How can I print the code that is built at runtime by construct_runtime?

Question

I cloned the substrate repository. In bin/node-template/runtime/src/lib.rs, construct_runtime! is called to create the runtime. I found the definition of construct_runtime in frame/support/procedural/src/construct_runtime/mod.rs. It calls construct_runtime_parsed which builds a block of code during runtime.

let res = quote!(
        #scrate_decl

        #[derive(Clone, Copy, PartialEq, Eq, #scrate::sp_runtime::RuntimeDebug)]
        pub struct #name;
        impl #scrate::sp_runtime::traits::GetNodeBlockType for #name {
            type NodeBlock = #node_block;
        }
        impl #scrate::sp_runtime::traits::GetRuntimeBlockType for #name {
            type RuntimeBlock = #block;
        }

        #outer_event

        #outer_origin

        #all_modules

        #module_to_index

        #dispatch

        #metadata

        #outer_config

        #inherent

        #validate_unsigned

        #integrity_test
    );

Are there any ways that I can print or check the code passed to quote! that is built by construct_runtime_parsed?

Answer 1

You can point cargo expand at the runtime/src/lib.rs file and it will output the expanded source code.