ctest: add tests for aliases, structs, unions, as well as a test crate.

ctest-next/src/ast/constant.rs

@@ -3,7 +3,6 @@ use crate::BoxStr;
 /// Represents a constant variable defined in Rust.
 #[derive(Debug, Clone)]
 pub struct Const {
-    #[expect(unused)]
     pub(crate) public: bool,
     pub(crate) ident: BoxStr,
     pub(crate) ty: syn::Type,

ctest-next/src/ast/field.rs

@@ -3,7 +3,6 @@ use crate::BoxStr;
 /// Represents a field in a struct or union defined in Rust.
 #[derive(Debug, Clone)]
 pub struct Field {
-    #[expect(unused)]
     pub(crate) public: bool,
     pub(crate) ident: BoxStr,
     pub(crate) ty: syn::Type,

ctest-next/src/ast/function.rs

@@ -5,11 +5,11 @@ use crate::{Abi, BoxStr, Parameter};
 /// This structure is only used for parsing functions in extern blocks.
 #[derive(Debug, Clone)]
 pub struct Fn {
-    #[expect(unused)]
     pub(crate) public: bool,
     #[expect(unused)]
     pub(crate) abi: Abi,
     pub(crate) ident: BoxStr,
+    pub(crate) link_name: Option<BoxStr>,
     #[expect(unused)]
     pub(crate) parameters: Vec<Parameter>,
     #[expect(unused)]
@@ -21,4 +21,9 @@ impl Fn {
     pub fn ident(&self) -> &str {
         &self.ident
     }
+
+    /// Return the name of the function to be linked C side with.
+    pub fn link_name(&self) -> Option<&str> {
+        self.link_name.as_deref()
+    }
 }

ctest-next/src/ast/static_variable.rs

@@ -6,7 +6,6 @@ use crate::{Abi, BoxStr};
 /// as a result it does not have a field for storing the expression.
 #[derive(Debug, Clone)]
 pub struct Static {
-    #[expect(unused)]
     pub(crate) public: bool,
     #[expect(unused)]
     pub(crate) abi: Abi,

ctest-next/src/ast/structure.rs

@@ -3,10 +3,8 @@ use crate::{BoxStr, Field};
 /// Represents a struct defined in Rust.
 #[derive(Debug, Clone)]
 pub struct Struct {
-    #[expect(unused)]
     pub(crate) public: bool,
     pub(crate) ident: BoxStr,
-    #[expect(unused)]
     pub(crate) fields: Vec<Field>,
 }
 
@@ -15,4 +13,9 @@ impl Struct {
     pub fn ident(&self) -> &str {
         &self.ident
     }
+
+    /// Return the public fields of the struct.
+    pub fn public_fields(&self) -> impl Iterator<Item = &Field> {
+        self.fields.iter().filter(|f| f.public)
+    }
 }

ctest-next/src/ast/type_alias.rs

@@ -3,7 +3,6 @@ use crate::BoxStr;
 /// Represents a type alias defined in Rust.
 #[derive(Debug, Clone)]
 pub struct Type {
-    #[expect(unused)]
     pub(crate) public: bool,
     pub(crate) ident: BoxStr,
     pub(crate) ty: syn::Type,

ctest-next/src/ast/union.rs

@@ -6,7 +6,6 @@ pub struct Union {
     #[expect(unused)]
     pub(crate) public: bool,
     pub(crate) ident: BoxStr,
-    #[expect(unused)]
     pub(crate) fields: Vec<Field>,
 }
 
@@ -15,4 +14,9 @@ impl Union {
     pub fn ident(&self) -> &str {
         &self.ident
     }
+
+    /// Return the public fields of the union.
+    pub(crate) fn public_fields(&self) -> impl Iterator<Item = &Field> {
+        self.fields.iter().filter(|f| f.public)
+    }
 }

ctest-next/src/ffi_items.rs

@@ -37,7 +37,6 @@ impl FfiItems {
     }
 
     /// Return a list of all type aliases found.
-    #[cfg_attr(not(test), expect(unused))]
     pub(crate) fn aliases(&self) -> &Vec<Type> {
         &self.aliases
     }
@@ -123,10 +122,32 @@ fn visit_foreign_item_fn(table: &mut FfiItems, i: &syn::ForeignItemFn, abi: &Abi
         syn::ReturnType::Type(_, ty) => Some(ty.deref().clone()),
     };
 
+    let mut link_name_iter = i
+        .attrs
+        .iter()
+        .filter(|attr| attr.path().is_ident("link_name"));
+
+    let link_name = link_name_iter.next().and_then(|attr| match &attr.meta {
+        syn::Meta::NameValue(nv) => {
+            if let syn::Expr::Lit(expr_lit) = &nv.value {
+                if let syn::Lit::Str(lit_str) = &expr_lit.lit {
+                    return Some(lit_str.value().into_boxed_str());
+                }
+            }
+            None
+        }
+        _ => None,
+    });
+
+    if let Some(attr) = link_name_iter.next() {
+        panic!("multiple `#[link_name = ...]` attributes found: {attr:?}");
+    }
+
     table.foreign_functions.push(Fn {
         public,
         abi,
         ident,
+        link_name,
         parameters,
         return_type,
     });