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

compiler/rustc_borrowck/src/diagnostics/bound_region_errors.rs

@@ -420,7 +420,7 @@ fn try_extract_error_from_fulfill_cx<'a, 'tcx>(
     // We generally shouldn't have errors here because the query was
     // already run, but there's no point using `span_delayed_bug`
     // when we're going to emit an error here anyway.
-    let _errors = ocx.select_all_or_error();
+    let _errors = ocx.evaluate_obligations_error_on_ambiguity();
     let region_constraints = ocx.infcx.with_region_constraints(|r| r.clone());
     try_extract_error_from_region_constraints(
         ocx.infcx,

compiler/rustc_borrowck/src/diagnostics/conflict_errors.rs

@@ -1313,7 +1313,7 @@ impl<'infcx, 'tcx> MirBorrowckCtxt<'_, 'infcx, 'tcx> {
             let ocx = ObligationCtxt::new_with_diagnostics(self.infcx);
             let cause = ObligationCause::misc(expr.span, self.mir_def_id());
             ocx.register_bound(cause, self.infcx.param_env, ty, clone_trait);
-            let errors = ocx.select_all_or_error();
+            let errors = ocx.evaluate_obligations_error_on_ambiguity();
             if errors.iter().all(|error| {
                 match error.obligation.predicate.as_clause().and_then(|c| c.as_trait_clause()) {
                     Some(clause) => match clause.self_ty().skip_binder().kind() {
@@ -1497,7 +1497,7 @@ impl<'infcx, 'tcx> MirBorrowckCtxt<'_, 'infcx, 'tcx> {
         let cause = ObligationCause::misc(span, self.mir_def_id());
 
         ocx.register_bound(cause, self.infcx.param_env, ty, def_id);
-        let errors = ocx.select_all_or_error();
+        let errors = ocx.evaluate_obligations_error_on_ambiguity();
 
         // Only emit suggestion if all required predicates are on generic
         let predicates: Result<Vec<_>, _> = errors

compiler/rustc_borrowck/src/diagnostics/region_errors.rs

@@ -1134,7 +1134,7 @@ impl<'infcx, 'tcx> MirBorrowckCtxt<'_, 'infcx, 'tcx> {
             Obligation::misc(tcx, span, self.mir_def_id(), self.infcx.param_env, pred)
         }));
 
-        if ocx.select_all_or_error().is_empty() && count > 0 {
+        if ocx.evaluate_obligations_error_on_ambiguity().is_empty() && count > 0 {
             diag.span_suggestion_verbose(
                 tcx.hir_body(*body).value.peel_blocks().span.shrink_to_lo(),
                 fluent::borrowck_dereference_suggestion,

compiler/rustc_borrowck/src/type_check/liveness/trace.rs

@@ -657,7 +657,7 @@ impl<'tcx> LivenessContext<'_, '_, 'tcx> {
                     let errors = match dropck_outlives::compute_dropck_outlives_with_errors(
                         &ocx, op, span,
                     ) {
-                        Ok(_) => ocx.select_all_or_error(),
+                        Ok(_) => ocx.evaluate_obligations_error_on_ambiguity(),
                         Err(e) => e,
                     };
 

compiler/rustc_codegen_ssa/src/base.rs

@@ -139,7 +139,7 @@ pub fn validate_trivial_unsize<'tcx>(
                 ) else {
                     return false;
                 };
-                if !ocx.select_all_or_error().is_empty() {
+                if !ocx.evaluate_obligations_error_on_ambiguity().is_empty() {
                     return false;
                 }
                 infcx.leak_check(universe, None).is_ok()

compiler/rustc_const_eval/src/check_consts/check.rs

@@ -415,7 +415,7 @@ impl<'mir, 'tcx> Checker<'mir, 'tcx> {
             )
         }));
 
-        let errors = ocx.select_all_or_error();
+        let errors = ocx.evaluate_obligations_error_on_ambiguity();
         if errors.is_empty() {
             Some(ConstConditionsHold::Yes)
         } else {

compiler/rustc_const_eval/src/check_consts/qualifs.rs

@@ -119,7 +119,7 @@ impl Qualif for HasMutInterior {
             ty::TraitRef::new(cx.tcx, freeze_def_id, [ty::GenericArg::from(ty)]),
         );
         ocx.register_obligation(obligation);
-        let errors = ocx.select_all_or_error();
+        let errors = ocx.evaluate_obligations_error_on_ambiguity();
         !errors.is_empty()
     }
 
@@ -197,7 +197,7 @@ impl Qualif for NeedsNonConstDrop {
                     },
                 ),
         ));
-        !ocx.select_all_or_error().is_empty()
+        !ocx.evaluate_obligations_error_on_ambiguity().is_empty()
     }
 
     fn is_structural_in_adt_value<'tcx>(cx: &ConstCx<'_, 'tcx>, adt: AdtDef<'tcx>) -> bool {

compiler/rustc_const_eval/src/util/compare_types.rs

@@ -43,5 +43,5 @@ pub fn relate_types<'tcx>(
         Ok(()) => {}
         Err(_) => return false,
     };
-    ocx.select_all_or_error().is_empty()
+    ocx.evaluate_obligations_error_on_ambiguity().is_empty()
 }

compiler/rustc_hir_analysis/src/autoderef.rs

@@ -199,7 +199,7 @@ impl<'a, 'tcx> Autoderef<'a, 'tcx> {
             // 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() {
             if self.infcx.next_trait_solver() {
                 unreachable!();

compiler/rustc_hir_analysis/src/check/always_applicable.rs

@@ -235,7 +235,7 @@ fn ensure_impl_predicates_are_implied_by_item_defn<'tcx>(
     // They can probably get removed with better treatment of the new `DropImpl`
     // obligation cause code, and perhaps some custom logic in `report_region_errors`.
 
-    let errors = ocx.select_all_or_error();
+    let errors = ocx.evaluate_obligations_error_on_ambiguity();
     if !errors.is_empty() {
         let mut guar = None;
         let mut root_predicates = FxHashSet::default();