Rollup merge of #80538 - JulianKnodt:err_usize, r=lcnr

Add check for `[T;N]`/`usize` mismatch in astconv

Helps clarify the issue in #80506
by adding a specific check for mismatches between [T;N] and usize.

r? `@lcnr`

compiler/rustc_middle/src/ty/mod.rs

@@ -801,6 +801,15 @@ impl GenericParamDefKind {
             GenericParamDefKind::Const => "constant",
         }
     }
+    pub fn to_ord(&self, tcx: TyCtxt<'_>) -> ast::ParamKindOrd {
+        match self {
+            GenericParamDefKind::Lifetime => ast::ParamKindOrd::Lifetime,
+            GenericParamDefKind::Type { .. } => ast::ParamKindOrd::Type,
+            GenericParamDefKind::Const => {
+                ast::ParamKindOrd::Const { unordered: tcx.features().const_generics }
+            }
+        }
+    }
 }
 
 #[derive(Clone, Debug, TyEncodable, TyDecodable, HashStable)]