feat: Add TraitConstraint type (#5499)

# Description

## Problem\*

Resolves #5480
Resolves #5481

## Summary\*

Adds:
- The `TraitConstraint` type
- `impl Eq for TraitConstraint`
- `impl Hash for TraitConstraint`
- `Quoted::as_trait_constraint`

## Additional Context

Ran into the type error when calling trait impls issue again while
working on this. Hence why it is a draft.

## Documentation\*

Check one:
- [ ] No documentation needed.
- [ ] Documentation included in this PR.
- [x] **[For Experimental Features]** Documentation to be submitted in a
separate PR.

# PR Checklist\*

- [x] I have tested the changes locally.
- [x] I have formatted the changes with [Prettier](https://prettier.io/)
and/or `cargo fmt` on default settings.

aztec_macros/src/transforms/note_interface.rs

@@ -73,6 +73,7 @@ pub fn generate_note_interface_impl(module: &mut SortedModule) -> Result<(), Azt
                 generics: vec![],
                 methods: vec![],
                 where_clause: vec![],
+                is_comptime: false,
             };
             module.impls.push(default_impl.clone());
             module.impls.last_mut().unwrap()

aztec_macros/src/transforms/storage.rs

@@ -248,6 +248,7 @@ pub fn generate_storage_implementation(
         methods: vec![(init, Span::default())],
 
         where_clause: vec![],
+        is_comptime: false,
     };
     module.impls.push(storage_impl);
 

compiler/noirc_frontend/src/ast/structure.rs

@@ -14,18 +14,7 @@ pub struct NoirStruct {
     pub generics: UnresolvedGenerics,
     pub fields: Vec<(Ident, UnresolvedType)>,
     pub span: Span,
-}
-
-impl NoirStruct {
-    pub fn new(
-        name: Ident,
-        attributes: Vec<SecondaryAttribute>,
-        generics: UnresolvedGenerics,
-        fields: Vec<(Ident, UnresolvedType)>,
-        span: Span,
-    ) -> NoirStruct {
-        NoirStruct { name, attributes, generics, fields, span }
-    }
+    pub is_comptime: bool,
 }
 
 impl Display for NoirStruct {

compiler/noirc_frontend/src/ast/traits.rs

@@ -53,6 +53,7 @@ pub struct TypeImpl {
     pub generics: UnresolvedGenerics,
     pub where_clause: Vec<UnresolvedTraitConstraint>,
     pub methods: Vec<(NoirFunction, Span)>,
+    pub is_comptime: bool,
 }
 
 /// Ast node for an implementation of a trait for a particular type
@@ -69,6 +70,8 @@ pub struct NoirTraitImpl {
     pub where_clause: Vec<UnresolvedTraitConstraint>,
 
     pub items: Vec<TraitImplItem>,
+
+    pub is_comptime: bool,
 }
 
 /// Represents a simple trait constraint such as `where Foo: TraitY<U, V>`
@@ -84,7 +87,7 @@ pub struct UnresolvedTraitConstraint {
 }
 
 /// Represents a single trait bound, such as `TraitX` or `TraitY<U, V>`
-#[derive(Clone, Debug, PartialEq, Eq)]
+#[derive(Clone, Debug, PartialEq, Eq, Hash)]
 pub struct TraitBound {
     pub trait_path: Path,
     pub trait_id: Option<TraitId>, // initially None, gets assigned during DC

compiler/noirc_frontend/src/elaborator/mod.rs

@@ -1636,17 +1636,25 @@ impl<'context> Elaborator<'context> {
             function_sets.push(UnresolvedFunctions { functions, file_id, trait_id, self_type });
         }
 
