Block indentation in chains

[dragostis]

Shouldn't chains with visual indentation indent blocks to the same visual indentation?

let a = b.iter()
         .map(|m| {
             m.hi()
         });

Instead of

let a = b.iter()
         .map(|m| {
             m.hi()
});

[dragostis]

A simple example is:

let grammar: Vec<_> = ast.attrs.iter().filter(|attr| {
    match attr.value {
        MetaItem::NameValue(ref ident, _) => format!("{}", ident) == "grammar",
        _ => false
    }
}).collect();

which gets formatted to:

let grammar: Vec<_> = ast.attrs.iter()
                         .filter(|attr| match attr.value {
    MetaItem::NameValue(ref ident, _) => format!("{}", ident) == "grammar",
    _ => false
 })
                         .collect();

[dragostis]

I'm interested to take a jab at this one if it doesn't require any major rearchitecturization.

[topecongiro]

Thank you for being interested in contributing to rustfmt!

I do not think we need major reachitecturization to fix this. However, mixing chains and closures with visual indent has been known to be complex. It may be difficult to come up with an implementation which works in every case.

FWIW in rustfmt 0.3.6, the above example will be formatted to somewhat better code:

    let grammar: Vec<_> =
        ast.attrs.iter()
           .filter(|attr| match attr.value {
                       MetaItem::NameValue(ref ident, _) => format!("{}", ident) == "grammar",
                       _ => false,
                   })
           .collect();