More precise spans for temps and their drops
This PR has two main enhancements:
1. when possible during code generation for a statement (like `expr();`), pass along the span of a statement, and then attribute the drops of temporaries from that statement to the statement's end-point (which will be the semicolon if it is a statement that is terminating by a semicolon).
2. when evaluating a block expression into a MIR temp, use the span of the block's tail expression (rather than the span of whole block including its statements and curly-braces) for the span of the temp.
Each of these individually increases the precision of our diagnostic output; together they combine to make a much clearer picture about the control flow through the spans.
Fix#54382
Make PhantomData #[structural_match]
fixes https://github.com/rust-lang/rust/issues/55028
This makes `PhantomData<T>` structurally matchable, irrespective of whether `T` is, per the discussion on this week's language team meeting (the general consensus was that this was a bug-fix).
All types containing `PhantomData<T>` and which used `#[derive(PartialEq, Eq)]` and were previously not `#[structural_match]` only because of `PhantomData<T>` will now be `#[structural_match]`.
r? @nikomatsakis
NLL Diagnostic Review 3: Unions not reinitialized after assignment into field
Fixes#55651, #55652.
This PR makes two changes:
First, it updates the dataflow builder to add an init for the place
containing a union if there is an assignment into the field of
that union.
Second, it stops a "use of uninitialized" error occuring when there is an
assignment into the field of an uninitialized union that was previously
initialized. Making this assignment would re-initialize the union, as
tested in `src/test/ui/borrowck/borrowck-union-move-assign.nll.stderr`.
The check for previous initialization ensures that we do not start
supporting partial initialization yet (cc #21232, #54499, #54986).
This PR also fixes#55652 which was marked as requiring investigation
as the changes in this PR add an error that was previously missing
(and mentioned in the review comments) and confirms that the error
that was present is correct and a result of earlier partial
initialization changes in NLL.
r? @pnkfelix (due to earlier work with partial initialization)
cc @nikomatsakis
resolve: Filter away macro prelude in modules with `#[no_implicit_prelude]` on 2018 edition
This is a tiny thing.
For historical reasons macro prelude (macros from `#[macro_use] extern crate ...`, including `extern crate std`) is still available in modules with `#[no_implicit_prelude]`.
This PR provides proper isolation and removes those names from scope.
`#[no_implicit_prelude]` modules still have built-in types (`u8`), built-in attributes (`#[inline]`) and built-in macros (`env!("PATH")`) in scope. We can introduce some `#[no_implicit_prelude_at_all]` to remove those as well, but that's a separate issue.
The change is done only on 2018 edition for backward compatibility.
I'm pretty sure this can be done on 2015 as well because `#[no_implicit_prelude]` is rarely used, but I don't want to go through the crater/deprecation process right now, maybe later.
cc https://github.com/rust-lang/rust/issues/53977
r? @ghost
ICE with #![feature(nll)] and elided lifetimes
Fixes#55394.
This commit fixes an ICE and determines the correct return span in cases
with a method implemented on a struct with an an elided lifetime.
r? @pnkfelix
NLL: Update box insensitivity test
This is just keeping one of our tests honest with respect to NLL, in two ways:
1. Adds uses of borrows that would otherwise be too short to observe the error that we would have expected to see...
2. ... I say "would have expected" because all of the errors in this file are part of the reversion of rust-lang/rfcs#130 that is attached to NLL (you can see more discussion of this here https://github.com/rust-lang/rust/issues/43234#issuecomment-411017768 )
Removed unneeded instance of `// revisions` from a lint test
Removed an unneeded instance of `// revisions`; the compare-mode=nll shows the output is identical now.
cc #54528
Take supertraits into account when calculating associated types
Fixes#24010 and #23856. Applies to trait aliases too.
As a by-product, this PR also makes repeated bindings of the same associated item in the same definition a hard error. This was previously a warning with a note about it becoming a hard error in the future. See #50589 for more info.
I talked about this with @nikomatsakis recently, but only very superficially, so this shouldn't stop anyone from assigning it to themself to review and r+.
N.B. The "WIP" commits represent imperfect attempts to solve the problem just for trait objects, but I've left them in for reference for the sake of whomever is reviewing this.
CC @carllerche @theemathas @durka @mbrubeck
Do not attempt to ascribe projections out of a ty var
If we encounter `_` ascribed to structural pattern like `(a, b)`, just skip relate_types.
Fix#55552
Bubble up an overflow error so that rustdoc can ignore it
fixes#54524
Idk how to write a test for this, other than trying to minimize the entire diesel crate. If desirable I will do that.
Note that there are many other such overflow errors hiding out there. Should we try to proactively eliminate them or do we just whack-a-mole them?
cc @GuillaumeGomez
r? @nikomatsakis
Update emscripten
This updates emscripten to 1.38.15, which is based on LLVM 6.0.1 and would allow us to drop code for handling LLVM 4.
The main issue I ran into is that exporting statics through `EXPORTED_FUNCTIONS` no longer works. As far as I understand exporting non-functions doesn't really make sense under emscripten anyway, so I've modified the symbol export code to not even try.
Closes#52323.
