add sim.fork_join() and fix Simulator to handle running futures with arbitrary wakers

README.md

@@ -12,7 +12,7 @@ Fayalite is a library for designing digital hardware -- a hardware description l
 
 [Blinky example]: crates/fayalite/examples/blinky.rs
 
-This uses the container image containing all the external programs and files that Fayalite needs to build for FPGAs, the sources for the container image are in https://git.libre-chip.org/libre-chip/fayalite-deps
+This uses the container image containing all the external programs and files that Fayalite needs to build for FPGAs, the sources for the container image are in <https://git.libre-chip.org/libre-chip/fayalite-deps>
 
 Steps:
 

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

@@ -87,7 +87,11 @@ impl ParsedBundle {
             no_static: _,
             no_runtime_generics: _,
             cmp_eq: _,
+            ref get,
         } = options.body;
+        if let Some((get, ..)) = get {
+            errors.error(get, "#[hdl(get(...))] is not allowed on structs");
+        }
         let mut fields = match fields {
             syn::Fields::Named(fields) => fields,
             syn::Fields::Unnamed(fields) => {
@@ -445,6 +449,7 @@ impl ToTokens for ParsedBundle {
             no_static,
             no_runtime_generics,
             cmp_eq,
+            get: _,
         } = &options.body;
         let target = get_target(target, ident);
         let mut item_attrs = attrs.clone();

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

@@ -159,10 +159,14 @@ impl ParsedEnum {
             no_static: _,
             no_runtime_generics: _,
             cmp_eq,
+            ref get,
         } = options.body;
         if let Some((cmp_eq,)) = cmp_eq {
             errors.error(cmp_eq, "#[hdl(cmp_eq)] is not yet implemented for enums");
         }
+        if let Some((get, ..)) = get {
+            errors.error(get, "#[hdl(get(...))] is not allowed on enums");
+        }
         attrs.retain(|attr| {
             if attr.path().is_ident("repr") {
                 errors.error(attr, "#[repr] is not supported on #[hdl] enums");
@@ -225,6 +229,7 @@ impl ToTokens for ParsedEnum {
             no_static,
             no_runtime_generics,
             cmp_eq: _, // TODO: implement cmp_eq for enums
+            get: _,
         } = &options.body;
         let target = get_target(target, ident);
         let mut struct_attrs = attrs.clone();

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

@@ -3,29 +3,264 @@
 use crate::{
     Errors, HdlAttr,
     hdl_type_common::{
-        ItemOptions, MakeHdlTypeExpr, MaybeParsed, ParsedGenerics, ParsedType, TypesParser,
-        get_target,
+        ItemOptions, MakeHdlTypeExpr, MaybeParsed, ParsedGenerics, ParsedType,
+        PhantomConstGetBound, TypesParser, WrappedInConst, common_derives, get_target, known_items,
     },
     kw,
 };
 use proc_macro2::TokenStream;
-use quote::ToTokens;
-use syn::{Attribute, Generics, Ident, ItemType, Token, Type, Visibility, parse_quote_spanned};
+use quote::{ToTokens, format_ident, quote_spanned};
+use syn::{
+    Attribute, Expr, Fields, GenericParam, Generics, Ident, ItemStruct, ItemType, Token, Type,
+    TypeGroup, TypeParam, TypeParen, Visibility, parse_quote_spanned, punctuated::Pair,
+    token::Paren,
+};
 
 #[derive(Clone, Debug)]
-pub(crate) struct ParsedTypeAlias {
-    pub(crate) attrs: Vec<Attribute>,
-    pub(crate) options: HdlAttr<ItemOptions, kw::hdl>,
-    pub(crate) vis: Visibility,
-    pub(crate) type_token: Token![type],
-    pub(crate) ident: Ident,
-    pub(crate) generics: MaybeParsed<ParsedGenerics, Generics>,
-    pub(crate) eq_token: Token![=],
-    pub(crate) ty: MaybeParsed<ParsedType, Type>,
-    pub(crate) semi_token: Token![;],
+pub(crate) struct PhantomConstAccessorTypeParam {
+    attrs: Vec<Attribute>,
+    ident: Ident,
+    colon_token: Token![:],
+    phantom_const_get_bound: PhantomConstGetBound,
+    plus_token: Option<Token![+]>,
+}
+
+impl From<PhantomConstAccessorTypeParam> for TypeParam {
+    fn from(value: PhantomConstAccessorTypeParam) -> Self {
+        let PhantomConstAccessorTypeParam {
+            attrs,
+            ident,
+            colon_token,
+            phantom_const_get_bound,
+            plus_token,
+        } = value;
+        TypeParam {
+            attrs,
+            ident,
+            colon_token: Some(colon_token),
+            bounds: FromIterator::from_iter([Pair::new(
+                phantom_const_get_bound.into(),
+                plus_token,
+            )]),
+            eq_token: None,
+            default: None,
+        }
+    }
+}
+
+impl From<PhantomConstAccessorTypeParam> for GenericParam {
+    fn from(value: PhantomConstAccessorTypeParam) -> Self {
+        TypeParam::from(value).into()
+    }
+}
+
+impl PhantomConstAccessorTypeParam {
+    fn parse_opt(generic_param: GenericParam) -> Option<Self> {
+        let GenericParam::Type(TypeParam {
+            attrs,
+            ident,
+            colon_token,
+            bounds,
+            eq_token: None,
+            default: None,
+        }) = generic_param
+        else {
+            return None;
+        };
+        let colon_token = colon_token.unwrap_or(Token![:](ident.span()));
+        let mut bounds = bounds.into_pairs();
+        let (bound, plus_token) = bounds.next()?.into_tuple();
+        let phantom_const_get_bound = PhantomConstGetBound::parse_type_param_bound(bound)
+            .ok()?
+            .ok()?;
+        let None = bounds.next() else {
+            return None;
+        };
+        Some(Self {
+            attrs,
+            ident,
+            colon_token,
+            phantom_const_get_bound,
+            plus_token,
+        })
+    }
+}
+
+#[derive(Clone, Debug)]
+pub(crate) struct PhantomConstAccessorGenerics {
+    lt_token: Token![<],
+    type_param: PhantomConstAccessorTypeParam,
+    comma_token: Option<Token![,]>,
+    gt_token: Token![>],
+}
+
+impl From<PhantomConstAccessorGenerics> for Generics {
+    fn from(value: PhantomConstAccessorGenerics) -> Self {
+        let PhantomConstAccessorGenerics {
+            lt_token,
+            type_param,
+            comma_token,
+            gt_token,
+        } = value;
+        Generics {
+            lt_token: Some(lt_token),
+            params: FromIterator::from_iter([Pair::new(type_param.into(), comma_token)]),
+            gt_token: Some(gt_token),
+            where_clause: None,
+        }
+    }
+}
+
+impl<'a> From<&'a PhantomConstAccessorGenerics> for Generics {
+    fn from(value: &'a PhantomConstAccessorGenerics) -> Self {
+        value.clone().into()
+    }
+}
+
+impl PhantomConstAccessorGenerics {
+    fn parse_opt(generics: Generics) -> Option<Self> {
+        let Generics {
+            lt_token,
+            params,
+            gt_token,
+            where_clause: None,
+        } = generics
+        else {
+            return None;
+        };
+        let mut params = params.into_pairs();
+        let (generic_param, comma_token) = params.next()?.into_tuple();
+        let type_param = PhantomConstAccessorTypeParam::parse_opt(generic_param)?;
+        let span = type_param.ident.span();
+        let lt_token = lt_token.unwrap_or(Token![<](span));
+        let gt_token = gt_token.unwrap_or(Token![>](span));
+        let None = params.next() else {
+            return None;
+        };
+        Some(Self {
+            lt_token,
+            type_param,
+            comma_token,
+            gt_token,
+        })
+    }
+}
+
+#[derive(Clone, Debug)]
+pub(crate) enum ParsedTypeAlias {
+    TypeAlias {
+        attrs: Vec<Attribute>,
+        options: HdlAttr<ItemOptions, kw::hdl>,
+        vis: Visibility,
+        type_token: Token![type],
+        ident: Ident,
+        generics: MaybeParsed<ParsedGenerics, Generics>,
+        eq_token: Token![=],
+        ty: MaybeParsed<ParsedType, Type>,
+        semi_token: Token![;],
+    },
+    PhantomConstAccessor {
+        attrs: Vec<Attribute>,
+        options: HdlAttr<ItemOptions, kw::hdl>,
+        get: (kw::get, Paren, Expr),
+        vis: Visibility,
+        type_token: Token![type],
+        ident: Ident,
+        generics: PhantomConstAccessorGenerics,
+        eq_token: Token![=],
+        ty: Type,
+        ty_is_dyn_size: Option<known_items::DynSize>,
+        semi_token: Token![;],
+    },
 }
 
 impl ParsedTypeAlias {
+    fn ty_is_dyn_size(ty: &Type) -> Option<known_items::DynSize> {
+        match ty {
+            Type::Group(TypeGroup {
+                group_token: _,
+                elem,
+            }) => Self::ty_is_dyn_size(elem),
+            Type::Paren(TypeParen {
+                paren_token: _,
+                elem,
+            }) => Self::ty_is_dyn_size(elem),
+            Type::Path(syn::TypePath { qself: None, path }) => {
+                known_items::DynSize::parse_path(path.clone()).ok()
+            }
+            _ => None,
+        }
+    }
+    fn parse_phantom_const_accessor(
+        item: ItemType,
+        mut errors: Errors,
+        options: HdlAttr<ItemOptions, kw::hdl>,
+        get: (kw::get, Paren, Expr),
+    ) -> syn::Result<Self> {
+        let ItemType {
+            attrs,
+            vis,
+            type_token,
+            ident,
+            generics,
+            eq_token,
+            ty,
+            semi_token,
+        } = item;
+        let ItemOptions {
+            outline_generated: _,
+            ref target,
+            custom_bounds,
+            no_static,
+            no_runtime_generics,
+            cmp_eq,
+            get: _,
+        } = options.body;
+        if let Some((no_static,)) = no_static {
+            errors.error(no_static, "no_static is not valid on type aliases");
+        }
+        if let Some((target, ..)) = target {
+            errors.error(
+                target,
+                "target is not implemented on PhantomConstGet type aliases",
+            );
+        }
+        if let Some((no_runtime_generics,)) = no_runtime_generics {
+            errors.error(
+                no_runtime_generics,
+                "no_runtime_generics is not implemented on PhantomConstGet type aliases",
+            );
+        }
+        if let Some((cmp_eq,)) = cmp_eq {
+            errors.error(cmp_eq, "cmp_eq is not valid on type aliases");
+        }
+        if let Some((custom_bounds,)) = custom_bounds {
+            errors.error(
+                custom_bounds,
+                "custom_bounds is not implemented on PhantomConstGet type aliases",
+            );
+        }
+        let Some(generics) = PhantomConstAccessorGenerics::parse_opt(generics) else {
+            errors.error(ident, "#[hdl(get(...))] type alias must be of the form:\ntype MyTypeGetter<P: PhantomConstGet<MyType>> = RetType;");
+            errors.finish()?;
+            unreachable!();
+        };
+        errors.finish()?;
+        let ty_is_dyn_size = Self::ty_is_dyn_size(&ty);
+        Ok(Self::PhantomConstAccessor {
+            attrs,
+            options,
+            get,
+            vis,
+            type_token,
+            ident,
+            generics,
+            eq_token,
+            ty: *ty,
+            ty_is_dyn_size,
+            semi_token,
+        })
+    }
     fn parse(item: ItemType) -> syn::Result<Self> {
         let ItemType {
             mut attrs,
@@ -51,7 +286,25 @@ impl ParsedTypeAlias {
             no_static,
             no_runtime_generics: _,
             cmp_eq,
+            ref mut get,
         } = options.body;
+        if let Some(get) = get.take() {
+            return Self::parse_phantom_const_accessor(
+                ItemType {
+                    attrs,
+                    vis,
+                    type_token,
+                    ident,
+                    generics,
+                    eq_token,
+                    ty,
+                    semi_token,
+                },
+                errors,
+                options,
+                get,
+            );
+        }
         if let Some((no_static,)) = no_static {
             errors.error(no_static, "no_static is not valid on type aliases");
         }
@@ -67,7 +320,7 @@ impl ParsedTypeAlias {
         };
         let ty = TypesParser::maybe_run(generics.as_ref(), *ty, &mut errors);
         errors.finish()?;
-        Ok(Self {
+        Ok(Self::TypeAlias {
             attrs,
             options,
             vis,
@@ -83,54 +336,155 @@ impl ParsedTypeAlias {
 
 impl ToTokens for ParsedTypeAlias {
     fn to_tokens(&self, tokens: &mut TokenStream) {
-        let Self {
-            attrs,
-            options,
-            vis,
-            type_token,
-            ident,
-            generics,
-            eq_token,
-            ty,
-            semi_token,
-        } = self;
-        let ItemOptions {
-            outline_generated: _,
-            target,
-            custom_bounds: _,
-            no_static: _,
-            no_runtime_generics,
-            cmp_eq: _,
-        } = &options.body;
-        let target = get_target(target, ident);
-        let mut type_attrs = attrs.clone();
-        type_attrs.push(parse_quote_spanned! {ident.span()=>
-            #[allow(type_alias_bounds)]
-        });
-        ItemType {
-            attrs: type_attrs,
-            vis: vis.clone(),
-            type_token: *type_token,
-            ident: ident.clone(),
-            generics: generics.into(),
-            eq_token: *eq_token,
-            ty: Box::new(ty.clone().into()),
-            semi_token: *semi_token,
-        }
-        .to_tokens(tokens);
-        if let (MaybeParsed::Parsed(generics), MaybeParsed::Parsed(ty), None) =
-            (generics, ty, no_runtime_generics)
-        {
-            generics.make_runtime_generics(tokens, vis, ident, &target, |context| {
-                ty.make_hdl_type_expr(context)
-            })
+        match self {
+            Self::TypeAlias {
+                attrs,
+                options,
+                vis,
+                type_token,
+                ident,
+                generics,
+                eq_token,
+                ty,
+                semi_token,
+            } => {
+                let ItemOptions {
+                    outline_generated: _,
+                    target,
+                    custom_bounds: _,
+                    no_static: _,
+                    no_runtime_generics,
+                    cmp_eq: _,
+                    get: _,
+                } = &options.body;
+                let target = get_target(target, ident);
+                let mut type_attrs = attrs.clone();
+                type_attrs.push(parse_quote_spanned! {ident.span()=>
+                    #[allow(type_alias_bounds)]
+                });
+                ItemType {
+                    attrs: type_attrs,
+                    vis: vis.clone(),
+                    type_token: *type_token,
+                    ident: ident.clone(),
+                    generics: generics.into(),
+                    eq_token: *eq_token,
+                    ty: Box::new(ty.clone().into()),
+                    semi_token: *semi_token,
+                }
+                .to_tokens(tokens);
+                if let (MaybeParsed::Parsed(generics), MaybeParsed::Parsed(ty), None) =
+                    (generics, ty, no_runtime_generics)
+                {
+                    generics.make_runtime_generics(tokens, vis, ident, &target, |context| {
+                        ty.make_hdl_type_expr(context)
+                    })
+                }
+            }
+            Self::PhantomConstAccessor {
+                attrs,
+                options,
+                get: (_get_kw, _get_paren, get_expr),
+                vis,
+                type_token,
+                ident,
+                generics,
+                eq_token,
+                ty,
+                ty_is_dyn_size,
+                semi_token,
+            } => {
+                let ItemOptions {
+                    outline_generated: _,
+                    target: _,
+                    custom_bounds: _,
+                    no_static: _,
+                    no_runtime_generics: _,
+                    cmp_eq: _,
+                    get: _,
+                } = &options.body;
+                let span = ident.span();
+                let mut type_attrs = attrs.clone();
+                type_attrs.push(parse_quote_spanned! {span=>
+                    #[allow(type_alias_bounds)]
+                });
+                let type_param_ident = &generics.type_param.ident;
+                let syn_generics = Generics::from(generics);
+                ItemType {
+                    attrs: type_attrs,
+                    vis: vis.clone(),
+                    type_token: *type_token,
+                    ident: ident.clone(),
+                    generics: syn_generics.clone(),
+                    eq_token: *eq_token,
+                    ty: parse_quote_spanned! {span=>
+                        <#ty as ::fayalite::phantom_const::ReturnSelfUnchanged<#type_param_ident>>::Type
+                    },
+                    semi_token: *semi_token,
+                }
+                .to_tokens(tokens);
+                let generics_accumulation_ident =
+                    format_ident!("__{}__GenericsAccumulation", ident);
+                ItemStruct {
+                    attrs: vec![
+                        common_derives(span),
+                        parse_quote_spanned! {span=>
+                            #[allow(non_camel_case_types)]
+                        },
+                    ],
+                    vis: vis.clone(),
+                    struct_token: Token![struct](span),
+                    ident: generics_accumulation_ident.clone(),
+                    generics: Generics::default(),
+                    fields: Fields::Unnamed(parse_quote_spanned! {span=>
+                        (())
+                    }),
+                    semi_token: Some(Token![;](span)),
+                }
+                .to_tokens(tokens);
+                quote_spanned! {span=>
+                    #[allow(non_upper_case_globals, dead_code)]
+                    #vis const #ident: #generics_accumulation_ident = #generics_accumulation_ident(());
+                }
+                .to_tokens(tokens);
+                let mut wrapped_in_const = WrappedInConst::new(tokens, span);
+                let tokens = wrapped_in_const.inner();
+                let (impl_generics, _type_generics, where_clause) = syn_generics.split_for_impl();
+                let phantom_const_get_ty = &generics.type_param.phantom_const_get_bound.ty;
+                let index_output = if let Some(ty_is_dyn_size) = ty_is_dyn_size {
+                    known_items::usize(ty_is_dyn_size.span).to_token_stream()
+                } else {
+                    ty.to_token_stream()
+                };
+                quote_spanned! {span=>
+                    #[allow(non_upper_case_globals)]
+                    #[automatically_derived]
+                    impl #impl_generics ::fayalite::__std::ops::Index<#type_param_ident>
+                    for #generics_accumulation_ident
+                    #where_clause
+                    {
+                        type Output = #index_output;
+
+                        fn index(&self, __param: #type_param_ident) -> &Self::Output {
+                            ::fayalite::phantom_const::type_alias_phantom_const_get_helper::<#phantom_const_get_ty, #index_output>(
+                                __param,
+                                #get_expr,
+                            )
+                        }
+                    }
+                }
+                .to_tokens(tokens);
+            }
         }
     }
 }
 
 pub(crate) fn hdl_type_alias_impl(item: ItemType) -> syn::Result<TokenStream> {
     let item = ParsedTypeAlias::parse(item)?;
-    let outline_generated = item.options.body.outline_generated;
+    let outline_generated = match &item {
+        ParsedTypeAlias::TypeAlias { options, .. }
+        | ParsedTypeAlias::PhantomConstAccessor { options, .. } => options.body.outline_generated,
+    };
     let mut contents = item.to_token_stream();
     if outline_generated.is_some() {
         contents = crate::outline_generated(contents, "hdl-type-alias-");

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

@@ -8,9 +8,9 @@ use syn::{
     AngleBracketedGenericArguments, Attribute, Block, ConstParam, Expr, ExprBlock, ExprGroup,
     ExprIndex, ExprParen, ExprPath, ExprTuple, Field, FieldMutability, Fields, FieldsNamed,
     FieldsUnnamed, GenericArgument, GenericParam, Generics, Ident, ImplGenerics, Index, ItemStruct,
-    Path, PathArguments, PathSegment, PredicateType, QSelf, Stmt, Token, Turbofish, Type,
-    TypeGenerics, TypeGroup, TypeParam, TypeParen, TypePath, TypeTuple, Visibility, WhereClause,
-    WherePredicate,
+    Path, PathArguments, PathSegment, PredicateType, QSelf, Stmt, Token, TraitBound, Turbofish,
+    Type, TypeGenerics, TypeGroup, TypeParam, TypeParamBound, TypeParen, TypePath, TypeTuple,
+    Visibility, WhereClause, WherePredicate,
     parse::{Parse, ParseStream},
     parse_quote, parse_quote_spanned,
     punctuated::{Pair, Punctuated},
@@ -27,6 +27,7 @@ crate::options! {
         NoStatic(no_static),
         NoRuntimeGenerics(no_runtime_generics),
         CmpEq(cmp_eq),
+        Get(get, Expr),
     }
 }
 
@@ -2045,6 +2046,7 @@ pub(crate) mod known_items {
     impl_known_item!(::fayalite::int::Size);
     impl_known_item!(::fayalite::int::UInt);
     impl_known_item!(::fayalite::int::UIntType);
+    impl_known_item!(::fayalite::phantom_const::PhantomConstGet);
     impl_known_item!(::fayalite::reset::ResetType);
     impl_known_item!(::fayalite::ty::CanonicalType);
     impl_known_item!(::fayalite::ty::StaticType);
@@ -2063,6 +2065,174 @@ pub(crate) mod known_items {
     );
 }
 
+#[derive(Clone, Debug)]
+pub(crate) struct PhantomConstGetBound {
+    pub(crate) phantom_const_get: known_items::PhantomConstGet,
+    pub(crate) colon2_token: Option<Token![::]>,
+    pub(crate) lt_token: Token![<],
+    pub(crate) ty: Type,
+    pub(crate) comma_token: Option<Token![,]>,
+    pub(crate) gt_token: Token![>],
+}
+
+impl PhantomConstGetBound {
+    pub(crate) fn parse_path_with_arguments(path: Path) -> syn::Result<Result<Self, Path>> {
+        match known_items::PhantomConstGet::parse_path_with_arguments(path) {
+            Ok((phantom_const_get, arguments)) => {
+                Self::parse_path_and_arguments(phantom_const_get, arguments).map(Ok)
+            }
+            Err(path) => Ok(Err(path)),
+        }
+    }
+    pub(crate) fn parse_path_and_arguments(
+        phantom_const_get: known_items::PhantomConstGet,
+        arguments: PathArguments,
+    ) -> syn::Result<Self> {
+        let error = |arguments: PathArguments, message: &str| {
+            let mut path = phantom_const_get.path.clone();
+            path.segments.last_mut().expect("known to exist").arguments = arguments;
+            syn::Error::new_spanned(path, message)
+        };
+        match arguments {
+            PathArguments::None => Err(error(arguments, "missing generics for PhantomConstGet")),
+            PathArguments::AngleBracketed(AngleBracketedGenericArguments {
+                colon2_token,
+                lt_token,
+                args,
+                gt_token,
+            }) => {
+                let error = |args: Punctuated<GenericArgument, Token![,]>, message| {
+                    error(
+                        PathArguments::AngleBracketed(AngleBracketedGenericArguments {
+                            colon2_token,
+                            lt_token,
+                            args,
+                            gt_token,
+                        }),
+                        message,
+                    )
+                };
+                let mut args = args.into_pairs().peekable();
+                let Some((generic_argument, comma_token)) = args.next().map(Pair::into_tuple)
+                else {
+                    return Err(error(
+                        Default::default(),
+                        "PhantomConstGet takes a type argument but no generic arguments were supplied",
+                    ));
+                };
+                if args.peek().is_some() {
+                    return Err(error(
+                        [Pair::new(generic_argument, comma_token)]
+                            .into_iter()
+                            .chain(args)
+                            .collect(),
+                        "PhantomConstGet takes a single type argument but too many generic arguments were supplied",
+                    ));
+                };
+                let GenericArgument::Type(ty) = generic_argument else {
+                    return Err(error(
+                        Punctuated::from_iter([Pair::new(generic_argument, comma_token)]),
+                        "PhantomConstGet requires a type argument",
+                    ));
+                };
+                Ok(Self {
+                    phantom_const_get,
+                    colon2_token,
+                    lt_token,
+                    ty,
+                    comma_token,
+                    gt_token,
+                })
+            }
+            PathArguments::Parenthesized(_) => Err(error(
+                arguments,
+                "parenthetical generics are not valid for PhantomConstGet",
+            )),
+        }
+    }
+    pub(crate) fn parse_type_param_bound(
+        bound: TypeParamBound,
+    ) -> syn::Result<Result<Self, TypeParamBound>> {
+        let TypeParamBound::Trait(TraitBound {
+            paren_token: None,
+            modifier: syn::TraitBoundModifier::None,
+            lifetimes: None,
+            path,
+        }) = bound
+        else {
+            return Ok(Err(bound));
+        };
+        Ok(match Self::parse_path_with_arguments(path)? {
+            Ok(v) => Ok(v),
+            Err(path) => Err(TypeParamBound::Trait(TraitBound {
+                paren_token: None,
+                modifier: syn::TraitBoundModifier::None,
+                lifetimes: None,
+                path,
+            })),
+        })
+    }
+}
+
+impl ToTokens for PhantomConstGetBound {
+    fn to_tokens(&self, tokens: &mut TokenStream) {
+        let Self {
+            phantom_const_get,
+            colon2_token,
+            lt_token,
+            ty,
+            comma_token,
+            gt_token,
+        } = self;
+        phantom_const_get.to_tokens(tokens);
+        colon2_token.to_tokens(tokens);
+        lt_token.to_tokens(tokens);
+        ty.to_tokens(tokens);
+        comma_token.to_tokens(tokens);
+        gt_token.to_tokens(tokens);
+    }
+}
+
+impl From<PhantomConstGetBound> for Path {
+    fn from(value: PhantomConstGetBound) -> Self {
+        let PhantomConstGetBound {
+            phantom_const_get,
+            colon2_token,
+            lt_token,
+            ty,
+            comma_token,
+            gt_token,
+        } = value;
+        let mut path = phantom_const_get.path;
+        path.segments.last_mut().expect("known to exist").arguments =
+            PathArguments::AngleBracketed(AngleBracketedGenericArguments {
+                colon2_token,
+                lt_token,
+                args: FromIterator::from_iter([Pair::new(GenericArgument::Type(ty), comma_token)]),
+                gt_token,
+            });
+        path
+    }
+}
+
+impl From<PhantomConstGetBound> for TraitBound {
+    fn from(value: PhantomConstGetBound) -> Self {
+        let path = Path::from(value);
+        TraitBound {
+            paren_token: None,
+            modifier: syn::TraitBoundModifier::None,
+            lifetimes: None,
+            path,
+        }
+    }
+}
+
+impl From<PhantomConstGetBound> for TypeParamBound {
+    fn from(value: PhantomConstGetBound) -> Self {
+        TraitBound::from(value).into()
+    }
+}
+
 macro_rules! impl_bounds {
     (
         #[struct = $struct_type:ident]
@@ -2070,6 +2240,10 @@ macro_rules! impl_bounds {
             $(
                 $Variant:ident,
             )*
+            $(
+                #[has_body]
+                $VariantHasBody:ident($variant_has_body_ty:ty),
+            )*
             $(
                 #[unknown]
                 $Unknown:ident,
@@ -2079,6 +2253,7 @@ macro_rules! impl_bounds {
         #[derive(Clone, Debug)]
         $vis enum $enum_type {
             $($Variant(known_items::$Variant),)*
+            $($VariantHasBody($variant_has_body_ty),)*
             $($Unknown(syn::TypeParamBound),)?
         }
 
@@ -2088,31 +2263,42 @@ macro_rules! impl_bounds {
             }
         })*
 
+        $(impl From<$variant_has_body_ty> for $enum_type {
+            fn from(v: $variant_has_body_ty) -> Self {
+                Self::$VariantHasBody(v)
+            }
+        })*
+
         impl ToTokens for $enum_type {
             fn to_tokens(&self, tokens: &mut TokenStream) {
                 match self {
                     $(Self::$Variant(v) => v.to_tokens(tokens),)*
+                    $(Self::$VariantHasBody(v) => v.to_tokens(tokens),)*
                     $(Self::$Unknown(v) => v.to_tokens(tokens),)?
                 }
             }
         }
 
         impl $enum_type {
-            $vis fn parse_path(path: Path) -> Result<Self, Path> {
+            $vis fn parse_path_with_arguments(path: Path) -> syn::Result<Result<Self, Path>> {
                 #![allow(unreachable_code)]
                 $(let path = match known_items::$Variant::parse_path(path) {
-                    Ok(v) => return Ok(Self::$Variant(v)),
+                    Ok(v) => return Ok(Ok(Self::$Variant(v))),
                     Err(path) => path,
                 };)*
-                $(return Ok(Self::$Unknown(syn::TraitBound {
+                $(let path = match <$variant_has_body_ty>::parse_path_with_arguments(path)? {
+                    Ok(v) => return Ok(Ok(Self::$VariantHasBody(v))),
+                    Err(path) => path,
+                };)*
+                $(return Ok(Ok(Self::$Unknown(syn::TraitBound {
                     paren_token: None,
                     modifier: syn::TraitBoundModifier::None,
                     lifetimes: None,
                     path,
-                }.into()));)?
-                Err(path)
+                }.into())));)?
+                Ok(Err(path))
             }
-            $vis fn parse_type_param_bound(mut type_param_bound: syn::TypeParamBound) -> Result<Self, syn::TypeParamBound> {
+            $vis fn parse_type_param_bound(mut type_param_bound: syn::TypeParamBound) -> syn::Result<Result<Self, syn::TypeParamBound>> {
                 #![allow(unreachable_code)]
                 if let syn::TypeParamBound::Trait(mut trait_bound) = type_param_bound {
                     if let syn::TraitBound {
@@ -2121,24 +2307,24 @@ macro_rules! impl_bounds {
                         lifetimes: None,
                         path: _,
                     } = trait_bound {
-                        match Self::parse_path(trait_bound.path) {
-                            Ok(retval) => return Ok(retval),
+                        match Self::parse_path_with_arguments(trait_bound.path)? {
+                            Ok(retval) => return Ok(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)
+                $(return Ok(Ok(Self::$Unknown(type_param_bound)));)?
+                Ok(Err(type_param_bound))
             }
         }
 
         impl Parse for $enum_type {
             fn parse(input: ParseStream) -> syn::Result<Self> {
-                Self::parse_type_param_bound(input.parse()?)
+                Self::parse_type_param_bound(input.parse()?)?
                     .map_err(|type_param_bound| syn::Error::new_spanned(
                         type_param_bound,
-                        format_args!("expected one of: {}", [$(stringify!($Variant)),*].join(", ")),
+                        format_args!("expected one of: {}", [$(stringify!($Variant),)* $(stringify!($VariantHasBody)),*].join(", ")),
                     ))
             }
         }
@@ -2147,6 +2333,7 @@ macro_rules! impl_bounds {
         #[allow(non_snake_case)]
         $vis struct $struct_type {
             $($vis $Variant: Option<known_items::$Variant>,)*
+            $($vis $VariantHasBody: Option<$variant_has_body_ty>,)*
             $($vis $Unknown: Vec<syn::TypeParamBound>,)?
         }
 
@@ -2159,6 +2346,11 @@ macro_rules! impl_bounds {
                     separator = Some(<Token![+]>::default());
                     v.to_tokens(tokens);
                 })*
+                $(if let Some(v) = &self.$VariantHasBody {
+                    separator.to_tokens(tokens);
+                    separator = Some(<Token![+]>::default());
+                    v.to_tokens(tokens);
+                })*
                 $(for v in &self.$Unknown {
                     separator.to_tokens(tokens);
                     separator = Some(<Token![+]>::default());
@@ -2172,6 +2364,7 @@ macro_rules! impl_bounds {
             #[allow(non_snake_case)]
             $vis struct Iter {
                 $($Variant: Option<known_items::$Variant>,)*
+                $($VariantHasBody: Option<$variant_has_body_ty>,)*
                 $($Unknown: std::vec::IntoIter<syn::TypeParamBound>,)?
             }
 
@@ -2182,6 +2375,7 @@ macro_rules! impl_bounds {
                 fn into_iter(self) -> Self::IntoIter {
                     Iter {
                         $($Variant: self.$Variant,)*
+                        $($VariantHasBody: self.$VariantHasBody,)*
                         $($Unknown: self.$Unknown.into_iter(),)?
                     }
                 }
@@ -2196,6 +2390,11 @@ macro_rules! impl_bounds {
                             return Some($enum_type::$Variant(value));
                         }
                     )*
+                    $(
+                        if let Some(value) = self.$VariantHasBody.take() {
+                            return Some($enum_type::$VariantHasBody(value));
+                        }
+                    )*
                     $(
                         if let Some(value) = self.$Unknown.next() {
                             return Some($enum_type::$Unknown(value));
@@ -2211,6 +2410,11 @@ macro_rules! impl_bounds {
                             init = f(init, $enum_type::$Variant(value));
                         }
                     )*
+                    $(
+                        if let Some(value) = self.$VariantHasBody.take() {
+                            init = f(init, $enum_type::$VariantHasBody(value));
+                        }
+                    )*
                     $(
                         if let Some(value) = self.$Unknown.next() {
                             init = f(init, $enum_type::$Unknown(value));
@@ -2227,6 +2431,9 @@ macro_rules! impl_bounds {
                     $($enum_type::$Variant(v) => {
                         self.$Variant = Some(v);
                     })*
+                    $($enum_type::$VariantHasBody(v) => {
+                        self.$VariantHasBody = Some(v);
+                    })*
                     $($enum_type::$Unknown(v) => {
                         self.$Unknown.push(v);
                     })?
@@ -2248,6 +2455,9 @@ macro_rules! impl_bounds {
                     $(if let Some(v) = v.$Variant {
                         self.$Variant = Some(v);
                     })*
+                    $(if let Some(v) = v.$VariantHasBody {
+                        self.$VariantHasBody = Some(v);
+                    })*
                     $(self.$Unknown.extend(v.$Unknown);)*
                 });
             }
@@ -2302,6 +2512,8 @@ impl_bounds! {
         Size,
         StaticType,
         Type,
+        #[has_body]
+        PhantomConstGet(PhantomConstGetBound),
         #[unknown]
         Unknown,
     }
@@ -2317,6 +2529,8 @@ impl_bounds! {
         ResetType,
         StaticType,
         Type,
+        #[has_body]
+        PhantomConstGet(PhantomConstGetBound),
         #[unknown]
         Unknown,
     }
@@ -2332,6 +2546,7 @@ impl From<ParsedTypeBound> for ParsedBound {
             ParsedTypeBound::ResetType(v) => ParsedBound::ResetType(v),
             ParsedTypeBound::StaticType(v) => ParsedBound::StaticType(v),
             ParsedTypeBound::Type(v) => ParsedBound::Type(v),
+            ParsedTypeBound::PhantomConstGet(v) => ParsedBound::PhantomConstGet(v),
             ParsedTypeBound::Unknown(v) => ParsedBound::Unknown(v),
         }
     }
@@ -2347,6 +2562,7 @@ impl From<ParsedTypeBounds> for ParsedBounds {
             ResetType,
             StaticType,
             Type,
+            PhantomConstGet,
             Unknown,
         } = value;
         Self {
@@ -2359,6 +2575,7 @@ impl From<ParsedTypeBounds> for ParsedBounds {
             Size: None,
             StaticType,
             Type,
+            PhantomConstGet,
             Unknown,
         }
     }
@@ -2395,6 +2612,10 @@ impl ParsedTypeBound {
                 ParsedTypeBound::Type(known_items::Type(span)),
             ]),
             Self::Type(v) => ParsedTypeBounds::from_iter([ParsedTypeBound::from(v)]),
+            Self::PhantomConstGet(v) => ParsedTypeBounds::from_iter([
+                ParsedTypeBound::from(v),
+                ParsedTypeBound::Type(known_items::Type(span)),
+            ]),
             Self::Unknown(v) => ParsedTypeBounds::from_iter([ParsedTypeBound::Unknown(v)]),
         }
     }
@@ -2430,6 +2651,7 @@ impl From<ParsedSizeTypeBounds> for ParsedBounds {
             Size,
             StaticType: None,
             Type: None,
+            PhantomConstGet: None,
             Unknown: vec![],
         }
     }
@@ -2532,6 +2754,9 @@ 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::PhantomConstGet(v) => {
+                ParsedBoundCategory::Type(ParsedTypeBound::PhantomConstGet(v))
+            }
             Self::Unknown(v) => ParsedBoundCategory::Unknown(v),
         }
     }
@@ -3417,7 +3642,8 @@ impl ParsedGenerics {
                                 | ParsedTypeBound::BundleType(_)
                                 | ParsedTypeBound::EnumType(_)
                                 | ParsedTypeBound::IntType(_)
-                                | ParsedTypeBound::ResetType(_) => {
+                                | ParsedTypeBound::ResetType(_)
+                                | ParsedTypeBound::PhantomConstGet(_) => {
                                     errors.error(bound, "bounds on mask types are not implemented");
                                 }
                                 ParsedTypeBound::StaticType(bound) => {

