diff options
Diffstat (limited to 'mingling_macros/src/func/program_final_gen.rs')
| -rw-r--r-- | mingling_macros/src/func/program_final_gen.rs | 22 |
1 files changed, 19 insertions, 3 deletions
diff --git a/mingling_macros/src/func/program_final_gen.rs b/mingling_macros/src/func/program_final_gen.rs index 8123eaf..ceee66d 100644 --- a/mingling_macros/src/func/program_final_gen.rs +++ b/mingling_macros/src/func/program_final_gen.rs @@ -273,9 +273,25 @@ pub(crate) fn program_final_gen_impl(_input: TokenStream) -> TokenStream { .collect(); let do_chain_fn = if chain_tokens.is_empty() { - quote! { - fn do_chain(_any: ::mingling::AnyOutput<Self::Enum>) -> ::mingling::ChainProcess<Self::Enum> { - ::core::panic!("No chain found for type id") + // An empty chain list is still valid, but the synthesized `do_chain` + // must match the trait signature for the enabled mode. The sync + // branch used unconditionally breaks the `async` feature (E0053), + // so dispatch on `ASYNC_ENABLED` here as well. + if ASYNC_ENABLED { + quote! { + fn do_chain( + _any: ::mingling::AnyOutput<Self::Enum>, + ) -> ::std::pin::Pin<::std::boxed::Box<dyn ::std::future::Future<Output = ::mingling::ChainProcess<Self::Enum>> + ::std::marker::Send>> { + ::std::boxed::Box::pin(async { + ::core::panic!("No chain found for type id") + }) + } + } + } else { + quote! { + fn do_chain(_any: ::mingling::AnyOutput<Self::Enum>) -> ::mingling::ChainProcess<Self::Enum> { + ::core::panic!("No chain found for type id") + } } } } else if ASYNC_ENABLED { |