump_generics[c1f6]::TheFoundation::'a): 0,
              DefId(0:52 ~ dump_generics[c1f6]::TheFoundation::U): 4,
          },
          has_self: false,
          has_late_bound_regions: None,
      }
  --> /checkout/tests/ui/attributes/dump_generics.rs:48:1
   |
LL | union TheFoundation<'a: 'a, 'b, const N: usize, T, U: Clone> {
   | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^

error: rustc_dump_generics: DefId(0:56 ~ dump_generics[c1f6]::i_dare_you)
##[error]  --> /checkout/tests/ui/attributes/dump_generics.rs:55:1
   |
LL | const fn i_dare_you<'a: 'a, 'b, const N: usize, T, U>(you_can: &'a bool, _: &'b [(T, U); N]) {
   | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
   |
note: Generics {
          parent: None,
          parent_count: 0,
          own_params: [
              GenericParamDef {
                  name: "'a",
                  def_id: DefId(0:57 ~ dump_generics[c1f6]::i_dare_you::'a),
                  index: 0,
                  pure_wrt_drop: false,
                  kind: Lifetime,
              },
              GenericParamDef {
                  name: "N",
                  def_id: DefId(0:59 ~ dump_generics[c1f6]::i_dare_you::N),
                  index: 1,
                  pure_wrt_drop: false,
                  kind: Const {
                      has_default: false,
                  },
              },
              GenericParamDef {
                  name: "T",
                  def_id: DefId(0:60 ~ dump_generics[c1f6]::i_dare_you::T),
                  index: 2,
                  pure_wrt_drop: false,
                  kind: Type {
                      has_default: false,
                      synthetic: false,
                  },
              },
              GenericParamDef {
                  name: "U",
                  def_id: DefId(0:61 ~ dump_generics[c1f6]::i_dare_you::U),
                  index: 3,
                  pure_wrt_drop: false,
                  kind: Type {
                      has_default: false,
                      synthetic: false,
                  },
              },
          ],
          param_def_id_to_index: {
              DefId(0:59 ~ dump_generics[c1f6]::i_dare_you::N): 1,
              DefId(0:57 ~ dump_generics[c1f6]::i_dare_you::'a): 0,
              DefId(0:61 ~ dump_generics[c1f6]::i_dare_you::U): 3,
              DefId(0:60 ~ dump_generics[c1f6]::i_dare_you::T): 2,
          },
          has_self: false,
          has_late_bound_regions: Some(
              /checkout/tests/ui/attributes/dump_generics.rs:55:29: 55:31 (#0),
          ),
      }
  --> /checkout/tests/ui/attributes/dump_generics.rs:55:1
   |
LL | const fn i_dare_you<'a: 'a, 'b, const N: usize, T, U>(you_can: &'a bool, _: &'b [(T, U); N]) {
   | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^

error: rustc_dump_generics: DefId(0:64 ~ dump_generics[c1f6]::IfYouNeed)
##[error]  --> /checkout/tests/ui/attributes/dump_generics.rs:66:1
   |
LL | trait IfYouNeed<'_a: '_a, '_b, const N: usize, T, U: Clone> {}
   | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
   |
note: Generics {
          parent: None,
          parent_count: 0,
          own_params: [
              GenericParamDef {
                  name: "Self",
                  def_id: DefId(0:64 ~ dump_generics[c1f6]::IfYouNeed),
                  index: 0,
                  pure_wrt_drop: false,

[addiesh]

That's frustrating. Why does it fail specifically on that target triple?

[fmease]

The specific target doesn't matter. You're printing a FxHashMap (param_def_id_to_index) whose entries don't have a "stable ordering" due to the hashing (it happens to be stable across compilations & re-runs but the behavior may differ by target; i686-gnu-nopt-1 differs most likely because it's a 32-bit arch).

You need to add another compiletest normalization rule to make the mapping stable by "normalizing away" the concrete indices.

[addiesh]

The specific target doesn't matter. You're printing a FxHashMap (param_def_id_to_index) whose entries don't have a "stable ordering" due to the hashing (it happens to be stable across compilations & re-runs but the behavior may differ by target; i686-gnu-nopt-1 differs most likely because it's a 32-bit arch).

You somehow need to compiletest-normalize away this mapping in the output.

Ah, I see. That makes sense. I'll try my best to do that.