+        let (comptime_trait_impls, trait_impls) =
+            items.trait_impls.into_iter().partition(|trait_impl| trait_impl.is_comptime);
+
+        let (comptime_structs, structs) =
+            items.types.into_iter().partition(|typ| typ.1.struct_def.is_comptime);
+
         let comptime = CollectedItems {
             functions: comptime_function_sets,
-            types: BTreeMap::new(),
+            types: comptime_structs,
             type_aliases: BTreeMap::new(),
             traits: BTreeMap::new(),
-            trait_impls: Vec::new(),
+            trait_impls: comptime_trait_impls,
             globals: Vec::new(),
             impls: rustc_hash::FxHashMap::default(),
         };
 
         items.functions = function_sets;
+        items.trait_impls = trait_impls;
+        items.types = structs;
         (comptime, items)
     }
 
@@ -1657,75 +1665,85 @@ impl<'context> Elaborator<'context> {
         location: Location,
     ) {
         for item in items {
-            match item {
-                TopLevelStatement::Function(function) => {
-                    let id = self.interner.push_empty_fn();
-                    let module = self.module_id();
-                    self.interner.push_function(id, &function.def, module, location);
-                    let functions = vec![(self.local_module, id, function)];
-                    generated_items.functions.push(UnresolvedFunctions {
-                        file_id: self.file,
-                        functions,
-                        trait_id: None,
-                        self_type: None,
-                    });
-                }
-                TopLevelStatement::TraitImpl(mut trait_impl) => {
-                    let methods = dc_mod::collect_trait_impl_functions(
-                        self.interner,
-                        &mut trait_impl,
-                        self.crate_id,
-                        self.file,
-                        self.local_module,
-                    );
+            self.add_item(item, generated_items, location);
+        }
+    }
 
-                    generated_items.trait_impls.push(UnresolvedTraitImpl {
-                        file_id: self.file,
-                        module_id: self.local_module,
-                        trait_generics: trait_impl.trait_generics,
-                        trait_path: trait_impl.trait_name,
-                        object_type: trait_impl.object_type,
-                        methods,
-                        generics: trait_impl.impl_generics,
-                        where_clause: trait_impl.where_clause,
-
-                        // These last fields are filled in later
-                        trait_id: None,
-                        impl_id: None,
-                        resolved_object_type: None,
-                        resolved_generics: Vec::new(),
-                        resolved_trait_generics: Vec::new(),
-                    });
-                }
-                TopLevelStatement::Global(global) => {
-                    let (global, error) = dc_mod::collect_global(
-                        self.interner,
-                        self.def_maps.get_mut(&self.crate_id).unwrap(),
-                        global,
-                        self.file,
-                        self.local_module,
-                    );
+    fn add_item(
+        &mut self,
+        item: TopLevelStatement,
+        generated_items: &mut CollectedItems,
+        location: Location,
+    ) {
+        match item {
+            TopLevelStatement::Function(function) => {
+                let id = self.interner.push_empty_fn();
+                let module = self.module_id();
+                self.interner.push_function(id, &function.def, module, location);
+                let functions = vec![(self.local_module, id, function)];
+                generated_items.functions.push(UnresolvedFunctions {
+                    file_id: self.file,
+                    functions,
+                    trait_id: None,
+                    self_type: None,
+                });
+            }
+            TopLevelStatement::TraitImpl(mut trait_impl) => {
+                let methods = dc_mod::collect_trait_impl_functions(
+                    self.interner,
+                    &mut trait_impl,
+                    self.crate_id,
+                    self.file,
+                    self.local_module,
+                );
 
