feat: add TraitImpl::trait_generic_args and TraitImpl::methods (#5722)

# Description

## Problem

Part of #5668

## Summary


## Additional Context


## 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.

Author: asterite

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

@@ -7,8 +7,8 @@ use acvm::{AcirField, FieldElement};
 use builtin_helpers::{
     check_argument_count, check_function_not_yet_resolved, check_one_argument,
     check_three_arguments, check_two_arguments, get_expr, get_function_def, get_module, get_quoted,
-    get_slice, get_struct, get_trait_constraint, get_trait_def, get_tuple, get_type, get_u32,
-    hir_pattern_to_tokens, mutate_func_meta_type, parse, parse_tokens,
+    get_slice, get_struct, get_trait_constraint, get_trait_def, get_trait_impl, get_tuple,
+    get_type, get_u32, hir_pattern_to_tokens, mutate_func_meta_type, parse, parse_tokens,
     replace_func_meta_parameters, replace_func_meta_return_type,
 };
 use iter_extended::{try_vecmap, vecmap};
@@ -86,6 +86,10 @@ impl<'local, 'context> Interpreter<'local, 'context> {
             }
             "trait_def_eq" => trait_def_eq(interner, arguments, location),
             "trait_def_hash" => trait_def_hash(interner, arguments, location),
+            "trait_impl_methods" => trait_impl_methods(interner, arguments, location),
+            "trait_impl_trait_generic_args" => {
+                trait_impl_trait_generic_args(interner, arguments, location)
+            }
             "type_as_array" => type_as_array(arguments, return_type, location),
             "type_as_constant" => type_as_constant(arguments, return_type, location),
             "type_as_integer" => type_as_integer(arguments, return_type, location),
@@ -630,6 +634,41 @@ fn trait_def_eq(
     Ok(Value::Bool(id_a == id_b))
 }
 
+// fn methods(self) -> [FunctionDefinition]
+fn trait_impl_methods(
+    interner: &mut NodeInterner,
+    arguments: Vec<(Value, Location)>,
+    location: Location,
+) -> IResult<Value> {
+    let argument = check_one_argument(arguments, location)?;
+
+    let trait_impl_id = get_trait_impl(argument)?;
+    let trait_impl = interner.get_trait_implementation(trait_impl_id);
+    let trait_impl = trait_impl.borrow();
+    let methods =
+        trait_impl.methods.iter().map(|func_id| Value::FunctionDefinition(*func_id)).collect();
+    let slice_type = Type::Slice(Box::new(Type::Quoted(QuotedType::FunctionDefinition)));
+
+    Ok(Value::Slice(methods, slice_type))
+}
+
+// fn trait_generic_args(self) -> [Type]
+fn trait_impl_trait_generic_args(
+    interner: &mut NodeInterner,
+    arguments: Vec<(Value, Location)>,
+    location: Location,
+) -> IResult<Value> {
+    let argument = check_one_argument(arguments, location)?;
+
+    let trait_impl_id = get_trait_impl(argument)?;
+    let trait_impl = interner.get_trait_implementation(trait_impl_id);
+    let trait_impl = trait_impl.borrow();
+    let trait_generics = trait_impl.trait_generics.iter().map(|t| Value::Type(t.clone())).collect();
+    let slice_type = Type::Slice(Box::new(Type::Quoted(QuotedType::Type)));
+
+    Ok(Value::Slice(trait_generics, slice_type))
+}
+
 // fn zeroed<T>() -> T
 fn zeroed(return_type: Type) -> IResult<Value> {
     match return_type {

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

@@ -14,7 +14,7 @@ use crate::{
         stmt::HirPattern,
     },
     macros_api::{NodeInterner, StructId},
-    node_interner::{FuncId, TraitId},
+    node_interner::{FuncId, TraitId, TraitImplId},
     parser::NoirParser,
     token::{Token, Tokens},
     QuotedType, Type,
@@ -77,8 +77,7 @@ pub(crate) fn get_array(
         value => {
             let type_var = Box::new(interner.next_type_variable());
             let expected = Type::Array(type_var.clone(), type_var);
-            let actual = value.get_type().into_owned();
-            Err(InterpreterError::TypeMismatch { expected, actual, location })
+            type_mismatch(value, expected, location)
         }
     }
 }
@@ -92,8 +91,7 @@ pub(crate) fn get_slice(
         value => {
             let type_var = Box::new(interner.next_type_variable());
             let expected = Type::Slice(type_var);
-            let actual = value.get_type().into_owned();
-            Err(InterpreterError::TypeMismatch { expected, actual, location })
+            type_mismatch(value, expected, location)
         }
     }
 }
@@ -107,19 +105,15 @@ pub(crate) fn get_tuple(
         value => {
             let type_var = interner.next_type_variable();
             let expected = Type::Tuple(vec![type_var]);
-            let actual = value.get_type().into_owned();
-            Err(InterpreterError::TypeMismatch { expected, actual, location })
+            type_mismatch(value, expected, location)
         }
     }
 }
 
