support unknown trait bounds in type parameters

crates/fayalite-proc-macros-impl/src/hdl_type_common.rs

@@ -2069,11 +2069,16 @@ macro_rules! impl_bounds {
             $(
                 $Variant:ident,
             )*
+            $(
+                #[unknown]
+                $Unknown:ident,
+            )?
         }
     ) => {
         #[derive(Clone, Debug)]
         $vis enum $enum_type {
             $($Variant(known_items::$Variant),)*
+            $($Unknown(syn::TypeParamBound),)?
         }
 
         $(impl From<known_items::$Variant> for $enum_type {
@@ -2086,28 +2091,54 @@ macro_rules! impl_bounds {
             fn to_tokens(&self, tokens: &mut TokenStream) {
                 match self {
                     $(Self::$Variant(v) => v.to_tokens(tokens),)*
+                    $(Self::$Unknown(v) => v.to_tokens(tokens),)?
                 }
             }
         }
 
         impl $enum_type {
             $vis fn parse_path(path: Path) -> Result<Self, Path> {
+                #![allow(unreachable_code)]
                 $(let path = match known_items::$Variant::parse_path(path) {
                     Ok(v) => return Ok(Self::$Variant(v)),
                     Err(path) => path,
                 };)*
+                $(return Ok(Self::$Unknown(syn::TraitBound {
+                    paren_token: None,
+                    modifier: syn::TraitBoundModifier::None,
+                    lifetimes: None,
+                    path,
+                }.into()));)?
                 Err(path)
             }
+            $vis fn parse_type_param_bound(mut type_param_bound: syn::TypeParamBound) -> Result<Self, syn::TypeParamBound> {
+                #![allow(unreachable_code)]
+                if let syn::TypeParamBound::Trait(mut trait_bound) = type_param_bound {
+                    if let syn::TraitBound {
+                        paren_token: _,
+                        modifier: syn::TraitBoundModifier::None,
+                        lifetimes: None,
+                        path: _,
+                    } = trait_bound {
+                        match Self::parse_path(trait_bound.path) {
+                            Ok(retval) => return Ok(retval),
+                            Err(path) => trait_bound.path = path,
+                        }
+                    }
+                    type_param_bound = trait_bound.into();
+                }
+                $(return Ok(Self::$Unknown(type_param_bound));)?
+                Err(type_param_bound)
+            }
         }
 
         impl Parse for $enum_type {
             fn parse(input: ParseStream) -> syn::Result<Self> {
-                Self::parse_path(Path::parse_mod_style(input)?).map_err(|path| {
+                Self::parse_type_param_bound(input.parse()?)
-                    syn::Error::new_spanned(
+                    .map_err(|type_param_bound| syn::Error::new_spanned(
-                        path,
+                        type_param_bound,
                         format_args!("expected one of: {}", [$(stringify!($Variant)),*].join(", ")),
-                    )
+                    ))
-                })
             }
         }
 
@@ -2115,6 +2146,7 @@ macro_rules! impl_bounds {
         #[allow(non_snake_case)]
         $vis struct $struct_type {
             $($vis $Variant: Option<known_items::$Variant>,)*
+            $($vis $Unknown: Vec<syn::TypeParamBound>,)?
         }
 
         impl ToTokens for $struct_type {
@@ -2126,42 +2158,63 @@ macro_rules! impl_bounds {
                     separator = Some(<Token![+]>::default());
                     v.to_tokens(tokens);
                 })*
+                $(for v in &self.$Unknown {
+                    separator.to_tokens(tokens);
+                    separator = Some(<Token![+]>::default());
+                    v.to_tokens(tokens);
+                })*
             }
         }
 
         const _: () = {
             #[derive(Clone, Debug)]
-            $vis struct Iter($vis $struct_type);
+            #[allow(non_snake_case)]
+            $vis struct Iter {
+                $($Variant: Option<known_items::$Variant>,)*
+                $($Unknown: std::vec::IntoIter<syn::TypeParamBound>,)?
+            }
 
             impl IntoIterator for $struct_type {
                 type Item = $enum_type;
                 type IntoIter = Iter;
 
                 fn into_iter(self) -> Self::IntoIter {
-                    Iter(self)
+                    Iter {
+                        $($Variant: self.$Variant,)*
+                        $($Unknown: self.$Unknown.into_iter(),)?
+                    }
                 }
             }
 
             impl Iterator for Iter {
                 type Item = $enum_type;
 
