People keep making fun of this signature for being so gnarly.
Associated type bounds lend it a much simpler scribbling.
ChangeOutputType can also come along for the ride.

Instead of not generating the function at all on big endian (which
makes the CHECK lines fail), instead use to_le() on big endian,
so that we essentially perform a bswap for both endiannesses.

…=scottmcm

DOC: Add FFI example for slice::from_raw_parts()

For some discussion, see https://users.rust-lang.org/t/missing-guidance-on-converting-ffi-ptr-length-to-slice/106048

See also rust-lang#120608.

…elix

Spell out other trait diagnostic

I recently saw somebody confused about the diagnostic thinking it was suggesting to add an `as` cast. This change is longer but I think it's clearer

…s, r=compiler-errors

Provide correct parent for nested anon const

Fixes rust-lang#126147

99% of this PR is just comments explaining what the issue is.

`tcx.parent(` and `hir().get_parent_item(` give different results as the hir owner for all the hir of anon consts is the enclosing function. I didn't attempt to change that as being a hir owner requires a `DefId` and long term we want to stop creating anon consts' `DefId`s before hir ty lowering.

So i just opted to change `generics_of` to use `tcx.parent` to get the parent for `AnonConst`'s. I'm not entirely sure about this being what we want, it does seem weird that we have two ways of getting the parent of an `AnonConst` and they both give different results.

Alternatively we could just go ahead and make `const_evaluatable_unchecked` a hard error and stop providing generics to repeat exprs. Then this isn't an issue. (The FCW has been around for almost 4 years now)

r? `@compiler-errors`

…gnature, r=scottmcm

Simplify `[T; N]::try_map` signature

People keep making fun of this signature for being so gnarly.
Associated type bounds admit a much simpler scribbling.

r? `@scottmcm`

…tlarsan68

Add {{target}} substitution to compiletest

In ferrocene we have ui tests testing the cli interface of the compiler, one of which tests the `--target` flag. To be able to run this on all targets we require a way to specify a valid target in the `compile-flags` directive that is target independent, as otherwise we can only run the test against the one target we choose to supply in the flags. See https:/ferrocene/ferrocene/blob/383cbc80f4e85859a4055f121f15dac329908346/tests/ui/ferrocene/compiler-arguments/target/target.rs

We figured the project might be able to make use of this substitution as well in the future.

try-job: dist-x86_64-msvc

…eyouxu

Make issue-122805.rs big endian compatible

Instead of not generating the function at all on big endian (which makes the CHECK lines fail), instead use to_le() on big endian, so that we essentially perform a bswap for both endiannesses.