Import asn1-rs-derive crate.upstream

Request Document: go/android-rust-importing-crates
For CL Reviewers: go/android3p#cl-review
For Build Team: go/ab-third-party-imports
Bug: 312436720
Test: Treehugger

Change-Id: I44b17fd2de8eeae4ee43fda51177bad85c99e4bc

5 files changed, 735 insertions, 0 deletions

diff --git a/src/alias.rs b/src/alias.rs
new file mode 100644
index 0000000..82ca68e
--- /dev/null
+++ b/src/alias.rs
@@ -0,0 +1,61 @@
+use crate::container::*;
+use proc_macro2::Span;
+use quote::quote;
+use syn::{Data, Ident};
+
+pub fn derive_ber_alias(s: synstructure::Structure) -> proc_macro2::TokenStream {
+    let ast = s.ast();
+
+    let container = match &ast.data {
+        Data::Struct(ds) => Container::from_datastruct(ds, ast, ContainerType::Alias),
+        _ => panic!("Unsupported type, cannot derive"),
+    };
+
+    let debug_derive = ast.attrs.iter().any(|attr| {
+        attr.path
+            .is_ident(&Ident::new("debug_derive", Span::call_site()))
+    });
+
+    let impl_tryfrom = container.gen_tryfrom();
+    let impl_tagged = container.gen_tagged();
+    let ts = s.gen_impl(quote! {
+        extern crate asn1_rs;
+
+        #impl_tryfrom
+        #impl_tagged
+    });
+    if debug_derive {
+        eprintln!("{}", ts);
+    }
+    ts
+}
+
+pub fn derive_der_alias(s: synstructure::Structure) -> proc_macro2::TokenStream {
+    let ast = s.ast();
+
+    let container = match &ast.data {
+        Data::Struct(ds) => Container::from_datastruct(ds, ast, ContainerType::Alias),
+        _ => panic!("Unsupported type, cannot derive"),
+    };
+
+    let debug_derive = ast.attrs.iter().any(|attr| {
+        attr.path
+            .is_ident(&Ident::new("debug_derive", Span::call_site()))
+    });
+    let impl_tryfrom = container.gen_tryfrom();
+    let impl_tagged = container.gen_tagged();
+    let impl_checkconstraints = container.gen_checkconstraints();
+    let impl_fromder = container.gen_fromder();
+    let ts = s.gen_impl(quote! {
+        extern crate asn1_rs;
+
+        #impl_tryfrom
+        #impl_tagged
+        #impl_checkconstraints
+        #impl_fromder
+    });
+    if debug_derive {
+        eprintln!("{}", ts);
+    }
+    ts
+}
diff --git a/src/container.rs b/src/container.rs
new file mode 100644
index 0000000..667992c
--- /dev/null
+++ b/src/container.rs
@@ -0,0 +1,488 @@
+use proc_macro2::{Literal, Span, TokenStream};
+use quote::{quote, ToTokens};
+use syn::{
+    parse::ParseStream, parse_quote, spanned::Spanned, Attribute, DataStruct, DeriveInput, Field,
+    Fields, Ident, Lifetime, LitInt, Meta, Type, WherePredicate,
+};
+
+#[derive(Copy, Clone, Debug, PartialEq)]
+pub enum ContainerType {
+    Alias,
+    Sequence,
+    Set,
+}
+
+impl ToTokens for ContainerType {
+    fn to_tokens(&self, tokens: &mut TokenStream) {
+        let s = match self {
+            ContainerType::Alias => quote! {},
+            ContainerType::Sequence => quote! { asn1_rs::Tag::Sequence },
+            ContainerType::Set => quote! { asn1_rs::Tag::Set },
+        };
+        s.to_tokens(tokens)
+    }
+}
+
+#[derive(Clone, Copy, Debug, PartialEq)]
+enum Asn1Type {
+    Ber,
+    Der,
+}
+
+#[derive(Copy, Clone, Debug, PartialEq)]
+pub enum Asn1TagKind {
+    Explicit,
+    Implicit,
+}
+
+impl ToTokens for Asn1TagKind {
+    fn to_tokens(&self, tokens: &mut TokenStream) {
+        let s = match self {
+            Asn1TagKind::Explicit => quote! { asn1_rs::Explicit },
+            Asn1TagKind::Implicit => quote! { asn1_rs::Implicit },
+        };
+        s.to_tokens(tokens)
+    }
+}
+
+#[derive(Copy, Clone, Debug, PartialEq)]
+pub enum Asn1TagClass {
+    Universal,
+    Application,
+    ContextSpecific,
+    Private,
+}
+
+impl ToTokens for Asn1TagClass {
+    fn to_tokens(&self, tokens: &mut TokenStream) {
+        let s = match self {
+            Asn1TagClass::Application => quote! { asn1_rs::Class::APPLICATION },
+            Asn1TagClass::ContextSpecific => quote! { asn1_rs::Class::CONTEXT_SPECIFIC },
