 530be10e72
			
		
	
	
		530be10e72
		
	
	
	
	
		
			
			# Objective Prevent future unsoundness that was seen in #6623. ## Solution Newtype both indexes in `Archetype` and `Table` as `ArchetypeRow` and `TableRow`. This avoids weird numerical manipulation on the indices, and can be stored and treated opaquely. Also enforces the source and destination of where these indices at a type level. --- ## Changelog Changed: `Archetype` indices and `Table` rows have been newtyped as `ArchetypeRow` and `TableRow`.
		
			
				
	
	
		
			469 lines
		
	
	
		
			18 KiB
		
	
	
	
		
			Rust
		
	
	
	
	
	
			
		
		
	
	
			469 lines
		
	
	
		
			18 KiB
		
	
	
	
		
			Rust
		
	
	
	
	
	
| use proc_macro::TokenStream;
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| use proc_macro2::{Ident, Span};
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| use quote::{quote, ToTokens};
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| use syn::{
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|     parse::{Parse, ParseStream},
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|     parse_quote,
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|     punctuated::Punctuated,
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|     Attribute, Data, DataStruct, DeriveInput, Field, Fields,
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| };
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| 
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| use crate::bevy_ecs_path;
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| 
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| #[derive(Default)]
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| struct FetchStructAttributes {
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|     pub is_mutable: bool,
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|     pub derive_args: Punctuated<syn::NestedMeta, syn::token::Comma>,
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| }
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| 
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| static MUTABLE_ATTRIBUTE_NAME: &str = "mutable";
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| static DERIVE_ATTRIBUTE_NAME: &str = "derive";
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| 
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| mod field_attr_keywords {
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|     syn::custom_keyword!(ignore);
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| }
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| 
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| pub static WORLD_QUERY_ATTRIBUTE_NAME: &str = "world_query";
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| 
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| pub fn derive_world_query_impl(ast: DeriveInput) -> TokenStream {
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|     let visibility = ast.vis;
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| 
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|     let mut fetch_struct_attributes = FetchStructAttributes::default();
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|     for attr in &ast.attrs {
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|         if !attr
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|             .path
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|             .get_ident()
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|             .map_or(false, |ident| ident == WORLD_QUERY_ATTRIBUTE_NAME)
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|         {
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|             continue;
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|         }
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| 
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|         attr.parse_args_with(|input: ParseStream| {
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|             let meta = input.parse_terminated::<syn::Meta, syn::token::Comma>(syn::Meta::parse)?;
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|             for meta in meta {
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|                 let ident = meta.path().get_ident().unwrap_or_else(|| {
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|                     panic!(
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|                         "Unrecognized attribute: `{}`",
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|                         meta.path().to_token_stream()
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|                     )
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|                 });
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|                 if ident == MUTABLE_ATTRIBUTE_NAME {
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|                     if let syn::Meta::Path(_) = meta {
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|                         fetch_struct_attributes.is_mutable = true;
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|                     } else {
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|                         panic!(
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|                             "The `{}` attribute is expected to have no value or arguments",
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|                             MUTABLE_ATTRIBUTE_NAME
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|                         );
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|                     }
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|                 } else if ident == DERIVE_ATTRIBUTE_NAME {
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|                     if let syn::Meta::List(meta_list) = meta {
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|                         fetch_struct_attributes
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|                             .derive_args
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|                             .extend(meta_list.nested.iter().cloned());
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|                     } else {
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|                         panic!(
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|                             "Expected a structured list within the `{}` attribute",
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|                             DERIVE_ATTRIBUTE_NAME
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|                         );
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|                     }
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|                 } else {
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|                     panic!(
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|                         "Unrecognized attribute: `{}`",
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|                         meta.path().to_token_stream()
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|                     );
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|                 }
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|             }
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|             Ok(())
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|         })
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|         .unwrap_or_else(|_| panic!("Invalid `{WORLD_QUERY_ATTRIBUTE_NAME}` attribute format"));
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|     }
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| 
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|     let path = bevy_ecs_path();
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| 
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|     let user_generics = ast.generics.clone();
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|     let (user_impl_generics, user_ty_generics, user_where_clauses) = user_generics.split_for_impl();
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|     let user_generics_with_world = {
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|         let mut generics = ast.generics.clone();
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|         generics.params.insert(0, parse_quote!('__w));
