[rustc.git] / src / doc / style / changing / unclear.md

% Changes with unclear timing

### Associated items

* Many traits that currently take type parameters should instead use associated
  types; this will _drastically_ simplify signatures in some cases.

* Associated constants would be useful in a few places, e.g. traits for
  numerics, traits for paths.

### Anonymous, unboxed return types (aka `impl Trait` types)

* See https://github.com/rust-lang/rfcs/pull/105

* Could affect API design in several places, e.g. the `Iterator` trait.

### Default type parameters

We are already using this in a few places (e.g. `HashMap`), but it's
feature-gated.

### Compile-time function evaluation (CTFE)

https://github.com/mozilla/rust/issues/11621

### Improved constant folding

https://github.com/rust-lang/rust/issues/7834
Commit	Line	Data
85aaf69f SL	1	% Changes with unclear timing
	2
	3	### Associated items
	4
	5	* Many traits that currently take type parameters should instead use associated
	6	types; this will _drastically_ simplify signatures in some cases.
	7
	8	* Associated constants would be useful in a few places, e.g. traits for
	9	numerics, traits for paths.
	10
	11	### Anonymous, unboxed return types (aka `impl Trait` types)
	12
	13	* See https://github.com/rust-lang/rfcs/pull/105
	14
	15	* Could affect API design in several places, e.g. the `Iterator` trait.
	16
	17	### Default type parameters
	18
	19	We are already using this in a few places (e.g. `HashMap`), but it's
	20	feature-gated.
	21
	22	### Compile-time function evaluation (CTFE)
	23
	24	https://github.com/mozilla/rust/issues/11621
	25
	26	### Improved constant folding
	27
	28	https://github.com/rust-lang/rust/issues/7834