Implement Recursive Referential Params

[azriel91]

Closes #119.

Handy for checking parameter expansion and getting actual errors annotated on code:

cargo expand --tests --package workspace_tests params::enum_recursive_marker_no_bounds \
  | sd -f cm '^    #\[doc\(hidden\)\][\n](^[ ]{4}[a-z# ].+[\n])+^[ ]{4}\};\n' '' \
  | sd -f cm '^    #\[automatically_derived\][\n](^[ ]{4}[# a-z{].*[\n])+^[ ]{4}\{?\}\n' '' \
  | sd -f cm '^    #\[allow\(unused_qualifications\)\][\n](^[ ]{4}[# a-z{].*[\n])+^[ ]{4}\}\n' '' \
  | sd -f cm '^    #\[serde\(bound = ""\)\]' '    #[derive(Serialize, Deserialize)]\n    #[serde(bound = "")]' \
  | sd -f cm '^    extern crate test;[\n](^[ ]{4}.*[\n])+^\}' '}' \
  | sd -f cm '^(    pub struct [A-Za-z0-9_]+Partial)' '    #[derive(PartialEq, Eq)]\n$1' \
  | sd -f cm '^(    #\[derivative\()' '    #[derive(derivative::Derivative)]\n$1' \
  | xclip -se c

Unused useful snippets

pub fn intersect_generics(
    parent_type_generics: &Generics,
    field_generics: &PathArguments,
) -> Option<proc_macro2::TokenStream> {
    match field_generics {
        PathArguments::None => None,
        PathArguments::AngleBracketed(angle_bracketed) => {
            let field_generics = &angle_bracketed.args;
            let intersect_generics = field_generics
                .iter()
                .filter(|field_generic| {
                    let field_argument_as_param: GenericParam = parse_quote!(#field_generic);

                    parent_type_generics
                        .params
                        .iter()
                        .any(|parent_generic| parent_generic == &field_argument_as_param)
                })
                .collect::<Vec<&GenericArgument>>();
            if intersect_generics.is_empty() {
                None
            } else {
                Some(quote!(<#(#intersect_generics,)*>))
            }
        }
        PathArguments::Parenthesized(_) => None,
    }
}

/// Appends a `marker: #marker_ty` to the Fields.
///
/// A `Unit` struct is turned into a tuple struct.
pub fn fields_append_marker(fields: &Fields, marker_ty: Type) {
    match fields {
        Fields::Named(fields_named) => {
            let marker_field = {
                let fields_named_marker: FieldsNamed = parse_quote!({
                    marker: #marker_ty,
                });
                fields_named_marker.named.into_iter().next()
            };
            if let Some(marker_field) = marker_field {
                fields_named.named.push(marker_field);
            }
        }
        Fields::Unnamed(fields_unnamed) => {
            let marker_field = {
                let fields_unnamed_marker: FieldsUnnamed = parse_quote!((#marker_ty));
                fields_unnamed_marker.unnamed.into_iter().next()
            };
            if let Some(marker_field) = marker_field {
                fields_unnamed.unnamed.push(marker_field);
            }
        }
        Fields::Unit => todo!(),
    }
}

[codecov]

Codecov Report

Patch coverage: 91.66% and project coverage change: -0.41 ⚠️

Comparison is base (fee352f) 91.97% compared to head (312da29) 91.56%.

Additional details and impacted files

@@            Coverage Diff             @@
##             main     #121      +/-   ##
==========================================
- Coverage   91.97%   91.56%   -0.41%     
==========================================
  Files         299      322      +23     
  Lines       25375    29172    +3797     
==========================================
+ Hits        23338    26711    +3373     
- Misses       2037     2461     +424     

Impacted Files	Coverage Δ
crate/params/src/mapping_fn.rs	81.25% <ø> (ø)
crate/params/src/params_resolve_error.rs	0.00% <ø> (ø)
crate/params/src/params_specs.rs	84.21% <ø> (ø)
crate/params/src/std_impl.rs	0.00% <0.00%> (ø)
...e/params_derive/src/field_wise_enum_builder_ctx.rs	0.00% <0.00%> (ø)
crate/rt_model/src/item_spec_boxed.rs	84.21% <ø> (ø)
crate/rt_model/src/item_spec_params_serializer.rs	0.00% <ø> (ø)
crate/rt_model/src/params_specs_serializer.rs	62.72% <ø> (ø)
crate/rt_model_core/src/error.rs	2.00% <ø> (ø)
item_specs/blank/src/blank_dest.rs	0.00% <0.00%> (ø)
... and 40 more

... and 15 files with indirect coverage changes

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