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|         generics
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|     };
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|     let (user_impl_generics_with_world, user_ty_generics_with_world, user_where_clauses_with_world) =
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|         user_generics_with_world.split_for_impl();
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| 
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|     let struct_name = ast.ident.clone();
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|     let read_only_struct_name = if fetch_struct_attributes.is_mutable {
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|         Ident::new(&format!("{struct_name}ReadOnly"), Span::call_site())
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|     } else {
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|         struct_name.clone()
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|     };
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| 
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|     let item_struct_name = Ident::new(&format!("{struct_name}Item"), Span::call_site());
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|     let read_only_item_struct_name = if fetch_struct_attributes.is_mutable {
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|         Ident::new(&format!("{struct_name}ReadOnlyItem"), Span::call_site())
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|     } else {
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|         item_struct_name.clone()
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|     };
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| 
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|     let fetch_struct_name = Ident::new(&format!("{struct_name}Fetch"), Span::call_site());
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|     let read_only_fetch_struct_name = if fetch_struct_attributes.is_mutable {
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|         Ident::new(&format!("{struct_name}ReadOnlyFetch"), Span::call_site())
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|     } else {
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|         fetch_struct_name.clone()
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|     };
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| 
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|     let state_struct_name = Ident::new(&format!("{struct_name}State"), Span::call_site());
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| 
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|     let fields = match &ast.data {
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|         Data::Struct(DataStruct {
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|             fields: Fields::Named(fields),
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|             ..
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|         }) => &fields.named,
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|         _ => panic!("Expected a struct with named fields"),
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|     };
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| 
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|     let mut ignored_field_attrs = Vec::new();
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|     let mut ignored_field_visibilities = Vec::new();
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|     let mut ignored_field_idents = Vec::new();
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|     let mut ignored_field_types = Vec::new();
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|     let mut field_attrs = Vec::new();
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|     let mut field_visibilities = Vec::new();
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|     let mut field_idents = Vec::new();
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|     let mut field_types = Vec::new();
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|     let mut read_only_field_types = Vec::new();
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| 
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|     for field in fields {
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|         let WorldQueryFieldInfo { is_ignored, attrs } = read_world_query_field_info(field);
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| 
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|         let field_ident = field.ident.as_ref().unwrap().clone();
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|         if is_ignored {
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|             ignored_field_attrs.push(attrs);
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|             ignored_field_visibilities.push(field.vis.clone());
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|             ignored_field_idents.push(field_ident.clone());
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|             ignored_field_types.push(field.ty.clone());
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|         } else {
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|             field_attrs.push(attrs);
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|             field_visibilities.push(field.vis.clone());
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|             field_idents.push(field_ident.clone());
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|             let field_ty = field.ty.clone();
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|             field_types.push(quote!(#field_ty));
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|             read_only_field_types.push(quote!(<#field_ty as #path::query::WorldQuery>::ReadOnly));
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|         }
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|     }
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| 
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|     let derive_args = &fetch_struct_attributes.derive_args;
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|     // `#[derive()]` is valid syntax
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|     let derive_macro_call = quote! { #[derive(#derive_args)] };
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| 
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|     let impl_fetch = |is_readonly: bool| {
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|         let struct_name = if is_readonly {
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|             &read_only_struct_name
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|         } else {
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|             &struct_name
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|         };
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|         let item_struct_name = if is_readonly {
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|             &read_only_item_struct_name
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|         } else {
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|             &item_struct_name
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|         };
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|         let fetch_struct_name = if is_readonly {
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|             &read_only_fetch_struct_name
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|         } else {
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|             &fetch_struct_name
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|         };
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| 
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|         let field_types = if is_readonly {
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|             &read_only_field_types
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|         } else {
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|             &field_types
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|         };
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| 
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|         quote! {
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|             #derive_macro_call