+            Asn1TagClass::Private => quote! { asn1_rs::Class::PRIVATE },
+            Asn1TagClass::Universal => quote! { asn1_rs::Class::UNIVERSAL },
+        };
+        s.to_tokens(tokens)
+    }
+}
+
+pub struct Container {
+    pub container_type: ContainerType,
+    pub fields: Vec<FieldInfo>,
+    pub where_predicates: Vec<WherePredicate>,
+    pub error: Option<Attribute>,
+
+    is_any: bool,
+}
+
+impl Container {
+    pub fn from_datastruct(
+        ds: &DataStruct,
+        ast: &DeriveInput,
+        container_type: ContainerType,
+    ) -> Self {
+        let mut is_any = false;
+        match (container_type, &ds.fields) {
+            (ContainerType::Alias, Fields::Unnamed(f)) => {
+                if f.unnamed.len() != 1 {
+                    panic!("Alias: only tuple fields with one element are supported");
+                }
+                match &f.unnamed[0].ty {
+                    Type::Path(type_path)
+                        if type_path
+                            .clone()
+                            .into_token_stream()
+                            .to_string()
+                            .starts_with("Any") =>
+                    {
+                        is_any = true;
+                    }
+                    _ => (),
+                }
+            }
+            (ContainerType::Alias, _) => panic!("BER/DER alias must be used with tuple strucs"),
+            (_, Fields::Unnamed(_)) => panic!("BER/DER sequence cannot be used on tuple structs"),
+            _ => (),
+        }
+
+        let fields = ds.fields.iter().map(FieldInfo::from).collect();
+
+        // get lifetimes from generics
+        let lfts: Vec<_> = ast.generics.lifetimes().collect();
+        let mut where_predicates = Vec::new();
+        if !lfts.is_empty() {
+            // input slice must outlive all lifetimes from Self
+            let lft = Lifetime::new("'ber", Span::call_site());
+            let wh: WherePredicate = parse_quote! { #lft: #(#lfts)+* };
+            where_predicates.push(wh);
+        };
+
+        // get custom attributes on container
+        let error = ast
+            .attrs
+            .iter()
+            .find(|attr| attr.path.is_ident(&Ident::new("error", Span::call_site())))
+            .cloned();
+
+        Container {
+            container_type,
+            fields,
+            where_predicates,
+            error,
+            is_any,
+        }
+    }
+
+    pub fn gen_tryfrom(&self) -> TokenStream {
+        let field_names = &self.fields.iter().map(|f| &f.name).collect::<Vec<_>>();
+        let parse_content =
+            derive_ber_sequence_content(&self.fields, Asn1Type::Ber, self.error.is_some());
+        let lifetime = Lifetime::new("'ber", Span::call_site());
+        let wh = &self.where_predicates;
+        let error = if let Some(attr) = &self.error {
+            get_attribute_meta(attr).expect("Invalid error attribute format")
+        } else {
+            quote! { asn1_rs::Error }
+        };
+
+        let fn_content = if self.container_type == ContainerType::Alias {
+            // special case: is this an alias for Any
+            if self.is_any {
+                quote! { Ok(Self(any)) }
+            } else {
+                quote! {
+                    let res = TryFrom::try_from(any)?;
+                    Ok(Self(res))
+                }
+            }
+        } else {
+            quote! {
+                use asn1_rs::nom::*;
+                any.tag().assert_eq(Self::TAG)?;
+
+                // no need to parse sequence, we already have content
+                let i = any.data;
+                //
+                #parse_content
+                //
+                let _ = i; // XXX check if empty?
+                Ok(Self{#(#field_names),*})
+            }
+        };
+        // note: `gen impl` in synstructure takes care of appending extra where clauses if any, and removing
+        // the `where` statement if there are none.
