Mostly to fix ui/issues/issue-37311-type-length-limit/issue-37311.rs.
Most parts of the compiler can handle deeply nested types with a lot
of duplicates just fine, but some parts still attempt to naively
traverse type tree.
Before such problems were caught by type length limit check,
but now these places will have to be changed to handle
duplicated types gracefully.
This fixes#72408.
Nested closures were resulting in exponential compilation time.
As a performance optimization this change introduces MiniSet,
which is a simple small storage optimized set.
[beta] Revert "Promote missing_fragment_specifier to hard error #75516"
This reverts "Promote missing_fragment_specifier to hard error #75516" on just beta. I would like us to explore a more principled fix, perhaps along the lines `@petrochenkov` suggested in #76605, on master when we have more time to test it but I don't want us shipping the breakage in the meantime. I don't personally feel comfortable immediately backporting anything more than a revert here.
cc `@matklad`
[beta] backports
This backports the following:
* revert const_type_id stabilization #77083
* [mir-opt] Disable the `ConsideredEqual` logic in SimplifyBranchSame opt #76837
* Rename Iterator::get_unchecked #77201 (manually, because of file renaming and other issues on master causing literal cherry-pick to fail)
* Rebase LLVM onto 11.0.0-rc3 #77063 (bumping direct to master, see https://github.com/rust-lang/rust/pull/77063#issuecomment-700231036).
The last two have not yet been approved by compiler team, but I'm posting this now and going to go ahead and approve as I expect both to get approved and we want testing as much as possible before release in ~2 weeks.
r? `@ghost`
[beta] backports
* Ignore rustc_private items from std docs #76571
* Fix HashMap visualizers in Visual Studio (Code) #76389
* Account for version number in NtIdent hack #76331
* Account for async functions when suggesting new named lifetime #75867
* Fix loading pretty-printers in rust-lldb script #76015
This also bumps to the released stable compiler.
Issue #74616 tracks a backwards-compatibility hack for certain macros.
This has is implemented by hard-coding the filenames and macro names of
certain code that we want to continue to compile.
However, the initial implementation of the hack was based on the
directory structure when building the crate from its repository (e.g.
`js-sys/src/lib.rs`). When the crate is build as a dependency, it will
include a version number from the clone from the cargo registry (e.g.
`js-sys-0.3.17/src/lib.rs`), which would fail the check.
This commit modifies the backwards-compatibility hack to check that
desired crate name (`js-sys` or `time-macros-impl`) is a prefix of the
proper part of the path.
See https://github.com/rust-lang/rust/issues/76070#issuecomment-687215646
for more details.
CDB doesn't care that you're using static_cast between unrelated types.
VS(C) does. These should've been reinterpret_cast or C casts.
Cast is from e.g. `u8*` to `tuple<$T1, $T2>*`
[beta] Backport fix for swapped stability attributes
This backports the only commit in https://github.com/rust-lang/rust/pull/75953/, fixing one unstable lint which ran on stable and one stable lint which only ran on nightly. This change can be replicated with
```
git fetch origin
git checkout origin/beta
git cherry-pick 29399fad5f
```
Refactor the partitioning module to make it easier to introduce new algorithms
I've split the `librustc_mir::monomorphize::partitioning` module into a few files and introduced a `Partitioner` trait which allows us to decouple the partitioning algorithm from the code which integrates it into the query system. This should allow us to introduce new partitioning algorithms much more easily. I've also gone ahead and added a `-Z` flag to control which algorithm is used (currently there is only the `default`).
I left a few comments in places where things might be improved further.
