This commit upgrades the dist builders for OSX to Travis's new `xcode9.3-moar`
image which has 3 cores available to it instead of 2. This should help us
provide speedier builds on OSX and hit timeouts less in theory!
Note that historically the dist builders for OSX have been a different version
than the ones that are running tests. I had forgotten why this was the case and
digging around brought up 307615567 where apparently Xcode 8 wasn't able to
compile LLVM with `MACOSX_DEPLOYMENT_TARGET=10.7` which we desired. On a whim I
gave this PR a spin and it [looks like][green] this has since been fixed (maybe
in LLVM?). In any case those green builds should hopefully mean that we can
safely upgrade and get faster infrastructure to boot.
This commit also includes an upgrade of OpenSSL. This is not done for security
reasons but rather build system reasons. Originally builds with the new image
[did not succeed][red] due to weird build failures in OpenSSL, but upgrading
seems to have made the spurious errors go away to here's to also hoping that's
fixed!
[green]: https://travis-ci.org/rust-lang/rust/builds/351353412
[red]: https://travis-ci.org/rust-lang/rust/builds/350969248
Replace all const evaluation with miri
* error reporting in constants prints a stacktrace through all called const fns
* Trivial constant propagation and folding in MIR (always active, irrelevant of the optimization level)
* can now use floating constants in patterns (previously only floating point literals were allowed)
* the future compat lint is still produced for both cases
* can index into constant arrays during const eval (previously feature gated)
* can create a constant union value with field `a` and read from field `b`
* can dereference references into constants
* can create references inside constants (`const X: &u32 = &22`)
* Tuple struct constructors can be used in constants
* regression in const eval errors spans (some of these need improvements in mir debug info)
* can cast floats to ints and vice versa (in constants, and even nan/inf constants)
* Mir dump prints false/true instead of 0u8/1u8
* `1i8 >> [8][0]` does not lint about exceeding bitshifts anymore.
* Needs const propagation across projections
* `foo[I]` produces a const eval lint if `foo: [T; N]` and `N < I`
* Essentially all builtin panics produce lints if they can be statically proven to trigger at runtime. This is on a best effort basis, so there might be some complex cases that don't trigger. (The runtime panic stays there, irrelevant of whether the lint is produced or not)
* can use `union`s to implement `transmute` for `Copy` types in constants without a feature gate. With all the greatness and nasal demons that come with this.
* can convert integers to `&'static T` in constants (useful for embedded)
fixes#34997 (stack overflow with many constants)
fixes#25574 (deref byte strings in patterns)
fixes#27918 (broken mir ICE)
fixes#46114 (ICE on struct constructors in patterns)
fixes#37448 (`SomeStruct { foo } as SomeStruct`)
fixes#43754 (`return` in const fn)
fixes#41898 (tuple struct constructors)
fixes#31364 (infinite recursion with const fn, fixed by miri's recursion limit)
closes#29947 (const indexing stabilization)
fixes#45044 (pattern matching repeat expressions)
fixes#47971 (ICE on const fn + references)
fixes#48081 (ICE on cyclic assoc const error)
fixes#48746 (nonhelpful error message with unions)
r? @eddyb
even though 1k loc are added in tests, this PR reduces the loc in this repository by 700