+        quote! {
+            use asn1_rs::{Any, FromBer};
+            use core::convert::TryFrom;
+
+            gen impl<#lifetime> TryFrom<Any<#lifetime>> for @Self where #(#wh)+* {
+                type Error = #error;
+
+                fn try_from(any: Any<#lifetime>) -> asn1_rs::Result<Self, #error> {
+                    #fn_content
+                }
+            }
+        }
+    }
+
+    pub fn gen_tagged(&self) -> TokenStream {
+        let tag = if self.container_type == ContainerType::Alias {
+            // special case: is this an alias for Any
+            if self.is_any {
+                return quote! {};
+            }
+            // find type of sub-item
+            let ty = &self.fields[0].type_;
+            quote! { <#ty as asn1_rs::Tagged>::TAG }
+        } else {
+            let container_type = self.container_type;
+            quote! { #container_type }
+        };
+        quote! {
+            gen impl<'ber> asn1_rs::Tagged for @Self {
+                const TAG: asn1_rs::Tag = #tag;
+            }
+        }
+    }
+
+    pub fn gen_checkconstraints(&self) -> TokenStream {
+        let lifetime = Lifetime::new("'ber", Span::call_site());
+        let wh = &self.where_predicates;
+        // let parse_content = derive_ber_sequence_content(&field_names, Asn1Type::Der);
+
+        let fn_content = if self.container_type == ContainerType::Alias {
+            // special case: is this an alias for Any
+            if self.is_any {
+                return quote! {};
+            }
+            let ty = &self.fields[0].type_;
+            quote! {
+                any.tag().assert_eq(Self::TAG)?;
+                <#ty>::check_constraints(any)
+            }
+        } else {
+            let check_fields: Vec<_> = self
+                .fields
+                .iter()
+                .map(|field| {
+                    let ty = &field.type_;
+                    quote! {
+                        let (rem, any) = Any::from_der(rem)?;
+                        <#ty as CheckDerConstraints>::check_constraints(&any)?;
+                    }
+                })
+                .collect();
+            quote! {
+                any.tag().assert_eq(Self::TAG)?;
+                let rem = &any.data;
+                #(#check_fields)*
+                Ok(())
+            }
+        };
+
+        // note: `gen impl` in synstructure takes care of appending extra where clauses if any, and removing
+        // the `where` statement if there are none.
+        quote! {
+            use asn1_rs::{CheckDerConstraints, Tagged};
+            gen impl<#lifetime> CheckDerConstraints for @Self where #(#wh)+* {
+                fn check_constraints(any: &Any) -> asn1_rs::Result<()> {
+                    #fn_content
+                }
+            }
+        }
+    }
+
+    pub fn gen_fromder(&self) -> TokenStream {
+        let lifetime = Lifetime::new("'ber", Span::call_site());
+        let wh = &self.where_predicates;
+        let field_names = &self.fields.iter().map(|f| &f.name).collect::<Vec<_>>();
+        let parse_content =
+            derive_ber_sequence_content(&self.fields, Asn1Type::Der, self.error.is_some());
+        let error = if let Some(attr) = &self.error {
+            get_attribute_meta(attr).expect("Invalid error attribute format")
+        } else {
+            quote! { asn1_rs::Error }
+        };
+
+        let fn_content = if self.container_type == ContainerType::Alias {
+            // special case: is this an alias for Any
+            if self.is_any {
+                quote! {
+                    let (rem, any) = asn1_rs::Any::from_der(bytes).map_err(asn1_rs::nom::Err::convert)?;
+                    Ok((rem,Self(any)))
+                }
+            } else {
+                quote! {
+                    let (rem, any) = asn1_rs::Any::from_der(bytes).map_err(asn1_rs::nom::Err::convert)?;
+                    any.header.assert_tag(Self::TAG).map_err(|e| asn1_rs::nom::Err::Error(e.into()))?;
+                    let res = TryFrom::try_from(any)?;
+                    Ok((rem,Self(res)))
+                }
+            }
+        } else {
+            quote! {
+                let (rem, any) = asn1_rs::Any::from_der(bytes).map_err(asn1_rs::nom::Err::convert)?;
+                any.header.assert_tag(Self::TAG).map_err(|e| asn1_rs::nom::Err::Error(e.into()))?;
+                let i = any.data;
+                //
+                #parse_content
+                //
+                // let _ = i; // XXX check if empty?
