Use the generated DispatchError instead of the hardcoded Substrate one (#394)

* WIP DispatchError generic param

* main crate now compiling with new E generic param for DispatchError

* Remove E param from RpcClient since it doesn't really need it

* Point to generated DispatchError in codegen so no need for additional param there

* More error hunting; cargo check --all-targets passes now

* Use our own RuntimeVersion struct (for now) to avoid error decoding into sp_version::RuntimeVersion

* cargo fmt

* fix docs and expose private documented thing that I think should be pub

* move error info to compile time so that we can make DispatchError a little nicer to work with

* cargo fmt

* clippy

* Rework error handling to remove <E> param in most cases

* fix Error doc ambiguity (hopefully)

* doc tweaks

* docs: remove dismbiguation thing that isn't needed now

* One more Error<E> that can be a BasicError

* rewrite pallet errors thing into normal loops to tidy

* tidy errors codegen a little

* tidy examples/custom_type_derives.rs a little

* cargo fmt

* silcnce clippy in example

src/metadata.rs

@@ -84,7 +84,6 @@ pub struct Metadata {
     metadata: RuntimeMetadataLastVersion,
     pallets: HashMap<String, PalletMetadata>,
     events: HashMap<(u8, u8), EventMetadata>,
-    errors: HashMap<(u8, u8), ErrorMetadata>,
 }
 
 impl Metadata {
@@ -108,19 +107,6 @@ impl Metadata {
         Ok(event)
     }
 
-    /// Returns the metadata for the error at the given pallet and error indices.
-    pub fn error(
-        &self,
-        pallet_index: u8,
-        error_index: u8,
-    ) -> Result<&ErrorMetadata, MetadataError> {
-        let error = self
-            .errors
-            .get(&(pallet_index, error_index))
-            .ok_or(MetadataError::ErrorNotFound(pallet_index, error_index))?;
-        Ok(error)
-    }
-
     /// Resolve a type definition.
     pub fn resolve_type(&self, id: u32) -> Option<&Type<PortableForm>> {
         self.metadata.types.resolve(id)
@@ -207,30 +193,6 @@ impl EventMetadata {
     }
 }
 
-#[derive(Clone, Debug)]
-pub struct ErrorMetadata {
-    pallet: String,
-    error: String,
-    variant: Variant<PortableForm>,
-}
-
-impl ErrorMetadata {
-    /// Get the name of the pallet from which the error originates.
-    pub fn pallet(&self) -> &str {
-        &self.pallet
-    }
-
-    /// Get the name of the specific pallet error.
-    pub fn error(&self) -> &str {
-        &self.error
-    }
-
-    /// Get the description of the specific pallet error.
-    pub fn description(&self) -> &[String] {
-        self.variant.docs()
-    }
-}
-
 #[derive(Debug, thiserror::Error)]
 pub enum InvalidMetadataError {
     #[error("Invalid prefix")]
@@ -331,36 +293,10 @@ impl TryFrom<RuntimeMetadataPrefixed> for Metadata {
             })
             .collect();
 
-        let pallet_errors = metadata
-            .pallets
-            .iter()
-            .filter_map(|pallet| {
-                pallet.error.as_ref().map(|error| {
-                    let type_def_variant = get_type_def_variant(error.ty.id())?;
-                    Ok((pallet, type_def_variant))
-                })
-            })
-            .collect::<Result<Vec<_>, _>>()?;
-        let errors = pallet_errors
-            .iter()
-            .flat_map(|(pallet, type_def_variant)| {
-                type_def_variant.variants().iter().map(move |var| {
-                    let key = (pallet.index, var.index());
-                    let value = ErrorMetadata {
-                        pallet: pallet.name.clone(),
-                        error: var.name().clone(),
-                        variant: var.clone(),
-                    };
-                    (key, value)
-                })
-            })
-            .collect();
-
         Ok(Self {
             metadata,
             pallets,
             events,
-            errors,
         })
     }
 }