diff --git a/jaclang/compiler/absyntree.py b/jaclang/compiler/absyntree.py
index 21a9a6382..3243397e4 100644
--- a/jaclang/compiler/absyntree.py
+++ b/jaclang/compiler/absyntree.py
@@ -271,12 +271,16 @@ def __init__(
         body: Sequence[ElementStmt | String | EmptyToken],
         is_imported: bool,
         kid: Sequence[AstNode],
+        impl_mod: Optional[Module] = None,
+        test_mod: Optional[Module] = None,
     ) -> None:
         """Initialize whole program node."""
         self.name = name
         self.source = source
         self.body = body
         self.is_imported = is_imported
+        self.impl_mod = impl_mod
+        self.test_mod = test_mod
         self.mod_deps: dict[str, Module] = {}
         AstNode.__init__(self, kid=kid)
         AstDocNode.__init__(self, doc=doc)
diff --git a/jaclang/compiler/passes/main/import_pass.py b/jaclang/compiler/passes/main/import_pass.py
index b753ebdec..8621e6e37 100644
--- a/jaclang/compiler/passes/main/import_pass.py
+++ b/jaclang/compiler/passes/main/import_pass.py
@@ -27,6 +27,7 @@ def before_pass(self) -> None:
     def enter_module(self, node: ast.Module) -> None:
         """Run Importer."""
         self.cur_node = node
+        self.annex_impl(node)
         self.terminate()  # Turns off auto traversal for deliberate traversal
         self.run_again = True
         while self.run_again:
@@ -35,25 +36,42 @@ def enter_module(self, node: ast.Module) -> None:
             for i in all_imports:
                 if i.lang.tag.value == "jac" and not i.sub_module:
                     self.run_again = True
-                    mod = (
-                        self.import_module(
-                            node=i,
-                            mod_path=node.loc.mod_path,
-                        )
-                        if i.lang.tag.value == "jac"
-                        else self.import_py_module(node=i, mod_path=node.loc.mod_path)
+                    mod = self.import_module(
+                        node=i,
+                        mod_path=node.loc.mod_path,
                     )
                     if not mod:
                         self.run_again = False
                         continue
+                    self.annex_impl(mod)
                     i.sub_module = mod
                     i.add_kids_right([mod], pos_update=False)
                 # elif i.lang.tag.value == "py":
                 #     self.import_py_module(node=i, mod_path=node.loc.mod_path)
                 self.enter_import(i)
             SubNodeTabPass(prior=self, input_ir=node)
+        self.annex_impl(node)
         node.mod_deps = self.import_table
 
+    def annex_impl(self, node: ast.Module) -> None:
+        """Annex impl and test modules."""
+        if not node.loc.mod_path:
+            self.error("Module has no path")
+        if node.loc.mod_path.endswith(".jac") and path.exists(
+            f"{node.loc.mod_path[:-4]}.impl.jac"
+        ):
+            mod = self.import_mod_from_file(f"{node.loc.mod_path[:-4]}.impl.jac")
+            if mod:
+                node.impl_mod = mod
+                node.add_kids_right([mod], pos_update=False)
+        if node.loc.mod_path.endswith(".jac") and path.exists(
+            f"{node.loc.mod_path[:-4]}.test.jac"
+        ):
+            mod = self.import_mod_from_file(f"{node.loc.mod_path[:-4]}.test.jac")
+            if mod:
+                node.test_mod = mod
+                node.add_kids_right([mod], pos_update=False)
+
     def enter_import(self, node: ast.Import) -> None:
         """Sub objects.
 
@@ -73,19 +91,22 @@ def enter_import(self, node: ast.Import) -> None:
 
     def import_module(self, node: ast.Import, mod_path: str) -> ast.Module | None:
         """Import a module."""
-        from jaclang.compiler.transpiler import jac_file_to_pass
-        from jaclang.compiler.passes.main import SubNodeTabPass
-
         self.cur_node = node  # impacts error reporting
         target = import_target_to_relative_path(
             node.path.path_str, path.dirname(node.loc.mod_path)
         )
+        return self.import_mod_from_file(target)
 
-        if target in self.import_table:
-            return self.import_table[target]
+    def import_mod_from_file(self, target: str) -> ast.Module | None:
+        """Import a module from a file."""
+        from jaclang.compiler.transpiler import jac_file_to_pass
+        from jaclang.compiler.passes.main import SubNodeTabPass
 
         if not path.exists(target):
-            self.error(f"Could not find module {target}", node_override=node)
+            self.error(f"Could not find module {target}")
+            return None
+        if target in self.import_table:
+            return self.import_table[target]
         try:
             mod_pass = jac_file_to_pass(file_path=target, target=SubNodeTabPass)
             self.errors_had += mod_pass.errors_had
@@ -99,9 +120,7 @@ def import_module(self, node: ast.Import, mod_path: str) -> ast.Module | None:
             mod.is_imported = True
             return mod
         else:
-            self.error(
-                f"Module {target} is not a valid Jac module.", node_override=node
-            )
+            self.error(f"Module {target} is not a valid Jac module.")
             return None
 
     def import_py_module(self, node: ast.Import, mod_path: str) -> Optional[ast.Module]: