fix: parse AsTraitPath in type expressions

compiler/noirc_frontend/src/parser/parser/type_expression.rs

@@ -143,6 +143,7 @@ impl Parser<'_> {
     /// AtomTypeExpression
     ///     = ConstantTypeExpression
     ///     | VariableTypeExpression
+    ///     | AsTraitPathTypeExpression
     ///     | ParenthesizedTypeExpression
     fn parse_atom_type_expression(&mut self) -> Option<UnresolvedTypeExpression> {
         if let Some(type_expr) = self.parse_constant_type_expression() {
@@ -153,6 +154,10 @@ impl Parser<'_> {
             return Some(type_expr);
         }
 
+        if let Some(as_trait_path) = self.parse_as_trait_path() {
+            return Some(UnresolvedTypeExpression::AsTraitPath(Box::new(as_trait_path)));
+        }
+
         if let Some(type_expr) = self.parse_parenthesized_type_expression() {
             return Some(type_expr);
         }
@@ -474,6 +479,18 @@ mod tests {
         assert_eq!(expr.to_string(), "(0 - N)");
     }
 
+    #[test]
+    fn parses_as_trait_path_type_expression() {
+        let src = "<Type as Trait>::AssociatedType";
+        let typ = parse_type_expression_no_errors(src);
+        let UnresolvedTypeExpression::AsTraitPath(as_trait_path) = typ else {
+            panic!("Expected AsTraitPath");
+        };
+        assert_eq!(as_trait_path.typ.to_string(), "Type");
+        assert_eq!(as_trait_path.trait_path.to_string(), "Trait");
+        assert_eq!(as_trait_path.impl_item.to_string(), "AssociatedType");
+    }
+
     #[test]
     fn parse_type_or_type_expression_constant() {
         let src = "42";

test_programs/compile_success_empty/as_trait_path_type_expression/Nargo.toml

@@ -0,0 +1,6 @@
+[package]
+name = "as_trait_path_type_expression"
+type = "bin"
+authors = [""]
+
+[dependencies]

test_programs/compile_success_empty/as_trait_path_type_expression/src/main.nr

@@ -0,0 +1,14 @@
+use std::mem::zeroed;
+
+trait Trait {
+    let N: u32;
+}
+
+impl Trait for Field {
+    let N: u32 = 10;
+}
+
+fn main() {
+    let something: [Field; <Field as Trait>::N] = zeroed();
+    assert_eq(something.len(), <Field as Trait>::N);
+}

tooling/nargo_cli/build.rs

@@ -178,7 +178,7 @@ const TESTS_WITHOUT_STDOUT_CHECK: [&str; 0] = [];
 /// These tests are ignored because of existing bugs in `nargo expand`.
 /// As the bugs are fixed these tests should be removed from this list.
 /// (some are ignored on purpose for the same reason as `IGNORED_NARGO_EXPAND_EXECUTION_TESTS`)
-const IGNORED_NARGO_EXPAND_COMPILE_SUCCESS_EMPTY_TESTS: [&str; 14] = [
+const IGNORED_NARGO_EXPAND_COMPILE_SUCCESS_EMPTY_TESTS: [&str; 8] = [
     // bug
     "associated_type_bounds",
     // bug
@@ -189,25 +189,13 @@ const IGNORED_NARGO_EXPAND_COMPILE_SUCCESS_EMPTY_TESTS: [&str; 14] = [
     // because it references another project by a relative path
     "reexports",
     // bug
-    "serialize_1",
-    // bug
-    "serialize_2",
-    // bug
-    "serialize_3",
-    // bug
-    "serialize_4",
-    // bug
     "trait_function_calls",
     // bug
     "trait_method_mut_self",
     // bug
     "trait_static_methods",
     // There's no "src/main.nr" here so it's trickier to make this work
     "workspace_reexport_bug",
-    // bug
-    "type_trait_method_call_multiple_candidates",
-    // bug
-    "alias_trait_method_call_multiple_candidates",
 ];
 
 /// These tests are ignored because of existing bugs in `nargo expand`.
@@ -223,8 +211,6 @@ const IGNORED_NARGO_EXPAND_COMPILE_SUCCESS_NO_BUG_TESTS: [&str; 10] = [
     "noirc_frontend_tests_traits_accesses_associated_type_inside_trait_impl_using_self",
     "noirc_frontend_tests_traits_accesses_associated_type_inside_trait_using_self",
     "noirc_frontend_tests_u32_globals_as_sizes_in_types",
-    // "noirc_frontend_tests_traits_as_trait_path_called_multiple_times_for_different_t_1",
-    // "noirc_frontend_tests_traits_as_trait_path_called_multiple_times_for_different_t_2",
 ];
 
 const IGNORED_NARGO_EXPAND_COMPILE_SUCCESS_WITH_BUG_TESTS: [&str; 1] =