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

@@ -76,6 +76,7 @@ mod kw {
     custom_keyword!(connect_inexact);
     custom_keyword!(custom_bounds);
     custom_keyword!(flip);
+    custom_keyword!(get);
     custom_keyword!(hdl);
     custom_keyword!(hdl_module);
     custom_keyword!(incomplete_wire);

crates/fayalite/src/build/external.rs

@@ -12,7 +12,7 @@ use crate::{
 };
 use base64::{Engine, prelude::BASE64_URL_SAFE_NO_PAD};
 use clap::builder::OsStringValueParser;
-use eyre::{Context, bail, ensure, eyre};
+use eyre::{Context, ensure, eyre};
 use serde::{
     Deserialize, Deserializer, Serialize, Serializer,
     de::{DeserializeOwned, Error},
@@ -26,6 +26,7 @@ use std::{
     io::Write,
     marker::PhantomData,
     path::{Path, PathBuf},
+    process::ExitStatus,
     sync::OnceLock,
 };
 
@@ -365,13 +366,17 @@ impl ExternalJobCaching {
             .stdin(std::process::Stdio::null());
         Ok(cmd)
     }
-    pub fn run<F: FnOnce(std::process::Command) -> eyre::Result<()>>(
+    pub fn run<F>(
         self,
         command_line: Interned<[Interned<OsStr>]>,
         input_file_paths: impl IntoIterator<Item = Interned<Path>>,
         output_file_paths: impl IntoIterator<Item = Interned<Path>> + Clone,
         run_fn: F,
-    ) -> eyre::Result<()> {
+        exit_status_to_error: impl FnOnce(ExitStatus) -> eyre::Report,
+    ) -> eyre::Result<()>
+    where
+        F: FnOnce(std::process::Command) -> eyre::Result<Result<(), ExitStatus>>,
+    {
         let mut hasher = JobCacheHasher::default();
         hasher.hash_iter(command_line.iter(), |hasher, arg| {
             hasher.hash_sized_os_str(arg)
@@ -419,7 +424,26 @@ impl ExternalJobCaching {
                 })
                 .expect("spawn shouldn't fail");
             run_fn(cmd)
-        });
+        })?;
+        if let Err(exit_status) = result {
+            // check if the user may have terminated it or something, don't cache the failure
+            let user_maybe_terminated;
+            #[cfg(unix)]
+            {
+                user_maybe_terminated = std::os::unix::process::ExitStatusExt::signal(&exit_status)
+                    .is_some()
+                    || exit_status.code().is_none_or(|code| code > 1);
+            }
+            #[cfg(not(unix))]
+            {
+                user_maybe_terminated = !exit_status.success();
+            }
+            if user_maybe_terminated {
+                let _ = std::fs::remove_file(self.cache_json_path);
+                return Err(exit_status_to_error(exit_status));
+            }
+        }
+        let result = result.map_err(exit_status_to_error);
         ExternalJobCacheV2 {
             version: ExternalJobCacheVersion::CURRENT,
             inputs_hash,
@@ -444,16 +468,26 @@ impl ExternalJobCaching {
         .write_to_file(self.cache_json_path)?;
         result
     }
-    pub fn run_maybe_cached<F: FnOnce(std::process::Command) -> eyre::Result<()>>(
+    pub fn run_maybe_cached<F>(
         this: Option<Self>,
         command_line: Interned<[Interned<OsStr>]>,
         input_file_paths: impl IntoIterator<Item = Interned<Path>>,
         output_file_paths: impl IntoIterator<Item = Interned<Path>> + Clone,
         run_fn: F,
-    ) -> eyre::Result<()> {
+        exit_status_to_error: impl FnOnce(ExitStatus) -> eyre::Report,
+    ) -> eyre::Result<()>
+    where
+        F: FnOnce(std::process::Command) -> eyre::Result<Result<(), ExitStatus>>,
+    {
         match this {
-            Some(this) => this.run(command_line, input_file_paths, output_file_paths, run_fn),
-            None => run_fn(Self::make_command(command_line)?),
+            Some(this) => this.run(
+                command_line,
+                input_file_paths,
+                output_file_paths,
+                run_fn,
+                exit_status_to_error,
+            ),
+            None => run_fn(Self::make_command(command_line)?)?.map_err(exit_status_to_error),
         }
     }
 }
@@ -1119,10 +1153,12 @@ impl<T: ExternalCommand> JobKind for ExternalCommandJobKind<T> {
                 }
                 let status = acquired_job.run_command(cmd, |cmd| cmd.status())?;
                 if !status.success() {
-                    bail!("running {command_line:?} failed: {status}")
+                    Ok(Err(status))
+                } else {
+                    Ok(Ok(()))
                 }
-                Ok(())
             },
+            |status| eyre!("running {command_line:?} failed: {status}"),
         )?;
         Ok(job
             .output_paths()

crates/fayalite/src/build/graph.rs

@@ -703,8 +703,12 @@ impl JobGraph {
             }
             let mut running_jobs = HashMap::default();
             let (finished_jobs_sender, finished_jobs_receiver) = mpsc::channel();
+            let mut next_finished_job = None;
             loop {
-                while let Some(finished_job) = finished_jobs_receiver.try_recv().ok() {
+                if let Some(finished_job) = next_finished_job
+                    .take()
+                    .or_else(|| finished_jobs_receiver.try_recv().ok())
+                {
                     let Some(RunningJob { job, thread }) = running_jobs.remove(&finished_job)
                     else {
                         unreachable!();
@@ -736,6 +740,7 @@ impl JobGraph {
                             }
                         }
                     }
+                    continue;
                 }
                 if let Some(WaitingJobState {
                     job_node_id,
@@ -791,12 +796,15 @@ impl JobGraph {
                                 .expect("failed to spawn thread for job"),
                         },
                     );
+                    continue;
                 }
                 if running_jobs.is_empty() {
                     assert!(item_name_to_waiting_jobs_map.is_empty());
                     assert!(ready_jobs.is_empty());
                     return Ok(());
                 }
+                // nothing to do yet, block to avoid busy waiting
+                next_finished_job = finished_jobs_receiver.recv().ok();
             }
         })
     }

crates/fayalite/src/lib.rs

@@ -4,6 +4,18 @@
 // TODO: enable:
 // #![warn(missing_docs)]
 
+#![deny(
+    rustdoc::bare_urls,
+    rustdoc::broken_intra_doc_links,
+    rustdoc::invalid_codeblock_attributes,
+    rustdoc::invalid_html_tags,
+    rustdoc::invalid_rust_codeblocks,
+    rustdoc::private_doc_tests,
+    rustdoc::private_intra_doc_links,
+    rustdoc::redundant_explicit_links,
+    rustdoc::unescaped_backticks
+)]
+
 //! [Main Documentation][_docs]
 
 extern crate self as fayalite;
@@ -74,6 +86,135 @@ macro_rules! __cfg_expansion_helper {
 pub use fayalite_proc_macros::hdl_module;
 
 #[doc(inline)]
+/// The `#[hdl]` attribute is supported on several different kinds of [Rust Items](https://doc.rust-lang.org/reference/items.html):
+///
+/// # Functions and Methods
+/// Enable's the stuff that you can use inside a [module's body](crate::_docs::modules::module_bodies),
+/// but without being a module or changing the function's signature.
+/// The only exception is that you can't use stuff that requires the automatically-provided `m` variable.
+///
+/// # Structs
+// TODO: expand on struct docs
+/// e.g.:
+/// ```
+/// # use fayalite::prelude::*;
+/// # #[hdl]
+/// # pub struct OtherStruct {}
+/// #[hdl]
+/// pub struct MyStruct {
+///     #[hdl(flip)]
+///     pub a: UInt<5>,
+///     pub b: Bool,
+///     #[hdl(flip)]
+///     pub c: OtherStruct,
+/// }
+/// ```
+///
+/// # Enums
+// TODO: expand on enum docs
+/// e.g.:
+/// ```
+/// # use fayalite::prelude::*;
+/// # #[hdl]
+/// # pub struct MyStruct {}
+/// #[hdl]
+/// pub enum MyEnum {
+///     A(UInt<3>),
+///     B,
+///     C(MyStruct),
+/// }
+/// ```
+///
+/// # Type Aliases
+///
+/// There's three different ways you can create a type alias:
+///
+/// # Normal Type Alias
+///
+/// This works exactly how you'd expect:
+/// ```
+/// # use fayalite::prelude::*;
+/// # #[hdl]
+/// # pub struct MyStruct<T: Type> {
+/// #     v: T,
+/// # }
+/// #[hdl]
+/// pub type MyType<T: Type> = MyStruct<T>;
+///
+/// // you can then use Fayalite's standard syntax for creating dynamic types at runtime:
+///
+/// let ty = MyType[UInt[3]];
+/// assert_eq!(ty, MyStruct[UInt[3]]);
+/// ```
+///
+/// # Type Alias that gets a [`Type`] from a [`PhantomConst`]
+///
+/// This allows you to use some computed property of a [`PhantomConst`] to get a [`Type`] that you can use in other #[hdl] types.
+///
+/// ```
+/// # use fayalite::{intern::Intern, prelude::*};
+/// #[derive(Clone, PartialEq, Eq, Hash, Debug, serde::Serialize, serde::Deserialize)]
+/// pub struct Config {
+///     pub foo: usize,
+///     pub bar: Bundle,
+/// }
+///
+/// // the expression inside `get` is called with `Interned<Config>` and returns `Array<Bundle>`
+/// #[hdl(get(|config| Array[config.bar][config.foo]))]
+/// pub type GetMyArray<P: PhantomConstGet<Config>> = Array<Bundle>;
+///
+/// // you can then use it in other types:
+///
+/// #[hdl(no_static)]
+/// pub struct WrapMyArray<P: PhantomConstGet<Config>> {
+///     pub my_array: GetMyArray<P>,
+/// }
+///
+/// // you can then use Fayalite's standard syntax for creating dynamic types at runtime:
+/// let bar = Bundle::new(Default::default());
+/// let config = PhantomConst::new(Config { foo: 12, bar }.intern_sized());
+/// let ty = WrapMyArray[config];
+/// assert_eq!(ty.my_array, Array[bar][12]);
+/// ```
+///
+/// # Type Alias that gets a [`Size`] from a [`PhantomConst`]
+///
+/// This allows you to use some computed property of a [`PhantomConst`] to get a [`Size`] that you can use in other #[hdl] types.
+///
+/// ```
+/// # use fayalite::{intern::Intern, prelude::*};
+/// # #[derive(Clone, PartialEq, Eq, Hash, Debug, serde::Serialize, serde::Deserialize)]
+/// # pub struct ConfigItem {}
+/// # impl ConfigItem {
+/// #     pub fn new() -> Self {
+/// #         Self {}
+/// #     }
+/// # }
+/// #[derive(Clone, PartialEq, Eq, Hash, Debug, serde::Serialize, serde::Deserialize)]
+/// pub struct Config {
+///     pub items: Vec<ConfigItem>,
+/// }
+///
+/// // the expression inside `get` is called with `Interned<Config>` and returns `usize` (not DynSize)
+/// #[hdl(get(|config| config.items.len()))]
+/// pub type GetItemsLen<P: PhantomConstGet<Config>> = DynSize; // must be DynSize
+///
+/// // you can then use it in other types:
+///
+/// #[hdl(no_static)]
+/// pub struct FlagPerItem<P: PhantomConstGet<Config>> {
+///     pub flags: ArrayType<Bool, GetItemsLen<P>>,
+/// }
+///
+/// // you can then use Fayalite's standard syntax for creating dynamic types at runtime:
+/// let config = PhantomConst::new(Config { items: vec![ConfigItem::new(); 5] }.intern_sized());
+/// let ty = FlagPerItem[config];
+/// assert_eq!(ty.flags, Array[Bool][5]);
+/// ```
+///
+/// [`PhantomConst`]: crate::phantom_const::PhantomConst
+/// [`Size`]: crate::int::Size
+/// [`Type`]: crate::ty::Type
 pub use fayalite_proc_macros::hdl;
 
 pub use bitvec;

crates/fayalite/src/phantom_const.rs

@@ -415,3 +415,71 @@ impl<T: ?Sized + PhantomConstValue> ToSimValueWithType<CanonicalType> for Phanto
         SimValue::into_canonical(SimValue::from_value(Self::from_canonical(ty), *self))
     }
 }
+
+mod sealed {
+    pub trait Sealed<T: ?Sized> {}
+}
+
+pub trait PhantomConstGet<T: ?Sized + PhantomConstValue>: sealed::Sealed<T> {
+    fn get(&self) -> Interned<T>;
+}
+
+impl<T: ?Sized + PhantomConstValue, This: ?Sized + std::ops::Deref<Target: PhantomConstGet<T>>>
+    sealed::Sealed<T> for This
+{
+}
+
+impl<T: ?Sized + PhantomConstValue, This: ?Sized + std::ops::Deref<Target: PhantomConstGet<T>>>
+    PhantomConstGet<T> for This
+{
+    fn get(&self) -> Interned<T> {
+        This::Target::get(&**self)
+    }
+}
+
+macro_rules! impl_phantom_const_get {
+    (
+        impl PhantomConstGet<$T:ident> for $ty:ty {
+            fn $get:ident(&$get_self:ident) -> _ $get_body:block
+        }
+    ) => {
+        impl<$T: ?Sized + PhantomConstValue> sealed::Sealed<$T> for $ty {}
+
+        impl<$T: ?Sized + PhantomConstValue> PhantomConstGet<$T> for $ty {
+            fn $get(&$get_self) -> Interned<$T> $get_body
+        }
+    };
+}
+
+impl_phantom_const_get! {
+    impl PhantomConstGet<T> for PhantomConst<T> {
+        fn get(&self) -> _ {
+            PhantomConst::get(*self)
+        }
+    }
+}
+
+impl_phantom_const_get! {
+    impl PhantomConstGet<T> for Expr<PhantomConst<T>> {
+        fn get(&self) -> _ {
+            PhantomConst::get(Expr::ty(*self))
+        }
+    }
+}
+
+#[doc(hidden)]
+pub trait ReturnSelfUnchanged<T: ?Sized> {
+    type Type: ?Sized;
+}
+
+impl<This: ?Sized, T: ?Sized> ReturnSelfUnchanged<T> for This {
+    type Type = This;
+}
+
+#[doc(hidden)]
+pub fn type_alias_phantom_const_get_helper<T: ?Sized + PhantomConstValue, R: Intern + Clone>(
+    param: impl PhantomConstGet<T>,
+    get: impl FnOnce(Interned<T>) -> R,
+) -> &'static R {
+    Interned::into_inner(get(param.get()).intern_sized())
+}

crates/fayalite/src/prelude.rs

@@ -27,7 +27,7 @@ pub use crate::{
         Instance, Module, ModuleBuilder, annotate, connect, connect_any, incomplete_wire, instance,
         memory, memory_array, memory_with_init, reg_builder, wire,
     },
-    phantom_const::PhantomConst,
+    phantom_const::{PhantomConst, PhantomConstGet},
     platform::{DynPlatform, Platform, PlatformIOBuilder, peripherals},
     reg::Reg,
     reset::{AsyncReset, Reset, SyncReset, ToAsyncReset, ToReset, ToSyncReset},

crates/fayalite/tests/hdl_types.rs

@@ -4,7 +4,6 @@ use fayalite::{
     bundle::BundleType,
     enum_::EnumType,
     int::{BoolOrIntType, IntType},
-    phantom_const::PhantomConst,
     prelude::*,
     ty::StaticType,
 };
@@ -197,3 +196,21 @@ check_bounds!(CheckBoundsTTT2<#[a, Type] A: BundleType +, #[b, Type] B: Type +,
 check_bounds!(CheckBoundsTTT3<#[a, Type] A: EnumType +, #[b, Type] B: Type +, #[c, Type] C: Type +>);
 check_bounds!(CheckBoundsTTT4<#[a, Type] A: IntType +, #[b, Type] B: Type +, #[c, Type] C: Type +>);
 check_bounds!(CheckBoundsTTT5<#[a, Type] A: StaticType +, #[b, Type] B: Type +, #[c, Type] C: Type +>);
+
+#[derive(Clone, PartialEq, Eq, Hash, Debug, serde::Serialize, serde::Deserialize)]
+pub struct MyPhantomConstInner {
+    pub a: usize,
+    pub b: UInt,
+}
+
+#[hdl(outline_generated, get(|v| v.a))]
+pub type GetA<P: PhantomConstGet<MyPhantomConstInner>> = DynSize;
+
+#[hdl(outline_generated, get(|v| v.b))]
+pub type GetB<P: PhantomConstGet<MyPhantomConstInner>> = UInt;
+
+#[hdl(outline_generated, no_static)]
+pub struct MyTypeWithPhantomConstParameter<P: PhantomConstGet<MyPhantomConstInner>> {
+    pub a: ArrayType<Bool, GetA<P>>,
+    pub b: HdlOption<GetB<P>>,
+}

crates/fayalite/tests/sim.rs

@@ -3,7 +3,7 @@
 
 use fayalite::{
     memory::{ReadStruct, ReadWriteStruct, WriteStruct},
-    module::{instance_with_loc, reg_builder_with_loc},
+    module::{instance_with_loc, memory_with_init_and_loc, reg_builder_with_loc},
     prelude::*,
     reset::ResetType,
     sim::vcd::VcdWriterDecls,
@@ -1261,6 +1261,310 @@ fn test_memories3() {
     }
 }
 
