- fixes evaluation of array length for zero-sized type referenced by
rvalue operand.
- adds test to verify fix.
Cause of the issue.
Zero-sized aggregates are handled as operands, not lvalues. Therefore while
visiting Assign statement by LocalAnalyser, mark_as_lvalue() is not called for
related Local. This behaviour is controlled by rvalue_creates_operand() method.
As result it causes error later, when rvalue operand is evaluated in
trans_rvalue_operand() while handling Rvalue::Len case. Array length evaluation
invokes trans_lvalue() which expects referenced Local to be value, not operand.
How it is fixed.
In certain cases result of Rvalue::Len can be evaluated without calling
trans_lvalue(). Method evaluate_array_len() is introduced to handle length
evaluation for zero-sized types referenced by Locals.
Support dynamically-linked and/or native musl targets
These changes allow native compilation on musl-based distributions and the use of dynamic libraries on linux-musl targets. This is intended to remove limitations based on past assumptions about musl targets, while maintaining existing behavior by default.
A minor related bugfix is included.
Before `#[must_use]` for functions was implemented, a `#[must_use]` attribute
on a function was a no-op. To avoid a breaking change in this behavior, we add
an option for "this-and-such feature is experimental" feature-gate messages to
be a mere warning rather than a compilation-halting failure (so old code that
used to have a useless no-op `#[must_use]` attribute now warns rather than
breaking). When we're on stable, we add a help note to clarify that the feature
isn't "on."
This is in support of #43302.
We'll actually want a new "soft" warning-only gate to maintain
backwards-compatibility, but it's cleaner to start out with the established,
well-understood gate before implementing the alternative warn-only behavior in
a later commit.
This is in the matter of #43302.
Now that musl supports dynamic libraries (although not by default)
enable the tests that now pass. Additional currently-ignored tests
will pass if rustc is built with crt_static=false in config.toml.
Make sure crates not opting in to staged_api don't use staged_api
This also fixes the problem that with `-Zforce-unstable-if-unmarked` set, crates could not use `#[deprecated]`.
If you prefer, I can instead submit another version which just fixes this problem, but still allows the staged API attributes for all crates when `-Zforce-unstable-if-unmarked` is set. I have prepared that at <https://github.com/RalfJung/rust/tree/staged2>. As yet another alternative, @alexcrichton suggested to turn this error into a lint, but that seems to be much more work, so is it worth it?
Cc @alexcrichton #43975
Point out missing if conditional
On a case where an else conditional is missing, point this out
instead of the token immediately after the (incorrect) else block:
```
error: missing condition for `if` statemementt push fork -f
--> $DIR/issue-13483.rs:16:5
|
13 | } else if {
| ^ expected if condition here
```
instead of
```
error: expected `{`, found `else`
--> ../../src/test/ui/issue-13483.rs:14:7
|
14 | } else {
| ^^^^
```
Fix#13483.
Generate builtin impls for `Clone`
This fixes a long-standing ICE and limitation where some builtin types implement `Copy` but not `Clone` (whereas `Clone` is a super trait of `Copy`).
However, this PR has a few side-effects:
* `Clone` is now marked as a lang item.
* `[T; N]` is now `Clone` if `T: Clone` (currently, only if `T: Copy` and for `N <= 32`).
* `fn foo<'a>() where &'a mut (): Clone { }` won't compile anymore because of how bounds for builtin traits are handled (e.g. same thing currently if you replace `Clone` by `Copy` in this example). Of course this function is unusable anyway, an error would pop as soon as it is called.
Hence, I'm wondering wether this PR would need an RFC...
Also, cc-ing @nikomatsakis, @arielb1.
Related issues: #28229, #24000.
syntax: Relax path grammar
TLDR: Accept the disambiguator `::` in "type" paths (`Type::<Args>`), accept the disambiguator `::` before parenthesized generic arguments (`Fn::(Args)`).
The "turbofish" disambiguator `::<>` in expression paths is a necessary evil required for path parsing to be both simple and to give reasonable results.
Since paths in expressions usually refer to values (but not necessarily, e.g. `Struct::<u8> { field: 0 }` is disambiguated, but refers to a type), people often consider `::<>` to be inherent to *values*, and not *expressions* and want to write disambiguated paths for values even in contexts where disambiguation is not strictly necessary, for example when a path is passed to a macro `m!(Vec::<i32>::new)`.
The problem is that currently, if the disambiguator is not *required*, then it's *prohibited*. This results in confusion - see https://github.com/rust-lang/rust/issues/41740, https://internals.rust-lang.org/t/macro-path-uses-novel-syntax/5561.
This PR makes the disambiguator *optional* instead of prohibited in contexts where it's not strictly required, so people can pass paths to macros in whatever form they consider natural (e.g. disambiguated form for value paths).
This PR also accepts the disambiguator in paths with parenthesized arguments (`Fn::(Args)`) for consistency and to simplify testing of stuff like https://github.com/rust-lang/rust/pull/41856#issuecomment-301219194.
Closes https://github.com/rust-lang/rust/issues/41740
cc @rust-lang/lang
r? @nikomatsakis
rustc: Add `Local` to the HIR map of parents
When walking parents for lints we want to be sure to hit `let` statements which
can have attributes, so hook up these statements in the HIR map.
Closes#43910
When walking parents for lints we want to be sure to hit `let` statements which
can have attributes, so hook up these statements in the HIR map.
Closes#43910
On a case where an else conditional is missing, point this out
instead of the token immediately after the (incorrect) else block:
```
error: missing condition for `if` statemementt push fork -f
--> $DIR/issue-13483.rs:16:5
|
13 | } else if {
| ^ expected if condition here
```
instead of
```
error: expected `{`, found `else`
--> ../../src/test/ui/issue-13483.rs:14:7
|
14 | } else {
| ^^^^
```
