Add has_default to GenericParamDefKind::Const

This currently creates a field which is always false on GenericParamDefKind for future use when
consts are permitted to have defaults

Update const_generics:default locations

Previously just ignored them, now actually do something about them.

Fix using type check instead of value

Add parsing

This adds all the necessary changes to lower const-generics defaults from parsing.

Change P<Expr> to AnonConst

This matches the arguments passed to instantiations of const generics, and makes it specific to
just anonymous constants.

Attempt to fix lowering bugs

1 files changed, 7 insertions, 2 deletions

diff --git a/compiler/rustc_privacy/src/lib.rs b/compiler/rustc_privacy/src/lib.rs
index de264b5bb04..9ba9524ee1a 100644
--- a/compiler/rustc_privacy/src/lib.rs
+++ b/compiler/rustc_privacy/src/lib.rs
@@ -928,8 +928,13 @@ impl ReachEverythingInTheInterfaceVisitor<'_, 'tcx> {
                         self.visit(self.ev.tcx.type_of(param.def_id));
                     }
                 }
-                GenericParamDefKind::Const => {
+                GenericParamDefKind::Const { has_default, .. } => {
                     self.visit(self.ev.tcx.type_of(param.def_id));
+                    if has_default {
+                        // how should the error case be handled here?
+                        // let default_const = self.ev.tcx.const_eval_poly(param.def_id).unwrap();
+                        // self.visit(default_const);
+                    }
                 }
             }
         }
@@ -1741,7 +1746,7 @@ impl SearchInterfaceForPrivateItemsVisitor<'tcx> {
                         self.visit(self.tcx.type_of(param.def_id));
                     }
                 }
-                GenericParamDefKind::Const => {
+                GenericParamDefKind::Const { .. } => {
                     self.visit(self.tcx.type_of(param.def_id));
                 }
             }