+#[hdl_module(outline_generated)]
+pub fn many_memories() {
+    #[hdl]
+    let r: Array<ReadStruct<Bool, ConstUsize<4>>, 8> = m.input();
+    #[hdl]
+    let w: Array<WriteStruct<Bool, ConstUsize<4>>, 8> = m.input();
+    for (mem_index, (r, w)) in r.into_iter().zip(w).enumerate() {
+        let mut mem = memory_with_init_and_loc(
+            &format!("mem_{mem_index}"),
+            (0..16)
+                .map(|bit_index| mem_index.pow(5).to_expr()[bit_index])
+                .collect::<Vec<_>>(),
+            SourceLocation::caller(),
+        );
+        connect_any(mem.new_read_port(), r);
+        connect_any(mem.new_write_port(), w);
+    }
+}
+
+#[hdl]
+#[test]
+fn test_many_memories() {
+    let _n = SourceLocation::normalize_files_for_tests();
+    let mut sim = Simulation::new(many_memories());
+    let mut writer = RcWriter::default();
+    sim.add_trace_writer(VcdWriterDecls::new(writer.clone()));
+    for r in sim.io().r {
+        sim.write_clock(r.clk, false);
+    }
+    for w in sim.io().w {
+        sim.write_clock(w.clk, false);
+    }
+    #[hdl(cmp_eq)]
+    struct IO {
+        r_addr: UInt<4>,
+        r_en: Bool,
+        r_data: Array<Bool, 8>,
+        w_addr: UInt<4>,
+        w_en: Bool,
+        w_data: Array<Bool, 8>,
+        w_mask: Array<Bool, 8>,
+    }
+    let io_cycles = [
+        #[hdl(sim)]
+        IO {
+            r_addr: 0_hdl_u4,
+            r_en: false,
+            r_data: [false; 8],
+            w_addr: 0_hdl_u4,
+            w_en: false,
+            w_data: [false; 8],
+            w_mask: [false; 8],
+        },
+        #[hdl(sim)]
+        IO {
+            r_addr: 0_hdl_u4,
+            r_en: true,
+            r_data: [false, true, false, true, false, true, false, true],
+            w_addr: 0_hdl_u4,
+            w_en: true,
+            w_data: [true; 8],
+            w_mask: [true; 8],
+        },
+        #[hdl(sim)]
+        IO {
+            r_addr: 0_hdl_u4,
+            r_en: true,
+            r_data: [true; 8],
+            w_addr: 0_hdl_u4,
+            w_en: true,
+            w_data: [false; 8],
+            w_mask: [true; 8],
+        },
+        #[hdl(sim)]
+        IO {
+            r_addr: 0_hdl_u4,
+            r_en: true,
+            r_data: [false; 8],
+            w_addr: 0_hdl_u4,
+            w_en: false,
+            w_data: [false; 8],
+            w_mask: [true; 8],
+        },
+        #[hdl(sim)]
+        IO {
+            r_addr: 1_hdl_u4,
+            r_en: true,
+            r_data: [false, false, false, true, false, false, false, true],
+            w_addr: 0_hdl_u4,
+            w_en: false,
+            w_data: [false; 8],
+            w_mask: [true; 8],
+        },
+        #[hdl(sim)]
+        IO {
+            r_addr: 2_hdl_u4,
+            r_en: true,
+            r_data: [false, false, false, false, false, true, false, true],
+            w_addr: 0_hdl_u4,
+            w_en: false,
+            w_data: [false; 8],
+            w_mask: [true; 8],
+        },
+        #[hdl(sim)]
+        IO {
+            r_addr: 3_hdl_u4,
+            r_en: true,
+            r_data: [false, false, false, false, false, false, false, false],
+            w_addr: 0_hdl_u4,
+            w_en: false,
+            w_data: [false; 8],
+            w_mask: [true; 8],
+        },
+        #[hdl(sim)]
+        IO {
+            r_addr: 4_hdl_u4,
+            r_en: true,
+            r_data: [false, false, false, true, false, true, false, false],
+            w_addr: 0_hdl_u4,
+            w_en: false,
+            w_data: [false; 8],
+            w_mask: [true; 8],
+        },
+        #[hdl(sim)]
+        IO {
+            r_addr: 5_hdl_u4,
+            r_en: true,
+            r_data: [false, false, true, true, false, true, true, true],
+            w_addr: 0_hdl_u4,
+            w_en: false,
+            w_data: [false; 8],
+            w_mask: [true; 8],
+        },
+        #[hdl(sim)]
+        IO {
+            r_addr: 6_hdl_u4,
+            r_en: true,
+            r_data: [false, false, false, true, false, false, true, false],
+            w_addr: 0_hdl_u4,
+            w_en: false,
+            w_data: [false; 8],
+            w_mask: [true; 8],
+        },
+        #[hdl(sim)]
+        IO {
+            r_addr: 7_hdl_u4,
+            r_en: true,
+            r_data: [false, false, false, true, false, false, false, true],
+            w_addr: 0_hdl_u4,
+            w_en: false,
+            w_data: [false; 8],
+            w_mask: [true; 8],
+        },
+        #[hdl(sim)]
+        IO {
+            r_addr: 8_hdl_u4,
+            r_en: true,
+            r_data: [false, false, false, false, false, false, false, true],
+            w_addr: 0_hdl_u4,
+            w_en: false,
+            w_data: [false; 8],
+            w_mask: [true; 8],
+        },
+        #[hdl(sim)]
+        IO {
+            r_addr: 9_hdl_u4,
+            r_en: true,
+            r_data: [false, false, false, false, false, false, true, false],
+            w_addr: 0_hdl_u4,
+            w_en: false,
+            w_data: [false; 8],
+            w_mask: [true; 8],
+        },
+        #[hdl(sim)]
+        IO {
+            r_addr: 0xA_hdl_u4,
+            r_en: true,
+            r_data: [false, false, false, false, true, true, true, false],
+            w_addr: 0_hdl_u4,
+            w_en: false,
+            w_data: [false; 8],
+            w_mask: [true; 8],
+        },
+        #[hdl(sim)]
+        IO {
+            r_addr: 0xB_hdl_u4,
+            r_en: true,
+            r_data: [false, false, false, false, false, true, true, false],
+            w_addr: 0_hdl_u4,
+            w_en: false,
+            w_data: [false; 8],
+            w_mask: [true; 8],
+        },
+        #[hdl(sim)]
+        IO {
+            r_addr: 0xC_hdl_u4,
+            r_en: true,
+            r_data: [false, false, false, false, false, false, true, false],
+            w_addr: 0_hdl_u4,
+            w_en: false,
+            w_data: [false; 8],
+            w_mask: [true; 8],
+        },
+        #[hdl(sim)]
+        IO {
+            r_addr: 0xD_hdl_u4,
+            r_en: true,
+            r_data: [false, false, false, false, false, false, false, false],
+            w_addr: 0_hdl_u4,
+            w_en: false,
+            w_data: [false; 8],
+            w_mask: [true; 8],
+        },
+        #[hdl(sim)]
+        IO {
+            r_addr: 0xE_hdl_u4,
+            r_en: true,
+            r_data: [false, false, false, false, false, false, false, true],
+            w_addr: 0_hdl_u4,
+            w_en: false,
+            w_data: [false; 8],
+            w_mask: [true; 8],
+        },
+        #[hdl(sim)]
+        IO {
+            r_addr: 0xF_hdl_u4,
+            r_en: true,
+            r_data: [false, false, false, false, false, false, false, false],
+            w_addr: 0_hdl_u4,
+            w_en: false,
+            w_data: [false; 8],
+            w_mask: [true; 8],
+        },
+    ];
+    for (cycle, expected) in io_cycles.into_iter().enumerate() {
+        #[hdl(sim)]
+        let IO {
+            r_addr,
+            r_en,
+            r_data: _,
+            w_addr,
+            w_en,
+            w_data,
+            w_mask,
+        } = expected;
+        for (((r, w), w_data), w_mask) in sim
+            .io()
+            .r
+            .into_iter()
+            .zip(sim.io().w)
+            .zip(w_data.iter())
+            .zip(w_mask.iter())
+        {
+            sim.write(r.addr, &r_addr);
+            sim.write(r.en, &r_en);
+            sim.write(w.addr, &w_addr);
+            sim.write(w.en, &w_en);
+            sim.write(w.data, w_data);
+            sim.write(w.mask, w_mask);
+        }
+        let io = #[hdl(sim)]
+        IO {
+            r_addr,
+            r_en,
+            r_data: std::array::from_fn(|i| sim.read(sim.io().r[i].data)),
+            w_addr,
+            w_en,
+            w_data,
+            w_mask,
+        };
+        assert_eq!(
+            expected,
+            io,
+            "vcd:\n{}\ncycle: {cycle}",
+            String::from_utf8(writer.take()).unwrap(),
+        );
+        sim.advance_time(SimDuration::from_micros(1));
+        for r in sim.io().r {
+            sim.write_clock(r.clk, true);
+        }
+        for w in sim.io().w {
+            sim.write_clock(w.clk, true);
+        }
+        sim.advance_time(SimDuration::from_micros(1));
+        for r in sim.io().r {
+            sim.write_clock(r.clk, false);
+        }
+        for w in sim.io().w {
+            sim.write_clock(w.clk, false);
+        }
+    }
+    sim.flush_traces().unwrap();
+    let vcd = String::from_utf8(writer.take()).unwrap();
+    println!("####### VCD:\n{vcd}\n#######");
+    if vcd != include_str!("sim/expected/many_memories.vcd") {
+        panic!();
+    }
+    let sim_debug = format!("{sim:#?}");
+    println!("#######\n{sim_debug}\n#######");
+    if sim_debug != include_str!("sim/expected/many_memories.txt") {
+        panic!();
+    }
+}
+
 #[hdl_module(outline_generated)]
 pub fn duplicate_names() {
     #[hdl]
@@ -1722,3 +2026,85 @@ fn test_sim_only_connects() {
         panic!();
     }
 }
+
+#[hdl_module(outline_generated, extern)]
+pub fn sim_fork_join<const N: usize>()
+where
+    ConstUsize<N>: KnownSize,
+{
+    #[hdl]
+    let clocks: Array<Clock, N> = m.input();
+    #[hdl]
+    let outputs: Array<UInt<8>, N> = m.output();
+    m.extern_module_simulation_fn((clocks, outputs), |(clocks, outputs), mut sim| async move {
+        sim.write(outputs, [0u8; N]).await;
+        loop {
+            sim.fork_join(
+                clocks
+                    .into_iter()
+                    .zip(outputs)
+                    .map(|(clock, output)| {
+                        move |mut sim: ExternModuleSimulationState| async move {
+                            sim.wait_for_clock_edge(clock).await;
+                            let v = sim
+                                .read_bool_or_int(output)
+                                .await
+                                .to_bigint()
+                                .try_into()
+                                .expect("known to be in range");
+                            sim.write(output, 1u8.wrapping_add(v)).await;
+                        }
+                    })
+                    .collect::<Vec<_>>(),
+            )
+            .await;
+        }
+    });
+}
+
+#[test]
+fn test_sim_fork_join() {
+    let _n = SourceLocation::normalize_files_for_tests();
+    const N: usize = 3;
+    let mut sim = Simulation::new(sim_fork_join::<N>());
+    let mut writer = RcWriter::default();
+    sim.add_trace_writer(VcdWriterDecls::new(writer.clone()));
+    sim.write(sim.io().clocks, [false; N]);
+    let mut clocks_triggered = [false; N];
+    let mut expected = [0u8; N];
+    for i0 in 0..N {
+        for i1 in 0..N {
+            for i2 in 0..N {
+                for i3 in 0..N {
+                    let indexes = [i0, i1, i2, i3];
+                    for i in indexes {
+                        sim.advance_time(SimDuration::from_micros(1));
+                        sim.write(sim.io().clocks[i], true);
+                        sim.advance_time(SimDuration::from_micros(1));
+                        sim.write(sim.io().clocks[i], false);
+                        if !clocks_triggered[i] {
+                            expected[i] = expected[i].wrapping_add(1);
+                        }
+                        clocks_triggered[i] = true;
+                        if clocks_triggered == [true; N] {
+                            clocks_triggered = [false; N];
+                        }
+                        let output = sim.read(sim.io().outputs);
+                        assert_eq!(output, expected.to_sim_value(), "indexes={indexes:?} i={i}");
+                    }
+                }
+            }
+        }
+    }
+    sim.flush_traces().unwrap();
+    let vcd = String::from_utf8(writer.take()).unwrap();
+    println!("####### VCD:\n{vcd}\n#######");
+    if vcd != include_str!("sim/expected/sim_fork_join.vcd") {
+        panic!();
+    }
+    let sim_debug = format!("{sim:#?}");
+    println!("#######\n{sim_debug}\n#######");
+    if sim_debug != include_str!("sim/expected/sim_fork_join.txt") {
+        panic!();
+    }
+}

crates/fayalite/tests/sim/expected/array_rw.txt

@@ -828,7 +828,6 @@ Simulation {
         did_initial_settle: true,
     },
     extern_modules: [],
-    state_ready_to_run: false,
     trace_decls: TraceModule {
         name: "array_rw",
         children: [
@@ -1699,7 +1698,12 @@ Simulation {
             },
         ),
     ],
-    instant: 34 μs,
     clocks_triggered: [],
+    event_queue: EventQueue(EventQueueData {
+        instant: 34 μs,
+        events: {},
+    }),
+    waiting_sensitivity_sets_by_address: {},
+    waiting_sensitivity_sets_by_compiled_value: {},
     ..
 }

crates/fayalite/tests/sim/expected/conditional_assignment_last.txt

@@ -124,7 +124,6 @@ Simulation {
         did_initial_settle: true,
     },
     extern_modules: [],
-    state_ready_to_run: false,
     trace_decls: TraceModule {
         name: "conditional_assignment_last",
         children: [
@@ -177,7 +176,12 @@ Simulation {
             },
         ),
     ],
-    instant: 2 μs,
     clocks_triggered: [],
+    event_queue: EventQueue(EventQueueData {
+        instant: 2 μs,
+        events: {},
+    }),
+    waiting_sensitivity_sets_by_address: {},
+    waiting_sensitivity_sets_by_compiled_value: {},
     ..
 }

crates/fayalite/tests/sim/expected/connect_const.txt

@@ -100,7 +100,6 @@ Simulation {
         did_initial_settle: true,
     },
     extern_modules: [],
-    state_ready_to_run: false,
     trace_decls: TraceModule {
         name: "connect_const",
         children: [
@@ -130,7 +129,12 @@ Simulation {
     ],
     trace_memories: {},
     trace_writers: [],
-    instant: 0 s,
     clocks_triggered: [],
+    event_queue: EventQueue(EventQueueData {
+        instant: 0 s,
+        events: {},
+    }),
+    waiting_sensitivity_sets_by_address: {},
+    waiting_sensitivity_sets_by_compiled_value: {},
     ..
 }

