decide whether "b; c" should match "{ a; b; c; d }"

[mvdan]

Reasons to:

• Useful. I just needed it right now.
• Using $*_; b; c; $*_ is not as useful, as it also prints the stuff on the sides.

Reasons not to:

• If we really want a statement list with just b; c, there wouldn't be another way to express that. { b; c } does not cover it, as it wouldn't match statement lists outside block statements such as switch case bodies.

[rogpeppe]

I think that statements are a bit different from expressions in this respect. That is, I think it probably should match, because a sequence of statements are logically just a sequence rather than a hierarchy.

I can't currently think of a use case for requiring a statement list with just b; c.

[mvdan]

If we changed this, I would like to change it consistently for all lists of nodes. I noticed your point about expressions, but I'm not sure if I agree, and I'm defaulting on consistency.

Perhaps one way around this would be for { b; c } to match case foo: b; c;. In other words, treat source code almost as if case expr: stmt-list was case expr: { stmt-list; }. That way, b; c would match any list with that sub-list, and { b; c } would match any list exactly equal to that list.

This would also apply to all other implicit blocks, as defined in the spec.

The only disadvantage I can think of is when one really wanted an explicit block, but not an implicit one. Like when one wants to convert an explicit case foo: { b; c } to case foo: b; c. Perhaps this should be done as part of #4, i.e. only match real blocks with implicit blocks in the aggressive mode.

[mvdan]

The implicit blocks section on the spec: https://golang.org/ref/spec#Blocks

Also, I completely contradicted myself in the last comment. My solution concerns statements, not expressions. So it would treat them differently, as you said.

Perhaps it's a good idea to start with this, and we can revisit other node type sub-lists if we find a use for those.

[mvdan]

Blocks can now be matched aggressively: 1af77ee

So I'll get to this now.