Currently LIGO fails with an error on type-checking when compiling a contract that applies set or ticket to a non-comparable type:
$ cat not_comparable.mligo let main ((_u, s) : (int set) set * unit) : operation list * unit = ([] : operation list), s$ ligo compile contract not_comparable.mligo Error(s) occurred while type checking the contract:At (unshown) location 2, ill formed type: 1: { parameter (set (set int)) ; 2: storage unit ; 3: code { CDR ; NIL operation ; PAIR } }At line 1 characters 17 to 25,comparable type expected.Type set int is not comparable.
This is not a very helpful message for the user, as the locations warned in the error refer to Michelson and not to LIGO.
Description
This MR introduces a check at 15-self_mini_c.
Types of changes
Bug fix (non-breaking change which fixes an issue)
New feature (non-breaking change which adds functionality)
Breaking change (fix or feature that would cause existing functionality to not work as expected)
Performance improvement (non-breaking change that improves performance)
None (change with no changelog)
Changelog
Before change
$ ligo compile contract not_comparable.mligo Error(s) occurred while type checking the contract:At (unshown) location 2, ill formed type: 1: { parameter (set (set int)) ; 2: storage unit ; 3: code { CDR ; NIL operation ; PAIR } }At line 1 characters 17 to 25,comparable type expected.Type set int is not comparable.
After change
$ ligo compile contract not_comparable.mligo File "not_comparable.mligo", line 1, characters 21-28: 1 | let main ((_u, s) : (int set) set * unit) : operation list * unit = ([] : operation list), sThe set constructor needs a comparable type argument, but it was given a non-comparable one.
Checklist:
Changes follow the existing coding style (use dune @fmt to check).
Tests for the changes have been added (for bug fixes / feature).
Documentation has been updated.
Changelog description has been added (if appropriate).
Examples in changed behaviour have been added to the changelog (for breaking change / feature).