crates/fayalite/tests/sim/expected/connect_const_reset.txt

@@ -143,7 +143,6 @@ Simulation {
         did_initial_settle: true,
     },
     extern_modules: [],
-    state_ready_to_run: false,
     trace_decls: TraceModule {
         name: "connect_const_reset",
         children: [
@@ -197,7 +196,12 @@ Simulation {
             },
         ),
     ],
-    instant: 1 μs,
     clocks_triggered: [],
+    event_queue: EventQueue(EventQueueData {
+        instant: 1 μs,
+        events: {},
+    }),
+    waiting_sensitivity_sets_by_address: {},
+    waiting_sensitivity_sets_by_compiled_value: {},
     ..
 }

crates/fayalite/tests/sim/expected/counter_async.txt

@@ -263,7 +263,6 @@ Simulation {
         did_initial_settle: true,
     },
     extern_modules: [],
-    state_ready_to_run: false,
     trace_decls: TraceModule {
         name: "counter",
         children: [
@@ -329,7 +328,7 @@ Simulation {
                 index: StatePartIndex<BigSlots>(0),
             },
             state: 0x1,
-            last_state: 0x1,
+            last_state: 0x0,
         },
         SimTrace {
             id: TraceScalarId(1),
@@ -355,7 +354,7 @@ Simulation {
                 ty: UInt<4>,
             },
             state: 0x3,
-            last_state: 0x3,
+            last_state: 0x2,
         },
     ],
     trace_memories: {},
@@ -368,9 +367,14 @@ Simulation {
             },
         ),
     ],
-    instant: 66 μs,
     clocks_triggered: [
         StatePartIndex<SmallSlots>(1),
     ],
+    event_queue: EventQueue(EventQueueData {
+        instant: 66 μs,
+        events: {},
+    }),
+    waiting_sensitivity_sets_by_address: {},
+    waiting_sensitivity_sets_by_compiled_value: {},
     ..
 }

crates/fayalite/tests/sim/expected/counter_async.vcd

@@ -26,192 +26,192 @@ b11 $
 0!
 #3000000
 1!
-b100 $
 b100 #
+b100 $
 #4000000
 0!
 #5000000
 1!
-b101 $
 b101 #
+b101 $
 #6000000
 0!
 #7000000
 1!
-b110 $
 b110 #
+b110 $
 #8000000
 0!
 #9000000
 1!
-b111 $
 b111 #
+b111 $
 #10000000
 0!
 #11000000
 1!
-b1000 $
 b1000 #
+b1000 $
 #12000000
 0!
 #13000000
 1!
-b1001 $
 b1001 #
+b1001 $
 #14000000
 0!
 #15000000
 1!
-b1010 $
 b1010 #
+b1010 $
 #16000000
 0!
 #17000000
 1!
-b1011 $
 b1011 #
+b1011 $
 #18000000
 0!
 #19000000
 1!
-b1100 $
 b1100 #
+b1100 $
 #20000000
 0!
 #21000000
 1!
-b1101 $
 b1101 #
+b1101 $
 #22000000
 0!
 #23000000
 1!
-b1110 $
 b1110 #
+b1110 $
 #24000000
 0!
 #25000000
 1!
-b1111 $
 b1111 #
+b1111 $
 #26000000
 0!
 #27000000
 1!
-b0 $
 b0 #
+b0 $
 #28000000
 0!
 #29000000
 1!
-b1 $
 b1 #
+b1 $
 #30000000
 0!
 #31000000
 1!
-b10 $
 b10 #
+b10 $
 #32000000
 0!
 #33000000
 1!
-b11 $
 b11 #
+b11 $
 #34000000
 0!
 #35000000
 1!
-b100 $
 b100 #
+b100 $
 #36000000
 0!
 #37000000
 1!
-b101 $
 b101 #
+b101 $
 #38000000
 0!
 #39000000
 1!
-b110 $
 b110 #
+b110 $
 #40000000
 0!
 #41000000
 1!
-b111 $
 b111 #
+b111 $
 #42000000
 0!
 #43000000
 1!
-b1000 $
 b1000 #
+b1000 $
 #44000000
 0!
 #45000000
 1!
-b1001 $
 b1001 #
+b1001 $
 #46000000
 0!
 #47000000
 1!
-b1010 $
 b1010 #
+b1010 $
 #48000000
 0!
 #49000000
 1!
-b1011 $
 b1011 #
+b1011 $
 #50000000
 0!
 #51000000
 1!
-b1100 $
 b1100 #
+b1100 $
 #52000000
 0!
 #53000000
 1!
-b1101 $
 b1101 #
+b1101 $
 #54000000
 0!
 #55000000
 1!
-b1110 $
 b1110 #
+b1110 $
 #56000000
 0!
 #57000000
 1!
-b1111 $
 b1111 #
+b1111 $
 #58000000
 0!
 #59000000
 1!
-b0 $
 b0 #
+b0 $
 #60000000
 0!
 #61000000
 1!
-b1 $
 b1 #
+b1 $
 #62000000
 0!
 #63000000
 1!
-b10 $
 b10 #
+b10 $
 #64000000
 0!
 #65000000
 1!
-b11 $
 b11 #
+b11 $
 #66000000

crates/fayalite/tests/sim/expected/counter_sync.txt

@@ -244,7 +244,6 @@ Simulation {
         did_initial_settle: true,
     },
     extern_modules: [],
-    state_ready_to_run: false,
     trace_decls: TraceModule {
         name: "counter",
         children: [
@@ -310,7 +309,7 @@ Simulation {
                 index: StatePartIndex<BigSlots>(0),
             },
             state: 0x1,
-            last_state: 0x1,
+            last_state: 0x0,
         },
         SimTrace {
             id: TraceScalarId(1),
@@ -336,7 +335,7 @@ Simulation {
                 ty: UInt<4>,
             },
             state: 0x3,
-            last_state: 0x3,
+            last_state: 0x2,
         },
     ],
     trace_memories: {},
@@ -349,9 +348,14 @@ Simulation {
             },
         ),
     ],
-    instant: 66 μs,
     clocks_triggered: [
         StatePartIndex<SmallSlots>(1),
     ],
+    event_queue: EventQueue(EventQueueData {
+        instant: 66 μs,
+        events: {},
+    }),
+    waiting_sensitivity_sets_by_address: {},
+    waiting_sensitivity_sets_by_compiled_value: {},
     ..
 }

crates/fayalite/tests/sim/expected/counter_sync.vcd

@@ -16,199 +16,199 @@ b0 $
 $end
 #1000000
 1!
-b11 $
 b11 #
+b11 $
 0"
 #2000000
 0!
 #3000000
 1!
-b100 $
 b100 #
+b100 $
 #4000000
 0!
 #5000000
 1!
-b101 $
 b101 #
+b101 $
 #6000000
 0!
 #7000000
 1!
-b110 $
 b110 #
+b110 $
 #8000000
 0!
 #9000000
 1!
-b111 $
 b111 #
+b111 $
 #10000000
 0!
 #11000000
 1!
-b1000 $
 b1000 #
+b1000 $
 #12000000
 0!
 #13000000
 1!
-b1001 $
 b1001 #
+b1001 $
 #14000000
 0!
 #15000000
 1!
-b1010 $
 b1010 #
+b1010 $
 #16000000
 0!
 #17000000
 1!
-b1011 $
 b1011 #
+b1011 $
 #18000000
 0!
 #19000000
 1!
-b1100 $
 b1100 #
+b1100 $
 #20000000
 0!
 #21000000
 1!
-b1101 $
 b1101 #
+b1101 $
 #22000000
 0!
 #23000000
 1!
-b1110 $
 b1110 #
+b1110 $
 #24000000
 0!
 #25000000
 1!
-b1111 $
 b1111 #
+b1111 $
 #26000000
 0!
 #27000000
 1!
-b0 $
 b0 #
+b0 $
 #28000000
 0!
 #29000000
 1!
-b1 $
 b1 #
+b1 $
 #30000000
 0!
 #31000000
 1!
-b10 $
 b10 #
+b10 $
 #32000000
 0!
 #33000000
 1!
-b11 $
 b11 #
+b11 $
 #34000000
 0!
 #35000000
 1!
-b100 $
 b100 #
+b100 $
 #36000000
 0!
 #37000000
 1!
-b101 $
 b101 #
+b101 $
 #38000000
 0!
 #39000000
 1!
-b110 $
 b110 #
+b110 $
 #40000000
 0!
 #41000000
 1!
-b111 $
 b111 #
+b111 $
 #42000000
 0!
 #43000000
 1!
-b1000 $
 b1000 #
+b1000 $
 #44000000
 0!
 #45000000
 1!
-b1001 $
 b1001 #
+b1001 $
 #46000000
 0!
 #47000000
 1!
-b1010 $
 b1010 #
+b1010 $
 #48000000
 0!
 #49000000
 1!
-b1011 $
 b1011 #
+b1011 $
 #50000000
 0!
 #51000000
 1!
-b1100 $
 b1100 #
+b1100 $
 #52000000
 0!
 #53000000
 1!
-b1101 $
 b1101 #
+b1101 $
 #54000000
 0!
 #55000000
 1!
-b1110 $
 b1110 #
+b1110 $
 #56000000
 0!
 #57000000
 1!
-b1111 $
 b1111 #
+b1111 $
 #58000000
 0!
 #59000000
 1!
-b0 $
 b0 #
+b0 $
 #60000000
 0!
 #61000000
 1!
-b1 $
 b1 #
+b1 $
 #62000000
 0!
 #63000000
 1!
-b10 $
 b10 #
+b10 $
 #64000000
 0!
 #65000000
 1!
-b11 $
 b11 #
+b11 $
 #66000000

crates/fayalite/tests/sim/expected/duplicate_names.txt

@@ -104,7 +104,6 @@ Simulation {
         did_initial_settle: true,
     },
     extern_modules: [],
-    state_ready_to_run: false,
     trace_decls: TraceModule {
         name: "duplicate_names",
         children: [
@@ -160,7 +159,12 @@ Simulation {
             },
         ),
     ],
-    instant: 1 μs,
     clocks_triggered: [],
+    event_queue: EventQueue(EventQueueData {
+        instant: 1 μs,
+        events: {},
+    }),
+    waiting_sensitivity_sets_by_address: {},
+    waiting_sensitivity_sets_by_compiled_value: {},
     ..
 }

crates/fayalite/tests/sim/expected/enums.txt

@@ -1456,7 +1456,6 @@ Simulation {
         did_initial_settle: true,
     },
     extern_modules: [],
-    state_ready_to_run: false,
     trace_decls: TraceModule {
         name: "enums",
         children: [
@@ -1744,7 +1743,7 @@ Simulation {
                 index: StatePartIndex<BigSlots>(0),
             },
             state: 0x1,
-            last_state: 0x1,
+            last_state: 0x0,
         },
         SimTrace {
             id: TraceScalarId(1),
@@ -1924,9 +1923,14 @@ Simulation {
             },
         ),
     ],
-    instant: 16 μs,
     clocks_triggered: [
         StatePartIndex<SmallSlots>(3),
     ],
+    event_queue: EventQueue(EventQueueData {
+        instant: 16 μs,
+        events: {},
+    }),
+    waiting_sensitivity_sets_by_address: {},
+    waiting_sensitivity_sets_by_compiled_value: {},
     ..
 }

crates/fayalite/tests/sim/expected/extern_module.txt

@@ -186,14 +186,8 @@ Simulation {
             running_generator: Some(
                 ...,
             ),
-            wait_targets: {
-                Instant(
-                    20.500000000000 μs,
-                ),
-            },
         },
     ],
-    state_ready_to_run: false,
     trace_decls: TraceModule {
         name: "extern_module",
         children: [
@@ -247,7 +241,14 @@ Simulation {
             },
         ),
     ],
-    instant: 20 μs,
     clocks_triggered: [],
+    event_queue: EventQueue(EventQueueData {
+        instant: 20 μs,
+        events: {
+            Event { instant: 20.500000000000 μs, kind: ExternModule(0) }: 1,
+        },
+    }),
+    waiting_sensitivity_sets_by_address: {},
+    waiting_sensitivity_sets_by_compiled_value: {},
     ..
 }

crates/fayalite/tests/sim/expected/extern_module.vcd

@@ -6,8 +6,9 @@ $upscope $end
 $enddefinitions $end
 $dumpvars
 0!
-1"
+0"
 $end
+1"
 #500000
 #1500000
 0"

crates/fayalite/tests/sim/expected/extern_module2.txt

@@ -234,55 +234,8 @@ Simulation {
             running_generator: Some(
                 ...,
             ),
-            wait_targets: {
-                Change {
-                    key: CompiledValue {
-                        layout: CompiledTypeLayout {
-                            ty: Clock,
-                            layout: TypeLayout {
-                                small_slots: StatePartLayout<SmallSlots> {
-                                    len: 0,
-                                    debug_data: [],
-                                    ..
-                                },
-                                big_slots: StatePartLayout<BigSlots> {
-                                    len: 1,
-                                    debug_data: [
-                                        SlotDebugData {
-                                            name: "InstantiatedModule(extern_module2: extern_module2).extern_module2::clk",
-                                            ty: Clock,
-                                        },
-                                    ],
-                                    ..
-                                },
-                                sim_only_slots: StatePartLayout<SimOnlySlots> {
-                                    len: 0,
-                                    debug_data: [],
-                                    layout_data: [],
-                                    ..
-                                },
-                            },
-                            body: Scalar,
-                        },
-                        range: TypeIndexRange {
-                            small_slots: StatePartIndexRange<SmallSlots> { start: 0, len: 0 },
-                            big_slots: StatePartIndexRange<BigSlots> { start: 1, len: 1 },
-                            sim_only_slots: StatePartIndexRange<SimOnlySlots> { start: 0, len: 0 },
-                        },
-                        write: None,
-                    },
-                    value: SimValue {
-                        ty: Clock,
-                        value: OpaqueSimValue {
-                            bits: 0x1_u1,
-                            sim_only_values: [],
-                        },
-                    },
-                },
-            },
         },
     ],
-    state_ready_to_run: false,
     trace_decls: TraceModule {
         name: "extern_module2",
         children: [
@@ -356,7 +309,113 @@ Simulation {
             },
         ),
     ],
-    instant: 60 μs,
     clocks_triggered: [],
+    event_queue: EventQueue(EventQueueData {
+        instant: 60 μs,
+        events: {},
+    }),
+    waiting_sensitivity_sets_by_address: {
+        SensitivitySet {
+            id: 59,
+            values: {
+                CompiledValue {
+                    layout: CompiledTypeLayout {
+                        ty: Clock,
+                        layout: TypeLayout {
+                            small_slots: StatePartLayout<SmallSlots> {
+                                len: 0,
+                                debug_data: [],
+                                ..
+                            },
+                            big_slots: StatePartLayout<BigSlots> {
+                                len: 1,
+                                debug_data: [
+                                    SlotDebugData {
+                                        name: "InstantiatedModule(extern_module2: extern_module2).extern_module2::clk",
+                                        ty: Clock,
+                                    },
+                                ],
+                                ..
+                            },
+                            sim_only_slots: StatePartLayout<SimOnlySlots> {
+                                len: 0,
+                                debug_data: [],
+                                layout_data: [],
+                                ..
+                            },
+                        },
+                        body: Scalar,
+                    },
+                    range: TypeIndexRange {
+                        small_slots: StatePartIndexRange<SmallSlots> { start: 0, len: 0 },
+                        big_slots: StatePartIndexRange<BigSlots> { start: 1, len: 1 },
+                        sim_only_slots: StatePartIndexRange<SimOnlySlots> { start: 0, len: 0 },
+                    },
+                    write: None,
+                }: SimValue {
+                    ty: Clock,
+                    value: OpaqueSimValue {
+                        bits: 0x1_u1,
+                        sim_only_values: [],
+                    },
+                },
+            },
+            changed: Cell {
+                value: false,
+            },
+            ..
+        },
+    },
+    waiting_sensitivity_sets_by_compiled_value: {
+        CompiledValue {
+            layout: CompiledTypeLayout {
+                ty: Clock,
+                layout: TypeLayout {
+                    small_slots: StatePartLayout<SmallSlots> {
+                        len: 0,
+                        debug_data: [],
+                        ..
+                    },
+                    big_slots: StatePartLayout<BigSlots> {
+                        len: 1,
+                        debug_data: [
+                            SlotDebugData {
+                                name: "InstantiatedModule(extern_module2: extern_module2).extern_module2::clk",
+                                ty: Clock,
+                            },
+                        ],
+                        ..
+                    },
+                    sim_only_slots: StatePartLayout<SimOnlySlots> {
+                        len: 0,
+                        debug_data: [],
+                        layout_data: [],
+                        ..
+                    },
+                },
+                body: Scalar,
+            },
+            range: TypeIndexRange {
+                small_slots: StatePartIndexRange<SmallSlots> { start: 0, len: 0 },
+                big_slots: StatePartIndexRange<BigSlots> { start: 1, len: 1 },
+                sim_only_slots: StatePartIndexRange<SimOnlySlots> { start: 0, len: 0 },
+            },
+            write: None,
+        }: (
+            SimValue {
+                ty: Clock,
+                value: OpaqueSimValue {
+                    bits: 0x1_u1,
+                    sim_only_values: [],
+                },
+            },
+            {
+                SensitivitySet {
+                    id: 59,
+                    ..
+                },
+            },
+        ),
+    },
     ..
 }