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|             #[doc = "Automatically generated [`WorldQuery`] item type for [`"]
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|             #[doc = stringify!(#struct_name)]
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|             #[doc = "`], returned when iterating over query results."]
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|             #[automatically_derived]
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|             #visibility struct #item_struct_name #user_impl_generics_with_world #user_where_clauses_with_world {
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|                 #(#(#field_attrs)* #field_visibilities #field_idents: <#field_types as #path::query::WorldQuery>::Item<'__w>,)*
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|                 #(#(#ignored_field_attrs)* #ignored_field_visibilities #ignored_field_idents: #ignored_field_types,)*
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|             }
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| 
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|             #[doc(hidden)]
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|             #[doc = "Automatically generated internal [`WorldQuery`] fetch type for [`"]
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|             #[doc = stringify!(#struct_name)]
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|             #[doc = "`], used to define the world data accessed by this query."]
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|             #[automatically_derived]
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|             #visibility struct #fetch_struct_name #user_impl_generics_with_world #user_where_clauses_with_world {
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|                 #(#field_idents: <#field_types as #path::query::WorldQuery>::Fetch<'__w>,)*
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|                 #(#ignored_field_idents: #ignored_field_types,)*
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|             }
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| 
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|             // SAFETY: `update_component_access` and `update_archetype_component_access` are called on every field
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|             unsafe impl #user_impl_generics #path::query::WorldQuery
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|                 for #struct_name #user_ty_generics #user_where_clauses {
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| 
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|                 type Item<'__w> = #item_struct_name #user_ty_generics_with_world;
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|                 type Fetch<'__w> = #fetch_struct_name #user_ty_generics_with_world;
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|                 type ReadOnly = #read_only_struct_name #user_ty_generics;
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|                 type State = #state_struct_name #user_ty_generics;
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| 
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|                 fn shrink<'__wlong: '__wshort, '__wshort>(
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|                     item: <#struct_name #user_ty_generics as #path::query::WorldQuery>::Item<'__wlong>
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|                 ) -> <#struct_name #user_ty_generics as #path::query::WorldQuery>::Item<'__wshort> {
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|                     #item_struct_name {
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|                         #(
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|                             #field_idents: <#field_types>::shrink(item.#field_idents),
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|                         )*
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|                         #(
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|                             #ignored_field_idents: item.#ignored_field_idents,
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|                         )*
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|                     }
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|                 }
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| 
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|                 unsafe fn init_fetch<'__w>(
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|                     _world: &'__w #path::world::World,
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|                     state: &Self::State,
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|                     _last_change_tick: u32,
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|                     _change_tick: u32
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|                 ) -> <Self as #path::query::WorldQuery>::Fetch<'__w> {
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|                     #fetch_struct_name {
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|                         #(#field_idents:
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|                             <#field_types>::init_fetch(
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|                                 _world,
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|                                 &state.#field_idents,
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|                                 _last_change_tick,
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|                                 _change_tick
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|                             ),
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|                         )*
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|                         #(#ignored_field_idents: Default::default(),)*
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|                     }
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|                 }
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| 
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|                 unsafe fn clone_fetch<'__w>(
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|                     _fetch: &<Self as #path::query::WorldQuery>::Fetch<'__w>
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|                 ) -> <Self as #path::query::WorldQuery>::Fetch<'__w> {
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|                     #fetch_struct_name {
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|                         #(
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|                             #field_idents: <#field_types>::clone_fetch(& _fetch. #field_idents),
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|                         )*
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|                         #(
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|                             #ignored_field_idents: Default::default(),
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|                         )*
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|                     }
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|                 }
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| 
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|                 const IS_DENSE: bool = true #(&& <#field_types>::IS_DENSE)*;
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| 
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|                 const IS_ARCHETYPAL: bool = true #(&& <#field_types>::IS_ARCHETYPAL)*;
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| 
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|                 /// SAFETY: we call `set_archetype` for each member that implements `Fetch`
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|                 #[inline]
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|                 unsafe fn set_archetype<'__w>(
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|                     _fetch: &mut <Self as #path::query::WorldQuery>::Fetch<'__w>,
