From c05bdbb5f2d5213b04b0f08761c6403069e61179 Mon Sep 17 00:00:00 2001
From: Hannes Vogt <vogt@hey.com>
Date: Wed, 13 Sep 2023 15:12:52 +0200
Subject: [PATCH] address review comment

---
 src/gt4py/next/iterator/embedded.py         | 14 +++++++++-----
 tests/next_tests/integration_tests/cases.py |  2 +-
 2 files changed, 10 insertions(+), 6 deletions(-)

diff --git a/src/gt4py/next/iterator/embedded.py b/src/gt4py/next/iterator/embedded.py
index b0e309f707..673a825a15 100644
--- a/src/gt4py/next/iterator/embedded.py
+++ b/src/gt4py/next/iterator/embedded.py
@@ -707,7 +707,7 @@ def _make_tuple(
     named_indices: NamedFieldIndices,
     *,
     column_axis: Literal[None] = None,
-) -> tuple[tuple | npt.DTypeLike, ...]:  # arbitrary nesting
+) -> tuple[tuple | npt.DTypeLike | Undefined, ...]:  # arbitrary nesting
     ...
 
 
@@ -724,7 +724,7 @@ def _make_tuple(
     named_indices: NamedFieldIndices,
     *,
     column_axis: Literal[None] = None,
-) -> npt.DTypeLike:
+) -> npt.DTypeLike | Undefined:
     ...
 
 
@@ -733,7 +733,7 @@ def _make_tuple(
     named_indices: NamedFieldIndices,
     *,
     column_axis: Optional[Tag] = None,
-) -> Column | npt.DTypeLike | tuple[tuple | Column | npt.DTypeLike, ...] | Undefined:
+) -> Column | npt.DTypeLike | tuple[tuple | Column | npt.DTypeLike | Undefined, ...] | Undefined:
     if column_axis is None:
         if isinstance(field_or_tuple, tuple):
             return tuple(_make_tuple(f, named_indices) for f in field_or_tuple)
@@ -753,7 +753,7 @@ def _make_tuple(
             try:
                 col.append(
                     tuple(
-                        _make_tuple(
+                        _make_tuple(  # type: ignore[misc] # TODO(havogt) don't want to waste time now trying to fix the error "Generator has incompatible item type"
                             f,
                             _single_vertical_idx(
                                 named_indices, column_axis, i - column_range.start
@@ -770,7 +770,11 @@ def _make_tuple(
             except embedded_exceptions.IndexOutOfBounds:
                 col.append(_UNDEFINED)
 
-        first = next((v for v in col if v != _UNDEFINED))
+        first = next((v for v in col if v != _UNDEFINED), None)
+        if first is None:
+            raise RuntimeError(
+                "Found 'Undefined' value, this should not happen for a legal program."
+            )
         dtype = _column_dtype(first)
         return Column(column_range.start, np.asarray(col, dtype=dtype))
 
diff --git a/tests/next_tests/integration_tests/cases.py b/tests/next_tests/integration_tests/cases.py
index a7f795f454..ee0074e65f 100644
--- a/tests/next_tests/integration_tests/cases.py
+++ b/tests/next_tests/integration_tests/cases.py
@@ -74,7 +74,7 @@
 C2E = gtx.FieldOffset("E2V", source=Edge, target=(Cell, C2EDim))
 
 ScalarValue: TypeAlias = np.int32 | np.int64 | np.float32 | np.float64 | np.generic
-FieldValue: TypeAlias = gtx.Field  # | embedded.LocatedFieldImpl
+FieldValue: TypeAlias = gtx.Field
 FieldViewArg: TypeAlias = FieldValue | ScalarValue | tuple["FieldViewArg", ...]
 FieldViewInout: TypeAlias = FieldValue | tuple["FieldViewInout", ...]
 ReferenceValue: TypeAlias = (