-
                 fn next(&mut self) -> Option<Self::Item> {
                     $(
-                        if let Some(value) = self.0.$Variant.take() {
+                        if let Some(value) = self.$Variant.take() {
                             return Some($enum_type::$Variant(value));
                         }
                     )*
+                    $(
+                        if let Some(value) = self.$Unknown.next() {
+                            return Some($enum_type::$Unknown(value));
+                        }
+                    )?
                     None
                 }
 
                 #[allow(unused_mut, unused_variables)]
                 fn fold<B, F: FnMut(B, Self::Item) -> B>(mut self, mut init: B, mut f: F) -> B {
                     $(
-                        if let Some(value) = self.0.$Variant.take() {
+                        if let Some(value) = self.$Variant.take() {
                             init = f(init, $enum_type::$Variant(value));
                         }
                     )*
+                    $(
+                        if let Some(value) = self.$Unknown.next() {
+                            init = f(init, $enum_type::$Unknown(value));
+                        }
+                    )?
                     init
                 }
             }
@@ -2173,6 +2226,9 @@ macro_rules! impl_bounds {
                     $($enum_type::$Variant(v) => {
                         self.$Variant = Some(v);
                     })*
+                    $($enum_type::$Unknown(v) => {
+                        self.$Unknown.push(v);
+                    })?
                 });
             }
         }
@@ -2191,6 +2247,7 @@ macro_rules! impl_bounds {
                     $(if let Some(v) = v.$Variant {
                         self.$Variant = Some(v);
                     })*
+                    $(self.$Unknown.extend(v.$Unknown);)*
                 });
             }
         }
@@ -2244,6 +2301,8 @@ impl_bounds! {
         Size,
         StaticType,
         Type,
+        #[unknown]
+        Unknown,
     }
 }
 
@@ -2257,6 +2316,8 @@ impl_bounds! {
         ResetType,
         StaticType,
         Type,
+        #[unknown]
+        Unknown,
     }
 }
 
@@ -2270,6 +2331,7 @@ impl From<ParsedTypeBound> for ParsedBound {
             ParsedTypeBound::ResetType(v) => ParsedBound::ResetType(v),
             ParsedTypeBound::StaticType(v) => ParsedBound::StaticType(v),
             ParsedTypeBound::Type(v) => ParsedBound::Type(v),
+            ParsedTypeBound::Unknown(v) => ParsedBound::Unknown(v),
         }
     }
 }
@@ -2284,6 +2346,7 @@ impl From<ParsedTypeBounds> for ParsedBounds {
             ResetType,
             StaticType,
             Type,
+            Unknown,
         } = value;
         Self {
             BoolOrIntType,
@@ -2295,6 +2358,7 @@ impl From<ParsedTypeBounds> for ParsedBounds {
             Size: None,
             StaticType,
             Type,
+            Unknown,
         }
     }
 }
@@ -2330,6 +2394,7 @@ impl ParsedTypeBound {
                 ParsedTypeBound::Type(known_items::Type(span)),
             ]),
             Self::Type(v) => ParsedTypeBounds::from_iter([ParsedTypeBound::from(v)]),
+            Self::Unknown(v) => ParsedTypeBounds::from_iter([ParsedTypeBound::Unknown(v)]),
         }
     }
 }
@@ -2364,6 +2429,7 @@ impl From<ParsedSizeTypeBounds> for ParsedBounds {
             Size,
             StaticType: None,
             Type: None,
+            Unknown: vec![],
         }
     }
 }
@@ -2391,6 +2457,7 @@ impl ParsedBounds {
     fn categorize(self, errors: &mut Errors, span: Span) -> ParsedBoundsCategory {
         let mut type_bounds = None;
         let mut size_type_bounds = None;
+        let mut unknown_bounds = vec![];
         self.into_iter().for_each(|bound| match bound.categorize() {
             ParsedBoundCategory::Type(bound) => {
                 type_bounds
@@ -2402,15 +2469,37 @@ impl ParsedBounds {
                     .get_or_insert_with(ParsedSizeTypeBounds::default)
                     .extend([bound]);
             }
+            ParsedBoundCategory::Unknown(bound) => unknown_bounds.push(bound),
         });
-        match (type_bounds, size_type_bounds) {
+        match (type_bounds, size_type_bounds, unknown_bounds.is_empty()) {
-            (None, None) => ParsedBoundsCategory::Type(ParsedTypeBounds {
+            (None, None, true) => ParsedBoundsCategory::Type(ParsedTypeBounds {
                 Type: Some(known_items::Type(span)),
                 ..Default::default()
             }),
-            (None, Some(bounds)) => ParsedBoundsCategory::SizeType(bounds),
+            (None, None, false) => {
-            (Some(bounds), None) => ParsedBoundsCategory::Type(bounds),
+                errors.error(
-            (Some(type_bounds), Some(size_type_bounds)) => {
+                    unknown_bounds.remove(0),
+                    "unknown bounds: must use at least one known bound (such as `Type`) with any unknown bounds",
+                );
+                ParsedBoundsCategory::Type(ParsedTypeBounds {
+                    Unknown: unknown_bounds,
+                    ..Default::default()
+                })
+            }
+            (None, Some(bounds), true) => ParsedBoundsCategory::SizeType(bounds),
+            (None, Some(bounds), false) => {
+                // TODO: implement
+                errors.error(
+                    unknown_bounds.remove(0),
+                    "unknown bounds with `Size` bounds are not implemented",
+                );
+                ParsedBoundsCategory::SizeType(bounds)
+            }
+            (Some(bounds), None, _) => ParsedBoundsCategory::Type(ParsedTypeBounds {
+                Unknown: unknown_bounds,
+                ..bounds
+            }),
+            (Some(type_bounds), Some(size_type_bounds), _) => {
                 errors.error(
                     size_type_bounds
                         .Size
@@ -2427,6 +2516,7 @@ impl ParsedBounds {
 pub(crate) enum ParsedBoundCategory {
     Type(ParsedTypeBound),
     SizeType(ParsedSizeTypeBound),
+    Unknown(syn::TypeParamBound),
 }
 
