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Diffstat (limited to 'vendor/serde_derive/src/pretend.rs')
| -rw-r--r-- | vendor/serde_derive/src/pretend.rs | 185 |
1 files changed, 0 insertions, 185 deletions
diff --git a/vendor/serde_derive/src/pretend.rs b/vendor/serde_derive/src/pretend.rs deleted file mode 100644 index 2c9e779..0000000 --- a/vendor/serde_derive/src/pretend.rs +++ /dev/null @@ -1,185 +0,0 @@ -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)*) -} |