RFC: Add syntaxic sugar for struct expressions fields from variables of the same name

[SimonSapin]

The general syntax for a struct pattern is:

StructName { field_name: new_variable_name }

But when the desired variable name is the same as the field name, it does not need to be repeated:

let MyStruct { name } = struct_value;
do_something_with(name);

This proposal is to add similar syntax sugar for struct expressions:

let name = …;
let struct_value = MyStruct { name };

… would be the same as:

let name = …;
let struct_value = MyStruct { name: name };

CC: @eddyb

[rapha]

OCaml has this. It's nice. I'd support it.

[alexcrichton]

Closed with [my comment] on #11994.

[alexcrichton]

Oh hm, no, I should leave this open.

Today's meeting notes: https://github.com/rust-lang/meeting-minutes/blob/master/weekly-meetings/2014-02-11.md#binding-in-struct-patterns

[nham]

Triage bump.

[eddyb]

Shouldn't this have to go through the RFC process now?

[rust-highfive]

This issue has been moved to the RFCs repo: rust-lang/rfcs#306