feat: Allow inserting new structs and into programs from attributes (#…

…5927)

# Description

## Problem\*

Resolves #5913

## Summary\*

Allows inserting new structs and impls into the program from comptime
attributes.

## Additional Context

Inserting new structs wasn't allowed originally since functions wouldn't
be able to refer to them in their signature. This use case isn't needed
for aztec currently so I'm adding this feature now and we can look into
expanding it later. See #5926

## Documentation\*

Check one:
- [x] No documentation needed.
- [ ] Documentation included in this PR.
- [ ] **[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.

compiler/noirc_frontend/src/elaborator/comptime.rs

@@ -385,14 +385,30 @@ impl<'context> Elaborator<'context> {
                     self.errors.push(error);
                 }
             }
+            TopLevelStatement::Struct(struct_def) => {
+                if let Some((type_id, the_struct)) = dc_mod::collect_struct(
+                    self.interner,
+                    self.def_maps.get_mut(&self.crate_id).unwrap(),
+                    struct_def,
+                    self.file,
+                    self.local_module,
+                    self.crate_id,
+                    &mut self.errors,
+                ) {
+                    generated_items.types.insert(type_id, the_struct);
+                }
+            }
+            TopLevelStatement::Impl(r#impl) => {
+                let module = self.module_id();
+                dc_mod::collect_impl(self.interner, generated_items, r#impl, self.file, module);
+            }
+
             // Assume that an error has already been issued
             TopLevelStatement::Error => (),
 
             TopLevelStatement::Module(_)
             | TopLevelStatement::Import(..)
-            | TopLevelStatement::Struct(_)
             | TopLevelStatement::Trait(_)
-            | TopLevelStatement::Impl(_)
             | TopLevelStatement::TypeAlias(_)
             | TopLevelStatement::SubModule(_)
             | TopLevelStatement::InnerAttribute(_) => {

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

@@ -488,7 +488,7 @@ impl<'a> From<&'a InterpreterError> for CustomDiagnostic {
             InterpreterError::UnsupportedTopLevelItemUnquote { item, location } => {
                 let msg = "Unsupported statement type to unquote".into();
                 let secondary =
-                    "Only functions, globals, and trait impls can be unquoted here".into();
+                    "Only functions, structs, globals, and impls can be unquoted here".into();
                 let mut error = CustomDiagnostic::simple_error(msg, secondary, location.span);
                 error.add_note(format!("Unquoted item was:\n{item}"));
                 error