+                Ok((rem,Self{#(#field_names),*}))
+            }
+        };
+        // note: `gen impl` in synstructure takes care of appending extra where clauses if any, and removing
+        // the `where` statement if there are none.
+        quote! {
+            use asn1_rs::FromDer;
+
+            gen impl<#lifetime> asn1_rs::FromDer<#lifetime, #error> for @Self where #(#wh)+* {
+                fn from_der(bytes: &#lifetime [u8]) -> asn1_rs::ParseResult<#lifetime, Self, #error> {
+                    #fn_content
+                }
+            }
+        }
+    }
+}
+
+#[derive(Debug)]
+pub struct FieldInfo {
+    pub name: Ident,
+    pub type_: Type,
+    pub default: Option<TokenStream>,
+    pub optional: bool,
+    pub tag: Option<(Asn1TagKind, Asn1TagClass, u16)>,
+    pub map_err: Option<TokenStream>,
+}
+
+impl From<&Field> for FieldInfo {
+    fn from(field: &Field) -> Self {
+        // parse attributes and keep supported ones
+        let mut optional = false;
+        let mut tag = None;
+        let mut map_err = None;
+        let mut default = None;
+        let name = field
+            .ident
+            .as_ref()
+            .map_or_else(|| Ident::new("_", Span::call_site()), |s| s.clone());
+        for attr in &field.attrs {
+            let ident = match attr.path.get_ident() {
+                Some(ident) => ident.to_string(),
+                None => continue,
+            };
+            match ident.as_str() {
+                "map_err" => {
+                    let expr: syn::Expr = attr.parse_args().expect("could not parse map_err");
+                    map_err = Some(quote! { #expr });
+                }
+                "default" => {
+                    let expr: syn::Expr = attr.parse_args().expect("could not parse default");
+                    default = Some(quote! { #expr });
+                    optional = true;
+                }
+                "optional" => optional = true,
+                "tag_explicit" => {
+                    if tag.is_some() {
+                        panic!("tag cannot be set twice!");
+                    }
+                    let (class, value) = attr.parse_args_with(parse_tag_args).unwrap();
+                    tag = Some((Asn1TagKind::Explicit, class, value));
+                }
+                "tag_implicit" => {
+                    if tag.is_some() {
+                        panic!("tag cannot be set twice!");
+                    }
+                    let (class, value) = attr.parse_args_with(parse_tag_args).unwrap();
+                    tag = Some((Asn1TagKind::Implicit, class, value));
+                }
+                // ignore unknown attributes
+                _ => (),
+            }
+        }
+        FieldInfo {
+            name,
+            type_: field.ty.clone(),
+            default,
+            optional,
+            tag,
+            map_err,
+        }
+    }
+}
+
+fn parse_tag_args(stream: ParseStream) -> Result<(Asn1TagClass, u16), syn::Error> {
+    let tag_class: Option<Ident> = stream.parse()?;
+    let tag_class = if let Some(ident) = tag_class {
+        let s = ident.to_string().to_uppercase();
+        match s.as_str() {
+            "UNIVERSAL" => Asn1TagClass::Universal,
+            "CONTEXT-SPECIFIC" => Asn1TagClass::ContextSpecific,
+            "APPLICATION" => Asn1TagClass::Application,
+            "PRIVATE" => Asn1TagClass::Private,
+            _ => {
+                return Err(syn::Error::new(stream.span(), "Invalid tag class"));
+            }
+        }
+    } else {
+        Asn1TagClass::ContextSpecific
+    };
+    let lit: LitInt = stream.parse()?;
+    let value = lit.base10_parse::<u16>()?;
+    Ok((tag_class, value))
+}
+
+fn derive_ber_sequence_content(
+    fields: &[FieldInfo],
+    asn1_type: Asn1Type,
+    custom_errors: bool,
+) -> TokenStream {
+    let field_parsers: Vec<_> = fields
+        .iter()
+        .map(|f| get_field_parser(f, asn1_type, custom_errors))
+        .collect();
+
+    quote! {
