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allow #[from] and #[backtrace] on same field

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See https://github.com/dtolnay/thiserror/pull/93#pullrequestreview-666213667
This commit is contained in:
Andrew Straw 2021-06-11 22:17:47 +02:00
parent a37b5ab11f
commit 86993c25ab
2 changed files with 80 additions and 27 deletions
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79
impl/src/expand.rs
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@ -58,18 +58,25 @@ fn impl_struct(input: Struct) -> TokenStream {
self.#source.as_dyn_error().backtrace()
}
};
let combinator = if type_is_option(backtrace_field.ty) {
if &source_field.member == backtrace {
quote! {
#source_backtrace.or(self.#backtrace.as_ref())
use thiserror::private::AsDynError;
#source_backtrace
}
} else {
let combinator = if type_is_option(backtrace_field.ty) {
quote! {
#source_backtrace.or(self.#backtrace.as_ref())
}
} else {
quote! {
std::option::Option::Some(#source_backtrace.unwrap_or(&self.#backtrace))
}
};
quote! {
std::option::Option::Some(#source_backtrace.unwrap_or(&self.#backtrace))
use thiserror::private::AsDynError;
#combinator
}
};
quote! {
use thiserror::private::AsDynError;
#combinator
}
} else if type_is_option(backtrace_field.ty) {
quote! {
@ -123,20 +130,21 @@ fn impl_struct(input: Struct) -> TokenStream {
}
});
let from_impl = input.from_field().map(|from_field| {
let backtrace_field = input.backtrace_field();
let from = from_field.ty;
let body = from_initializer(from_field, backtrace_field);
quote! {
#[allow(unused_qualifications)]
impl #impl_generics std::convert::From<#from> for #ty #ty_generics #where_clause {
#[allow(deprecated)]
fn from(source: #from) -> Self {
#ty #body
let from_impl = input.from_and_distinct_backtrace_fields().map(
|(from_field, backtrace_field)| {
let from = from_field.ty;
let body = from_initializer(from_field, backtrace_field);
quote! {
#[allow(unused_qualifications)]
impl #impl_generics std::convert::From<#from> for #ty #ty_generics #where_clause {
#[allow(deprecated)]
fn from(source: #from) -> Self {
#ty #body
}
}
}
}
});
},
);
let error_trait = spanned_error_trait(input.original);
@ -235,14 +243,32 @@ fn impl_enum(input: Enum) -> TokenStream {
}
}
(Some(backtrace_field), _) => {
let source = variant.from_field().map(|f| &f.member);
let backtrace = &backtrace_field.member;
let body = if type_is_option(backtrace_field.ty) {
quote!(backtrace.as_ref())
if source == Some(backtrace) {
let varsource = quote!(source);
let source_backtrace = quote_spanned! {source.span()=>
#varsource.as_dyn_error().backtrace()
};
quote! {
#ty::#ident {
#source: #varsource,
..
} => {
use thiserror::private::AsDynError;
#source_backtrace
}
}
} else {
quote!(std::option::Option::Some(backtrace))
};
quote! {
#ty::#ident {#backtrace: backtrace, ..} => #body,
let body = if type_is_option(backtrace_field.ty) {
quote!(backtrace.as_ref())
} else {
quote!(std::option::Option::Some(backtrace))
};
quote! {
#ty::#ident {#backtrace: backtrace, ..} => #body,
}
}
}
(None, _) => quote! {
@ -315,8 +341,7 @@ fn impl_enum(input: Enum) -> TokenStream {
};
let from_impls = input.variants.iter().filter_map(|variant| {
let from_field = variant.from_field()?;
let backtrace_field = variant.backtrace_field();
let (from_field, backtrace_field) = variant.from_and_distinct_backtrace_fields()?;
let variant = &variant.ident;
let from = from_field.ty;
let body = from_initializer(from_field, backtrace_field);