feat: allow unquoting TraitConstraint in trait impl position (#7395)

compiler/noirc_frontend/src/ast/traits.rs

@@ -69,9 +69,7 @@ pub struct TypeImpl {
 pub struct NoirTraitImpl {
     pub impl_generics: UnresolvedGenerics,
 
-    pub trait_name: Path,
-
-    pub trait_generics: GenericTypeArgs,
+    pub r#trait: UnresolvedType,
 
     pub object_type: UnresolvedType,
 
@@ -247,7 +245,7 @@ impl Display for NoirTraitImpl {
             )?;
         }
 
-        write!(f, " {}{} for {}", self.trait_name, self.trait_generics, self.object_type)?;
+        write!(f, " {} for {}", self.r#trait, self.object_type)?;
         if !self.where_clause.is_empty() {
             write!(
                 f,

compiler/noirc_frontend/src/ast/visitor.rs

@@ -602,7 +602,7 @@ impl NoirTraitImpl {
     }
 
     pub fn accept_children(&self, visitor: &mut impl Visitor) {
-        self.trait_name.accept(visitor);
+        self.r#trait.accept(visitor);
         self.object_type.accept(visitor);
 
         for item in &self.items {

compiler/noirc_frontend/src/elaborator/comptime.rs

@@ -397,8 +397,7 @@ impl<'context> Elaborator<'context> {
                 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,
+                    r#trait: trait_impl.r#trait,
                     object_type: trait_impl.object_type,
                     methods,
                     generics: trait_impl.impl_generics,

compiler/noirc_frontend/src/elaborator/mod.rs

@@ -11,14 +11,15 @@ use crate::{
     },
     graph::CrateId,
     hir::{
-        def_collector::dc_crate::{
-            filter_literal_globals, CollectedItems, CompilationError, ImplMap, UnresolvedEnum,
-            UnresolvedFunctions, UnresolvedGlobal, UnresolvedStruct, UnresolvedTraitImpl,
-            UnresolvedTypeAlias,
+        def_collector::{
+            dc_crate::{
+                filter_literal_globals, CollectedItems, CompilationError, ImplMap, UnresolvedEnum,
+                UnresolvedFunctions, UnresolvedGlobal, UnresolvedStruct, UnresolvedTraitImpl,
+                UnresolvedTypeAlias,
+            },
+            errors::DefCollectorErrorKind,
         },
-        def_collector::errors::DefCollectorErrorKind,
-        def_map::{DefMaps, ModuleData},
-        def_map::{LocalModuleId, ModuleId, MAIN_FUNCTION},
+        def_map::{DefMaps, LocalModuleId, ModuleData, ModuleId, MAIN_FUNCTION},
         resolution::errors::ResolverError,
         scope::ScopeForest as GenericScopeForest,
         type_check::{generics::TraitGenerics, TypeCheckError},
@@ -1458,9 +1459,26 @@ impl<'context> Elaborator<'context> {
             }
 
             let trait_generics = trait_impl.resolved_trait_generics.clone();
+            let ident = match &trait_impl.r#trait.typ {
+                UnresolvedTypeData::Named(trait_path, _, _) => trait_path.last_ident(),
+                UnresolvedTypeData::Resolved(quoted_type_id) => {
+                    let typ = self.interner.get_quoted_type(*quoted_type_id);
+                    let name = if let Type::TraitAsType(_, name, _) = typ {
+                        name.to_string()
+                    } else {
+                        typ.to_string()
+                    };
+                    Ident::new(name, trait_impl.r#trait.span)
+                }
+                _ => {
+                    // We don't error in this case because an error will be produced later on when
+                    // solving the trait impl trait type
+                    Ident::new(trait_impl.r#trait.to_string(), trait_impl.r#trait.span)
+                }
+            };
 
             let resolved_trait_impl = Shared::new(TraitImpl {
-                ident: trait_impl.trait_path.last_ident(),
+                ident,
                 typ: self_type.clone(),
                 trait_id,
                 trait_generics,
@@ -1983,7 +2001,49 @@ impl<'context> Elaborator<'context> {
             self.file = trait_impl.file_id;
             self.local_module = trait_impl.module_id;
 
