Some improvements to the Cargo compiler file.
Use rustc's errorformat and add option to specify permanent parameters.
Updates based on kballard's feedback.
Fix decoding of unboxed closure kinds

Closes #18378.  Note that cross-crate unboxed closures are
still unimplemented and will fail to work currently.
Treat cross-crate unboxed closure def IDs consistently

Always translate the ID into the local crate ID space since
presently the only way to encounter an unboxed closure type
from another crate is to inline once of its functions.

This may need to change if abstract return types are added.

Closes #18543
Add regression test for #16790, #18378 and #18543
Add tests for E-needstest issues
rustc: Default to static linking dylibs

If a dylib is being produced, the compiler will now first check to see if it can
be created entirely statically before falling back to dynamic dependencies. This
behavior can be overridden with `-C prefer-dynamic`.

Due to the alteration in behavior, this is a breaking change. Any previous users
relying on dylibs implicitly maximizing dynamic dependencies should start
passing `-C prefer-dynamic` to compilations.

Closes #18499
[breaking-change]
Translate SIMD construction as `insertelement`s and a single store.

This almost completely avoids GEPi's and pointer manipulation,
postponing it until the end with one big write of the whole vector. This
leads to a small speed-up in compilation, and makes it easier for LLVM
to work with the values, e.g. with `--opt-level=0`,

    pub fn foo() -> f32x4 {
        f32x4(0.,0.,0.,0.)
    }

was previously compiled to

    define <4 x float> @_ZN3foo20h74913e8b13d89666eaaE() unnamed_addr #0 {
    entry-block:
      %sret_slot = alloca <4 x float>
      %0 = getelementptr inbounds <4 x float>* %sret_slot, i32 0, i32 0
      store float 0.000000e+00, float* %0
      %1 = getelementptr inbounds <4 x float>* %sret_slot, i32 0, i32 1
      store float 0.000000e+00, float* %1
      %2 = getelementptr inbounds <4 x float>* %sret_slot, i32 0, i32 2
      store float 0.000000e+00, float* %2
      %3 = getelementptr inbounds <4 x float>* %sret_slot, i32 0, i32 3
      store float 0.000000e+00, float* %3
      %4 = load <4 x float>* %sret_slot
      ret <4 x float> %4
    }

but now becomes

    define <4 x float> @_ZN3foo20h74913e8b13d89666eaaE() unnamed_addr #0 {
    entry-block:
      ret <4 x float> zeroinitializer
    }
rustc: Support stability attributes on crates

This commit adds support for linting `extern crate` statements for stability
attributes attached to the crate itself. This is likely to be the mechanism used
to deny access to experimental crates that are part of the standard
distribution.

cc #18585
Added check for absolute file path, removed hard tab, and added documentation for new option.
std::error: fix stray doc comment
test: correct spelling error & inverted match.
libsyntax: Forbid escapes in the inclusive range `\x80`-`\xff` in
Unicode characters and strings.

Use `\u0080`-`\u00ff` instead. ASCII/byte literals are unaffected.

This PR introduces a new function, `escape_default`, into the ASCII
module. This was necessary for the pretty printer to continue to
function.

RFC #326.

Closes #18062.

[breaking-change]
librustc_back: Fix triple for linux armhf.
auto merge of #18504 : pcwalton/rust/small-escapes, r=pcwalton

Use `\u0080`-`\u00ff` instead. ASCII/byte literals are unaffected.

This PR introduces a new function, `escape_default`, into the ASCII
module. This was necessary for the pretty printer to continue to
function.

RFC #326.

Closes #18062.

[breaking-change]

r? @aturon
librustc: Call return_type only for functions.
Make trans::adt know that some structs are unsized
Test
auto merge of #18592 : alexcrichton/rust/dylib-harder, r=pcwalton

If a dylib is being produced, the compiler will now first check to see if it can
be created entirely statically before falling back to dynamic dependencies. This
behavior can be overridden with `-C prefer-dynamic`.

Due to the alteration in behavior, this is a breaking change. Any previous users
relying on dylibs implicitly maximizing dynamic dependencies should start
passing `-C prefer-dynamic` to compilations.

Closes #18499
[breaking-change]