-                    generated_items.globals.push(global);
-                    if let Some(error) = error {
-                        self.errors.push(error);
-                    }
-                }
-                // Assume that an error has already been issued
-                TopLevelStatement::Error => (),
-
-                TopLevelStatement::Module(_)
-                | TopLevelStatement::Import(_)
-                | TopLevelStatement::Struct(_)
-                | TopLevelStatement::Trait(_)
-                | TopLevelStatement::Impl(_)
-                | TopLevelStatement::TypeAlias(_)
-                | TopLevelStatement::SubModule(_) => {
-                    let item = item.to_string();
-                    let error = InterpreterError::UnsupportedTopLevelItemUnquote { item, location };
-                    self.errors.push(error.into_compilation_error_pair());
+                generated_items.trait_impls.push(UnresolvedTraitImpl {
+                    file_id: self.file,
+                    module_id: self.local_module,
+                    trait_generics: trait_impl.trait_generics,
+                    trait_path: trait_impl.trait_name,
+                    object_type: trait_impl.object_type,
+                    methods,
+                    generics: trait_impl.impl_generics,
+                    where_clause: trait_impl.where_clause,
+                    is_comptime: trait_impl.is_comptime,
+
+                    // These last fields are filled in later
+                    trait_id: None,
+                    impl_id: None,
+                    resolved_object_type: None,
+                    resolved_generics: Vec::new(),
+                    resolved_trait_generics: Vec::new(),
+                });
+            }
+            TopLevelStatement::Global(global) => {
+                let (global, error) = dc_mod::collect_global(
+                    self.interner,
+                    self.def_maps.get_mut(&self.crate_id).unwrap(),
+                    global,
+                    self.file,
+                    self.local_module,
+                );
+
+                generated_items.globals.push(global);
+                if let Some(error) = error {
+                    self.errors.push(error);
                 }
             }
+            // Assume that an error has already been issued
+            TopLevelStatement::Error => (),
+
+            TopLevelStatement::Module(_)
+            | TopLevelStatement::Import(_)
+            | TopLevelStatement::Struct(_)
+            | TopLevelStatement::Trait(_)
+            | TopLevelStatement::Impl(_)
+            | TopLevelStatement::TypeAlias(_)
+            | TopLevelStatement::SubModule(_) => {
+                let item = item.to_string();
+                let error = InterpreterError::UnsupportedTopLevelItemUnquote { item, location };
+                self.errors.push(error.into_compilation_error_pair());
+            }
         }
     }
 

compiler/noirc_frontend/src/hir/comptime/interpreter/builtin.rs

@@ -1,11 +1,16 @@
-use std::rc::Rc;
+use std::{
+    hash::{Hash, Hasher},
+    rc::Rc,
+};
 
+use chumsky::Parser;
 use noirc_errors::Location;
 
 use crate::{
-    ast::IntegerBitSize,
+    ast::{IntegerBitSize, TraitBound},
     hir::comptime::{errors::IResult, InterpreterError, Value},
     macros_api::{NodeInterner, Signedness},
+    parser,
     token::{SpannedToken, Token, Tokens},
     QuotedType, Type,
 };
@@ -29,6 +34,9 @@ pub(super) fn call_builtin(
         "struct_def_as_type" => struct_def_as_type(interner, arguments, location),
         "struct_def_fields" => struct_def_fields(interner, arguments, location),
         "struct_def_generics" => struct_def_generics(interner, arguments, location),
+        "trait_constraint_eq" => trait_constraint_eq(interner, arguments, location),
+        "trait_constraint_hash" => trait_constraint_hash(interner, arguments, location),
+        "quoted_as_trait_constraint" => quoted_as_trait_constraint(interner, arguments, location),
         _ => {
             let item = format!("Comptime evaluation for builtin function {name}");
             Err(InterpreterError::Unimplemented { item, location })
@@ -79,6 +87,26 @@ fn get_u32(value: Value, location: Location) -> IResult<u32> {
     }
 }
 
+fn get_trait_constraint(value: Value, location: Location) -> IResult<TraitBound> {
+    match value {
+        Value::TraitConstraint(bound) => Ok(bound),
+        value => {
+            let expected = Type::Quoted(QuotedType::TraitConstraint);
+            Err(InterpreterError::TypeMismatch { expected, value, location })
+        }
+    }
+}
+
+fn get_quoted(value: Value, location: Location) -> IResult<Rc<Tokens>> {
+    match value {
+        Value::Code(tokens) => Ok(tokens),
+        value => {
+            let expected = Type::Quoted(QuotedType::Quoted);
+            Err(InterpreterError::TypeMismatch { expected, value, location })
+        }
+    }
+}
+
 fn array_len(
     interner: &NodeInterner,
     mut arguments: Vec<(Value, Location)>,
@@ -231,7 +259,7 @@ fn slice_remove(
     interner: &mut NodeInterner,
     mut arguments: Vec<(Value, Location)>,
     location: Location,
-) -> Result<Value, InterpreterError> {
+) -> IResult<Value> {
     check_argument_count(2, &arguments, location)?;
 
