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Merged
merged 2 commits into from
Oct 6, 2024
Merged

Upgrade to syn v2.0 #13

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3838cfe
Upgrade to syn v2.0
juntyr Oct 5, 2024
74dca17
Improve attribute parsing error spans
juntyr Oct 6, 2024
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2 changes: 1 addition & 1 deletion const-type-layout-derive/Cargo.toml
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Original file line number Diff line number Diff line change
Expand Up @@ -16,7 +16,7 @@ proc-macro = true
# See more keys and their definitions at https://doc.rust-lang.org/cargo/reference/manifest.html

[dependencies]
syn = { version = "1.0", features = ["clone-impls", "derive", "parsing", "printing", "proc-macro"], default-features = false }
syn = { version = "2.0", features = ["clone-impls", "derive", "parsing", "printing", "proc-macro"], default-features = false }
quote = { version = "1.0", default-features = false }
proc-macro2 = { version = "1.0", default-features = false }
proc-macro-error2 = { version = "2.0", default-features = false }
Expand Down
192 changes: 86 additions & 106 deletions const-type-layout-derive/src/lib.rs
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Original file line number Diff line number Diff line change
Expand Up @@ -139,102 +139,108 @@ fn parse_attributes(attrs: &[syn::Attribute], type_params: &mut Vec<&syn::Ident>
let mut crate_path = None;

for attr in attrs {
if attr.path.is_ident("repr") {
if let Ok(syn::Meta::List(syn::MetaList { nested, .. })) = attr.parse_meta() {
#[allow(clippy::collapsible_if)]
if attr.path().is_ident("repr") {
if let Ok(nested) = attr.parse_args_with(
syn::punctuated::Punctuated::<syn::Meta, syn::Token![,]>::parse_terminated,
) {
for meta in nested {
reprs.push(match meta {
syn::NestedMeta::Lit(lit) => lit_to_string(&lit),
syn::NestedMeta::Meta(meta) => meta_to_string(&meta),
});
reprs.push(quote!(#meta).to_string());
}
} else {
emit_warning!(
attr.span(),
"[const-type-layout]: #[repr] attribute is not in meta list format."
);
}
} else if attr.path.is_ident("layout") {
if let Ok(syn::Meta::List(list)) = attr.parse_meta() {
for meta in &list.nested {
if let syn::NestedMeta::Meta(syn::Meta::NameValue(syn::MetaNameValue {
path,
lit: syn::Lit::Str(s),
..
})) = &meta
{
if path.is_ident("free") {
match syn::parse_str::<syn::Ident>(&s.value()) {
Ok(param) => {
type_params.iter().position(|ty| **ty == param).map_or_else(
|| {
emit_error!(
s.span(),
"[const-type-layout]: Invalid #[layout(free)] \
attribute: \"{}\" is either not a type parameter \
or has already been freed (duplicate attribute).",
param,
);
},
|i| {
type_params.swap_remove(i);
},
);
},
Err(err) => emit_error!(
s.span(),
"[const-type-layout]: Invalid #[layout(free = \"<type>\")] \
attribute: {}.",
err
),
}
} else if path.is_ident("bound") {
match syn::parse_str(&s.value()) {
Ok(bound) => extra_bounds.push(bound),
Err(err) => emit_error!(
s.span(),
"[const-type-layout]: Invalid #[layout(bound = \
\"<where-predicate>\")] attribute: {}.",
err
),
}
} else if path.is_ident("crate") {
match syn::parse_str::<syn::Path>(&s.value()) {
Ok(new_crate_path) => {
if crate_path.is_none() {
crate_path = Some(
syn::parse_quote_spanned! { s.span() => #new_crate_path },
);
} else {
} else if attr.path().is_ident("layout") {
#[allow(clippy::blocks_in_conditions)]
if attr
.parse_nested_meta(|meta| {
let Ok(value) = meta.value() else {
emit_error!(
meta.path.span(),
"[const-type-layout]: Expected #[layout(attr = \"value\")] syntax."
);
return Ok(());
};
let Ok(s) = <syn::LitStr as syn::parse::Parse>::parse(value) else {
emit_error!(
value.span(),
"[const-type-layout]: Expected #[layout(attr = \"value\")] syntax."
);
return Ok(());
};