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|                     _state: &Self::State,
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|                     _archetype: &'__w #path::archetype::Archetype,
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|                     _table: &'__w #path::storage::Table
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|                 ) {
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|                     #(<#field_types>::set_archetype(&mut _fetch.#field_idents, &_state.#field_idents, _archetype, _table);)*
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|                 }
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| 
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|                 /// SAFETY: we call `set_table` for each member that implements `Fetch`
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|                 #[inline]
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|                 unsafe fn set_table<'__w>(
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|                     _fetch: &mut <Self as #path::query::WorldQuery>::Fetch<'__w>,
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|                     _state: &Self::State,
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|                     _table: &'__w #path::storage::Table
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|                 ) {
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|                     #(<#field_types>::set_table(&mut _fetch.#field_idents, &_state.#field_idents, _table);)*
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|                 }
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| 
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|                 /// SAFETY: we call `fetch` for each member that implements `Fetch`.
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|                 #[inline(always)]
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|                 unsafe fn fetch<'__w>(
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|                     _fetch: &mut <Self as #path::query::WorldQuery>::Fetch<'__w>,
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|                     _entity: #path::entity::Entity,
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|                     _table_row: #path::storage::TableRow,
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|                 ) -> <Self as #path::query::WorldQuery>::Item<'__w> {
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|                     Self::Item {
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|                         #(#field_idents: <#field_types>::fetch(&mut _fetch.#field_idents, _entity, _table_row),)*
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|                         #(#ignored_field_idents: Default::default(),)*
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|                     }
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|                 }
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| 
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|                 #[allow(unused_variables)]
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|                 #[inline(always)]
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|                 unsafe fn filter_fetch<'__w>(
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|                     _fetch: &mut <Self as #path::query::WorldQuery>::Fetch<'__w>,
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|                     _entity: #path::entity::Entity,
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|                     _table_row: #path::storage::TableRow,
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|                 ) -> bool {
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|                     true #(&& <#field_types>::filter_fetch(&mut _fetch.#field_idents, _entity, _table_row))*
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|                 }
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| 
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|                 fn update_component_access(state: &Self::State, _access: &mut #path::query::FilteredAccess<#path::component::ComponentId>) {
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|                     #( <#field_types>::update_component_access(&state.#field_idents, _access); )*
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|                 }
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| 
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|                 fn update_archetype_component_access(
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|                     state: &Self::State,
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|                     _archetype: &#path::archetype::Archetype,
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|                     _access: &mut #path::query::Access<#path::archetype::ArchetypeComponentId>
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|                 ) {
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|                     #(
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|                         <#field_types>::update_archetype_component_access(&state.#field_idents, _archetype, _access);
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|                     )*
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|                 }
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| 
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|                 fn init_state(world: &mut #path::world::World) -> #state_struct_name #user_ty_generics {
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|                     #state_struct_name {
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|                         #(#field_idents: <#field_types>::init_state(world),)*
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|                         #(#ignored_field_idents: Default::default(),)*
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|                     }
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|                 }
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| 
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|                 fn matches_component_set(state: &Self::State, _set_contains_id: &impl Fn(#path::component::ComponentId) -> bool) -> bool {
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|                     true #(&& <#field_types>::matches_component_set(&state.#field_idents, _set_contains_id))*
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|                 }
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|             }
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|         }
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|     };
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| 
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|     let mutable_impl = impl_fetch(false);
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|     let readonly_impl = if fetch_struct_attributes.is_mutable {
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|         let world_query_impl = impl_fetch(true);
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|         quote! {
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|             #[doc(hidden)]
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|             #[doc = "Automatically generated internal [`WorldQuery`] type for [`"]
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|             #[doc = stringify!(#struct_name)]
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|             #[doc = "`], used for read-only access."]
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|             #[automatically_derived]
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|             #visibility struct #read_only_struct_name #user_impl_generics #user_where_clauses {
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|                 #( #field_idents: #read_only_field_types, )*
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|                 #(#(#ignored_field_attrs)* #ignored_field_visibilities #ignored_field_idents: #ignored_field_types,)*
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|             }
