chore: add vendor dependencies for kauma build

vendor/serde_derive/src/pretend.rs

@@ -0,0 +1,185 @@
+use crate::internals::ast::{Container, Data, Field, Style, Variant};
+use proc_macro2::TokenStream;
+use quote::{format_ident, quote};
+
+// Suppress dead_code warnings that would otherwise appear when using a remote
+// derive. Other than this pretend code, a struct annotated with remote derive
+// never has its fields referenced and an enum annotated with remote derive
+// never has its variants constructed.
+//
+//     warning: field is never used: `i`
+//      --> src/main.rs:4:20
+//       |
+//     4 | struct StructDef { i: i32 }
+//       |                    ^^^^^^
+//
+//     warning: variant is never constructed: `V`
+//      --> src/main.rs:8:16
+//       |
+//     8 | enum EnumDef { V }
+//       |                ^
+//
+pub fn pretend_used(cont: &Container, is_packed: bool) -> TokenStream {
+    let pretend_fields = pretend_fields_used(cont, is_packed);
+    let pretend_variants = pretend_variants_used(cont);
+
+    quote! {
+        #pretend_fields
+        #pretend_variants
+    }
+}
+
+// For structs with named fields, expands to:
+//
+//     match None::<&T> {
+//         Some(T { a: __v0, b: __v1 }) => {}
+//         _ => {}
+//     }
+//
+// For packed structs on sufficiently new rustc, expands to:
+//
+//     match None::<&T> {
+//         Some(__v @ T { a: _, b: _ }) => {
+//             let _ = addr_of!(__v.a);
+//             let _ = addr_of!(__v.b);
+//         }
+//         _ => {}
+//     }
+//
+// For packed structs on older rustc, we assume Sized and !Drop, and expand to:
+//
+//     match None::<T> {
+//         Some(T { a: __v0, b: __v1 }) => {}
+//         _ => {}
+//     }
+//
+// For enums, expands to the following but only including struct variants:
+//
+//     match None::<&T> {
+//         Some(T::A { a: __v0 }) => {}
+//         Some(T::B { b: __v0 }) => {}
+//         _ => {}
+//     }
+//
+fn pretend_fields_used(cont: &Container, is_packed: bool) -> TokenStream {
+    match &cont.data {
+        Data::Enum(variants) => pretend_fields_used_enum(cont, variants),
+        Data::Struct(Style::Struct | Style::Tuple | Style::Newtype, fields) => {
+            if is_packed {
+                pretend_fields_used_struct_packed(cont, fields)
+            } else {
+                pretend_fields_used_struct(cont, fields)
+            }
+        }
+        Data::Struct(Style::Unit, _) => quote!(),
+    }
+}
+
+fn pretend_fields_used_struct(cont: &Container, fields: &[Field]) -> TokenStream {
+    let type_ident = &cont.ident;
+    let (_, ty_generics, _) = cont.generics.split_for_impl();
+
+    let members = fields.iter().map(|field| &field.member);
+    let placeholders = (0usize..).map(|i| format_ident!("__v{}", i));
+
+    quote! {
+        match _serde::__private::None::<&#type_ident #ty_generics> {
+            _serde::__private::Some(#type_ident { #(#members: #placeholders),* }) => {}
+            _ => {}
+        }
+    }
+}
+
+fn pretend_fields_used_struct_packed(cont: &Container, fields: &[Field]) -> TokenStream {
+    let type_ident = &cont.ident;
+    let (_, ty_generics, _) = cont.generics.split_for_impl();
+
+    let members = fields.iter().map(|field| &field.member).collect::<Vec<_>>();
+
+    quote! {
+        match _serde::__private::None::<&#type_ident #ty_generics> {
+            _serde::__private::Some(__v @ #type_ident { #(#members: _),* }) => {
+                #(
+                    let _ = _serde::__private::ptr::addr_of!(__v.#members);
+                )*
+            }
+            _ => {}
+        }
+    }
+}
+
+fn pretend_fields_used_enum(cont: &Container, variants: &[Variant]) -> TokenStream {
+    let type_ident = &cont.ident;
+    let (_, ty_generics, _) = cont.generics.split_for_impl();
+
+    let patterns = variants
+        .iter()
+        .filter_map(|variant| match variant.style {
+            Style::Struct | Style::Tuple | Style::Newtype => {
+                let variant_ident = &variant.ident;
+                let members = variant.fields.iter().map(|field| &field.member);
+                let placeholders = (0usize..).map(|i| format_ident!("__v{}", i));
+                Some(quote!(#type_ident::#variant_ident { #(#members: #placeholders),* }))
+            }
+            Style::Unit => None,
+        })
+        .collect::<Vec<_>>();
+
+    quote! {
+        match _serde::__private::None::<&#type_ident #ty_generics> {
+            #(
+                _serde::__private::Some(#patterns) => {}
+            )*
+            _ => {}
+        }
+    }
+}
+
+// Expands to one of these per enum variant:
+//
+//     match None {
+//         Some((__v0, __v1,)) => {
+//             let _ = E::V { a: __v0, b: __v1 };
+//         }
+//         _ => {}
+//     }
+//
+fn pretend_variants_used(cont: &Container) -> TokenStream {
+    let variants = match &cont.data {
+        Data::Enum(variants) => variants,
+        Data::Struct(_, _) => {
+            return quote!();
+        }
+    };
+
+    let type_ident = &cont.ident;
+    let (_, ty_generics, _) = cont.generics.split_for_impl();
+    let turbofish = ty_generics.as_turbofish();
+
+    let cases = variants.iter().map(|variant| {
+        let variant_ident = &variant.ident;
+        let placeholders = &(0..variant.fields.len())
+            .map(|i| format_ident!("__v{}", i))
+            .collect::<Vec<_>>();
+
+        let pat = match variant.style {
+            Style::Struct => {
+                let members = variant.fields.iter().map(|field| &field.member);
+                quote!({ #(#members: #placeholders),* })
+            }
+            Style::Tuple | Style::Newtype => quote!(( #(#placeholders),* )),
+            Style::Unit => quote!(),
+        };
+
+        quote! {
+            match _serde::__private::None {
+                _serde::__private::Some((#(#placeholders,)*)) => {
+                    let _ = #type_ident::#variant_ident #turbofish #pat;
+                }
+                _ => {}
+            }
+        }
+    });
+
+    quote!(#(#cases)*)
+}