frame: Abuse Deref to resolve runtime_metadata

Signed-off-by: Alexandru Vasile <[email protected]>

frame/support/procedural/src/construct_runtime/expand/metadata.rs

@@ -111,6 +111,8 @@ pub fn expand_runtime_metadata(
 			}
 
 			fn metadata_v15() -> #scrate::metadata::RuntimeMetadataPrefixed {
+				let rt = #runtime;
+
 				#scrate::metadata::v15::RuntimeMetadataLastVersion::new(
 					#scrate::sp_std::vec![ #(#pallets),* ],
 					#scrate::metadata::ExtrinsicMetadata {
@@ -130,7 +132,7 @@ pub fn expand_runtime_metadata(
 								.collect(),
 					},
 					#scrate::scale_info::meta_type::<#runtime>(),
-					#runtime::runtime_metadata(),
+					(&rt).runtime_metadata(),
 				).into()
 			}
 		}

frame/support/procedural/src/construct_runtime/mod.rs

@@ -289,6 +289,14 @@ fn construct_runtime_final_expansion(
 			type RuntimeBlock = #block;
 		}
 
+		trait InternalConstructRuntime {
+			#[inline(always)]
+			fn runtime_metadata(&self) -> #scrate::sp_std::vec::Vec<#scrate::metadata::v15::TraitMetadata> {
+				Default::default()
+			}
+		}
+		impl InternalConstructRuntime for &#name {}
+
 		#outer_event
 
 		#outer_origin

primitives/api/proc-macro/src/runtime_metadata.rs

@@ -496,11 +496,13 @@ pub fn generate_runtime_metadata2(impls: &[ItemImpl], crate_: &TokenStream) -> R
 	}
 
 	Ok(quote!(
-		impl #runtime_name {
-			pub fn runtime_metadata() -> #crate_::vec::Vec<#crate_::metadata::v15::TraitMetadata> {
+		trait InternalImplRuntimeApis {
+			#[inline(always)]
+			fn runtime_metadata(&self) -> #crate_::vec::Vec<#crate_::metadata::v15::TraitMetadata> {
 				#crate_::vec![ #( #metadata, )* ]
 			}
 		}
+		impl InternalImplRuntimeApis for #runtime_name {}
 	))
 }