     let index = get_u32(arguments.pop().unwrap().0, location)? as usize;
@@ -257,7 +285,7 @@ fn slice_push_front(
     interner: &mut NodeInterner,
     mut arguments: Vec<(Value, Location)>,
     location: Location,
-) -> Result<Value, InterpreterError> {
+) -> IResult<Value> {
     check_argument_count(2, &arguments, location)?;
 
     let (element, _) = arguments.pop().unwrap();
@@ -270,7 +298,7 @@ fn slice_pop_front(
     interner: &mut NodeInterner,
     mut arguments: Vec<(Value, Location)>,
     location: Location,
-) -> Result<Value, InterpreterError> {
+) -> IResult<Value> {
     check_argument_count(1, &arguments, location)?;
 
     let (mut values, typ) = get_slice(interner, arguments.pop().unwrap().0, location)?;
@@ -284,7 +312,7 @@ fn slice_pop_back(
     interner: &mut NodeInterner,
     mut arguments: Vec<(Value, Location)>,
     location: Location,
-) -> Result<Value, InterpreterError> {
+) -> IResult<Value> {
     check_argument_count(1, &arguments, location)?;
 
     let (mut values, typ) = get_slice(interner, arguments.pop().unwrap().0, location)?;
@@ -298,7 +326,7 @@ fn slice_insert(
     interner: &mut NodeInterner,
     mut arguments: Vec<(Value, Location)>,
     location: Location,
-) -> Result<Value, InterpreterError> {
+) -> IResult<Value> {
     check_argument_count(3, &arguments, location)?;
 
     let (element, _) = arguments.pop().unwrap();
@@ -307,3 +335,54 @@ fn slice_insert(
     values.insert(index as usize, element);
     Ok(Value::Slice(values, typ))
 }
+
+// fn as_trait_constraint(quoted: Quoted) -> TraitConstraint
+fn quoted_as_trait_constraint(
+    _interner: &mut NodeInterner,
+    mut arguments: Vec<(Value, Location)>,
+    location: Location,
+) -> IResult<Value> {
+    check_argument_count(1, &arguments, location)?;
+
+    let tokens = get_quoted(arguments.pop().unwrap().0, location)?;
+    let quoted = tokens.as_ref().clone();
+
+    let trait_bound = parser::trait_bound().parse(quoted).map_err(|mut errors| {
+        let error = errors.swap_remove(0);
+        let rule = "a trait constraint";
+        InterpreterError::FailedToParseMacro { error, tokens, rule, file: location.file }
+    })?;
+
+    Ok(Value::TraitConstraint(trait_bound))
+}
+
+// fn constraint_hash(constraint: TraitConstraint) -> Field
+fn trait_constraint_hash(
+    _interner: &mut NodeInterner,
+    mut arguments: Vec<(Value, Location)>,
+    location: Location,
+) -> IResult<Value> {
+    check_argument_count(1, &arguments, location)?;
+
+    let bound = get_trait_constraint(arguments.pop().unwrap().0, location)?;
+
+    let mut hasher = std::collections::hash_map::DefaultHasher::new();
+    bound.hash(&mut hasher);
+    let hash = hasher.finish();
+
+    Ok(Value::Field((hash as u128).into()))
+}
+
+// fn constraint_eq(constraint_a: TraitConstraint, constraint_b: TraitConstraint) -> bool
+fn trait_constraint_eq(
+    _interner: &mut NodeInterner,
+    mut arguments: Vec<(Value, Location)>,
+    location: Location,
+) -> IResult<Value> {
+    check_argument_count(2, &arguments, location)?;
+
+    let constraint_b = get_trait_constraint(arguments.pop().unwrap().0, location)?;
+    let constraint_a = get_trait_constraint(arguments.pop().unwrap().0, location)?;
+
+    Ok(Value::Bool(constraint_a == constraint_b))
+}