Allow Self in prop fields (yewstack#3569)

* added replacement of `Self` in fields and attrs

* added more tests

* todo -> unimplemented

Author: its-the-shrimp

packages/yew-macro/src/derive_props/field.rs

@@ -12,7 +12,7 @@ use crate::derive_props::generics::push_type_param;
 
 #[allow(clippy::large_enum_variant)]
 #[derive(PartialEq, Eq)]
-enum PropAttr {
+pub enum PropAttr {
     Required { wrapped_name: Ident },
     PropOr(Expr),
     PropOrElse(Expr),
@@ -21,9 +21,9 @@ enum PropAttr {
 
 #[derive(Eq)]
 pub struct PropField {
-    ty: Type,
+    pub ty: Type,
     name: Ident,
-    attr: PropAttr,
+    pub attr: PropAttr,
     extra_attrs: Vec<Attribute>,
 }
 

packages/yew-macro/src/derive_props/mod.rs

@@ -10,9 +10,16 @@ use field::PropField;
 use proc_macro2::{Ident, Span};
 use quote::{format_ident, quote, ToTokens};
 use syn::parse::{Parse, ParseStream, Result};
-use syn::{Attribute, DeriveInput, Generics, Visibility};
+use syn::punctuated::Pair;
+use syn::visit_mut::VisitMut;
+use syn::{
+    AngleBracketedGenericArguments, Attribute, ConstParam, DeriveInput, GenericArgument,
+    GenericParam, Generics, Path, PathArguments, PathSegment, Type, TypeParam, TypePath,
+    Visibility,
+};
 use wrapper::PropsWrapper;
 
+use self::field::PropAttr;
 use self::generics::to_arguments;
 
 pub struct DerivePropsInput {
@@ -23,6 +30,76 @@ pub struct DerivePropsInput {
     preserved_attrs: Vec<Attribute>,
 }
 
+/// AST visitor that replaces all occurences of the keyword `Self` with `new_self`
+struct Normaliser<'ast> {
+    new_self: &'ast Ident,
+    generics: &'ast Generics,
+    /// `Option` for one-time initialisation
+    new_self_full: Option<PathSegment>,
+}
+
+impl<'ast> Normaliser<'ast> {
+    pub fn new(new_self: &'ast Ident, generics: &'ast Generics) -> Self {
+        Self {
+            new_self,
+            generics,
+            new_self_full: None,
+        }
+    }
+
+    fn get_new_self(&mut self) -> PathSegment {
+        self.new_self_full
+            .get_or_insert_with(|| {
+                PathSegment {
+                    ident: self.new_self.clone(),
+                    arguments: if self.generics.lt_token.is_some() {
+                        PathArguments::AngleBracketed(AngleBracketedGenericArguments {
+                            colon2_token: Some(Default::default()),
+                            lt_token: Default::default(),
+                            args: self
+                                .generics
+                                .params
+                                .pairs()
+                                .map(|pair| {
+                                    let (value, punct) = pair.cloned().into_tuple();
+                                    let value = match value {
+                                        GenericParam::Lifetime(param) => {
+                                            GenericArgument::Lifetime(param.lifetime)
+                                        }
+                                        GenericParam::Type(TypeParam { ident, .. })
+                                        | GenericParam::Const(ConstParam { ident, .. }) => {
+                                            GenericArgument::Type(Type::Path(TypePath {
+                                                qself: None,
+                                                path: ident.into(),
+                                            }))
+                                        }
+                                    };
+                                    Pair::new(value, punct)
+                                })
+                                .collect(),
+                            gt_token: Default::default(),
+                        })
+                    } else {
+                        // if no generics were defined for the struct
+                        PathArguments::None
+                    },
+                }
+            })
+            .clone()
+    }
+}
+
+impl VisitMut for Normaliser<'_> {
+    fn visit_path_mut(&mut self, path: &mut Path) {
+        if let Some(first) = path.segments.first_mut() {
+            if first.ident == "Self" {
+                *first = self.get_new_self();
+            }
+            syn::visit_mut::visit_path_mut(self, path)
+        }
+    }
+}
+
 /// Some attributes on the original struct are to be preserved and added to the builder struct,
 /// in order to avoid warnings (sometimes reported as errors) in the output.
 fn should_preserve_attr(attr: &Attribute) -> bool {
@@ -74,22 +151,33 @@ impl Parse for DerivePropsInput {
     }
 }
 
