Remove trait LengthAtMost32
This is a continuation of https://github.com/rust-lang/rust/pull/74026 preserving the original burrbull's commit.
I talked to @burrbull, he suggested me to finish his PR.
Normalize bounds fully when checking defaulted types
When checking that the default type for `<T as X>::Y` is valid in this example:
```
trait X { type Y: PartialEq<<Self as X>::Y> }
impl X for T { default type Y = S; }
```
We will have to prove the bound `S: PartialEq<<T as X>::Y>`. In this case
we want `<T as X>::Y` to normalize to `S`. This is valid because we are
checking the default value specifically here. Add `<T as X>::Y = S` to the
ParamEnv for normalization _of the bound we are checking_ only.
Fixes#73818.
---
I noticed that adding this to the env for bounds checking didn't break any tests. Not sure if this is because we can't rely on it to prove anything, or because of missing test coverage.
r? @matthewjasper, @nikomatsakis
Fix panic message when `RangeFrom` index is out of bounds
Before, the `Range` method was called with `end = slice.len()`. Unfortunately, because `Range::index` first checks the order of the indices (start has to be smaller than end), an out of bounds index leads to `core::slice::slice_index_order_fail` being called. This prints the message 'slice index starts at 27 but ends at 10', which is worse than 'index 27 out of range for slice of length 10'. This is not only useful to normal users reading panic messages, but also for people inspecting assembly and being confused by `slice_index_order_fail` calls.
You can see the produced assembly [here](https://rust.godbolt.org/z/GzMGWf) and try on Playground [here](https://play.rust-lang.org/?version=stable&mode=debug&edition=2018&gist=aada5996b2f3848075a6d02cf4055743). (By the way. this is only about which panic function is called; I'm pretty sure it does not improve anything about performance).
Optimize away BitAnd and BitOr when possible
This PR lets `const_prop` optimize away `a | true == true` , `a & false == false` and `a * 0 = 0`. While I was writing this I've realized that constant propagation misses a lot of opportunities. For example: https://play.rust-lang.org/?version=stable&mode=debug&edition=2018&gist=2a4b45e772f214210a36749b27223bb0
Constant propagation doesn't seem to... propagate constants, additionally the way constant propagation is currently setup makes it tricky to add cases like `a | false == a`.
I tried to organize `eval_rvalue_with_identities` to make the pattern of the optimizations easier to see but it still obscurs what should be a simple peephole optmization.
cc @oli-obk
correctly deal with unsorted generic parameters
We now stop sorting generic params and instead correctly handle unsorted params in the rest of the compiler.
We still restrict const params to come after type params though, so this PR does not change anything which
is visible to users.
This might slightly influence perf, so let's prevent any unintentional rollups. @bors rollup=never
r? @varkor
Fix ICE while building MIR with type errors
See https://github.com/rust-lang/rust/issues/74047#issuecomment-663290913 for background. Replacing a binding with `PatKind::Wild` (introduced in #51789 and later refactored in #67439) caused an ICE downstream while building MIR.
I noticed that taking this code out no longer triggers the ICEs it was added to prevent. I'm not sure what else changed, or if this change is _correct_, but it does seem to be passing ui tests at least.
r? @oli-obk
cc @estebank
Fixes#74047.
Internally unify rustc_deprecated and deprecated
This PR intentionally tries to be "featureless" in that the behavior is not altered for either attribute, though it more clearly exposes cases where that is the case in the code.
Rollup of 8 pull requests
Successful merges:
- #74141 (libstd/libcore: fix various typos)
- #74490 (add a Backtrace::disabled function)
- #74548 (one more Path::with_extension example, to demonstrate behavior)
- #74587 (Prefer constant over function)
- #74606 (Remove Linux workarounds for missing CLOEXEC support)
- #74637 (Make str point to primitive page)
- #74654 (require type defaults to be after const generic parameters)
- #74659 (Improve codegen for unchecked float casts on wasm)
Failed merges:
r? @ghost
Improve codegen for unchecked float casts on wasm
This commit improves codegen for unchecked casts on WebAssembly targets
to use the singluar `iNN.trunc_fMM_{u,s}` instructions. Previously rustc
would codegen a bare `fptosi` and `fptoui` for float casts but for
WebAssembly targets the codegen for these instructions is quite large.
This large codegen is due to the fact that LLVM can speculate these
instructions so the trapping behavior of WebAssembly needs to be
protected against in case they're speculated.
The change here is to update the codegen for the unchecked cast
intrinsics to have a wasm-specific case where they call the appropriate
LLVM intrinsic to generate the right wasm instruction. The intrinsic is
explicitly opting-in to undefined behavior so a trap here for
out-of-bounds inputs on wasm should be acceptable.
cc #73591
require type defaults to be after const generic parameters
From current discussions it seems like the goal here is for type and const parameters to be unordered and allow things like `struct Foo<const N: usize, T = u32>(T)` and `struct Foo<T, const N: usize = 7>` this way.
Note: This means that using `min_const_generics` it will not be possible for an adt to have both type defaults and const parameters.
closes#70471
r? @varkor @eddyb
Guard against non-monomorphized type_id intrinsic call
This PR checks whether the type is sufficient monomorphized when calling type_id or type_name intrinsics. If the type is not sufficiently monomorphized, e.g. used in a pattern, the code will be rejected.
Fixes#73976
rustdoc: Always warn when linking from public to private items
Change the logic such that linking from a public to a private item always triggers `intra_doc_link_resolution_failure`.
Previously, the warning was not emitted when `--document-private-items` is passed.
This came up during the discussion in https://github.com/rust-lang/rust/pull/74147#discussion_r452597901.
This commit improves codegen for unchecked casts on WebAssembly targets
to use the singluar `iNN.trunc_fMM_{u,s}` instructions. Previously rustc
would codegen a bare `fptosi` and `fptoui` for float casts but for
WebAssembly targets the codegen for these instructions is quite large.
This large codegen is due to the fact that LLVM can speculate these
instructions so the trapping behavior of WebAssembly needs to be
protected against in case they're speculated.
The change here is to update the codegen for the unchecked cast
intrinsics to have a wasm-specific case where they call the appropriate
LLVM intrinsic to generate the right wasm instruction. The intrinsic is
explicitly opting-in to undefined behavior so a trap here for
out-of-bounds inputs on wasm should be acceptable.
cc #73591
Change the logic such that linking from a public to a private item always
triggers intra_doc_link_resolution_failure. Previously, the warning was
not emitted when --document-private-items is passed.
Also don't rely anymore on the item's visibility, which would falsely trigger
the lint now that the check for --document-private-items is gone.
Disable polymorphisation
Fixes#74614.
This PR disables polymorphisation to fix the regression in #74614 after investigation into the issue makes it clear that the fix won't be trivial. ~~I'll file an issue shortly to replace #74614 with the findings so far.~~ #74636 has been filed to track the fix of the underlying regression.
r? @eddyb
