Infered types (_) in #[ts(as = "...")] (#299)

--------- Co-authored-by: NyxCode <[email protected]>
Aleph-Alpha · Apr 10, 2024 · e671a7a · e671a7a
1 parent b9a4cca
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diff --git a/CHANGELOG.md b/CHANGELOG.md
@@ -11,10 +11,12 @@
 - Add support for `#[ts(type = "..")]` directly on structs and enums ([#286](https://github.com/Aleph-Alpha/ts-rs/pull/286))
 - Add support for `#[ts(as = "..")]` directly on structs and enums ([#288](https://github.com/Aleph-Alpha/ts-rs/pull/288))
 - Add support for `#[ts(rename_all = "SCREAMING-KEBAB-CASE")]` ([#298](https://github.com/Aleph-Alpha/ts-rs/pull/298))
+- Support `_` in `#[ts(type = "..")]` to refer to the type of the field ([#299](https://github.com/Aleph-Alpha/ts-rs/pull/299))
 
 ### Fixes
 
 - Fix `#[ts(rename_all_fields = "...")]` on enums containing tuple or unit variants ([#287](https://github.com/Aleph-Alpha/ts-rs/pull/287))
+- Fix "overflow evaluating the requirement" and "reached the recursion limit" errors in some cases ([#293](https://github.com/Aleph-Alpha/ts-rs/pull/293))
 
 # 8.1.0
 

diff --git a/macros/src/attr/field.rs b/macros/src/attr/field.rs
@@ -1,11 +1,15 @@
-use syn::{Attribute, Field, Ident, Result, Type};
+use syn::{
+    AngleBracketedGenericArguments, Attribute, Field, GenericArgument, Ident, PathArguments,
+    Result, ReturnType, Type, TypeArray, TypeGroup, TypeParen, TypePath, TypePtr, TypeReference,
+    TypeSlice, TypeTuple,
+};
 
 use super::{parse_assign_from_str, parse_assign_str, Attr, Serde};
 use crate::utils::{parse_attrs, parse_docs};
 
 #[derive(Default)]
 pub struct FieldAttr {
-    pub type_as: Option<Type>,
+    type_as: Option<Type>,
     pub type_override: Option<String>,
     pub rename: Option<String>,
     pub inline: bool,
@@ -41,6 +45,15 @@ impl FieldAttr {
 
         Ok(result)
     }
+
+    pub fn type_as(&self, original_type: &Type) -> Type {
+        if let Some(mut ty) = self.type_as.clone() {
+            replace_underscore(&mut ty, original_type);
+            ty
+        } else {
+            original_type.clone()
+        }
+    }
 }
 
 impl Attr for FieldAttr {
@@ -202,3 +215,58 @@ impl_parse! {
         },
     }
 }
+
+fn replace_underscore(ty: &mut Type, with: &Type) {
+    match ty {
+        Type::Infer(_) => *ty = with.clone(),
+        Type::Array(TypeArray { elem, .. })
+        | Type::Group(TypeGroup { elem, .. })
+        | Type::Paren(TypeParen { elem, .. })
+        | Type::Ptr(TypePtr { elem, .. })
+        | Type::Reference(TypeReference { elem, .. })
+        | Type::Slice(TypeSlice { elem, .. }) => {
+            replace_underscore(elem, with);
+        }
+        Type::Tuple(TypeTuple { elems, .. }) => {
+            for elem in elems {
+                replace_underscore(elem, with);
+            }
+        }
+        Type::Path(TypePath { path, qself: None }) => {
+            for segment in &mut path.segments {
+                match &mut segment.arguments {
+                    PathArguments::None => (),
+                    PathArguments::AngleBracketed(a) => {
+                        replace_underscore_in_angle_bracketed(a, with);
+                    }
+                    PathArguments::Parenthesized(p) => {
+                        for input in &mut p.inputs {
+                            replace_underscore(input, with);
+                        }
+                        if let ReturnType::Type(_, output) = &mut p.output {
+                            replace_underscore(output, with);
+                        }
+                    }
+                }
+            }
+        }
+        _ => (),
+    }
+}
+
+fn replace_underscore_in_angle_bracketed(args: &mut AngleBracketedGenericArguments, with: &Type) {
+    for arg in &mut args.args {
+        match arg {
+            GenericArgument::Type(ty) => {
+                replace_underscore(ty, with);
+            }
+            GenericArgument::AssocType(assoc_ty) => {
+                replace_underscore(&mut assoc_ty.ty, with);
+                for g in &mut assoc_ty.generics {
+                    replace_underscore_in_angle_bracketed(g, with);
+                }
+            }
+            _ => (),
+        }
+    }
+}
diff --git a/macros/src/types/enum.rs b/macros/src/types/enum.rs
@@ -135,30 +135,16 @@ fn format_variant(
 
                 field_attr.assert_validity(field)?;
 
