More inference-friendly API for lazy

2022-10-29T08:56:20+00:00

The signature for new was ``` fn new(f: F) -> Lazy ``` Notably, with `F` unconstrained, `T` can be literally anything, and just `let _ = Lazy::new(|| 92)` would not typecheck. This historiacally was a necessity -- `new` is a `const` function, it couldn't have any bounds. Today though, we can move `new` under the `F: FnOnce() -> T` bound, which gives the compiler enough data to infer the type of T from closure.

Move/rename `lazy::Sync{OnceCell,Lazy}` to `sync::{Once,Lazy}Lock`

2022-06-16T15:54:42+00:00

rust/library/std/src/sync/lazy_lock, branch 1.75.0

More inference-friendly API for lazy

Move/rename `lazy::Sync{OnceCell,Lazy}` to `sync::{Once,Lazy}Lock`