Proposal to always automatically import core into every Sway project

[emilyaherbert]

The core library is what allows the compiler to handle operations like 1 + 2, true == false, etc. When the core library isn't listed as a dependency (or std isn't listed as a dependency, because it automatically brings in core), then the user gets a confusing error message about how core::ops::Add isn't imported, etc. I feel that because operations like 1 + 2 and true == false are so ubiquitous, that core should be automatically imported always. It also isn't a very good user experience to have to remember to import a library in order to use +, IMO.

• Related to Create an implicit Sway prelude #841

[adlerjohn]

Note that the only people that would be affected by this are us, since users are always expected to disable implicit std importing.

[tritao]

FWIW just hit this issue while trying to match an enum and was pretty confused at first what was going on.

21 | 
22 |     match(x) {
   |           ^ Module "core::ops" could not be found.
23 |         MyEnum::Point(x, y) => {
24 |         }

At the very least we should probably add to the error message here to mention that core needs to be imported.

[mohammadfawaz]

This is complete. We have a pretty extensive core and std preludes now and Forc.toml imports std and core automatically.