Auto merge of #147111 - BoxyUwU:rename_obligation_processing_apis, r=lcnr

rename `select_where_possible` and `select_all_or_error`

r? `@lcnr`

I find that people get confused by what these methods do. The verb "select" is not really that helpful and is just a reference to somewhat of an implementation detail of the trait solvers that doesn't even apply to most obligation kinds.

I went with `try_evaluate_obligations` and  `evaluate_obligations_error_on_ambiguity`. This maintains consistency with the new solvers `evalute_goal` entry point. it's unfortunate that we say obligations rather than goals but this maintains consistency with `register_obligation` functions which I think is a good thing. In the long term possibly we rename `Obligation` or `Goal` 🤷‍♀️

Author: bors

crates/hir-ty/src/autoderef.rs

@@ -304,7 +304,7 @@ fn structurally_normalize_ty<'db>(
         // evaluate/fulfill mismatches, but that's not a reason for an ICE.
         return None;
     };
-    let errors = ocx.select_where_possible();
+    let errors = ocx.try_evaluate_obligations();
     if !errors.is_empty() {
         unreachable!();
     }

crates/hir-ty/src/infer/coerce.rs

@@ -160,7 +160,7 @@ impl<'a, 'b, 'db> Coerce<'a, 'b, 'db> {
                 Ok(InferOk { value, obligations }) => {
                     let mut ocx = ObligationCtxt::new(this.infer_ctxt());
                     ocx.register_obligations(obligations);
-                    if ocx.select_where_possible().is_empty() {
+                    if ocx.try_evaluate_obligations().is_empty() {
                         Ok(InferOk { value, obligations: ocx.into_pending_obligations() })
                     } else {
                         Err(TypeError::Mismatch)
@@ -743,7 +743,7 @@ impl<'a, 'b, 'db> Coerce<'a, 'b, 'db> {
                 Some(PredicateKind::AliasRelate(..)) => {
                     let mut ocx = ObligationCtxt::new(self.infer_ctxt());
                     ocx.register_obligation(obligation);
-                    if !ocx.select_where_possible().is_empty() {
+                    if !ocx.try_evaluate_obligations().is_empty() {
                         return Err(TypeError::Mismatch);
                     }
                     coercion.obligations.extend(ocx.into_pending_obligations());
@@ -1119,7 +1119,7 @@ impl<'db> InferenceContext<'db> {
                                 prev_ty,
                                 new_ty,
                             )?;
-                            if ocx.select_where_possible().is_empty() {
+                            if ocx.try_evaluate_obligations().is_empty() {
                                 Ok(InferOk { value, obligations: ocx.into_pending_obligations() })
                             } else {
                                 Err(TypeError::Mismatch)

crates/hir-ty/src/infer/expr.rs

@@ -2151,7 +2151,7 @@ impl<'db> InferenceContext<'db> {
                             expected_output.to_nextsolver(interner),
                             formal_output,
                         )?;
-                        if !ocx.select_where_possible().is_empty() {
+                        if !ocx.try_evaluate_obligations().is_empty() {
                             return Err(crate::next_solver::TypeError::Mismatch);
                         }
 

crates/hir-ty/src/infer/unify.rs

@@ -818,7 +818,7 @@ impl<'db> InferenceTable<'db> {
     }
 
     pub(crate) fn select_obligations_where_possible(&mut self) {
-        self.fulfillment_cx.select_where_possible(&self.infer_ctxt);
+        self.fulfillment_cx.try_evaluate_obligations(&self.infer_ctxt);
     }
 
     pub(super) fn register_predicate(

crates/hir-ty/src/method_resolution.rs

@@ -1785,7 +1785,7 @@ fn is_valid_trait_method_candidate(
                         let mut ctxt = ObligationCtxt::new(&table.infer_ctxt);
                         ctxt.register_obligations(infer_ok.into_obligations());
                         // FIXME: Are we doing this correctly? Probably better to follow rustc more closely.
-                        check_that!(ctxt.select_where_possible().is_empty());
+                        check_that!(ctxt.try_evaluate_obligations().is_empty());
                     }
 
                     check_that!(table.unify(receiver_ty, &expected_receiver));
@@ -1871,7 +1871,7 @@ fn is_valid_impl_fn_candidate(
             )
         }));
 
-        if ctxt.select_where_possible().is_empty() {
+        if ctxt.try_evaluate_obligations().is_empty() {
             IsValidCandidate::Yes
         } else {
             IsValidCandidate::No