 impl ParsedBound {
@@ -2441,12 +2531,14 @@ impl ParsedBound {
             Self::Size(v) => ParsedBoundCategory::SizeType(ParsedSizeTypeBound::Size(v)),
             Self::StaticType(v) => ParsedBoundCategory::Type(ParsedTypeBound::StaticType(v)),
             Self::Type(v) => ParsedBoundCategory::Type(ParsedTypeBound::Type(v)),
+            Self::Unknown(v) => ParsedBoundCategory::Unknown(v),
         }
     }
     fn implied_bounds(self) -> ParsedBounds {
         match self.categorize() {
             ParsedBoundCategory::Type(v) => v.implied_bounds().into(),
             ParsedBoundCategory::SizeType(v) => v.implied_bounds().into(),
+            ParsedBoundCategory::Unknown(v) => ParsedBounds::from_iter([ParsedBound::Unknown(v)]),
         }
     }
 }
@@ -3325,7 +3417,7 @@ impl ParsedGenerics {
                                 | ParsedTypeBound::EnumType(_)
                                 | ParsedTypeBound::IntType(_)
                                 | ParsedTypeBound::ResetType(_) => {
-                                    errors.error(bound, "bound on mask type not implemented");
+                                    errors.error(bound, "bounds on mask types are not implemented");
                                 }
                                 ParsedTypeBound::StaticType(bound) => {
                                     if bounds.StaticType.is_none() {
@@ -3337,6 +3429,12 @@ impl ParsedGenerics {
                                     }
                                 }
                                 ParsedTypeBound::Type(_) => {}
+                                ParsedTypeBound::Unknown(_) => {
+                                    errors.error(
+                                        bound,
+                                        "unknown bounds on mask types are not implemented",
+                                    );
+                                }
                             }
                         }
                         bounds.add_implied_bounds();

crates/fayalite/tests/module.rs

@@ -191,10 +191,14 @@ circuit check_array_repeat:
     };
 }
 
+pub trait UnknownTrait {}
+
+impl<T: ?Sized> UnknownTrait for T {}
+
 #[hdl_module(outline_generated)]
 pub fn check_skipped_generics<T, #[hdl(skip)] U, const N: usize, #[hdl(skip)] const M: usize>(v: U)
 where
-    T: StaticType,
+    T: StaticType + UnknownTrait,
     ConstUsize<N>: KnownSize,
     U: std::fmt::Display,
 {