chore: add test to check that duplicate definitions generated from ma…

…cros throws error (#6351)

…

# Description

## Problem\*

Resolves <!-- Link to GitHub Issue -->

## Summary\*

This PR adds a test to sanity check that we will throw an error on
duplicate named functions being injected by macros as reported in
https://aztecprotocol.slack.com/archives/C0183F0V42V/p1729855935233669

## Additional Context



## 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/tests/metaprogramming.rs

@@ -1,6 +1,15 @@
-use crate::hir::{
-    def_collector::dc_crate::CompilationError, resolution::errors::ResolverError,
-    type_check::TypeCheckError,
+use noirc_errors::Spanned;
+
+use crate::{
+    ast::Ident,
+    hir::{
+        def_collector::{
+            dc_crate::CompilationError,
+            errors::{DefCollectorErrorKind, DuplicateType},
+        },
+        resolution::errors::ResolverError,
+        type_check::TypeCheckError,
+    },
 };
 
 use super::{assert_no_errors, get_program_errors};
@@ -96,3 +105,39 @@ fn allows_references_to_structs_generated_by_macros() {
 
     assert_no_errors(src);
 }
+
+#[test]
+fn errors_if_macros_inject_functions_with_name_collisions() {
+    let src = r#"
+    comptime fn make_colliding_functions(_s: StructDefinition) -> Quoted {
+        quote { 
+            fn foo() {}
+        }
+    }
+
+    #[make_colliding_functions]
+    struct Foo {}
+
+    #[make_colliding_functions]
+    struct Bar {}
+
+    fn main() {
+        let _ = Foo {};
+        let _ = Bar {};
+        foo();
+    }
+    "#;
+
+    let errors = get_program_errors(src);
+    assert_eq!(errors.len(), 1);
+    assert!(matches!(
+        &errors[0].0,
+        CompilationError::DefinitionError(
+            DefCollectorErrorKind::Duplicate {
+                typ: DuplicateType::Function,
+                first_def: Ident(Spanned { contents, .. }),
+                ..
+            },
+        ) if contents == "foo"
+    ));
+}