crates/fayalite/tests/sim/expected/extern_module2.vcd

@@ -8,8 +8,9 @@ $enddefinitions $end
 $dumpvars
 1!
 0"
-b1001000 #
+b0 #
 $end
+b1001000 #
 #1000000
 1"
 b1100101 #

crates/fayalite/tests/sim/expected/memories.txt

@@ -721,7 +721,6 @@ Simulation {
         did_initial_settle: true,
     },
     extern_modules: [],
-    state_ready_to_run: false,
     trace_decls: TraceModule {
         name: "memories",
         children: [
@@ -1616,10 +1615,15 @@ Simulation {
             },
         ),
     ],
-    instant: 22 μs,
     clocks_triggered: [
         StatePartIndex<SmallSlots>(1),
         StatePartIndex<SmallSlots>(6),
     ],
+    event_queue: EventQueue(EventQueueData {
+        instant: 22 μs,
+        events: {},
+    }),
+    waiting_sensitivity_sets_by_address: {},
+    waiting_sensitivity_sets_by_compiled_value: {},
     ..
 }

crates/fayalite/tests/sim/expected/memories.vcd

@@ -234,13 +234,13 @@ b100000 6
 b10000 9
 b100000 I
 1#
-1(
-1/
-14
 b10000 $
 b100000 %
+1(
+1/
 b10000 0
 b100000 1
+14
 #4000000
 0#
 0(
@@ -256,11 +256,11 @@ b1000000 6
 b10000 9
 b1000000 I
 1#
+b1000000 %
 1(
 1/
-14
-b1000000 %
 b1000000 1
+14
 #6000000
 0#
 0(
@@ -278,11 +278,11 @@ b1100000 6
 b1010000 9
 b1000000 I
 1#
+b1010000 $
 1(
 1/
-14
-b1010000 $
 b1010000 0
+14
 #8000000
 0#
 0(

crates/fayalite/tests/sim/expected/memories2.txt

@@ -679,7 +679,6 @@ Simulation {
         did_initial_settle: true,
     },
     extern_modules: [],
-    state_ready_to_run: false,
     trace_decls: TraceModule {
         name: "memories2",
         children: [
@@ -1260,9 +1259,14 @@ Simulation {
             },
         ),
     ],
-    instant: 22 μs,
     clocks_triggered: [
         StatePartIndex<SmallSlots>(3),
     ],
+    event_queue: EventQueue(EventQueueData {
+        instant: 22 μs,
+        events: {},
+    }),
+    waiting_sensitivity_sets_by_address: {},
+    waiting_sensitivity_sets_by_compiled_value: {},
     ..
 }

crates/fayalite/tests/sim/expected/memories2.vcd

@@ -100,8 +100,8 @@ $end
 1)
 #1250000
 1#
-1*
 b11 $
+1*
 sHdlSome\x20(1) +
 1,
 #1500000
@@ -113,8 +113,8 @@ sHdlSome\x20(1) +
 0)
 #2250000
 1#
-1*
 b0 $
+1*
 sHdlNone\x20(0) +
 0,
 #2500000
@@ -303,8 +303,8 @@ b11 !
 b11 (
 #17250000
 1#
-1*
 b11 $
+1*
 sHdlSome\x20(1) +
 1,
 #17500000
@@ -316,8 +316,8 @@ b10 !
 b10 (
 #18250000
 1#
-1*
 b0 $
+1*
 sHdlNone\x20(0) +
 0,
 #18500000
@@ -339,8 +339,8 @@ b1 !
 b1 (
 #20250000
 1#
-1*
 b1 $
+1*
 sHdlSome\x20(1) +
 #20500000
 #20750000
@@ -353,8 +353,8 @@ b0 (
 0)
 #21250000
 1#
-1*
 b0 $
+1*
 sHdlNone\x20(0) +
 #21500000
 #21750000

crates/fayalite/tests/sim/expected/memories3.txt

@@ -1763,7 +1763,6 @@ Simulation {
         did_initial_settle: true,
     },
     extern_modules: [],
-    state_ready_to_run: false,
     trace_decls: TraceModule {
         name: "memories3",
         children: [
@@ -3275,10 +3274,15 @@ Simulation {
             },
         ),
     ],
-    instant: 15 μs,
     clocks_triggered: [
         StatePartIndex<SmallSlots>(1),
         StatePartIndex<SmallSlots>(6),
     ],
+    event_queue: EventQueue(EventQueueData {
+        instant: 15 μs,
+        events: {},
+    }),
+    waiting_sensitivity_sets_by_address: {},
+    waiting_sensitivity_sets_by_compiled_value: {},
     ..
 }

crates/fayalite/tests/sim/expected/memories3.vcd

@@ -420,6 +420,10 @@ b10000 T
 1\
 #3250000
 1#
+b110100 %
+b1111000 '
+b10011010 (
+b11110000 +
 1.
 1A
 b110100 C
@@ -427,10 +431,6 @@ b1111000 E
 b10011010 F
 b11110000 I
 1L
-b110100 %
-b1111000 '
-b10011010 (
-b11110000 +
 #3500000
 #3750000
 0#
@@ -508,6 +508,14 @@ b1010100 '"
 b110010 /"
 b10000 7"
 1#
+b11111110 $
+b11011100 %
+b10111010 &
+b10011000 '
+b1110110 (
+b1010100 )
+b110010 *
+b10000 +
 1.
 1A
 b11111110 B
@@ -519,14 +527,6 @@ b1010100 G
 b110010 H
 b10000 I
 1L
-b11111110 $
-b11011100 %
-b10111010 &
-b10011000 '
-b1110110 (
-b1010100 )
-b110010 *
-b10000 +
 #6500000
 #6750000
 0#
@@ -562,6 +562,14 @@ b1000110 ("
 b10001010 0"
 b11001110 8"
 1#
+b0 $
+b0 %
+b0 &
+b0 '
+b0 (
+b0 )
+b0 *
+b0 +
 1.
 1A
 b0 B
@@ -573,14 +581,6 @@ b0 G
 b0 H
 b0 I
 1L
-b0 $
-b0 %
-b0 &
-b0 '
-b0 (
-b0 )
-b0 *
-b0 +
 #7500000
 #7750000
 0#
@@ -688,6 +688,14 @@ b1 !
 b1 ?
 #10250000
 1#
+b11111110 $
+b11011100 %
+b10111010 &
+b10011000 '
+b1110110 (
+b1010100 )
+b110010 *
+b10000 +
 1.
 1A
 b11111110 B
@@ -699,14 +707,6 @@ b1010100 G
 b110010 H
 b10000 I
 1L
-b11111110 $
-b11011100 %
-b10111010 &
-b10011000 '
-b1110110 (
-b1010100 )
-b110010 *
-b10000 +
 #10500000
 #10750000
 0#
@@ -718,6 +718,14 @@ b10 !
 b10 ?
 #11250000
 1#
+b10011 $
+b1010111 %
+b10011011 &
+b11011111 '
+b10 (
+b1000110 )
+b10001010 *
+b11001110 +
 1.
 1A
 b10011 B
@@ -729,14 +737,6 @@ b1000110 G
 b10001010 H
 b11001110 I
 1L
-b10011 $
-b1010111 %
-b10011011 &
-b11011111 '
-b10 (
-b1000110 )
-b10001010 *
-b11001110 +
 #11500000
 #11750000
 0#
@@ -748,6 +748,14 @@ b11 !
 b11 ?
 #12250000
 1#
+b1110100 $
+b1100101 %
+b1110011 &
+b1110100 '
+b1101001 (
+b1101110 )
+b1100111 *
+b100001 +
 1.
 1A
 b1110100 B
@@ -759,14 +767,6 @@ b1101110 G
 b1100111 H
 b100001 I
 1L
-b1110100 $
-b1100101 %
-b1110011 &
-b1110100 '
-b1101001 (
-b1101110 )
-b1100111 *
-b100001 +
 #12500000
 #12750000
 0#
@@ -780,6 +780,14 @@ b0 ?
 0@
 #13250000
 1#
+b1101101 $
+b1101111 %
+b1110010 &
+b1100101 '
+b100000 (
+b1110100 )
+b1110011 *
+b1110100 +
 1.
 1A
 b1101101 B
@@ -791,14 +799,6 @@ b1110100 G
 b1110011 H
 b1110100 I
 1L
-b1101101 $
-b1101111 %
-b1110010 &
-b1100101 '
-b100000 (
-b1110100 )
-b1110011 *
-b1110100 +
 #13500000
 #13750000
 0#
@@ -808,6 +808,14 @@ b1110100 +
 #14000000
 #14250000
 1#
+b0 $
+b0 %
+b0 &
+b0 '
+b0 (
+b0 )
+b0 *
+b0 +
 1.
 1A
 b0 B
@@ -819,14 +827,6 @@ b0 G
 b0 H
 b0 I
 1L
-b0 $
-b0 %
-b0 &
-b0 '
-b0 (
-b0 )
-b0 *
-b0 +
 #14500000
 #14750000
 0#

crates/fayalite/tests/sim/expected/mod1.txt

@@ -276,7 +276,6 @@ Simulation {
         did_initial_settle: true,
     },
     extern_modules: [],
-    state_ready_to_run: false,
     trace_decls: TraceModule {
         name: "mod1",
         children: [
@@ -558,7 +557,12 @@ Simulation {
             },
         ),
     ],
-    instant: 2 μs,
     clocks_triggered: [],
+    event_queue: EventQueue(EventQueueData {
+        instant: 2 μs,
+        events: {},
+    }),
+    waiting_sensitivity_sets_by_address: {},
+    waiting_sensitivity_sets_by_compiled_value: {},
     ..
 }

crates/fayalite/tests/sim/expected/ripple_counter.txt

@@ -827,52 +827,6 @@ Simulation {
             running_generator: Some(
                 ...,
             ),
-            wait_targets: {
-                Change {
-                    key: CompiledValue {
-                        layout: CompiledTypeLayout {
-                            ty: Clock,
-                            layout: TypeLayout {
-                                small_slots: StatePartLayout<SmallSlots> {
-                                    len: 0,
-                                    debug_data: [],
-                                    ..
-                                },
-                                big_slots: StatePartLayout<BigSlots> {
-                                    len: 1,
-                                    debug_data: [
-                                        SlotDebugData {
-                                            name: "InstantiatedModule(ripple_counter.bit_reg_1: sw_reg).sw_reg::clk",
-                                            ty: Clock,
-                                        },
-                                    ],
-                                    ..
-                                },
-                                sim_only_slots: StatePartLayout<SimOnlySlots> {
-                                    len: 0,
-                                    debug_data: [],
-                                    layout_data: [],
-                                    ..
-                                },
-                            },
-                            body: Scalar,
-                        },
-                        range: TypeIndexRange {
-                            small_slots: StatePartIndexRange<SmallSlots> { start: 3, len: 0 },
-                            big_slots: StatePartIndexRange<BigSlots> { start: 33, len: 1 },
-                            sim_only_slots: StatePartIndexRange<SimOnlySlots> { start: 0, len: 0 },
-                        },
-                        write: None,
-                    },
-                    value: SimValue {
-                        ty: Clock,
-                        value: OpaqueSimValue {
-                            bits: 0x0_u1,
-                            sim_only_values: [],
-                        },
-                    },
-                },
-            },
         },
         SimulationExternModuleState {
             module_state: SimulationModuleState {
@@ -956,52 +910,6 @@ Simulation {
             running_generator: Some(
                 ...,
             ),
-            wait_targets: {
-                Change {
-                    key: CompiledValue {
-                        layout: CompiledTypeLayout {
-                            ty: Clock,
-                            layout: TypeLayout {
-                                small_slots: StatePartLayout<SmallSlots> {
-                                    len: 0,
-                                    debug_data: [],
-                                    ..
-                                },
-                                big_slots: StatePartLayout<BigSlots> {
-                                    len: 1,
-                                    debug_data: [
-                                        SlotDebugData {
-                                            name: "InstantiatedModule(ripple_counter.bit_reg_3: sw_reg).sw_reg::clk",
-                                            ty: Clock,
-                                        },
-                                    ],
-                                    ..
-                                },
-                                sim_only_slots: StatePartLayout<SimOnlySlots> {
-                                    len: 0,
-                                    debug_data: [],
-                                    layout_data: [],
-                                    ..
-                                },
-                            },
-                            body: Scalar,
-                        },
-                        range: TypeIndexRange {
-                            small_slots: StatePartIndexRange<SmallSlots> { start: 6, len: 0 },
-                            big_slots: StatePartIndexRange<BigSlots> { start: 44, len: 1 },
-                            sim_only_slots: StatePartIndexRange<SimOnlySlots> { start: 0, len: 0 },
-                        },
-                        write: None,
-                    },
-                    value: SimValue {
-                        ty: Clock,
-                        value: OpaqueSimValue {
-                            bits: 0x0_u1,
-                            sim_only_values: [],
-                        },
-                    },
-                },
-            },
         },
         SimulationExternModuleState {
             module_state: SimulationModuleState {
@@ -1085,55 +993,8 @@ Simulation {
             running_generator: Some(
                 ...,
             ),
-            wait_targets: {
-                Change {
-                    key: CompiledValue {
-                        layout: CompiledTypeLayout {
-                            ty: Clock,
-                            layout: TypeLayout {
-                                small_slots: StatePartLayout<SmallSlots> {
-                                    len: 0,
-                                    debug_data: [],
-                                    ..
-                                },
-                                big_slots: StatePartLayout<BigSlots> {
-                                    len: 1,
-                                    debug_data: [
-                                        SlotDebugData {
-                                            name: "InstantiatedModule(ripple_counter.bit_reg_5: sw_reg).sw_reg::clk",
-                                            ty: Clock,
-                                        },
-                                    ],
-                                    ..
-                                },
-                                sim_only_slots: StatePartLayout<SimOnlySlots> {
-                                    len: 0,
-                                    debug_data: [],
-                                    layout_data: [],
-                                    ..
-                                },
-                            },
-                            body: Scalar,
-                        },
-                        range: TypeIndexRange {
-                            small_slots: StatePartIndexRange<SmallSlots> { start: 9, len: 0 },
-                            big_slots: StatePartIndexRange<BigSlots> { start: 55, len: 1 },
-                            sim_only_slots: StatePartIndexRange<SimOnlySlots> { start: 0, len: 0 },
-                        },
-                        write: None,
-                    },
-                    value: SimValue {
-                        ty: Clock,
-                        value: OpaqueSimValue {
-                            bits: 0x0_u1,
-                            sim_only_values: [],
-                        },
-                    },
-                },
-            },
         },
     ],
-    state_ready_to_run: false,
     trace_decls: TraceModule {
         name: "ripple_counter",
         children: [
@@ -1593,11 +1454,315 @@ Simulation {
             },
         ),
     ],
-    instant: 256 μs,
     clocks_triggered: [
         StatePartIndex<SmallSlots>(1),
         StatePartIndex<SmallSlots>(4),
         StatePartIndex<SmallSlots>(7),
     ],
+    event_queue: EventQueue(EventQueueData {
+        instant: 256 μs,
+        events: {},
+    }),
+    waiting_sensitivity_sets_by_address: {
+        SensitivitySet {
+            id: 152,
+            values: {
+                CompiledValue {
+                    layout: CompiledTypeLayout {
+                        ty: Clock,
+                        layout: TypeLayout {
+                            small_slots: StatePartLayout<SmallSlots> {
+                                len: 0,
+                                debug_data: [],
+                                ..
+                            },
+                            big_slots: StatePartLayout<BigSlots> {
+                                len: 1,
+                                debug_data: [
+                                    SlotDebugData {
+                                        name: "InstantiatedModule(ripple_counter.bit_reg_5: sw_reg).sw_reg::clk",
+                                        ty: Clock,
+                                    },
+                                ],
+                                ..
+                            },
+                            sim_only_slots: StatePartLayout<SimOnlySlots> {
+                                len: 0,
+                                debug_data: [],
+                                layout_data: [],
+                                ..
+                            },
+                        },
+                        body: Scalar,
+                    },
+                    range: TypeIndexRange {
+                        small_slots: StatePartIndexRange<SmallSlots> { start: 9, len: 0 },
+                        big_slots: StatePartIndexRange<BigSlots> { start: 55, len: 1 },
+                        sim_only_slots: StatePartIndexRange<SimOnlySlots> { start: 0, len: 0 },
+                    },
+                    write: None,
+                }: SimValue {
+                    ty: Clock,
+                    value: OpaqueSimValue {
+                        bits: 0x0_u1,
+                        sim_only_values: [],
+                    },
+                },
+            },
+            changed: Cell {
+                value: false,
+            },
+            ..
+        },
+        SensitivitySet {
+            id: 167,
+            values: {
+                CompiledValue {
+                    layout: CompiledTypeLayout {
+                        ty: Clock,
+                        layout: TypeLayout {
+                            small_slots: StatePartLayout<SmallSlots> {
+                                len: 0,
+                                debug_data: [],
+                                ..
+                            },
+                            big_slots: StatePartLayout<BigSlots> {
+                                len: 1,
+                                debug_data: [
+                                    SlotDebugData {
+                                        name: "InstantiatedModule(ripple_counter.bit_reg_3: sw_reg).sw_reg::clk",
+                                        ty: Clock,
+                                    },
+                                ],
+                                ..
+                            },
+                            sim_only_slots: StatePartLayout<SimOnlySlots> {
+                                len: 0,
+                                debug_data: [],
+                                layout_data: [],
+                                ..
+                            },
+                        },
+                        body: Scalar,
+                    },
+                    range: TypeIndexRange {
+                        small_slots: StatePartIndexRange<SmallSlots> { start: 6, len: 0 },
+                        big_slots: StatePartIndexRange<BigSlots> { start: 44, len: 1 },
+                        sim_only_slots: StatePartIndexRange<SimOnlySlots> { start: 0, len: 0 },
+                    },
+                    write: None,
+                }: SimValue {
+                    ty: Clock,
+                    value: OpaqueSimValue {
+                        bits: 0x0_u1,
+                        sim_only_values: [],
+                    },
+                },
+            },
+            changed: Cell {
+                value: false,
+            },
+            ..
+        },
+        SensitivitySet {
+            id: 170,
+            values: {
+                CompiledValue {
+                    layout: CompiledTypeLayout {
+                        ty: Clock,
+                        layout: TypeLayout {
+                            small_slots: StatePartLayout<SmallSlots> {
+                                len: 0,
+                                debug_data: [],
+                                ..
+                            },
+                            big_slots: StatePartLayout<BigSlots> {
+                                len: 1,
+                                debug_data: [
+                                    SlotDebugData {
+                                        name: "InstantiatedModule(ripple_counter.bit_reg_1: sw_reg).sw_reg::clk",
+                                        ty: Clock,
+                                    },
+                                ],
+                                ..
+                            },
+                            sim_only_slots: StatePartLayout<SimOnlySlots> {
+                                len: 0,
+                                debug_data: [],
+                                layout_data: [],
+                                ..
+                            },
+                        },
+                        body: Scalar,
+                    },
+                    range: TypeIndexRange {
+                        small_slots: StatePartIndexRange<SmallSlots> { start: 3, len: 0 },
+                        big_slots: StatePartIndexRange<BigSlots> { start: 33, len: 1 },
+                        sim_only_slots: StatePartIndexRange<SimOnlySlots> { start: 0, len: 0 },
+                    },
+                    write: None,
+                }: SimValue {
+                    ty: Clock,
+                    value: OpaqueSimValue {
+                        bits: 0x0_u1,
+                        sim_only_values: [],
+                    },
+                },
+            },
+            changed: Cell {
+                value: false,
+            },
+            ..
+        },
+    },
+    waiting_sensitivity_sets_by_compiled_value: {
+        CompiledValue {
+            layout: CompiledTypeLayout {
+                ty: Clock,
+                layout: TypeLayout {
+                    small_slots: StatePartLayout<SmallSlots> {
+                        len: 0,
+                        debug_data: [],
+                        ..
+                    },
+                    big_slots: StatePartLayout<BigSlots> {
+                        len: 1,
+                        debug_data: [
+                            SlotDebugData {
+                                name: "InstantiatedModule(ripple_counter.bit_reg_1: sw_reg).sw_reg::clk",
+                                ty: Clock,
+                            },
+                        ],
+                        ..
+                    },
+                    sim_only_slots: StatePartLayout<SimOnlySlots> {
+                        len: 0,
+                        debug_data: [],
+                        layout_data: [],
+                        ..
+                    },
+                },
+                body: Scalar,
+            },
+            range: TypeIndexRange {
+                small_slots: StatePartIndexRange<SmallSlots> { start: 3, len: 0 },
+                big_slots: StatePartIndexRange<BigSlots> { start: 33, len: 1 },
+                sim_only_slots: StatePartIndexRange<SimOnlySlots> { start: 0, len: 0 },
+            },
+            write: None,
+        }: (
+            SimValue {
+                ty: Clock,
+                value: OpaqueSimValue {
+                    bits: 0x0_u1,
+                    sim_only_values: [],
+                },
+            },
+            {
+                SensitivitySet {
+                    id: 170,
+                    ..
+                },
+            },
+        ),
+        CompiledValue {
+            layout: CompiledTypeLayout {
+                ty: Clock,
+                layout: TypeLayout {
+                    small_slots: StatePartLayout<SmallSlots> {
+                        len: 0,
+                        debug_data: [],
+                        ..
+                    },
+                    big_slots: StatePartLayout<BigSlots> {
+                        len: 1,
+                        debug_data: [
+                            SlotDebugData {
+                                name: "InstantiatedModule(ripple_counter.bit_reg_3: sw_reg).sw_reg::clk",
+                                ty: Clock,
+                            },
+                        ],
+                        ..
+                    },
+                    sim_only_slots: StatePartLayout<SimOnlySlots> {
+                        len: 0,
+                        debug_data: [],
+                        layout_data: [],
+                        ..
+                    },
+                },
+                body: Scalar,
+            },
+            range: TypeIndexRange {
+                small_slots: StatePartIndexRange<SmallSlots> { start: 6, len: 0 },
+                big_slots: StatePartIndexRange<BigSlots> { start: 44, len: 1 },
+                sim_only_slots: StatePartIndexRange<SimOnlySlots> { start: 0, len: 0 },
+            },
+            write: None,
+        }: (
+            SimValue {
+                ty: Clock,
+                value: OpaqueSimValue {
+                    bits: 0x0_u1,
+                    sim_only_values: [],
+                },
+            },
+            {
+                SensitivitySet {
+                    id: 167,
+                    ..
+                },
+            },
+        ),
+        CompiledValue {
+            layout: CompiledTypeLayout {
+                ty: Clock,
+                layout: TypeLayout {
+                    small_slots: StatePartLayout<SmallSlots> {
+                        len: 0,
+                        debug_data: [],
+                        ..
+                    },
+                    big_slots: StatePartLayout<BigSlots> {
+                        len: 1,
+                        debug_data: [
+                            SlotDebugData {
+                                name: "InstantiatedModule(ripple_counter.bit_reg_5: sw_reg).sw_reg::clk",
+                                ty: Clock,
+                            },
+                        ],
+                        ..
+                    },
+                    sim_only_slots: StatePartLayout<SimOnlySlots> {
+                        len: 0,
+                        debug_data: [],
+                        layout_data: [],
+                        ..
+                    },
+                },
+                body: Scalar,
+            },
+            range: TypeIndexRange {
+                small_slots: StatePartIndexRange<SmallSlots> { start: 9, len: 0 },
+                big_slots: StatePartIndexRange<BigSlots> { start: 55, len: 1 },
+                sim_only_slots: StatePartIndexRange<SimOnlySlots> { start: 0, len: 0 },
+            },
+            write: None,
+        }: (
+            SimValue {
+                ty: Clock,
+                value: OpaqueSimValue {
+                    bits: 0x0_u1,
+                    sim_only_values: [],
+                },
+            },
+            {
+                SensitivitySet {
+                    id: 152,
+                    ..
+                },
+            },
+        ),
+    },
     ..
 }