r? @pnkfelix cc @rust-lang/wg-incr-comp
Bump LLVM on CI to 10.0.0
This PR bumps the LLVM version we use on our macOS and Windows CI to 10.0.0, fixing a breakage we noticed today:
```
2020-08-25T14:24:28.5939568Z FAILED: lib/Support/CMakeFiles/LLVMSupport.dir/AMDGPUMetadata.cpp.obj
2020-08-25T14:24:28.5940317Z D:\a\rust\rust\build\bootstrap\debug\sccache-plus-cl.exe /nologo -TP -DGTEST_HAS_RTTI=0 -DUNICODE -D_CRT_NONSTDC_NO_DEPRECATE -D_CRT_NONSTDC_NO_WARNINGS -D_CRT_SECURE_NO_DEPRECATE -D_CRT_SECURE_NO_WARNINGS -D_HAS_EXCEPTIONS=0 -D_SCL_SECURE_NO_DEPRECATE -D_SCL_SECURE_NO_WARNINGS -D_UNICODE -D__STDC_CONSTANT_MACROS -D__STDC_FORMAT_MACROS -D__STDC_LIMIT_MACROS -Ilib\Support -ID:\a\rust\rust\src\llvm-project\llvm\lib\Support -Iinclude -ID:\a\rust\rust\src\llvm-project\llvm\include -nologo -MT -Brepro --target=x86_64-pc-windows-msvc /Zc:inline /Zc:strictStrings /Oi /Zc:rvalueCast /Brepro /W4 -Wextra -Wno-unused-parameter -Wwrite-strings -Wcast-qual -Wmissing-field-initializers -Wno-noexcept-type -Wno-comment /Gw /MT /O2 /Ob2 -UNDEBUG -std:c++14 /EHs-c- /GR- /showIncludes /Folib\Support\CMakeFiles\LLVMSupport.dir\AMDGPUMetadata.cpp.obj /Fdlib\Support\CMakeFiles\LLVMSupport.dir\LLVMSupport.pdb -c D:\a\rust\rust\src\llvm-project\llvm\lib\Support\AMDGPUMetadata.cpp
2020-08-25T14:24:28.5940861Z clang-cl: warning: argument unused during compilation: '-Brepro' [-Wunused-command-line-argument]
2020-08-25T14:24:28.5941076Z clang-cl: warning: argument unused during compilation: '-Brepro' [-Wunused-command-line-argument]
2020-08-25T14:24:28.5941321Z In file included from D:\a\rust\rust\src\llvm-project\llvm\lib\Support\AMDGPUMetadata.cpp:15:
2020-08-25T14:24:28.5941545Z In file included from D:\a\rust\rust\src\llvm-project\llvm\include\llvm/ADT/Twine.h:12:
2020-08-25T14:24:28.5941774Z In file included from D:\a\rust\rust\src\llvm-project\llvm\include\llvm/ADT/SmallVector.h:16:
2020-08-25T14:24:28.5942016Z In file included from D:\a\rust\rust\src\llvm-project\llvm\include\llvm/ADT/iterator_range.h:21:
2020-08-25T14:24:28.5942257Z In file included from C:\Program Files (x86)\Microsoft Visual Studio\2019\Enterprise\VC\Tools\MSVC\14.27.29110\include\iterator:9:
2020-08-25T14:24:28.5942542Z C:\Program Files (x86)\Microsoft Visual Studio\2019\Enterprise\VC\Tools\MSVC\14.27.29110\include\yvals_core.h(494,2): error: STL1000: Unexpected compiler version, expected Clang 10.0.0 or newer.
```
I uploaded both the new tarballs to our mirrors bucket.
Introduce expect snapshot testing library into rustc
Snapshot testing is a technique for writing maintainable unit tests.
Unlike usual `assert_eq!` tests, snapshot tests allow
to *automatically* upgrade expected values on test failure.
In a sense, snapshot tests are inline-version of our beloved
UI-tests.
Example:

A particular library we use, `expect_test` provides an `expect!`
macro, which creates a sort of self-updating string literal (by using
`file!` macro). Self-update is triggered by setting `UPDATE_EXPECT`
environmental variable (this info is printed during the test failure).
This library was extracted from rust-analyzer, where we use it for
most of our tests.
There are some other, more popular snapshot testing libraries:
* https://github.com/mitsuhiko/insta
* https://github.com/aaronabramov/k9
The main differences of `expect` are:
* first-class snapshot objects (so, tests can be written as functions,
rather than as macros)
* focus on inline-snapshots (but file snapshots are also supported)
* restricted feature set (only `assert_eq` and `assert_debug_eq`)
* no extra runtime (ie, no `cargo insta`)
See rust-analyzer/rust-analyzer#5101 for a
an extended comparison.
It is unclear if this testing style will stick with rustc in the long
run. At the moment, rustc is mainly tested via integrated UI tests.
But in the library-ified world, unit-tests will become somewhat more
important (that's why use use `rustc_lexer` library-ified library as
an example in this PR). Given that the cost of removal shouldn't be
too high, it probably makes sense to just see if this flies!
Call into fastfail on abort in libpanic_abort on Windows x86(_64)
This partially resolves#73215 though this is only for x86 targets. This code is directly lifted from [libstd](13290e83a6/library/std/src/sys/windows/mod.rs (L315)). `__fastfail` is the preferred way to abort a process on Windows as it will hook into debugger toolchains.
Other platforms expose a `_rust_abort` symbol which wraps `std::sys::abort_internal`. This would also work on Windows, but is a slightly largely change as we'd need to make sure that the symbol is properly exposed to the linker. I'm inlining the call to the `__fastfail`, but the indirection through `rust_abort` might be a cleaner approach.
A different instruction must be used on ARM architectures. I'd like to verify this works first before tackling ARM.
hir: consistent use and naming of lang items
This PR adjusts the naming of various lang items so that they are consistent and don't include prefixes containing the target or "LangItem". In addition, lang item variants are no longer exported from the `lang_items` module.
This is certainly subjective and while I think this is an improvement, if many in the team don't then we can just close this.