Fill in omitted patterns for GenericArguments match

    error: some variants are not matched explicitly
        --> serde_derive/src/internals/attr.rs:1823:31
         |
    1823 |                         match arg {
         |                               ^^^ patterns `&GenericArgument::Const(_)`, `&GenericArgument::AssocConst(_)` and `&GenericArgument::Constraint(_)` not covered
         |
         = help: ensure that all variants are matched explicitly by adding the suggested match arms
         = note: the matched value is of type `&GenericArgument` and the `non_exhaustive_omitted_patterns` attribute was found
    note: the lint level is defined here
        --> serde_derive/src/internals/attr.rs:1797:49
         |
    1797 |         #![cfg_attr(all(test, exhaustive), deny(non_exhaustive_omitted_patterns))]
         |                                                 ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^

serde_derive/src/internals/attr.rs

@@ -1829,7 +1829,10 @@ fn collect_lifetimes(ty: &syn::Type, out: &mut BTreeSet<syn::Lifetime>) {
                             syn::GenericArgument::AssocType(binding) => {
                                 collect_lifetimes(&binding.ty, out);
                             }
-                            _ => {}
+                            syn::GenericArgument::Const(_)
+                            | syn::GenericArgument::AssocConst(_)
+                            | syn::GenericArgument::Constraint(_)
+                            | _ => {}
                         }
                     }
                 }