[TMP] Add some FIXMEs

Author: fmease

compiler/rustc_hir_analysis/src/errors/wrong_number_of_generic_args.rs

@@ -1023,6 +1023,8 @@ impl<'a, 'tcx> WrongNumberOfGenericArgs<'a, 'tcx> {
                     .collect::<Vec<_>>();
 
                 if !suggestions.is_empty() {
+                    // FIXME: This suggests binding to an assoc ty even if the term is a const.
+                    // FIXME: Generalize this to cover assoc consts, too.
                     err.multipart_suggestion_verbose(
                         format!(
                             "replace the generic bound{s} with the associated type{s}",

compiler/rustc_hir_analysis/src/hir_ty_lowering/dyn_trait.rs

@@ -149,9 +149,13 @@ impl<'tcx> dyn HirTyLowerer<'tcx> + '_ {
         let mut projection_bounds = FxIndexMap::default();
         for (proj, proj_span) in elaborated_projection_bounds {
             let proj = proj.map_bound(|mut b| {
+                // FIXME(fmease): Surely we need to do that for const bindings, too.
                 if let Some(term_ty) = &b.term.as_type() {
                     let references_self = term_ty.walk().any(|arg| arg == dummy_self.into());
                     if references_self {
+                        // FIXME(fmease): The term "type alias" isn't relevant at all, those are
+                        //                expanded eagerly during HIR ty lowering.
+                        //                Rename diagnostic struct & prolly rephrase diag msg.
                         // With trait alias and type alias combined, type resolver
                         // may not be able to catch all illegal `Self` usages (issue 139082)
                         let guar = self.dcx().emit_err(SelfInTypeAlias { span });