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, 3 insertions, 2 deletions

diff --git a/compiler/rustc_infer/src/infer/error_reporting/mod.rs b/compiler/rustc_infer/src/infer/error_reporting/mod.rs
index eeff48a6395..d614f186106 100644
--- a/compiler/rustc_infer/src/infer/error_reporting/mod.rs
+++ b/compiler/rustc_infer/src/infer/error_reporting/mod.rs
@@ -963,10 +963,11 @@ impl<'a, 'tcx> InferCtxt<'a, 'tcx> {
             .rev()
             .filter_map(|param| match param.kind {
                 ty::GenericParamDefKind::Lifetime => None,
-                ty::GenericParamDefKind::Type { has_default, .. } => {
+
+                ty::GenericParamDefKind::Type { has_default, .. }
+                | ty::GenericParamDefKind::Const { has_default } => {
                     Some((param.def_id, has_default))
                 }
-                ty::GenericParamDefKind::Const => None, // FIXME(const_generics_defaults)
             })
             .peekable();
         let has_default = {