Go 1.20 update

[codeFather2]

This request updates the Go grammar, adding support for the new 1.20.* syntax.
Actual Go spec - Go/ref/spec

What's New

• Generic types, interfaces and function
• Interface constraints
• Underlying type operation

[kaby76]

This is great. Thanks for updating this grammar!

I'm not sure what should be done with these unused symbols/rules. Should the grammar be adjusted to be closer to the Spec or remove the rules?

$ bash /c/Users/Kenne/Documents/GitHub/g4-checks/unused.sh
No arguments were provided.
Finding unused parser symbols in grammars...
./desc.xml
GoParser.g4:L132: emptyStmt: EOS | SEMI;
                  ^
GoParser.g4:L373: receiverType: type_;
                  ^

[codeFather2]

@kaby76 I think it's best to remove unused rules. The receiverType rule is just a dummy layer for the next rule, and the empty statement doesn't really do anything because EOS and SEMI are covered by statementList.

[teverett]

@codeFather2 thanks!