if meta.path.is_ident("free") {
match syn::parse_str::<syn::Ident>(&s.value()) {
Ok(param) => {
type_params.iter().position(|ty| **ty == param).map_or_else(
|| {
emit_error!(
s.span(),
"[const-type-layout]: Duplicate #[layout(crate)] \
attribute: the crate path for `const-type-layout` \
can only be set once per `derive`.",
"[const-type-layout]: Invalid #[layout(free)] \
attribute: \"{}\" is either not a type parameter or \
has already been freed (duplicate attribute).",
param,
);
}
},
Err(err) => emit_error!(
s.span(),
"[const-type-layout]: Invalid #[layout(crate = \
\"<crate-path>\")] attribute: {}.",
err
),
}
} else {
emit_error!(
path.span(),
"[const-type-layout]: Unknown attribute, use `bound`, `crate`, or \
`free`."
);
},
|i| {
type_params.swap_remove(i);
},
);
},
Err(err) => emit_error!(
s.span(),
"[const-type-layout]: Invalid #[layout(free = \"<type>\")] \
attribute: {}.",
err
),
}
} else if meta.path.is_ident("bound") {
match syn::parse_str::<syn::WherePredicate>(&s.value()) {
Ok(bound) => extra_bounds.push(bound),
Err(err) => emit_error!(
s.span(),
"[const-type-layout]: Invalid #[layout(bound = \
\"<where-predicate>\")] attribute: {}.",
err
),
}
} else if meta.path.is_ident("crate") {
match syn::parse_str::<syn::Path>(&s.value()) {
Ok(new_crate_path) => {
if crate_path.is_none() {
crate_path = Some(
syn::parse_quote_spanned! { s.span() => #new_crate_path },
);
} else {
emit_error!(
meta.path.span(),
"[const-type-layout]: Duplicate #[layout(crate)] \
attribute: the crate path for `const-type-layout` can \
only be set once per `derive`.",
);
}
},
Err(err) => emit_error!(
s.span(),
"[const-type-layout]: Invalid #[layout(crate = \"<crate-path>\")] \
attribute: {}.",
err
),
}
} else {
emit_error!(
meta.span(),
"[const-type-layout]: Expected #[layout(attr = \"value\")] syntax."
meta.path.span(),
"[const-type-layout]: Unknown attribute, use `bound`, `crate`, or \
`free`."
);
}
}
} else {
Ok(())
})
.is_err()
{
emit_error!(
attr.span(),
"[const-type-layout]: Expected #[layout(attr = \"value\")] syntax."
Expand All @@ -257,32 +263,6 @@ fn parse_attributes(attrs: &[syn::Attribute], type_params: &mut Vec<&syn::Ident>
}
}

fn meta_to_string(meta: &syn::Meta) -> String {
match meta {
syn::Meta::List(syn::MetaList { path, nested, .. }) => {
let mut list = nested
.iter()
.map(|meta| match meta {
syn::NestedMeta::Lit(lit) => lit_to_string(lit),
syn::NestedMeta::Meta(meta) => meta_to_string(meta),
})
.collect::<Vec<_>>();
list.sort();
list.dedup();

format!("{}({})", quote!(#path), intersperse_commas(list))
},
syn::Meta::NameValue(syn::MetaNameValue { path, lit, .. }) => {
format!("{}={}", quote!(#path), lit_to_string(lit))
},
syn::Meta::Path(path) => quote!(#path).to_string(),
}
}

fn lit_to_string(lit: &syn::Lit) -> String {
quote!(#lit).to_string().escape_default().to_string()
}

fn intersperse_commas(items: Vec<String>) -> String {
let mut acc = String::with_capacity(
items.iter().map(String::len).sum::<usize>() + items.len().saturating_sub(1),
Expand Down
6 changes: 1 addition & 5 deletions try-crate/src/main.rs
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Original file line number Diff line number Diff line change
Expand Up @@ -159,12 +159,8 @@ pub struct MyPhantomData<T> {
#[repr(transparent)]
pub struct Wrapper(f64);

// FIXME: move bound from where clause to impl bound
// https://github.com/dtolnay/syn/issues/1238
#[derive(TypeLayout)]
pub struct Bounded<T>(T)
where
T: std::fmt::Debug + TypeGraphLayout;
pub struct Bounded<T: std::fmt::Debug + TypeGraphLayout>(T);

fn main() {
println!("{:#?}", Foo1::TYPE_GRAPH);
Expand Down