Add test cases for python#14209

test-data/unit/check-possibly-undefined.test

@@ -1043,3 +1043,40 @@ def foo(x: Union[int, str]) -> None:
         assert_never(x)
     f  # OK
 [builtins fixtures/tuple.pyi]
+
+[case testForLoopBreakElseDefinition]
+# flags: --enable-error-code possibly-undefined
+# Regression test for https://github.com/python/mypy/issues/14209
+for i in [1, 2, 3]:
+    if i:
+        b = i
+        break
+else:
+    b = 1
+
+b  # OK
+
+[case testForLoopBreakElseException]
+# flags: --enable-error-code possibly-undefined
+# Regression test for https://github.com/python/mypy/issues/14209
+for i in [1, 2, 3]:
+    if i:
+        b = i
+        break
+else:
+    raise BaseException()
+
+b  # OK
+[builtins fixtures/exception.pyi]
+
+[case testForLoopBreakElseEmpty]
+# flags: --enable-error-code possibly-undefined
+# Regression test for https://github.com/python/mypy/issues/14209
+for i in [1, 2, 3]:
+    b = i
+    if i:
+        break
+else:
+    b = 1
+
+b  # OK