-                let FieldAttr {
-                    type_as,
-                    type_override,
-                    skip,
-                    ..
-                } = field_attr;
-
-                if skip {
+                if field_attr.skip {
                     quote!(format!("{{ \"{}\": \"{}\" }}", #tag, #name))
                 } else {
-                    let ty = match (type_override, type_as) {
-                        (Some(_), Some(_)) => {
-                            unreachable!("This has been handled by assert_validity")
-                        }
-                        (Some(type_override), None) => quote! { #type_override },
-                        (None, Some(type_as)) => {
-                            quote!(<#type_as as #crate_rename::TS>::name())
-                        }
-                        (None, None) => {
-                            let ty = &unnamed.unnamed[0].ty;
+                    let ty = match field_attr.type_override {
+                        Some(type_override) => quote!(#type_override),
+                        None => {
+                            let ty = field_attr.type_as(&field.ty);
                             quote!(<#ty as #crate_rename::TS>::name())
                         }
                     };
-
                     quote!(format!("{{ \"{}\": \"{}\", \"{}\": {} }}", #tag, #name, #content, #ty))
                 }
             }
@@ -191,26 +177,13 @@ fn format_variant(
 
                     field_attr.assert_validity(field)?;
 
-                    let FieldAttr {
-                        type_as,
-                        skip,
-                        type_override,
-                        ..
-                    } = field_attr;
-
-                    if skip {
+                    if field_attr.skip {
                         quote!(format!("{{ \"{}\": \"{}\" }}", #tag, #name))
                     } else {
-                        let ty = match (type_override, type_as) {
-                            (Some(_), Some(_)) => {
-                                unreachable!("This has been handled by assert_validity")
-                            }
-                            (Some(type_override), None) => quote! { #type_override },
-                            (None, Some(type_as)) => {
-                                quote!(<#type_as as #crate_rename::TS>::name())
-                            }
-                            (None, None) => {
-                                let ty = &unnamed.unnamed[0].ty;
+                        let ty = match field_attr.type_override {
+                            Some(type_override) => quote! { #type_override },
+                            None => {
+                                let ty = field_attr.type_as(&field.ty);
                                 quote!(<#ty as #crate_rename::TS>::name())
                             }
                         };

diff --git a/macros/src/types/named.rs b/macros/src/types/named.rs
@@ -92,27 +92,13 @@ fn format_field(
 
     field_attr.assert_validity(field)?;
 
-    let FieldAttr {
-        type_as,
-        type_override,
-        rename,
-        inline,
-        skip,
-        optional,
-        flatten,
-        docs,
-
-        #[cfg(feature = "serde-compat")]
-            using_serde_with: _,
-    } = field_attr;
-
-    if skip {
+    if field_attr.skip {
         return Ok(());
     }
 
-    let parsed_ty = type_as.as_ref().unwrap_or(&field.ty).clone();
+    let parsed_ty = field_attr.type_as(&field.ty);
 
-    let (ty, optional_annotation) = match optional {
+    let (ty, optional_annotation) = match field_attr.optional {
         Optional {
             optional: true,
             nullable,
@@ -128,34 +114,37 @@ fn format_field(
         } => (&parsed_ty, ""),
     };
 
-    if flatten {
+    if field_attr.flatten {
         flattened_fields.push(quote!(<#ty as #crate_rename::TS>::inline_flattened()));
         dependencies.append_from(ty);
         return Ok(());
     }
 
-    let formatted_ty = type_override.map(|t| quote!(#t)).unwrap_or_else(|| {
-        if inline {
-            dependencies.append_from(ty);
-            quote!(<#ty as #crate_rename::TS>::inline())
-        } else {
-            dependencies.push(ty);
-            quote!(<#ty as #crate_rename::TS>::name())
-        }
-    });
+    let formatted_ty = field_attr
+        .type_override
+        .map(|t| quote!(#t))
+        .unwrap_or_else(|| {
+            if field_attr.inline {
+                dependencies.append_from(ty);
+                quote!(<#ty as #crate_rename::TS>::inline())
+            } else {
+                dependencies.push(ty);
+                quote!(<#ty as #crate_rename::TS>::name())
+            }
+        });
 
     let field_name = to_ts_ident(field.ident.as_ref().unwrap());
-    let name = match (rename, rename_all) {
+    let name = match (field_attr.rename, rename_all) {
         (Some(rn), _) => rn,
         (None, Some(rn)) => rn.apply(&field_name),
         (None, None) => field_name,
     };
     let valid_name = raw_name_to_ts_field(name);
 