-            let trait_id = self.resolve_trait_by_path(trait_impl.trait_path.clone());
+            let (trait_id, mut trait_generics, path_span) = match &trait_impl.r#trait.typ {
+                UnresolvedTypeData::Named(trait_path, trait_generics, _) => {
+                    let trait_id = self.resolve_trait_by_path(trait_path.clone());
+                    (trait_id, trait_generics.clone(), trait_path.span)
+                }
+                UnresolvedTypeData::Resolved(quoted_type_id) => {
+                    let typ = self.interner.get_quoted_type(*quoted_type_id);
+                    let span = trait_impl.r#trait.span;
+                    let Type::TraitAsType(trait_id, _, trait_generics) = typ else {
+                        let found = typ.to_string();
+                        self.push_err(ResolverError::ExpectedTrait { span, found });
+                        continue;
+                    };
+
+                    // In order to take associated types into account we turn these resolved generics
+                    // into unresolved ones, but ones that point to solved types.
+                    let trait_id = *trait_id;
+                    let trait_generics = trait_generics.clone();
+                    let trait_generics = GenericTypeArgs {
+                        ordered_args: vecmap(&trait_generics.ordered, |typ| {
+                            let quoted_type_id = self.interner.push_quoted_type(typ.clone());
+                            let typ = UnresolvedTypeData::Resolved(quoted_type_id);
+                            UnresolvedType { typ, span }
+                        }),
+                        named_args: vecmap(&trait_generics.named, |named_type| {
+                            let quoted_type_id =
+                                self.interner.push_quoted_type(named_type.typ.clone());
+                            let typ = UnresolvedTypeData::Resolved(quoted_type_id);
+                            (named_type.name.clone(), UnresolvedType { typ, span })
+                        }),
+                        kinds: Vec::new(),
+                    };
+
+                    (Some(trait_id), trait_generics, span)
+                }
+                _ => {
+                    let span = trait_impl.r#trait.span;
+                    let found = trait_impl.r#trait.typ.to_string();
+                    self.push_err(ResolverError::ExpectedTrait { span, found });
+                    continue;
+                }
+            };
+
             trait_impl.trait_id = trait_id;
             let unresolved_type = trait_impl.object_type.clone();
 
@@ -2006,14 +2066,12 @@ impl<'context> Elaborator<'context> {
                 method.def.where_clause.append(&mut trait_impl.where_clause.clone());
             }
 
-            // Add each associated type to the list of named type arguments
-            let mut trait_generics = trait_impl.trait_generics.clone();
-            trait_generics.named_args.extend(self.take_unresolved_associated_types(trait_impl));
-
             let impl_id = self.interner.next_trait_impl_id();
             self.current_trait_impl = Some(impl_id);
 
-            let path_span = trait_impl.trait_path.span;
+            // Add each associated type to the list of named type arguments
+            trait_generics.named_args.extend(self.take_unresolved_associated_types(trait_impl));
+
             let (ordered_generics, named_generics) = trait_impl
                 .trait_id
                 .map(|trait_id| {
@@ -2038,12 +2096,15 @@ impl<'context> Elaborator<'context> {
             self.generics.clear();
 
             if let Some(trait_id) = trait_id {
-                let trait_name = trait_impl.trait_path.last_ident();
-                self.interner.add_trait_reference(
-                    trait_id,
-                    Location::new(trait_name.span(), trait_impl.file_id),
-                    trait_name.is_self_type_name(),
-                );
+                let (span, is_self_type_name) = match &trait_impl.r#trait.typ {
+                    UnresolvedTypeData::Named(trait_path, _, _) => {
+                        let trait_name = trait_path.last_ident();
+                        (trait_name.span(), trait_name.is_self_type_name())
+                    }
+                    _ => (trait_impl.r#trait.span, false),
+                };
+                let location = Location::new(span, trait_impl.file_id);
+                self.interner.add_trait_reference(trait_id, location, is_self_type_name);
             }
         }
     }

compiler/noirc_frontend/src/hir/comptime/value.rs

@@ -519,6 +519,11 @@ impl Value {
             Value::UnresolvedType(typ) => {
                 Token::InternedUnresolvedTypeData(interner.push_unresolved_type_data(typ))
             }
+            Value::TraitConstraint(trait_id, generics) => {
+                let name = Rc::new(interner.get_trait(trait_id).name.0.contents.clone());
+                let typ = Type::TraitAsType(trait_id, name, generics);
+                Token::QuotedType(interner.push_quoted_type(typ))
+            }
             Value::TypedExpr(TypedExpr::ExprId(expr_id)) => Token::UnquoteMarker(expr_id),
             Value::U1(bool) => Token::Bool(bool),
             Value::U8(value) => Token::Int((value as u128).into()),

compiler/noirc_frontend/src/hir/def_collector/dc_crate.rs

@@ -21,8 +21,8 @@ use crate::node_interner::{
 };
 
 use crate::ast::{
-    ExpressionKind, GenericTypeArgs, Ident, ItemVisibility, LetStatement, Literal, NoirFunction,
-    NoirStruct, NoirTrait, NoirTypeAlias, Path, PathKind, PathSegment, UnresolvedGenerics,
+    ExpressionKind, Ident, ItemVisibility, LetStatement, Literal, NoirFunction, NoirStruct,
+    NoirTrait, NoirTypeAlias, Path, PathKind, PathSegment, UnresolvedGenerics,
     UnresolvedTraitConstraint, UnresolvedType, UnsupportedNumericGenericType,
 };
 
@@ -83,8 +83,7 @@ pub struct UnresolvedTrait {
 pub struct UnresolvedTraitImpl {
     pub file_id: FileId,
     pub module_id: LocalModuleId,
-    pub trait_generics: GenericTypeArgs,
-    pub trait_path: Path,
+    pub r#trait: UnresolvedType,
     pub object_type: UnresolvedType,
     pub methods: UnresolvedFunctions,
     pub generics: UnresolvedGenerics,

compiler/noirc_frontend/src/hir/def_collector/dc_mod.rs

@@ -198,8 +198,6 @@ impl<'a> ModCollector<'a> {
         let mut errors = Vec::new();
 
         for mut trait_impl in impls {
-            let trait_name = trait_impl.trait_name.clone();
-
             let (mut unresolved_functions, associated_types, associated_constants) =
                 collect_trait_impl_items(
                     &mut context.def_interner,
@@ -233,12 +231,11 @@ impl<'a> ModCollector<'a> {
             let unresolved_trait_impl = UnresolvedTraitImpl {
                 file_id: self.file_id,
                 module_id: self.module_id,
-                trait_path: trait_name,
+                r#trait: trait_impl.r#trait,
                 methods: unresolved_functions,
                 object_type: trait_impl.object_type,
                 generics: trait_impl.impl_generics,
                 where_clause: trait_impl.where_clause,
-                trait_generics: trait_impl.trait_generics,
                 associated_constants,
                 associated_types,
 

compiler/noirc_frontend/src/hir/resolution/errors.rs

@@ -180,6 +180,8 @@ pub enum ResolverError {
     },
     #[error("`loop` statements are not yet implemented")]
     LoopNotYetSupported { span: Span },
+    #[error("Expected a trait but found {found}")]
+    ExpectedTrait { found: String, span: Span },
 }
 
 impl ResolverError {
@@ -687,6 +689,13 @@ impl<'a> From<&'a ResolverError> for Diagnostic {
                     *span)
 
             }
+            ResolverError::ExpectedTrait { found, span  } => {
+                Diagnostic::simple_error(
+                    format!("Expected a trait, found {found}"), 
+                    String::new(),
+                    *span)
+
+            }
         }
     }
 }

compiler/noirc_frontend/src/parser/errors.rs

@@ -23,8 +23,6 @@ pub enum ParserErrorReason {
     ExpectedMutAfterAmpersand { found: Token },
     #[error("Invalid left-hand side of assignment")]
     InvalidLeftHandSideOfAssignment,
-    #[error("Expected trait, found {found}")]
-    ExpectedTrait { found: String },
     #[error("Visibility `{visibility}` is not followed by an item")]
     VisibilityNotFollowedByAnItem { visibility: ItemVisibility },
     #[error("`unconstrained` is not followed by an item")]