+        #(#field_parsers)*
+    }
+}
+
+fn get_field_parser(f: &FieldInfo, asn1_type: Asn1Type, custom_errors: bool) -> TokenStream {
+    let from = match asn1_type {
+        Asn1Type::Ber => quote! {FromBer::from_ber},
+        Asn1Type::Der => quote! {FromDer::from_der},
+    };
+    let name = &f.name;
+    let default = f
+        .default
+        .as_ref()
+        // use a type hint, otherwise compiler will not know what type provides .unwrap_or
+        .map(|x| quote! {let #name: Option<_> = #name; let #name = #name.unwrap_or(#x);});
+    let map_err = if let Some(tt) = f.map_err.as_ref() {
+        if asn1_type == Asn1Type::Ber {
+            Some(quote! { .finish().map_err(#tt) })
+        } else {
+            // Some(quote! { .map_err(|err| nom::Err::convert(#tt)) })
+            Some(quote! { .map_err(|err| err.map(#tt)) })
+        }
+    } else {
+        // add mapping functions only if custom errors are used
+        if custom_errors {
+            if asn1_type == Asn1Type::Ber {
+                Some(quote! { .finish() })
+            } else {
+                Some(quote! { .map_err(nom::Err::convert) })
+            }
+        } else {
+            None
+        }
+    };
+    if let Some((tag_kind, class, n)) = f.tag {
+        let tag = Literal::u16_unsuffixed(n);
+        // test if tagged + optional
+        if f.optional {
+            return quote! {
+                let (i, #name) = {
+                    if i.is_empty() {
+                        (i, None)
+                    } else {
+                        let (_, header): (_, asn1_rs::Header) = #from(i)#map_err?;
+                        if header.tag().0 == #tag {
+                            let (i, t): (_, asn1_rs::TaggedValue::<_, _, #tag_kind, {#class}, #tag>) = #from(i)#map_err?;
+                            (i, Some(t.into_inner()))
+                        } else {
+                            (i, None)
+                        }
+                    }
+                };
+                #default
+            };
+        } else {
+            // tagged, but not OPTIONAL
+            return quote! {
+                let (i, #name) = {
+                    let (i, t): (_, asn1_rs::TaggedValue::<_, _, #tag_kind, {#class}, #tag>) = #from(i)#map_err?;
+                    (i, t.into_inner())
+                };
+                #default
+            };
+        }
+    } else {
+        // neither tagged nor optional
+        quote! {
+            let (i, #name) = #from(i)#map_err?;
+            #default
+        }
+    }
+}
+
+fn get_attribute_meta(attr: &Attribute) -> Result<TokenStream, syn::Error> {
+    if let Ok(Meta::List(meta)) = attr.parse_meta() {
+        let content = &meta.nested;
+        Ok(quote! { #content })
+    } else {
+        Err(syn::Error::new(
+            attr.span(),
+            "Invalid error attribute format",
+        ))
+    }
+}
diff --git a/src/lib.rs b/src/lib.rs
new file mode 100644
index 0000000..c75cf37
--- /dev/null
+++ b/src/lib.rs
@@ -0,0 +1,64 @@
+mod alias;
+mod container;
+mod sequence;
+mod set;
+use alias::*;
+use sequence::*;
+use set::*;
+
+synstructure::decl_derive!([BerAlias, attributes(
+    debug_derive,
+    default,
+    optional,
+    tag_explicit,
+    tag_implicit,
+    error,
+    map_err
+)] => derive_ber_alias);
+synstructure::decl_derive!([DerAlias, attributes(
+    debug_derive,
+    default,
+    optional,
+    tag_explicit,
+    tag_implicit,
+    error,
+    map_err
+)] => derive_der_alias);
+
+synstructure::decl_derive!([BerSequence, attributes(
+    debug_derive,
+    default,
+    optional,
+    tag_explicit,
+    tag_implicit,
+    error,
+    map_err
+)] => derive_ber_sequence);
+synstructure::decl_derive!([DerSequence, attributes(
+    debug_derive,
+    default,
+    optional,
+    tag_explicit,
+    tag_implicit,
+    error,
+    map_err
+)] => derive_der_sequence);
+
+synstructure::decl_derive!([BerSet, attributes(
+    debug_derive,
+    default,
+    optional,
+    tag_explicit,
+    tag_implicit,