crates/fayalite/tests/sim/expected/shift_register.txt

@@ -339,7 +339,6 @@ Simulation {
         did_initial_settle: true,
     },
     extern_modules: [],
-    state_ready_to_run: false,
     trace_decls: TraceModule {
         name: "shift_register",
         children: [
@@ -440,7 +439,7 @@ Simulation {
                 index: StatePartIndex<BigSlots>(0),
             },
             state: 0x1,
-            last_state: 0x1,
+            last_state: 0x0,
         },
         SimTrace {
             id: TraceScalarId(1),
@@ -509,9 +508,14 @@ Simulation {
             },
         ),
     ],
-    instant: 66 μs,
     clocks_triggered: [
         StatePartIndex<SmallSlots>(1),
     ],
+    event_queue: EventQueue(EventQueueData {
+        instant: 66 μs,
+        events: {},
+    }),
+    waiting_sensitivity_sets_by_address: {},
+    waiting_sensitivity_sets_by_compiled_value: {},
     ..
 }

crates/fayalite/tests/sim/expected/shift_register.vcd

@@ -52,9 +52,9 @@ $end
 0!
 #11000000
 1!
+1$
 0&
 1(
-1$
 #12000000
 0!
 1#
@@ -67,10 +67,10 @@ $end
 0#
 #15000000
 1!
+0$
 0%
 1&
 0(
-0$
 #16000000
 0!
 1#
@@ -83,23 +83,23 @@ $end
 0!
 #19000000
 1!
+1$
 1&
 0'
 1(
-1$
 #20000000
 0!
 #21000000
 1!
+0$
 1'
 0(
-0$
 #22000000
 0!
 #23000000
 1!
-1(
 1$
+1(
 #24000000
 0!
 0#
@@ -120,8 +120,8 @@ $end
 0!
 #31000000
 1!
-0(
 0$
+0(
 #32000000
 0!
 #33000000

crates/fayalite/tests/sim/expected/sim_fork_join.txt

@@ -0,0 +1,523 @@
+Simulation {
+    state: State {
+        insns: Insns {
+            state_layout: StateLayout {
+                ty: TypeLayout {
+                    small_slots: StatePartLayout<SmallSlots> {
+                        len: 0,
+                        debug_data: [],
+                        ..
+                    },
+                    big_slots: StatePartLayout<BigSlots> {
+                        len: 6,
+                        debug_data: [
+                            SlotDebugData {
+                                name: "InstantiatedModule(sim_fork_join: sim_fork_join).sim_fork_join::clocks[0]",
+                                ty: Clock,
+                            },
+                            SlotDebugData {
+                                name: "InstantiatedModule(sim_fork_join: sim_fork_join).sim_fork_join::clocks[1]",
+                                ty: Clock,
+                            },
+                            SlotDebugData {
+                                name: "InstantiatedModule(sim_fork_join: sim_fork_join).sim_fork_join::clocks[2]",
+                                ty: Clock,
+                            },
+                            SlotDebugData {
+                                name: "InstantiatedModule(sim_fork_join: sim_fork_join).sim_fork_join::outputs[0]",
+                                ty: UInt<8>,
+                            },
+                            SlotDebugData {
+                                name: "InstantiatedModule(sim_fork_join: sim_fork_join).sim_fork_join::outputs[1]",
+                                ty: UInt<8>,
+                            },
+                            SlotDebugData {
+                                name: "InstantiatedModule(sim_fork_join: sim_fork_join).sim_fork_join::outputs[2]",
+                                ty: UInt<8>,
+                            },
+                        ],
+                        ..
+                    },
+                    sim_only_slots: StatePartLayout<SimOnlySlots> {
+                        len: 0,
+                        debug_data: [],
+                        layout_data: [],
+                        ..
+                    },
+                },
+                memories: StatePartLayout<Memories> {
+                    len: 0,
+                    debug_data: [],
+                    layout_data: [],
+                    ..
+                },
+            },
+            insns: [
+                // at: module-XXXXXXXXXX.rs:1:1
+                0: Return,
+            ],
+            ..
+        },
+        pc: 0,
+        memory_write_log: [],
+        memories: StatePart {
+            value: [],
+        },
+        small_slots: StatePart {
+            value: [],
+        },
+        big_slots: StatePart {
+            value: [
+                0,
+                0,
+                0,
+                49,
+                50,
+                50,
+            ],
+        },
+        sim_only_slots: StatePart {
+            value: [],
+        },
+    },
+    io: Instance {
+        name: <simulator>::sim_fork_join,
+        instantiated: Module {
+            name: sim_fork_join,
+            ..
+        },
+    },
+    main_module: SimulationModuleState {
+        base_targets: [
+            Instance {
+                name: <simulator>::sim_fork_join,
+                instantiated: Module {
+                    name: sim_fork_join,
+                    ..
+                },
+            }.clocks,
+            Instance {
+                name: <simulator>::sim_fork_join,
+                instantiated: Module {
+                    name: sim_fork_join,
+                    ..
+                },
+            }.outputs,
+        ],
+        uninitialized_ios: {},
+        io_targets: {
+            Instance {
+                name: <simulator>::sim_fork_join,
+                instantiated: Module {
+                    name: sim_fork_join,
+                    ..
+                },
+            }.clocks,
+            Instance {
+                name: <simulator>::sim_fork_join,
+                instantiated: Module {
+                    name: sim_fork_join,
+                    ..
+                },
+            }.clocks[0],
+            Instance {
+                name: <simulator>::sim_fork_join,
+                instantiated: Module {
+                    name: sim_fork_join,
+                    ..
+                },
+            }.clocks[1],
+            Instance {
+                name: <simulator>::sim_fork_join,
+                instantiated: Module {
+                    name: sim_fork_join,
+                    ..
+                },
+            }.clocks[2],
+            Instance {
+                name: <simulator>::sim_fork_join,
+                instantiated: Module {
+                    name: sim_fork_join,
+                    ..
+                },
+            }.outputs,
+            Instance {
+                name: <simulator>::sim_fork_join,
+                instantiated: Module {
+                    name: sim_fork_join,
+                    ..
+                },
+            }.outputs[0],
+            Instance {
+                name: <simulator>::sim_fork_join,
+                instantiated: Module {
+                    name: sim_fork_join,
+                    ..
+                },
+            }.outputs[1],
+            Instance {
+                name: <simulator>::sim_fork_join,
+                instantiated: Module {
+                    name: sim_fork_join,
+                    ..
+                },
+            }.outputs[2],
+        },
+        did_initial_settle: true,
+    },
+    extern_modules: [
+        SimulationExternModuleState {
+            module_state: SimulationModuleState {
+                base_targets: [
+                    ModuleIO {
+                        name: sim_fork_join::clocks,
+                        is_input: true,
+                        ty: Array<Clock, 3>,
+                        ..
+                    },
+                    ModuleIO {
+                        name: sim_fork_join::outputs,
+                        is_input: false,
+                        ty: Array<UInt<8>, 3>,
+                        ..
+                    },
+                ],
+                uninitialized_ios: {},
+                io_targets: {
+                    ModuleIO {
+                        name: sim_fork_join::clocks,
+                        is_input: true,
+                        ty: Array<Clock, 3>,
+                        ..
+                    },
+                    ModuleIO {
+                        name: sim_fork_join::clocks,
+                        is_input: true,
+                        ty: Array<Clock, 3>,
+                        ..
+                    }[0],
+                    ModuleIO {
+                        name: sim_fork_join::clocks,
+                        is_input: true,
+                        ty: Array<Clock, 3>,
+                        ..
+                    }[1],
+                    ModuleIO {
+                        name: sim_fork_join::clocks,
+                        is_input: true,
+                        ty: Array<Clock, 3>,
+                        ..
+                    }[2],
+                    ModuleIO {
+                        name: sim_fork_join::outputs,
+                        is_input: false,
+                        ty: Array<UInt<8>, 3>,
+                        ..
+                    },
+                    ModuleIO {
+                        name: sim_fork_join::outputs,
+                        is_input: false,
+                        ty: Array<UInt<8>, 3>,
+                        ..
+                    }[0],
+                    ModuleIO {
+                        name: sim_fork_join::outputs,
+                        is_input: false,
+                        ty: Array<UInt<8>, 3>,
+                        ..
+                    }[1],
+                    ModuleIO {
+                        name: sim_fork_join::outputs,
+                        is_input: false,
+                        ty: Array<UInt<8>, 3>,
+                        ..
+                    }[2],
+                },
+                did_initial_settle: true,
+            },
+            sim: ExternModuleSimulation {
+                generator: SimGeneratorFn {
+                    args: (
+                        ModuleIO {
+                            name: sim_fork_join::clocks,
+                            is_input: true,
+                            ty: Array<Clock, 3>,
+                            ..
+                        },
+                        ModuleIO {
+                            name: sim_fork_join::outputs,
+                            is_input: false,
+                            ty: Array<UInt<8>, 3>,
+                            ..
+                        },
+                    ),
+                    f: ...,
+                },
+                sim_io_to_generator_map: {
+                    ModuleIO {
+                        name: sim_fork_join::clocks,
+                        is_input: true,
+                        ty: Array<Clock, 3>,
+                        ..
+                    }: ModuleIO {
+                        name: sim_fork_join::clocks,
+                        is_input: true,
+                        ty: Array<Clock, 3>,
+                        ..
+                    },
+                    ModuleIO {
+                        name: sim_fork_join::outputs,
+                        is_input: false,
+                        ty: Array<UInt<8>, 3>,
+                        ..
+                    }: ModuleIO {
+                        name: sim_fork_join::outputs,
+                        is_input: false,
+                        ty: Array<UInt<8>, 3>,
+                        ..
+                    },
+                },
+                source_location: SourceLocation(
+                    module-XXXXXXXXXX.rs:4:1,
+                ),
+            },
+            running_generator: Some(
+                ...,
+            ),
+        },
+    ],
+    trace_decls: TraceModule {
+        name: "sim_fork_join",
+        children: [
+            TraceModuleIO {
+                name: "clocks",
+                child: TraceArray {
+                    name: "clocks",
+                    elements: [
+                        TraceClock {
+                            location: TraceScalarId(0),
+                            name: "[0]",
+                            flow: Source,
+                        },
+                        TraceClock {
+                            location: TraceScalarId(1),
+                            name: "[1]",
+                            flow: Source,
+                        },
+                        TraceClock {
+                            location: TraceScalarId(2),
+                            name: "[2]",
+                            flow: Source,
+                        },
+                    ],
+                    ty: Array<Clock, 3>,
+                    flow: Source,
+                },
+                ty: Array<Clock, 3>,
+                flow: Source,
+            },
+            TraceModuleIO {
+                name: "outputs",
+                child: TraceArray {
+                    name: "outputs",
+                    elements: [
+                        TraceUInt {
+                            location: TraceScalarId(3),
+                            name: "[0]",
+                            ty: UInt<8>,
+                            flow: Sink,
+                        },
+                        TraceUInt {
+                            location: TraceScalarId(4),
+                            name: "[1]",
+                            ty: UInt<8>,
+                            flow: Sink,
+                        },
+                        TraceUInt {
+                            location: TraceScalarId(5),
+                            name: "[2]",
+                            ty: UInt<8>,
+                            flow: Sink,
+                        },
+                    ],
+                    ty: Array<UInt<8>, 3>,
+                    flow: Sink,
+                },
+                ty: Array<UInt<8>, 3>,
+                flow: Sink,
+            },
+        ],
+    },
+    traces: [
+        SimTrace {
+            id: TraceScalarId(0),
+            kind: BigClock {
+                index: StatePartIndex<BigSlots>(0),
+            },
+            state: 0x0,
+            last_state: 0x0,
+        },
+        SimTrace {
+            id: TraceScalarId(1),
+            kind: BigClock {
+                index: StatePartIndex<BigSlots>(1),
+            },
+            state: 0x0,
+            last_state: 0x0,
+        },
+        SimTrace {
+            id: TraceScalarId(2),
+            kind: BigClock {
+                index: StatePartIndex<BigSlots>(2),
+            },
+            state: 0x0,
+            last_state: 0x1,
+        },
+        SimTrace {
+            id: TraceScalarId(3),
+            kind: BigUInt {
+                index: StatePartIndex<BigSlots>(3),
+                ty: UInt<8>,
+            },
+            state: 0x31,
+            last_state: 0x31,
+        },
+        SimTrace {
+            id: TraceScalarId(4),
+            kind: BigUInt {
+                index: StatePartIndex<BigSlots>(4),
+                ty: UInt<8>,
+            },
+            state: 0x32,
+            last_state: 0x32,
+        },
+        SimTrace {
+            id: TraceScalarId(5),
+            kind: BigUInt {
+                index: StatePartIndex<BigSlots>(5),
+                ty: UInt<8>,
+            },
+            state: 0x32,
+            last_state: 0x32,
+        },
+    ],
+    trace_memories: {},
+    trace_writers: [
+        Running(
+            VcdWriter {
+                finished_init: true,
+                timescale: 1 ps,
+                ..
+            },
+        ),
+    ],
+    clocks_triggered: [],
+    event_queue: EventQueue(EventQueueData {
+        instant: 648 μs,
+        events: {},
+    }),
+    waiting_sensitivity_sets_by_address: {
+        SensitivitySet {
+            id: 198,
+            values: {
+                CompiledValue {
+                    layout: CompiledTypeLayout {
+                        ty: Clock,
+                        layout: TypeLayout {
+                            small_slots: StatePartLayout<SmallSlots> {
+                                len: 0,
+                                debug_data: [],
+                                ..
+                            },
+                            big_slots: StatePartLayout<BigSlots> {
+                                len: 1,
+                                debug_data: [
+                                    SlotDebugData {
+                                        name: "",
+                                        ty: Clock,
+                                    },
+                                ],
+                                ..
+                            },
+                            sim_only_slots: StatePartLayout<SimOnlySlots> {
+                                len: 0,
+                                debug_data: [],
+                                layout_data: [],
+                                ..
+                            },
+                        },
+                        body: Scalar,
+                    },
+                    range: TypeIndexRange {
+                        small_slots: StatePartIndexRange<SmallSlots> { start: 0, len: 0 },
+                        big_slots: StatePartIndexRange<BigSlots> { start: 0, len: 1 },
+                        sim_only_slots: StatePartIndexRange<SimOnlySlots> { start: 0, len: 0 },
+                    },
+                    write: None,
+                }: SimValue {
+                    ty: Clock,
+                    value: OpaqueSimValue {
+                        bits: 0x0_u1,
+                        sim_only_values: [],
+                    },
+                },
+            },
+            changed: Cell {
+                value: false,
+            },
+            ..
+        },
+    },
+    waiting_sensitivity_sets_by_compiled_value: {
+        CompiledValue {
+            layout: CompiledTypeLayout {
+                ty: Clock,
+                layout: TypeLayout {
+                    small_slots: StatePartLayout<SmallSlots> {
+                        len: 0,
+                        debug_data: [],
+                        ..
+                    },
+                    big_slots: StatePartLayout<BigSlots> {
+                        len: 1,
+                        debug_data: [
+                            SlotDebugData {
+                                name: "",
+                                ty: Clock,
+                            },
+                        ],
+                        ..
+                    },
+                    sim_only_slots: StatePartLayout<SimOnlySlots> {
+                        len: 0,
+                        debug_data: [],
+                        layout_data: [],
+                        ..
+                    },
+                },
+                body: Scalar,
+            },
+            range: TypeIndexRange {
+                small_slots: StatePartIndexRange<SmallSlots> { start: 0, len: 0 },
+                big_slots: StatePartIndexRange<BigSlots> { start: 0, len: 1 },
+                sim_only_slots: StatePartIndexRange<SimOnlySlots> { start: 0, len: 0 },
+            },
+            write: None,
+        }: (
+            SimValue {
+                ty: Clock,
+                value: OpaqueSimValue {
+                    bits: 0x0_u1,
+                    sim_only_values: [],
+                },
+            },
+            {
+                SensitivitySet {
+                    id: 198,
+                    ..
+                },
+            },
+        ),
+    },
+    ..
+}