+impl DerivePropsInput {
+    /// Replaces all occurences of `Self` in the struct with the actual name of the struct.
+    /// Must be called before tokenising the struct.
+    pub fn normalise(&mut self) {
+        let mut normaliser = Normaliser::new(&self.props_name, &self.generics);
+        for field in &mut self.prop_fields {
+            normaliser.visit_type_mut(&mut field.ty);
+            if let PropAttr::PropOr(expr) | PropAttr::PropOrElse(expr) = &mut field.attr {
+                normaliser.visit_expr_mut(expr)
+            }
+        }
+    }
+}
+
 impl ToTokens for DerivePropsInput {
     fn to_tokens(&self, tokens: &mut proc_macro2::TokenStream) {
         let Self {
             generics,
             props_name,
+            prop_fields,
+            preserved_attrs,
             ..
         } = self;
 
         // The wrapper is a new struct which wraps required props in `Option`
         let wrapper_name = format_ident!("{}Wrapper", props_name, span = Span::mixed_site());
-        let wrapper = PropsWrapper::new(
-            &wrapper_name,
-            generics,
-            &self.prop_fields,
-            &self.preserved_attrs,
-        );
+        let wrapper = PropsWrapper::new(&wrapper_name, generics, prop_fields, preserved_attrs);
         tokens.extend(wrapper.into_token_stream());
 
         // The builder will only build if all required props have been set
@@ -101,7 +189,7 @@ impl ToTokens for DerivePropsInput {
             self,
             &wrapper_name,
             &check_all_props_name,
-            &self.preserved_attrs,
+            preserved_attrs,
         );
         let generic_args = to_arguments(generics);
         tokens.extend(builder.into_token_stream());

packages/yew-macro/src/derive_props/wrapper.rs

@@ -48,23 +48,21 @@ impl ToTokens for PropsWrapper<'_> {
     }
 }
 
-impl<'a> PropsWrapper<'_> {
+impl<'a> PropsWrapper<'a> {
     pub fn new(
         name: &'a Ident,
         generics: &'a Generics,
         prop_fields: &'a [PropField],
         extra_attrs: &'a [Attribute],
-    ) -> PropsWrapper<'a> {
+    ) -> Self {
         PropsWrapper {
             wrapper_name: name,
             generics,
             prop_fields,
             extra_attrs,
         }
     }
-}
 
-impl PropsWrapper<'_> {
     fn field_defs(&self) -> impl Iterator<Item = impl ToTokens + '_> {
         self.prop_fields.iter().map(|pf| pf.to_field_def())
     }

packages/yew-macro/src/lib.rs

@@ -108,7 +108,8 @@ fn is_ide_completion() -> bool {
 
 #[proc_macro_derive(Properties, attributes(prop_or, prop_or_else, prop_or_default))]
 pub fn derive_props(input: TokenStream) -> TokenStream {
-    let input = parse_macro_input!(input as DerivePropsInput);
+    let mut input = parse_macro_input!(input as DerivePropsInput);
+    input.normalise();
     TokenStream::from(input.into_token_stream())
 }
 

packages/yew-macro/tests/props_macro/props-pass.rs

@@ -56,6 +56,22 @@ pub struct RawIdentProps {
     r#pointless_raw_name: ::std::primitive::usize,
 }
 
+#[derive(::yew::Properties)]
+pub struct SelfRefProps<'a, T> {
+    x: ::std::boxed::Box<T>,
+    y: ::std::boxed::Box<Self>,
+    z: &'a Self,
+    a: ::std::marker::PhantomData<(&'a Self, Self)>,
+    b: ::std::marker::PhantomData<::std::boxed::Box<Self>>,
+    c: fn(&Self) -> Self,
+}
+
+impl<T> ::std::cmp::PartialEq for SelfRefProps<'_, T> {
+    fn eq(&self, _: &Self) -> ::std::primitive::bool {
+        ::std::unimplemented!()
+    }
+}
+
 fn pass_raw_idents() {
     ::yew::props!(RawIdentProps { r#true: 5 });
     let (r#true, r#pointless_raw_name) = (3, 5);