 pub(crate) fn get_field((value, location): (Value, Location)) -> IResult<FieldElement> {
     match value {
         Value::Field(value) => Ok(value),
-        value => {
-            let actual = value.get_type().into_owned();
-            Err(InterpreterError::TypeMismatch { expected: Type::FieldElement, actual, location })
-        }
+        value => type_mismatch(value, Type::FieldElement, location),
     }
 }
 
@@ -128,8 +122,7 @@ pub(crate) fn get_u8((value, location): (Value, Location)) -> IResult<u8> {
         Value::U8(value) => Ok(value),
         value => {
             let expected = Type::Integer(Signedness::Unsigned, IntegerBitSize::Eight);
-            let actual = value.get_type().into_owned();
-            Err(InterpreterError::TypeMismatch { expected, actual, location })
+            type_mismatch(value, expected, location)
         }
     }
 }
@@ -139,53 +132,36 @@ pub(crate) fn get_u32((value, location): (Value, Location)) -> IResult<u32> {
         Value::U32(value) => Ok(value),
         value => {
             let expected = Type::Integer(Signedness::Unsigned, IntegerBitSize::ThirtyTwo);
-            let actual = value.get_type().into_owned();
-            Err(InterpreterError::TypeMismatch { expected, actual, location })
+            type_mismatch(value, expected, location)
         }
     }
 }
 
 pub(crate) fn get_expr((value, location): (Value, Location)) -> IResult<ExpressionKind> {
     match value {
         Value::Expr(expr) => Ok(expr),
-        value => {
-            let expected = Type::Quoted(QuotedType::Expr);
-            let actual = value.get_type().into_owned();
-            Err(InterpreterError::TypeMismatch { expected, actual, location })
-        }
+        value => type_mismatch(value, Type::Quoted(QuotedType::Expr), location),
     }
 }
 
 pub(crate) fn get_function_def((value, location): (Value, Location)) -> IResult<FuncId> {
     match value {
         Value::FunctionDefinition(id) => Ok(id),
-        value => {
-            let expected = Type::Quoted(QuotedType::FunctionDefinition);
-            let actual = value.get_type().into_owned();
-            Err(InterpreterError::TypeMismatch { expected, actual, location })
-        }
+        value => type_mismatch(value, Type::Quoted(QuotedType::FunctionDefinition), location),
     }
 }
 
 pub(crate) fn get_module((value, location): (Value, Location)) -> IResult<ModuleId> {
     match value {
         Value::ModuleDefinition(module_id) => Ok(module_id),
-        value => {
-            let expected = Type::Quoted(QuotedType::Module);
-            let actual = value.get_type().into_owned();
-            Err(InterpreterError::TypeMismatch { expected, actual, location })
-        }
+        value => type_mismatch(value, Type::Quoted(QuotedType::Module), location),
     }
 }
 
 pub(crate) fn get_struct((value, location): (Value, Location)) -> IResult<StructId> {
     match value {
         Value::StructDefinition(id) => Ok(id),
-        _ => {
-            let expected = Type::Quoted(QuotedType::StructDefinition);
-            let actual = value.get_type().into_owned();
-            Err(InterpreterError::TypeMismatch { expected, location, actual })
-        }
+        _ => type_mismatch(value, Type::Quoted(QuotedType::StructDefinition), location),
     }
 }
 
