I though this might be tokenizer issue, but this is just large memory consumption for AST tree. Simpler example:

./python -c 'import ast; ast.parse("0,"*1000000, mode="eval")'

It takes over 450MB of memory on 32-bit system, over 450 bytes per tuple item. Increase the multiplier to 10000000 leads to swapping and failing with MemoryError.

Of course it would be nice to decrease memory consumption, but this looks rather as new feature.