Improve error message

CQCL · Jan 30, 2024 · 829bf20 · 829bf20
1 parent 5fa46f9
commit 829bf20
Show file tree

Hide file tree

Showing 2 changed files with 4 additions and 2 deletions.
diff --git a/guppylang/checker/expr_checker.py b/guppylang/checker/expr_checker.py
@@ -984,7 +984,9 @@ def _python_list_to_guppy_type(
         return None
     for v in rest:
         ty = python_value_to_guppy_type(v, node, globals)
-        if ty is None or (subst := unify(ty, el_ty, {})) is None:
+        if ty is None:
             return None
+        if (subst := unify(ty, el_ty, {})) is None:
+            raise GuppyError("Python list contains elements with different types", node)
         el_ty = el_ty.substitute(subst)
     return ListType(el_ty)
diff --git a/tests/error/py_errors/list_different_tys.err b/tests/error/py_errors/list_different_tys.err
@@ -4,4 +4,4 @@ Guppy compilation failed. Error in file $FILE:6
 5:    def foo() -> int:
 6:        return py([1, 1.0])
                  ^^^^^^^^^^^^
-GuppyError: Python expression of type `<class 'list'>` is not supported by Guppy
+GuppyError: Python list contains elements with different types