@@ -194,47 +170,43 @@ pub(crate) fn get_trait_constraint(
 ) -> IResult<(TraitId, Vec<Type>)> {
     match value {
         Value::TraitConstraint(trait_id, generics) => Ok((trait_id, generics)),
-        value => {
-            let expected = Type::Quoted(QuotedType::TraitConstraint);
-            let actual = value.get_type().into_owned();
-            Err(InterpreterError::TypeMismatch { expected, actual, location })
-        }
+        value => type_mismatch(value, Type::Quoted(QuotedType::TraitConstraint), location),
     }
 }
 
 pub(crate) fn get_trait_def((value, location): (Value, Location)) -> IResult<TraitId> {
     match value {
         Value::TraitDefinition(id) => Ok(id),
-        value => {
-            let expected = Type::Quoted(QuotedType::TraitDefinition);
-            let actual = value.get_type().into_owned();
-            Err(InterpreterError::TypeMismatch { expected, actual, location })
-        }
+        value => type_mismatch(value, Type::Quoted(QuotedType::TraitDefinition), location),
+    }
+}
+
+pub(crate) fn get_trait_impl((value, location): (Value, Location)) -> IResult<TraitImplId> {
+    match value {
+        Value::TraitImpl(id) => Ok(id),
+        value => type_mismatch(value, Type::Quoted(QuotedType::TraitImpl), location),
     }
 }
 
 pub(crate) fn get_type((value, location): (Value, Location)) -> IResult<Type> {
     match value {
         Value::Type(typ) => Ok(typ),
-        value => {
-            let expected = Type::Quoted(QuotedType::Type);
-            let actual = value.get_type().into_owned();
-            Err(InterpreterError::TypeMismatch { expected, actual, location })
-        }
+        value => type_mismatch(value, Type::Quoted(QuotedType::Type), location),
     }
 }
 
 pub(crate) fn get_quoted((value, location): (Value, Location)) -> IResult<Rc<Vec<Token>>> {
     match value {
         Value::Quoted(tokens) => Ok(tokens),
-        value => {
-            let expected = Type::Quoted(QuotedType::Quoted);
-            let actual = value.get_type().into_owned();
-            Err(InterpreterError::TypeMismatch { expected, actual, location })
-        }
+        value => type_mismatch(value, Type::Quoted(QuotedType::Quoted), location),
     }
 }
 
+fn type_mismatch<T>(value: Value, expected: Type, location: Location) -> IResult<T> {
+    let actual = value.get_type().into_owned();
+    Err(InterpreterError::TypeMismatch { expected, actual, location })
+}
+
 pub(crate) fn hir_pattern_to_tokens(
     interner: &NodeInterner,
     hir_pattern: &HirPattern,

noir_stdlib/src/meta/mod.nr

@@ -8,6 +8,7 @@ mod module;
 mod struct_def;
 mod trait_constraint;
 mod trait_def;
+mod trait_impl;
 mod typ;
 mod quoted;
 

noir_stdlib/src/meta/trait_impl.nr

@@ -0,0 +1,7 @@
+impl TraitImpl {
+    #[builtin(trait_impl_trait_generic_args)]
+    fn trait_generic_args(self) -> [Type] {}
+
+    #[builtin(trait_impl_methods)]
+    fn methods(self) -> [FunctionDefinition] {}
+}

test_programs/compile_success_empty/comptime_trait_impl/Nargo.toml

@@ -0,0 +1,7 @@
+[package]
+name = "comptime_trait_impl"
+type = "bin"
+authors = [""]
+compiler_version = ">=0.31.0"
+
+[dependencies]

test_programs/compile_success_empty/comptime_trait_impl/src/main.nr

@@ -0,0 +1,32 @@
+use std::meta::type_of;
+
+trait SomeTrait<X, Y> {
+    fn foo();
+}
+struct SomeStruct {
+
+}
+
+impl SomeTrait<i32, i64> for SomeStruct {
+    fn foo() {}
+}
+
+fn main() {
+    comptime
+    {
+        let some_struct = quote { SomeStruct }.as_type();
+        let some_trait = quote { SomeTrait<i32, i64> }.as_trait_constraint();
+        let trait_impl = some_struct.get_trait_impl(some_trait).unwrap();
+
+        // Check TraitImpl::trait_generic_args
+        let trait_generic_args = trait_impl.trait_generic_args();
+        assert_eq(trait_generic_args.len(), 2);
+        assert_eq(trait_generic_args[0], quote { i32 }.as_type());
+        assert_eq(trait_generic_args[1], quote { i64 }.as_type());
+
+        // Check TraitImpl::methods
+        let methods = trait_impl.methods();
+        assert_eq(methods.len(), 1);
+        assert_eq(methods[0].name(), quote { foo });
+    }
+}