crates/fayalite/tests/sim/expected/sim_only_connects.txt

@@ -717,52 +717,6 @@ Simulation {
             running_generator: Some(
                 ...,
             ),
-            wait_targets: {
-                Change {
-                    key: CompiledValue {
-                        layout: CompiledTypeLayout {
-                            ty: Clock,
-                            layout: TypeLayout {
-                                small_slots: StatePartLayout<SmallSlots> {
-                                    len: 0,
-                                    debug_data: [],
-                                    ..
-                                },
-                                big_slots: StatePartLayout<BigSlots> {
-                                    len: 1,
-                                    debug_data: [
-                                        SlotDebugData {
-                                            name: "",
-                                            ty: Clock,
-                                        },
-                                    ],
-                                    ..
-                                },
-                                sim_only_slots: StatePartLayout<SimOnlySlots> {
-                                    len: 0,
-                                    debug_data: [],
-                                    layout_data: [],
-                                    ..
-                                },
-                            },
-                            body: Scalar,
-                        },
-                        range: TypeIndexRange {
-                            small_slots: StatePartIndexRange<SmallSlots> { start: 0, len: 0 },
-                            big_slots: StatePartIndexRange<BigSlots> { start: 4, len: 1 },
-                            sim_only_slots: StatePartIndexRange<SimOnlySlots> { start: 6, len: 0 },
-                        },
-                        write: None,
-                    },
-                    value: SimValue {
-                        ty: Clock,
-                        value: OpaqueSimValue {
-                            bits: 0x1_u1,
-                            sim_only_values: [],
-                        },
-                    },
-                },
-            },
         },
         SimulationExternModuleState {
             module_state: SimulationModuleState {
@@ -922,55 +876,8 @@ Simulation {
             running_generator: Some(
                 ...,
             ),
-            wait_targets: {
-                Change {
-                    key: CompiledValue {
-                        layout: CompiledTypeLayout {
-                            ty: Clock,
-                            layout: TypeLayout {
-                                small_slots: StatePartLayout<SmallSlots> {
-                                    len: 0,
-                                    debug_data: [],
-                                    ..
-                                },
-                                big_slots: StatePartLayout<BigSlots> {
-                                    len: 1,
-                                    debug_data: [
-                                        SlotDebugData {
-                                            name: "",
-                                            ty: Clock,
-                                        },
-                                    ],
-                                    ..
-                                },
-                                sim_only_slots: StatePartLayout<SimOnlySlots> {
-                                    len: 0,
-                                    debug_data: [],
-                                    layout_data: [],
-                                    ..
-                                },
-                            },
-                            body: Scalar,
-                        },
-                        range: TypeIndexRange {
-                            small_slots: StatePartIndexRange<SmallSlots> { start: 4, len: 0 },
-                            big_slots: StatePartIndexRange<BigSlots> { start: 12, len: 1 },
-                            sim_only_slots: StatePartIndexRange<SimOnlySlots> { start: 13, len: 0 },
-                        },
-                        write: None,
-                    },
-                    value: SimValue {
-                        ty: Clock,
-                        value: OpaqueSimValue {
-                            bits: 0x1_u1,
-                            sim_only_values: [],
-                        },
-                    },
-                },
-            },
         },
     ],
-    state_ready_to_run: false,
     trace_decls: TraceModule {
         name: "sim_only_connects",
         children: [
@@ -1628,9 +1535,214 @@ Simulation {
             },
         ),
     ],
-    instant: 16 μs,
     clocks_triggered: [
         StatePartIndex<SmallSlots>(1),
     ],
+    event_queue: EventQueue(EventQueueData {
+        instant: 16 μs,
+        events: {},
+    }),
+    waiting_sensitivity_sets_by_address: {
+        SensitivitySet {
+            id: 30,
+            values: {
+                CompiledValue {
+                    layout: CompiledTypeLayout {
+                        ty: Clock,
+                        layout: TypeLayout {
+                            small_slots: StatePartLayout<SmallSlots> {
+                                len: 0,
+                                debug_data: [],
+                                ..
+                            },
+                            big_slots: StatePartLayout<BigSlots> {
+                                len: 1,
+                                debug_data: [
+                                    SlotDebugData {
+                                        name: "",
+                                        ty: Clock,
+                                    },
+                                ],
+                                ..
+                            },
+                            sim_only_slots: StatePartLayout<SimOnlySlots> {
+                                len: 0,
+                                debug_data: [],
+                                layout_data: [],
+                                ..
+                            },
+                        },
+                        body: Scalar,
+                    },
+                    range: TypeIndexRange {
+                        small_slots: StatePartIndexRange<SmallSlots> { start: 0, len: 0 },
+                        big_slots: StatePartIndexRange<BigSlots> { start: 4, len: 1 },
+                        sim_only_slots: StatePartIndexRange<SimOnlySlots> { start: 6, len: 0 },
+                    },
+                    write: None,
+                }: SimValue {
+                    ty: Clock,
+                    value: OpaqueSimValue {
+                        bits: 0x1_u1,
+                        sim_only_values: [],
+                    },
+                },
+            },
+            changed: Cell {
+                value: false,
+            },
+            ..
+        },
+        SensitivitySet {
+            id: 31,
+            values: {
+                CompiledValue {
+                    layout: CompiledTypeLayout {
+                        ty: Clock,
+                        layout: TypeLayout {
+                            small_slots: StatePartLayout<SmallSlots> {
+                                len: 0,
+                                debug_data: [],
+                                ..
+                            },
+                            big_slots: StatePartLayout<BigSlots> {
+                                len: 1,
+                                debug_data: [
+                                    SlotDebugData {
+                                        name: "",
+                                        ty: Clock,
+                                    },
+                                ],
+                                ..
+                            },
+                            sim_only_slots: StatePartLayout<SimOnlySlots> {
+                                len: 0,
+                                debug_data: [],
+                                layout_data: [],
+                                ..
+                            },
+                        },
+                        body: Scalar,
+                    },
+                    range: TypeIndexRange {
+                        small_slots: StatePartIndexRange<SmallSlots> { start: 4, len: 0 },
+                        big_slots: StatePartIndexRange<BigSlots> { start: 12, len: 1 },
+                        sim_only_slots: StatePartIndexRange<SimOnlySlots> { start: 13, len: 0 },
+                    },
+                    write: None,
+                }: SimValue {
+                    ty: Clock,
+                    value: OpaqueSimValue {
+                        bits: 0x1_u1,
+                        sim_only_values: [],
+                    },
+                },
+            },
+            changed: Cell {
+                value: false,
+            },
+            ..
+        },
+    },
+    waiting_sensitivity_sets_by_compiled_value: {
+        CompiledValue {
+            layout: CompiledTypeLayout {
+                ty: Clock,
+                layout: TypeLayout {
+                    small_slots: StatePartLayout<SmallSlots> {
+                        len: 0,
+                        debug_data: [],
+                        ..
+                    },
+                    big_slots: StatePartLayout<BigSlots> {
+                        len: 1,
+                        debug_data: [
+                            SlotDebugData {
+                                name: "",
+                                ty: Clock,
+                            },
+                        ],
+                        ..
+                    },
+                    sim_only_slots: StatePartLayout<SimOnlySlots> {
+                        len: 0,
+                        debug_data: [],
+                        layout_data: [],
+                        ..
+                    },
+                },
+                body: Scalar,
+            },
+            range: TypeIndexRange {
+                small_slots: StatePartIndexRange<SmallSlots> { start: 0, len: 0 },
+                big_slots: StatePartIndexRange<BigSlots> { start: 4, len: 1 },
+                sim_only_slots: StatePartIndexRange<SimOnlySlots> { start: 6, len: 0 },
+            },
+            write: None,
+        }: (
+            SimValue {
+                ty: Clock,
+                value: OpaqueSimValue {
+                    bits: 0x1_u1,
+                    sim_only_values: [],
+                },
+            },
+            {
+                SensitivitySet {
+                    id: 30,
+                    ..
+                },
+            },
+        ),
+        CompiledValue {
+            layout: CompiledTypeLayout {
+                ty: Clock,
+                layout: TypeLayout {
+                    small_slots: StatePartLayout<SmallSlots> {
+                        len: 0,
+                        debug_data: [],
+                        ..
+                    },
+                    big_slots: StatePartLayout<BigSlots> {
+                        len: 1,
+                        debug_data: [
+                            SlotDebugData {
+                                name: "",
+                                ty: Clock,
+                            },
+                        ],
+                        ..
+                    },
+                    sim_only_slots: StatePartLayout<SimOnlySlots> {
+                        len: 0,
+                        debug_data: [],
+                        layout_data: [],
+                        ..
+                    },
+                },
+                body: Scalar,
+            },
+            range: TypeIndexRange {
+                small_slots: StatePartIndexRange<SmallSlots> { start: 4, len: 0 },
+                big_slots: StatePartIndexRange<BigSlots> { start: 12, len: 1 },
+                sim_only_slots: StatePartIndexRange<SimOnlySlots> { start: 13, len: 0 },
+            },
+            write: None,
+        }: (
+            SimValue {
+                ty: Clock,
+                value: OpaqueSimValue {
+                    bits: 0x1_u1,
+                    sim_only_values: [],
+                },
+            },
+            {
+                SensitivitySet {
+                    id: 31,
+                    ..
+                },
+            },
+        ),
+    },
     ..
 }

crates/fayalite/tests/sim/expected/sim_only_connects.vcd

@@ -72,22 +72,22 @@ s{} 8
 $end
 #1000000
 1!
+s{\"extra\":\x20\"value\"} $
 1'
+s{\"extra\":\x20\"value\"} )
 1+
+s{\"extra\":\x20\"value\"} -
 10
 11
 15
-s{\"extra\":\x20\"value\"} $
-s{\"extra\":\x20\"value\"} )
-s{\"extra\":\x20\"value\"} -
-s{\"bar\":\x20\"\",\x20\"extra\":\x20\"value\",\x20\"foo\":\x20\"baz\"} *
-s{\"bar\":\x20\"\",\x20\"foo\":\x20\"baz\"} 4
 s{\"bar\":\x20\"\",\x20\"extra\":\x20\"value\",\x20\"foo\":\x20\"baz\"} %
-s{\"bar\":\x20\"\",\x20\"foo\":\x20\"baz\"} &
+s{\"bar\":\x20\"\",\x20\"extra\":\x20\"value\",\x20\"foo\":\x20\"baz\"} *
 s{\"bar\":\x20\"\",\x20\"extra\":\x20\"value\",\x20\"foo\":\x20\"baz\"} .
 s{\"bar\":\x20\"\",\x20\"extra\":\x20\"value\",\x20\"foo\":\x20\"baz\"} 3
 s{\"bar\":\x20\"\",\x20\"extra\":\x20\"value\",\x20\"foo\":\x20\"baz\"} 7
-s{\"bar\":\x20\"\",\x20\"foo\":\x20\"baz\"} 8
+s{\"bar\":\x20\"baz\",\x20\"extra\":\x20\"value\",\x20\"foo\":\x20\"baz\"} &
+s{\"bar\":\x20\"baz\",\x20\"extra\":\x20\"value\",\x20\"foo\":\x20\"baz\"} 4
+s{\"bar\":\x20\"baz\",\x20\"extra\":\x20\"value\",\x20\"foo\":\x20\"baz\"} 8
 #2000000
 0!
 0"
@@ -107,9 +107,6 @@ s{\"extra\":\x20\"value\"} /
 00
 11
 15
-s{\"bar\":\x20\"baz\",\x20\"extra\":\x20\"value\",\x20\"foo\":\x20\"baz\"} 4
-s{\"bar\":\x20\"baz\",\x20\"extra\":\x20\"value\",\x20\"foo\":\x20\"baz\"} &
-s{\"bar\":\x20\"baz\",\x20\"extra\":\x20\"value\",\x20\"foo\":\x20\"baz\"} 8
 #4000000
 0!
 0'