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| 
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|             #world_query_impl
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|         }
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|     } else {
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|         quote! {}
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|     };
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| 
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|     let read_only_asserts = if fetch_struct_attributes.is_mutable {
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|         quote! {
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|             // Double-check that the data fetched by `<_ as WorldQuery>::ReadOnly` is read-only.
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|             // This is technically unnecessary as `<_ as WorldQuery>::ReadOnly: ReadOnlyWorldQuery`
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|             // but to protect against future mistakes we assert the assoc type implements `ReadOnlyWorldQuery` anyway
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|             #( assert_readonly::<#read_only_field_types>(); )*
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|         }
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|     } else {
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|         quote! {
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|             // Statically checks that the safety guarantee of `ReadOnlyWorldQuery` for `$fetch_struct_name` actually holds true.
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|             // We need this to make sure that we don't compile `ReadOnlyWorldQuery` if our struct contains nested `WorldQuery`
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|             // members that don't implement it. I.e.:
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|             // ```
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|             // #[derive(WorldQuery)]
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|             // pub struct Foo { a: &'static mut MyComponent }
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|             // ```
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|             #( assert_readonly::<#field_types>(); )*
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|         }
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|     };
 | |
| 
 | |
|     TokenStream::from(quote! {
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|         #mutable_impl
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| 
 | |
|         #readonly_impl
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| 
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|         #[doc(hidden)]
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|         #[doc = "Automatically generated internal [`WorldQuery`] state type for [`"]
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|         #[doc = stringify!(#struct_name)]
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|         #[doc = "`], used for caching."]
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|         #[automatically_derived]
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|         #visibility struct #state_struct_name #user_impl_generics #user_where_clauses {
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|             #(#field_idents: <#field_types as #path::query::WorldQuery>::State,)*
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|             #(#ignored_field_idents: #ignored_field_types,)*
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|         }
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| 
 | |
|         /// SAFETY: we assert fields are readonly below
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|         unsafe impl #user_impl_generics #path::query::ReadOnlyWorldQuery
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|             for #read_only_struct_name #user_ty_generics #user_where_clauses {}
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| 
 | |
|         #[allow(dead_code)]
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|         const _: () = {
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|             fn assert_readonly<T>()
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|             where
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|                 T: #path::query::ReadOnlyWorldQuery,
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|             {
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|             }
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| 
 | |
|             // We generate a readonly assertion for every struct member.
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|             fn assert_all #user_impl_generics_with_world () #user_where_clauses_with_world {
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|                 #read_only_asserts
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|             }
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|         };
 | |
| 
 | |
|         // The original struct will most likely be left unused. As we don't want our users having
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|         // to specify `#[allow(dead_code)]` for their custom queries, we are using this cursed
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|         // workaround.
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|         #[allow(dead_code)]
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|         const _: () = {
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|             fn dead_code_workaround #user_impl_generics (
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|                 q: #struct_name #user_ty_generics,
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|                 q2: #read_only_struct_name #user_ty_generics
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|             ) #user_where_clauses {
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|                 #(q.#field_idents;)*
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|                 #(q.#ignored_field_idents;)*
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|                 #(q2.#field_idents;)*
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|                 #(q2.#ignored_field_idents;)*
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| 
 | |
|             }
 | |
|         };
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|     })
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| }
 | |
| 
 | |
| struct WorldQueryFieldInfo {
 | |
|     /// Has `#[fetch(ignore)]` or `#[filter_fetch(ignore)]` attribute.
 | |
|     is_ignored: bool,
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|     /// All field attributes except for `world_query` ones.
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|     attrs: Vec<Attribute>,
 | |
| }
 | |
| 
 | |
| fn read_world_query_field_info(field: &Field) -> WorldQueryFieldInfo {
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|     let is_ignored = field
 | |
|         .attrs
 | |
|         .iter()
 | |
|         .find(|attr| {
 | |
|             attr.path
 | |
|                 .get_ident()
 | |
|                 .map_or(false, |ident| ident == WORLD_QUERY_ATTRIBUTE_NAME)
 | |
|         })
 | |
|         .map_or(false, |attr| {
 | |
|             let mut is_ignored = false;
 | |
|             attr.parse_args_with(|input: ParseStream| {
 | |
|                 if input
 | |
|                     .parse::<Option<field_attr_keywords::ignore>>()?
 | |
|                     .is_some()
 | |
|                 {
 | |
|                     is_ignored = true;
 | |
|                 }
 | |
|                 Ok(())
 | |
|             })
 | |
|             .unwrap_or_else(|_| panic!("Invalid `{WORLD_QUERY_ATTRIBUTE_NAME}` attribute format"));
 | |
| 
 | |
|             is_ignored
 | |
|         });
 | |
| 
 | |
|     let attrs = field
 | |
|         .attrs
 | |
|         .iter()
 | |
|         .filter(|attr| {
 | |
|             attr.path
 | |
|                 .get_ident()
 | |
|                 .map_or(true, |ident| ident != WORLD_QUERY_ATTRIBUTE_NAME)
 | |
|         })
 | |
|         .cloned()
 | |
|         .collect();
 | |
| 
 | |
|     WorldQueryFieldInfo { is_ignored, attrs }
 | |
| }
 |