Add additional make_tuple test cases

src/gt4py/next/iterator/transforms/fuse_as_fieldop.py

@@ -310,6 +310,7 @@ def visit_FunCall(self, node: itir.FunCall, **kwargs):
             node = self.generic_visit(node, **kwargs)
 
         if cpm.is_call_to(node, "make_tuple"):
+            # TODO(tehrengruber): x, y = alpha * y, x is not fused
             as_fieldop_args = [arg for arg in node.args if cpm.is_applied_as_fieldop(arg)]
             distinct_domains = set(arg.fun.args[1] for arg in as_fieldop_args)  # type: ignore[attr-defined]  # ensured by cpm.is_applied_as_fieldop
             if len(distinct_domains) != len(as_fieldop_args):

tests/next_tests/unit_tests/iterator_tests/transforms_tests/test_fuse_as_fieldop.py

@@ -169,6 +169,45 @@ def test_make_tuple_fusion_trivial():
     )
     assert actual_simplified == expected
 
+def test_make_tuple_fusion_symref():
+    d = im.domain("cartesian_domain", {IDim: (0, 1)})
+    testee = im.make_tuple(
+        im.as_fieldop("deref", d)(im.ref("a", field_type)),
+        im.ref("b", field_type),
+    )
+    expected = im.as_fieldop(
+        im.lambda_("a", "b")(im.make_tuple(im.deref("a"), im.deref("b"))),
+        d,
+    )(im.ref("a", field_type), im.ref("b", field_type))
+    actual = fuse_as_fieldop.FuseAsFieldOp.apply(
+        testee, offset_provider_type={}, allow_undeclared_symbols=True
+    )
+    # simplify to remove unnecessary make_tuple call
+    actual_simplified = collapse_tuple.CollapseTuple.apply(
+        actual, within_stencil=False, allow_undeclared_symbols=True
+    )
+    assert actual_simplified == expected
+
+
+def test_make_tuple_fusion_symref2():
+    d = im.domain("cartesian_domain", {IDim: (0, 1)})
+    testee = im.make_tuple(
+        im.as_fieldop("deref", d)(im.ref("a", field_type)),
+        im.ref("a", field_type),
+    )
+    expected = im.as_fieldop(
+        im.lambda_("a")(im.make_tuple(im.deref("a"), im.deref("a"))),
+        d,
+    )(im.ref("a", field_type))
+    actual = fuse_as_fieldop.FuseAsFieldOp.apply(
+        testee, offset_provider_type={}, allow_undeclared_symbols=True
+    )
+    # simplify to remove unnecessary make_tuple call
+    actual_simplified = collapse_tuple.CollapseTuple.apply(
+        actual, within_stencil=False, allow_undeclared_symbols=True
+    )
+    assert actual_simplified == expected
+
 
 def test_make_tuple_fusion_different_domains():
     d1 = im.domain("cartesian_domain", {IDim: (0, 1)})