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Add more tests and support trait objects
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@JelteF
JelteF committed Jul 5, 2024
1 parent 16713df commit 659dfdb
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Showing 2 changed files with 140 additions and 68 deletions.
137 changes: 71 additions & 66 deletions impl/src/fmt/debug.rs
View file
Original file line number Diff line number Diff line change
Expand Up @@ -24,22 +24,21 @@ pub fn expand(input: &syn::DeriveInput, _: &str) -> syn::Result<TokenStream> {
.unwrap_or_default();
let ident = &input.ident;

let type_variables = input
let type_params: Vec<_> = input
.generics
.params
.iter()
.filter_map(|param| match param {
syn::GenericParam::Lifetime(_) => None,
syn::GenericParam::Type(ty) => Some(&ty.ident),
syn::GenericParam::Const(_) => None,
syn::GenericParam::Type(param) => Some(&param.ident),
_ => None,
})
.collect();

let (bounds, body) = match &input.data {
syn::Data::Struct(s) => {
expand_struct(attrs, ident, s, type_variables, &attr_name)
expand_struct(attrs, ident, s, &type_params, &attr_name)
}
syn::Data::Enum(e) => expand_enum(attrs, e, type_variables, &attr_name),
syn::Data::Enum(e) => expand_enum(attrs, e, &type_params, &attr_name),
syn::Data::Union(_) => {
return Err(syn::Error::new(
input.span(),
Expand Down Expand Up @@ -77,13 +76,13 @@ fn expand_struct(
attrs: ContainerAttributes,
ident: &Ident,
s: &syn::DataStruct,
type_variables: Vec<&syn::Ident>,
type_params: &[&syn::Ident],
attr_name: &syn::Ident,
) -> syn::Result<(Vec<syn::WherePredicate>, TokenStream)> {
let s = Expansion {
attr: &attrs,
fields: &s.fields,
type_variables: &type_variables,
type_params,
ident,
attr_name,
};
Expand Down Expand Up @@ -114,7 +113,7 @@ fn expand_struct(
fn expand_enum(
mut attrs: ContainerAttributes,
e: &syn::DataEnum,
type_variables: Vec<&syn::Ident>,
type_params: &[&syn::Ident],
attr_name: &syn::Ident,
) -> syn::Result<(Vec<syn::WherePredicate>, TokenStream)> {
if let Some(enum_fmt) = attrs.fmt.as_ref() {
Expand Down Expand Up @@ -152,7 +151,7 @@ fn expand_enum(
let v = Expansion {
attr: &attrs,
fields: &variant.fields,
type_variables: &type_variables,
type_params,
ident,
attr_name,
};
Expand Down Expand Up @@ -212,8 +211,8 @@ struct Expansion<'a> {
/// Struct or enum [`syn::Fields`].
fields: &'a syn::Fields,

/// Type variables in this struct or enum.
type_variables: &'a [&'a syn::Ident],
/// Type parameters in this struct or enum.
type_params: &'a [&'a syn::Ident],

/// Name of the attributes, considered by this macro.
attr_name: &'a syn::Ident,
Expand Down Expand Up @@ -356,7 +355,7 @@ impl<'a> Expansion<'a> {
if let Some(fmt) = self.attr.fmt.as_ref() {
out.extend(fmt.bounded_types(self.fields).filter_map(
|(ty, trait_name)| {
if !self.contains_type_variable(ty) {
if !self.contains_generic_param(ty) {
return None;
}

Expand All @@ -370,7 +369,7 @@ impl<'a> Expansion<'a> {
self.fields.iter().try_fold(out, |mut out, field| {
let ty = &field.ty;

if !self.contains_type_variable(ty) {
if !self.contains_generic_param(ty) {
return Ok(out);
}

Expand All @@ -394,61 +393,54 @@ impl<'a> Expansion<'a> {
}
}

fn contains_type_variable(&self, ty: &syn::Type) -> bool {
fn path_contains_generic_param(&self, path: &syn::Path) -> bool {
path.segments
.iter()
.any(|segment| match &segment.arguments {
syn::PathArguments::None => false,
syn::PathArguments::AngleBracketed(
syn::AngleBracketedGenericArguments { args, .. },
) => args.iter().any(|generic| match generic {
syn::GenericArgument::Type(ty)
| syn::GenericArgument::AssocType(syn::AssocType { ty, .. }) => {
self.contains_generic_param(ty)
}

syn::GenericArgument::Lifetime(_)
| syn::GenericArgument::Const(_)
| syn::GenericArgument::AssocConst(_)
| syn::GenericArgument::Constraint(_) => false,
_ => unimplemented!(
"syntax is not supported by derive_more, please report a bug"
),
}),
syn::PathArguments::Parenthesized(
syn::ParenthesizedGenericArguments { inputs, output, .. },
) => {
inputs.iter().any(|ty| self.contains_generic_param(ty))
|| match output {
syn::ReturnType::Default => false,
syn::ReturnType::Type(_, ty) => {
self.contains_generic_param(ty)
}
}
}
})
}

