add additional logging

Author: lcnr

compiler/rustc_borrowck/src/region_infer/opaque_types.rs

@@ -23,7 +23,7 @@ use rustc_trait_selection::opaque_types::{
 };
 use rustc_trait_selection::solve::NoSolution;
 use rustc_trait_selection::traits::query::type_op::custom::CustomTypeOp;
-use tracing::{debug, instrument};
+use tracing::{debug, debug_span, instrument};
 
 use super::reverse_sccs::ReverseSccGraph;
 use super::values::RegionValues;
@@ -196,6 +196,8 @@ pub(crate) fn handle_opaque_type_uses<'tcx>(
         })
         .collect::<Vec<_>>();
 
+    debug!(?opaque_types);
+
     collect_defining_uses(
         root_cx,
         infcx,
@@ -287,6 +289,7 @@ fn apply_member_constraints<'tcx>(
     defining_uses: &[DefiningUse<'tcx>],
 ) {
     for DefiningUse { opaque_type_key: _, arg_regions, hidden_type } in defining_uses {
+        let _span = debug_span!("apply_member_constraints", ?arg_regions, ?hidden_type);
         let mut visitor =
             ApplyMemberConstraintsVisitor { rcx, arg_regions, span: hidden_type.span, constraints };
         hidden_type.ty.visit_with(&mut visitor);
@@ -316,6 +319,7 @@ impl<'tcx> TypeVisitor<TyCtxt<'tcx>> for ApplyMemberConstraintsVisitor<'_, 'tcx>
     //
     // If there's a unique minimum choice, we emit a `'member: 'min_choice` constraint.
     // Note that we do not require the two regions to be equal... TODO examples
+    #[instrument(level = "debug", skip(self))]
     fn visit_region(&mut self, r: Region<'tcx>) {
         let member_vid = match r.kind() {
             ty::ReBound(..) => return,
@@ -445,6 +449,7 @@ fn map_defining_uses_to_definition_site<'tcx>(
             let vid = rcx.representative(r.as_var());
             rcx.definitions[vid].external_name.unwrap()
         });
+        let _span = debug_span!("map_defining_uses_to_definition_site", ?opaque_type_key, ?arg_regions, ?hidden_type);
         // TODO: explain what's going on here
         let mut visitor =
             HiddenTypeMeh { rcx, arg_regions, opaque_type_key, hidden_type, deferred_errors };