Accessing Memory objects with '[ ]' array syntax causes confusing build errors.

[WRansohoff]

It sounds like it is only possible to access Memory data with square-bracket array syntax (memory[ index ]) during simulation.

But when I try to build a bitstream from a design which uses that syntax, it seems to cause an infinite loop in nMigen instead of printing an error. Interrupting the process results in some nested LegalizeValue exceptions which eventually point to:

nmigen.back.rtlil.LegalizeValue: ((+ (sig addr) (const 2'd2)), range(0, 1028), ('[...]/nmigen/hdl/mem.py', 91))

It sounds like this can be fixed by using the Memory object's read/write ports like the examples/basic/mem.py file demonstrates, but an error message might help make that more discoverable. Thanks!

[FFY00]

Hum, shouldn't RecursionError be raised? I think it would be good to investigate why it isn't triggered.

[whitequark]

Hum, shouldn't RecursionError be raised? I think it would be good to investigate why it isn't triggered.

Because it's not an infinite loop or recursion. It's just really slow.

[whitequark]

amaranth-lang/rfcs#45 may address this issue if accepted.