fn contains_generic_param(&self, ty: &syn::Type) -> bool {
match ty {
syn::Type::Path(syn::TypePath { qself, path }) => {
if let Some(qself) = qself {
if self.contains_type_variable(&qself.ty) {
if self.contains_generic_param(&qself.ty) {
return true;
}
}

if let Some(ident) = path.get_ident() {
self.type_variables
.iter()
.any(|type_var| *type_var == ident)
self.type_params.iter().any(|param| *param == ident)
} else {
path.segments.iter().any(|segment| {
self.type_variables
.iter()
.any(|type_var| *type_var == &segment.ident)
|| match &segment.arguments {
syn::PathArguments::None => false,
syn::PathArguments::AngleBracketed(
syn::AngleBracketedGenericArguments {
args, ..
},
) => args.iter().any(|generic| match generic {
syn::GenericArgument::Type(ty)
| syn::GenericArgument::AssocType(
syn::AssocType { ty, .. },
) => self.contains_type_variable(ty),

syn::GenericArgument::Lifetime(_)
| syn::GenericArgument::Const(_)
| syn::GenericArgument::AssocConst(_)
| syn::GenericArgument::Constraint(_) => false,
_ => false,
}),
syn::PathArguments::Parenthesized(
syn::ParenthesizedGenericArguments {
inputs,
output,
..
},
) => {
inputs
.iter()
.any(|ty| self.contains_type_variable(ty))
|| match output {
syn::ReturnType::Default => false,
syn::ReturnType::Type(_, ty) => {
self.contains_type_variable(ty)
}
}
}
}
})
self.path_contains_generic_param(path)
}
}

Expand All @@ -458,29 +450,42 @@ impl<'a> Expansion<'a> {
| syn::Type::Ptr(syn::TypePtr { elem, .. })
| syn::Type::Reference(syn::TypeReference { elem, .. })
| syn::Type::Slice(syn::TypeSlice { elem, .. }) => {
self.contains_type_variable(elem)
self.contains_generic_param(elem)
}

syn::Type::BareFn(syn::TypeBareFn { inputs, output, .. }) => {
inputs
.iter()
.any(|arg| self.contains_type_variable(&arg.ty))
.any(|arg| self.contains_generic_param(&arg.ty))
|| match output {
syn::ReturnType::Default => false,
syn::ReturnType::Type(_, ty) => self.contains_type_variable(ty),
syn::ReturnType::Type(_, ty) => self.contains_generic_param(ty),
}
}
syn::Type::Tuple(syn::TypeTuple { elems, .. }) => {
elems.iter().any(|ty| self.contains_type_variable(ty))
elems.iter().any(|ty| self.contains_generic_param(ty))
}

syn::Type::ImplTrait(_) => false,
syn::Type::Infer(_) => false,
syn::Type::Macro(_) => false,
syn::Type::Never(_) => false,
syn::Type::TraitObject(_) => false,
syn::Type::TraitObject(syn::TypeTraitObject { bounds, .. }) => {
bounds.iter().any(|bound| match bound {
syn::TypeParamBound::Trait(syn::TraitBound { path, .. }) => {
self.path_contains_generic_param(path)
}
syn::TypeParamBound::Lifetime(_) => false,
syn::TypeParamBound::Verbatim(_) => false,
_ => unimplemented!(
"syntax is not supported by derive_more, please report a bug"
),
})
}
syn::Type::Verbatim(_) => false,
_ => false,
_ => unimplemented!(
"syntax is not supported by derive_more, please report a bug"
),
}
}
}
71 changes: 69 additions & 2 deletions tests/debug.rs
View file
Original file line number Diff line number Diff line change
Expand Up @@ -1954,8 +1954,75 @@ mod type_variables {

#[derive(Debug)]
enum ItemEnum {
Node { children: Vec<ItemEnum>, inner: i32 },
Leaf { inner: i32 },
Node {
children: std::vec::Vec<ItemEnum>,
inner: i32,
},
Leaf {
inner: i32,
},
}

#[derive(Debug)]
struct Vec {
next: std::vec::Vec<i32>,
}

#[derive(Debug)]
struct Array<T> {
#[debug("{t}")]
t: [T; 10],
}

mod parens {
#![allow(unused_parens)] // test that type is found even in parentheses
use derive_more::Debug;
#[derive(Debug)]
struct Paren<T> {
t: (T),
}
}

#[derive(Debug)]
struct ParenthesizedGenericArgumentsInput<T> {
t: dyn Fn(T) -> i32,
}

#[derive(Debug)]
struct ParenthesizedGenericArgumentsOutput<T> {
t: dyn Fn(i32) -> T,
}

#[derive(Debug)]
struct Ptr<T> {
t: *const T,
}

#[derive(Debug)]
struct Reference<'a, T> {
t: &'a T,
}

#[derive(Debug)]
struct Slice<'a, T> {
t: &'a [T],
}

#[derive(Debug)]
struct BareFn<T> {
t: Box<fn(T) -> T>,
}

#[derive(Debug)]
struct Tuple<T> {
t: Box<(T, T)>,
}

trait MyTrait<T> {}

#[derive(Debug)]
struct TraitObject<T> {
t: Box<dyn MyTrait<T>>,
}

#[test]
Expand Down

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