crates/hir-ty/src/next_solver/fulfill.rs

@@ -54,7 +54,7 @@ struct ObligationStorage<'db> {
     /// Obligations which resulted in an overflow in fulfillment itself.
     ///
     /// We cannot eagerly return these as error so we instead store them here
-    /// to avoid recomputing them each time `select_where_possible` is called.
+    /// to avoid recomputing them each time `try_evaluate_obligations` is called.
     /// This also allows us to return the correct `FulfillmentError` for them.
     overflowed: Vec<PredicateObligation<'db>>,
     pending: PendingObligations<'db>,
@@ -95,7 +95,7 @@ impl<'db> ObligationStorage<'db> {
             // IMPORTANT: we must not use solve any inference variables in the obligations
             // as this is all happening inside of a probe. We use a probe to make sure
             // we get all obligations involved in the overflow. We pretty much check: if
-            // we were to do another step of `select_where_possible`, which goals would
+            // we were to do another step of `try_evaluate_obligations`, which goals would
             // change.
             // FIXME: <https://github.com/Gankra/thin-vec/pull/66> is merged, this can be removed.
             self.overflowed.extend(
@@ -131,7 +131,7 @@ impl<'db> FulfillmentCtxt<'db> {
         infcx: &InferCtxt<'db>,
         obligation: PredicateObligation<'db>,
     ) {
-        // FIXME: See the comment in `select_where_possible()`.
+        // FIXME: See the comment in `try_evaluate_obligations()`.
         // assert_eq!(self.usable_in_snapshot, infcx.num_open_snapshots());
         self.obligations.register(obligation, None);
     }
@@ -141,7 +141,7 @@ impl<'db> FulfillmentCtxt<'db> {
         infcx: &InferCtxt<'db>,
         obligations: impl IntoIterator<Item = PredicateObligation<'db>>,
     ) {
-        // FIXME: See the comment in `select_where_possible()`.
+        // FIXME: See the comment in `try_evaluate_obligations()`.
         // assert_eq!(self.usable_in_snapshot, infcx.num_open_snapshots());
         obligations.into_iter().for_each(|obligation| self.obligations.register(obligation, None));
     }
@@ -158,7 +158,7 @@ impl<'db> FulfillmentCtxt<'db> {
             .collect()
     }
 
-    pub(crate) fn select_where_possible(
+    pub(crate) fn try_evaluate_obligations(
         &mut self,
         infcx: &InferCtxt<'db>,
     ) -> Vec<NextSolverError<'db>> {
@@ -223,11 +223,11 @@ impl<'db> FulfillmentCtxt<'db> {
         errors
     }
 
-    pub(crate) fn select_all_or_error(
+    pub(crate) fn evaluate_obligations_error_on_ambiguity(
         &mut self,
         infcx: &InferCtxt<'db>,
     ) -> Vec<NextSolverError<'db>> {
-        let errors = self.select_where_possible(infcx);
+        let errors = self.try_evaluate_obligations(infcx);
         if !errors.is_empty() {
             return errors;
         }

crates/hir-ty/src/next_solver/inspect.rs

@@ -92,7 +92,7 @@ impl<'db> NormalizesToTermHack<'db> {
         let mut ocx = ObligationCtxt::new(infcx);
         ocx.eq(&ObligationCause::dummy(), param_env, self.term, self.unconstrained_term)?;
         f(&mut ocx);
-        let errors = ocx.select_all_or_error();
+        let errors = ocx.evaluate_obligations_error_on_ambiguity();
         if errors.is_empty() {
             Ok(Certainty::Yes)
         } else if errors.iter().all(|e| !matches!(e, NextSolverError::TrueError(_))) {

crates/hir-ty/src/next_solver/normalize.rs

@@ -77,7 +77,7 @@ where
         stalled_coroutine_goals: vec![],
     };
     let value = value.try_fold_with(&mut folder)?;
-    let errors = folder.fulfill_cx.select_all_or_error(at.infcx);
+    let errors = folder.fulfill_cx.evaluate_obligations_error_on_ambiguity(at.infcx);
     if errors.is_empty() { Ok((value, folder.stalled_coroutine_goals)) } else { Err(errors) }
 }
 
@@ -138,7 +138,7 @@ impl<'db> NormalizationFolder<'_, 'db> {
     fn select_all_and_stall_coroutine_predicates(
         &mut self,
     ) -> Result<(), Vec<NextSolverError<'db>>> {
-        let errors = self.fulfill_cx.select_where_possible(self.at.infcx);
+        let errors = self.fulfill_cx.try_evaluate_obligations(self.at.infcx);
         if !errors.is_empty() {
             return Err(errors);
         }

crates/hir-ty/src/next_solver/obligation_ctxt.rs

@@ -144,13 +144,13 @@ impl<'a, 'db> ObligationCtxt<'a, 'db> {
     }
 
     #[must_use]
-    pub fn select_where_possible(&mut self) -> Vec<NextSolverError<'db>> {
-        self.engine.select_where_possible(self.infcx)
+    pub fn try_evaluate_obligations(&mut self) -> Vec<NextSolverError<'db>> {
+        self.engine.try_evaluate_obligations(self.infcx)
     }
 
     #[must_use]
-    pub fn select_all_or_error(&mut self) -> Vec<NextSolverError<'db>> {
-        self.engine.select_all_or_error(self.infcx)
+    pub fn evaluate_obligations_error_on_ambiguity(&mut self) -> Vec<NextSolverError<'db>> {
+        self.engine.evaluate_obligations_error_on_ambiguity(self.infcx)
     }
 
     /// Returns the not-yet-processed and stalled obligations from the

crates/hir-ty/src/next_solver/structural_normalize.rs

@@ -47,7 +47,7 @@ impl<'db> At<'_, 'db> {
         );
 
         fulfill_cx.register_predicate_obligation(self.infcx, obligation);
-        let errors = fulfill_cx.select_where_possible(self.infcx);
+        let errors = fulfill_cx.try_evaluate_obligations(self.infcx);
         if !errors.is_empty() {
             return Err(errors);
         }