Auto merge of #142088 - compiler-errors:perf-universal-stall, r=<try>

Filter out universals and lifetimes from `stalled_vars`

lol

r? lcnr

Author: rust-bors[bot]

compiler/rustc_infer/src/infer/context.rs

@@ -96,8 +96,8 @@ impl<'tcx> rustc_type_ir::InferCtxtLike for InferCtxt<'tcx> {
                 false
             }
             ty::GenericArgKind::Type(ty) => {
-                if let ty::Infer(infer_ty) = *ty.kind() {
-                    match infer_ty {
+                match *ty.kind() {
+                    ty::Infer(infer_ty) => match infer_ty {
                         ty::InferTy::TyVar(vid) => {
                             !self.probe_ty_var(vid).is_err_and(|_| self.root_var(vid) == vid)
                         }
@@ -119,22 +119,24 @@ impl<'tcx> rustc_type_ir::InferCtxtLike for InferCtxt<'tcx> {
                         }
                         ty::InferTy::FreshTy(_)
                         | ty::InferTy::FreshIntTy(_)
-                        | ty::InferTy::FreshFloatTy(_) => true,
-                    }
-                } else {
-                    true
+                        | ty::InferTy::FreshFloatTy(_) => unreachable!(),
+                    },
+                    // This was a canonicalized universal var, so it doesn't change.
+                    ty::Param(_) | ty::Placeholder(_) => false,
+                    _ => unreachable!("unexpected orig value: {arg}"),
                 }
             }
             ty::GenericArgKind::Const(ct) => {
-                if let ty::ConstKind::Infer(infer_ct) = ct.kind() {
-                    match infer_ct {
+                match ct.kind() {
+                    ty::ConstKind::Infer(infer_ct) => match infer_ct {
                         ty::InferConst::Var(vid) => !self
                             .probe_const_var(vid)
                             .is_err_and(|_| self.root_const_var(vid) == vid),
                         ty::InferConst::Fresh(_) => true,
-                    }
-                } else {
-                    true
+                    },
+                    // This was a canonicalized universal var, so it doesn't change.
+                    ty::ConstKind::Param(_) | ty::ConstKind::Placeholder(_) => false,
+                    _ => unreachable!("unexpected orig value: {arg}"),
                 }
             }
         }

compiler/rustc_next_trait_solver/src/solve/eval_ctxt/mod.rs

@@ -544,8 +544,8 @@ where
                 // to recompute this goal.
                 HasChanged::Yes => None,
                 HasChanged::No => {
-                    // Remove the unconstrained RHS arg, which is expected to have changed.
                     let mut stalled_vars = orig_values;
+                    // Remove the unconstrained RHS arg, which is expected to have changed.
                     if let Some(normalizes_to) = goal.predicate.as_normalizes_to() {
                         let normalizes_to = normalizes_to.skip_binder();
                         let rhs_arg: I::GenericArg = normalizes_to.term.into();

compiler/rustc_trait_selection/src/solve/fulfill/derive_errors.rs

@@ -120,13 +120,15 @@ pub(super) fn fulfillment_error_for_stalled<'tcx>(
                 false,
             ),
             Ok(GoalEvaluation { certainty: Certainty::Yes, .. }) => {
-                bug!(
+                span_bug!(
+                    root_obligation.cause.span,
                     "did not expect successful goal when collecting ambiguity errors for `{:?}`",
                     infcx.resolve_vars_if_possible(root_obligation.predicate),
                 )
             }
             Err(_) => {
-                bug!(
+                span_bug!(
+                    root_obligation.cause.span,
                     "did not expect selection error when collecting ambiguity errors for `{:?}`",
                     infcx.resolve_vars_if_possible(root_obligation.predicate),
                 )