Ast gen successful, but compile errors.

ast-generator/src/build_fn/polymorphic_enum_loop_build_fn.rs

@@ -90,7 +90,7 @@ pub fn make_polymorphic_enum_loop_build_fn(spec: &PolymorphicEnumLoopBuildSpec)
             let mut result: Option<#return_type_ident> = None;
             for inner_pair in #pair_ident.into_inner() {
                 match inner_pair.as_rule() {
-                    #(#match_arms,)*,
+                    #(#match_arms,)*
                     _ => unreachable!()
                 }
             }