     // Start every doc string with a newline, because when other characters are in front, it is not "understood" by VSCode
-    let docs = match docs.is_empty() {
+    let docs = match field_attr.docs.is_empty() {
         true => "".to_string(),
-        false => format!("\n{}", &docs),
+        false => format!("\n{}", &field_attr.docs),
     };
 
     formatted_fields.push(quote! {

diff --git a/macros/src/types/newtype.rs b/macros/src/types/newtype.rs
@@ -13,34 +13,25 @@ pub(crate) fn newtype(attr: &StructAttr, name: &str, fields: &FieldsUnnamed) ->
     let field_attr = FieldAttr::from_attrs(&inner.attrs)?;
     field_attr.assert_validity(inner)?;
 
-    let FieldAttr {
-        type_as,
-        type_override,
-        inline,
-        skip,
-        docs: _,
-        ..
-    } = field_attr;
-
     let crate_rename = attr.crate_rename();
 
-    if skip {
+    if field_attr.skip {
         return super::unit::null(attr, name);
     }
 
-    let inner_ty = type_as.as_ref().unwrap_or(&inner.ty).clone();
+    let inner_ty = field_attr.type_as(&inner.ty);
 
     let mut dependencies = Dependencies::new(crate_rename.clone());
 
-    match (&type_override, inline) {
+    match (&field_attr.type_override, field_attr.inline) {
         (Some(_), _) => (),
         (None, true) => dependencies.append_from(&inner_ty),
         (None, false) => dependencies.push(&inner_ty),
     };
 
-    let inline_def = match type_override {
+    let inline_def = match field_attr.type_override {
         Some(ref o) => quote!(#o.to_owned()),
-        None if inline => quote!(<#inner_ty as #crate_rename::TS>::inline()),
+        None if field_attr.inline => quote!(<#inner_ty as #crate_rename::TS>::inline()),
         None => quote!(<#inner_ty as #crate_rename::TS>::name()),
     };
 

diff --git a/macros/src/types/tuple.rs b/macros/src/types/tuple.rs
@@ -49,33 +49,19 @@ fn format_field(
     let field_attr = FieldAttr::from_attrs(&field.attrs)?;
     field_attr.assert_validity(field)?;
 
-    let FieldAttr {
-        type_as,
-        type_override,
-        rename: _,
-        inline,
-        skip,
-        optional: _,
-        flatten: _,
-        docs: _,
-
-        #[cfg(feature = "serde-compat")]
-            using_serde_with: _,
-    } = field_attr;
-
-    if skip {
+    if field_attr.skip {
         return Ok(());
     }
 
-    let ty = type_as.as_ref().unwrap_or(&field.ty).clone();
+    let ty = field_attr.type_as(&field.ty);
 
-    formatted_fields.push(match type_override {
+    formatted_fields.push(match field_attr.type_override {
         Some(ref o) => quote!(#o.to_owned()),
-        None if inline => quote!(<#ty as #crate_rename::TS>::inline()),
+        None if field_attr.inline => quote!(<#ty as #crate_rename::TS>::inline()),
         None => quote!(<#ty as #crate_rename::TS>::name()),
     });
 
-    match (inline, type_override) {
+    match (field_attr.inline, field_attr.type_override) {
         (_, Some(_)) => (),
         (false, _) => dependencies.push(&ty),
         (true, _) => dependencies.append_from(&ty),

diff --git a/ts-rs/src/lib.rs b/ts-rs/src/lib.rs
@@ -287,7 +287,8 @@ pub mod typelist;
 ///
 /// - **`#[ts(as = "..")]`**  
 ///   Overrides the type of the annotated field, using the provided Rust type instead.
-///   This is useful when there's a type for which you cannot derive `TS`.
+///   This is useful when there's a type for which you cannot derive `TS`.  
+///   `_` may be used to refer to the type of the field, e.g `#[ts(as = "Option<_>")]`.
 ///   <br/><br/>
 ///
 /// - **`#[ts(rename = "..")]`**  

diff --git a/ts-rs/tests/infer_as.rs b/ts-rs/tests/infer_as.rs
@@ -0,0 +1,15 @@
+#![allow(dead_code)]
+
+use ts_rs::TS;
+
+#[derive(TS)]
+#[ts(export)]
+struct Foo {
+    #[ts(optional, as = "Option<_>")]
+    my_optional_bool: bool,
+}
+
+#[test]
+fn test() {
+    assert_eq!(Foo::inline(), "{ my_optional_bool?: boolean, }");
+}