Basic unsafe support

[sbillig]

This adds basic support for unsafe functions and unsafe blocks. This doesn't add any built-in unsafe functions; someday soon there will be some fun unsafe fns in a std::evm module, but that'll come in a separate PR. So there's currently no point in using any of this.

I've decided to enforce the rule that contract functions can be either pub or unsafe, but not both. I don't have strong feelings about this, it just seemed reasonable.

To-Do

• OPTIONAL: Update Spec if applicable

• Add entry to the release notes (may forgo for trivial changes)

• Clean up commit history

[codecov-commenter]

Codecov Report

Merging #569 (f72b2bf) into master (a8c713e) will decrease coverage by 0.03%.
The diff coverage is 82.55%.

@@            Coverage Diff             @@
##           master     #569      +/-   ##
==========================================
- Coverage   86.67%   86.63%   -0.04%     
==========================================
  Files          87       87              
  Lines        6362     6428      +66     
==========================================
+ Hits         5514     5569      +55     
- Misses        848      859      +11     

Impacted Files	Coverage Δ
crates/analyzer/src/namespace/scopes.rs	77.34% <ø> (ø)
crates/lowering/src/mappers/module.rs	85.71% <ø> (ø)
crates/parser/src/grammar/contracts.rs	86.66% <ø> (ø)
crates/parser/src/lexer/token.rs	21.05% <0.00%> (-0.23%)	⬇️
crates/yulgen/src/mappers/functions.rs	92.53% <0.00%> (-4.34%)	⬇️
crates/parser/src/ast.rs	80.74% <37.50%> (-1.37%)	⬇️
crates/parser/src/grammar/module.rs	82.89% <44.44%> (+0.11%)	⬆️
crates/lowering/src/mappers/functions.rs	97.95% <80.00%> (-0.66%)	⬇️
crates/analyzer/src/db/queries/contracts.rs	94.32% <100.00%> (ø)
crates/analyzer/src/db/queries/functions.rs	97.89% <100.00%> (+0.19%)	⬆️
... and 6 more

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[cburgdorf]

Sweet helper :)

[cburgdorf]

Looks great! I think there's one incorrect error message though.

[cburgdorf]

I've decided to enforce the rule that contract functions can be either pub or unsafe, but not both

As I understand pub unsafe is a compile time error so the error message of "use pub unsafe here" seems to be misleading.

[sbillig]

pub unsafe is allowed on functions defined at the module level, and will be allowed for struct functions, but it is misleading for contracts. I guess I'm inclined to just leave this, rather than add special behavior here for fns inside contracts.

[cburgdorf]

Ah, understood 👍