Simplify API of solver a bit

compiler/rustc_trait_selection/src/solve/fulfill.rs

@@ -14,7 +14,7 @@ use rustc_middle::ty::{
 };
 use rustc_next_trait_solver::delegate::SolverDelegate as _;
 use rustc_next_trait_solver::solve::{
-    GenerateProofTree, GoalEvaluation, GoalStalledOn, HasChanged, SolverDelegateEvalExt as _,
+    GoalEvaluation, GoalStalledOn, HasChanged, SolverDelegateEvalExt as _,
 };
 use rustc_span::Span;
 use thin_vec::ThinVec;
@@ -106,14 +106,11 @@ impl<'tcx> ObligationStorage<'tcx> {
             self.overflowed.extend(
                 ExtractIf::new(&mut self.pending, |(o, stalled_on)| {
                     let goal = o.as_goal();
-                    let result = <&SolverDelegate<'tcx>>::from(infcx)
-                        .evaluate_root_goal(
-                            goal,
-                            GenerateProofTree::No,
-                            o.cause.span,
-                            stalled_on.take(),
-                        )
-                        .0;
+                    let result = <&SolverDelegate<'tcx>>::from(infcx).evaluate_root_goal(
+                        goal,
+                        o.cause.span,
+                        stalled_on.take(),
+                    );
                     matches!(result, Ok(GoalEvaluation { has_changed: HasChanged::Yes, .. }))
                 })
                 .map(|(o, _)| o),
@@ -207,14 +204,7 @@ where
                     continue;
                 }
 
-                let result = delegate
-                    .evaluate_root_goal(
-                        goal,
-                        GenerateProofTree::No,
-                        obligation.cause.span,
-                        stalled_on,
-                    )
-                    .0;
+                let result = delegate.evaluate_root_goal(goal, obligation.cause.span, stalled_on);
                 self.inspect_evaluated_obligation(infcx, &obligation, &result);
                 let GoalEvaluation { certainty, has_changed, stalled_on } = match result {
                     Ok(result) => result,

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

@@ -11,9 +11,7 @@ use rustc_middle::traits::query::NoSolution;
 use rustc_middle::ty::error::{ExpectedFound, TypeError};
 use rustc_middle::ty::{self, Ty, TyCtxt};
 use rustc_middle::{bug, span_bug};
-use rustc_next_trait_solver::solve::{
-    GenerateProofTree, GoalEvaluation, SolverDelegateEvalExt as _,
-};
+use rustc_next_trait_solver::solve::{GoalEvaluation, SolverDelegateEvalExt as _};
 use tracing::{instrument, trace};
 
 use crate::solve::delegate::SolverDelegate;
@@ -90,15 +88,11 @@ pub(super) fn fulfillment_error_for_stalled<'tcx>(
     root_obligation: PredicateObligation<'tcx>,
 ) -> FulfillmentError<'tcx> {
     let (code, refine_obligation) = infcx.probe(|_| {
-        match <&SolverDelegate<'tcx>>::from(infcx)
-            .evaluate_root_goal(
-                root_obligation.as_goal(),
-                GenerateProofTree::No,
-                root_obligation.cause.span,
-                None,
-            )
-            .0
-        {
+        match <&SolverDelegate<'tcx>>::from(infcx).evaluate_root_goal(
+            root_obligation.as_goal(),
+            root_obligation.cause.span,
+            None,
+        ) {
             Ok(GoalEvaluation { certainty: Certainty::Maybe(MaybeCause::Ambiguity), .. }) => {
                 (FulfillmentErrorCode::Ambiguity { overflow: None }, true)
             }

compiler/rustc_trait_selection/src/solve/inspect/analyse.rs

@@ -20,7 +20,7 @@ use rustc_middle::ty::{TyCtxt, VisitorResult, try_visit};
 use rustc_middle::{bug, ty};
 use rustc_next_trait_solver::resolve::eager_resolve_vars;
 use rustc_next_trait_solver::solve::inspect::{self, instantiate_canonical_state};
-use rustc_next_trait_solver::solve::{GenerateProofTree, MaybeCause, SolverDelegateEvalExt as _};
+use rustc_next_trait_solver::solve::{MaybeCause, SolverDelegateEvalExt as _};
 use rustc_span::Span;
 use tracing::instrument;
 
@@ -248,9 +248,7 @@ impl<'a, 'tcx> InspectCandidate<'a, 'tcx> {
                     // considering the constrained RHS, and pass the resulting certainty to
                     // `InspectGoal::new` so that the goal has the right result (and maintains
                     // the impression that we don't do this normalizes-to infer hack at all).
-                    let (nested, proof_tree) =
-                        infcx.evaluate_root_goal_raw(goal, GenerateProofTree::Yes, None);
-                    let proof_tree = proof_tree.unwrap();
+                    let (nested, proof_tree) = infcx.evaluate_root_goal_for_proof_tree(goal, span);
                     let nested_goals_result = nested.and_then(|(nested, _)| {
                         normalizes_to_term_hack.constrain_and(
                             infcx,
@@ -284,9 +282,8 @@ impl<'a, 'tcx> InspectCandidate<'a, 'tcx> {
                 // into another candidate who ends up with different inference
                 // constraints, we get an ICE if we already applied the constraints
                 // from the chosen candidate.
-                let proof_tree = infcx
-                    .probe(|_| infcx.evaluate_root_goal(goal, GenerateProofTree::Yes, span, None).1)
-                    .unwrap();
+                let proof_tree =
+                    infcx.probe(|_| infcx.evaluate_root_goal_for_proof_tree(goal, span).1);
                 InspectGoal::new(infcx, self.goal.depth + 1, proof_tree, None, source)
             }
         }
@@ -488,13 +485,8 @@ impl<'tcx> InferCtxt<'tcx> {
         depth: usize,
         visitor: &mut V,
     ) -> V::Result {
-        let (_, proof_tree) = <&SolverDelegate<'tcx>>::from(self).evaluate_root_goal(
-            goal,
-            GenerateProofTree::Yes,
-            visitor.span(),
-            None,
-        );
-        let proof_tree = proof_tree.unwrap();
+        let (_, proof_tree) = <&SolverDelegate<'tcx>>::from(self)
+            .evaluate_root_goal_for_proof_tree(goal, visitor.span());
         visitor.visit_goal(&InspectGoal::new(self, depth, proof_tree, None, GoalSource::Misc))
     }
 }