BUG: Post-merge fixup, raise on dimension-expanding (#40365)

Author: jbrockmendel

pandas/core/internals/managers.py

@@ -1647,6 +1647,9 @@ def getitem_mgr(self, indexer) -> SingleBlockManager:
         # similar to get_slice, but not restricted to slice indexer
         blk = self._block
         array = blk._slice(indexer)
+        if array.ndim > blk.values.ndim:
+            # This will be caught by Series._get_values
+            raise ValueError("dimension-expanding indexing not allowed")
         block = blk.make_block_same_class(array, placement=slice(0, len(array)))
         return type(self)(block, self.index[indexer])