+    error,
+    map_err
+)] => derive_ber_set);
+synstructure::decl_derive!([DerSet, attributes(
+    debug_derive,
+    default,
+    optional,
+    tag_explicit,
+    tag_implicit,
+    error,
+    map_err
+)] => derive_der_set);
diff --git a/src/sequence.rs b/src/sequence.rs
new file mode 100644
index 0000000..8a0d249
--- /dev/null
+++ b/src/sequence.rs
@@ -0,0 +1,61 @@
+use crate::container::*;
+use proc_macro2::Span;
+use quote::quote;
+use syn::{Data, Ident};
+
+pub fn derive_ber_sequence(s: synstructure::Structure) -> proc_macro2::TokenStream {
+    let ast = s.ast();
+
+    let container = match &ast.data {
+        Data::Struct(ds) => Container::from_datastruct(ds, ast, ContainerType::Sequence),
+        _ => panic!("Unsupported type, cannot derive"),
+    };
+
+    let debug_derive = ast.attrs.iter().any(|attr| {
+        attr.path
+            .is_ident(&Ident::new("debug_derive", Span::call_site()))
+    });
+
+    let impl_tryfrom = container.gen_tryfrom();
+    let impl_tagged = container.gen_tagged();
+    let ts = s.gen_impl(quote! {
+        extern crate asn1_rs;
+
+        #impl_tryfrom
+        #impl_tagged
+    });
+    if debug_derive {
+        eprintln!("{}", ts);
+    }
+    ts
+}
+
+pub fn derive_der_sequence(s: synstructure::Structure) -> proc_macro2::TokenStream {
+    let ast = s.ast();
+
+    let container = match &ast.data {
+        Data::Struct(ds) => Container::from_datastruct(ds, ast, ContainerType::Sequence),
+        _ => panic!("Unsupported type, cannot derive"),
+    };
+
+    let debug_derive = ast.attrs.iter().any(|attr| {
+        attr.path
+            .is_ident(&Ident::new("debug_derive", Span::call_site()))
+    });
+    let impl_tryfrom = container.gen_tryfrom();
+    let impl_tagged = container.gen_tagged();
+    let impl_checkconstraints = container.gen_checkconstraints();
+    let impl_fromder = container.gen_fromder();
+    let ts = s.gen_impl(quote! {
+        extern crate asn1_rs;
+
+        #impl_tryfrom
+        #impl_tagged
+        #impl_checkconstraints
+        #impl_fromder
+    });
+    if debug_derive {
+        eprintln!("{}", ts);
+    }
+    ts
+}
diff --git a/src/set.rs b/src/set.rs
new file mode 100644
index 0000000..90ea04a
--- /dev/null
+++ b/src/set.rs
@@ -0,0 +1,61 @@
+use crate::container::*;
+use proc_macro2::Span;
+use quote::quote;
+use syn::{Data, Ident};
+
+pub fn derive_ber_set(s: synstructure::Structure) -> proc_macro2::TokenStream {
+    let ast = s.ast();
+
+    let container = match &ast.data {
+        Data::Struct(ds) => Container::from_datastruct(ds, ast, ContainerType::Set),
+        _ => panic!("Unsupported type, cannot derive"),
+    };
+
+    let debug_derive = ast.attrs.iter().any(|attr| {
+        attr.path
+            .is_ident(&Ident::new("debug_derive", Span::call_site()))
+    });
+
+    let impl_tryfrom = container.gen_tryfrom();
+    let impl_tagged = container.gen_tagged();
+    let ts = s.gen_impl(quote! {
+        extern crate asn1_rs;
+
+        #impl_tryfrom
+        #impl_tagged
+    });
+    if debug_derive {
+        eprintln!("{}", ts);
+    }
+    ts
+}
+
+pub fn derive_der_set(s: synstructure::Structure) -> proc_macro2::TokenStream {
+    let ast = s.ast();
+
+    let container = match &ast.data {
+        Data::Struct(ds) => Container::from_datastruct(ds, ast, ContainerType::Set),
+        _ => panic!("Unsupported type, cannot derive"),
+    };
+
+    let debug_derive = ast.attrs.iter().any(|attr| {
+        attr.path
+            .is_ident(&Ident::new("debug_derive", Span::call_site()))
+    });
+    let impl_tryfrom = container.gen_tryfrom();
+    let impl_tagged = container.gen_tagged();
+    let impl_checkconstraints = container.gen_checkconstraints();
+    let impl_fromder = container.gen_fromder();
+    let ts = s.gen_impl(quote! {
+        extern crate asn1_rs;
+
+        #impl_tryfrom
+        #impl_tagged
+        #impl_checkconstraints
+        #impl_fromder
+    });
+    if debug_derive {
+        eprintln!("{}", ts);
+    }
+    ts
+}