Implement RFC 1260 with feature_name `imported_main`.
This is the second extraction part of #84062 plus additional adjustments.
This (mostly) implements RFC 1260.
However there's still one test case failure in the extern crate case. Maybe `LocalDefId` doesn't work here? I'm not sure.
cc https://github.com/rust-lang/rust/issues/28937
r? `@petrochenkov`
use correct feature flag for impl-block-level trait bounds on const fn
I am not sure what that special hack was needed for, but it doesn't seem needed any more...
This removes the last use of the `const_fn` feature flag -- Cc https://github.com/rust-lang/rust/issues/84510
r? `@oli-obk`
Adds feature-gated `#[no_coverage]` function attribute, to fix derived Eq `0` coverage issue #83601
Derived Eq no longer shows uncovered
The Eq trait has a special hidden function. MIR `InstrumentCoverage`
would add this function to the coverage map, but it is never called, so
the `Eq` trait would always appear uncovered.
Fixes: #83601
The fix required creating a new function attribute `no_coverage` to mark
functions that should be ignored by `InstrumentCoverage` and the
coverage `mapgen` (during codegen).
Adding a `no_coverage` feature gate with tracking issue #84605.
r? `@tmandry`
cc: `@wesleywiser`
Revert "Rollup merge of #82296 - spastorino:pubrules, r=nikomatsakis"
This reverts commit e2561c58a4, reversing
changes made to 2982ba50fc.
As discussed in #83641 this feature is not complete and in particular doesn't work cross macros and given that this is not going to be included in edition 2021 nobody seems to be trying to fix the underlying problem. When can add this again I guess, whenever somebody has the time to make it work cross crates.
r? `@nikomatsakis`
Always reject `const fn` in `trait` during parsing.
'const fn' in trait are rejected in the AST:
b78c0d8a4d/compiler/rustc_ast_passes/src/ast_validation.rs (L1411)
So this feature gate check is a NOP and we can just remove it.
The src/test/ui/feature-gates/feature-gate-min_const_fn.rs and src/test/ui/feature-gates/feature-gate-const_fn.rs tests ensure that we still reject `const fn` in `trait`
Cc https://github.com/rust-lang/rust/issues/84510
r? `@oli-obk`
Get rid of is_min_const_fn
This removes the last trace of the min_const_fn mechanism by making the unsafety checker agnostic about whether something is a min or "non-min" const fn. It seems this distinction was used to disallow some features inside `const fn`, but that is the responsibility of the const checker, not of the unsafety checker. No test seems to even notice this change in the unsafety checker so I guess we are good...
r? `@oli-obk`
Cc https://github.com/rust-lang/rust/issues/84510
Improve diagnostics for function passed when a type was expected.
This PR improves diagnostics, it provides more information when a function is passed where a type is expected.
r? `@lcnr`
Handle pretty printing of `else if let` clauses without ICEing
When pretty printing the HIR of `if ... {} else if let ... {}` clauses, this displays it the `else if let` part as `match` it gets desugared to, the same way normal `if let` statements are currently displayed, instead of ICEing.
```rust
pub fn main() {
if true {
// 1
} else if let a = 1 {
// 2
} else {
// 3
}
}
```
now gets desugared (via `rustc -Zunpretty=hir,typed src/x.rs`) to:
```rust
#[prelude_import]
use ::std::prelude::rust_2015::*;
#[macro_use]
extern crate std;
pub fn main() ({
(if (true as bool)
({
// 1
} as
()) else {match (1 as i32) {
a => {
// 2
}
_ => {
// 3
}
}} as ())
} as ())
```
For comparison, this code gets HIR prettyprinted the same way before and after this change:
```rust
pub fn main() {
if let a = 1 {
// 2
} else {
// 3
}
}
```
turns into
```rust
#[prelude_import]
use ::std::prelude::rust_2015::*;
#[macro_use]
extern crate std;
pub fn main() ({
(match (1 as i32) {
a => {
// 2
}
_ => {
// 3
}
} as ())
} as ())
```
This closes#82329. It closes#84434 as well, due to having the same root cause.
Give a better error when `std` or `core` are missing
- Suggest using `rustup target add` if `RUSTUP_HOME` is set. I don't know if there's any precedent for doing this, but it seems harmless enough and it will be a big help.
- On nightly, suggest using `cargo build -Z build-std` if `CARGO` is set
- Add a note about `#![no_std]` if `std` is missing but not core
- Add a note that std may be unsupported if `std` is missing but not core
Fixes https://github.com/rust-lang/rust/issues/84418.
r? `@petrochenkov`
- Suggest using `rustup target add` if `RUSTUP_HOME` is set. I don't know if there's any precedent for doing this, but it seems harmless enough and it will be a big help.
- Add a note about `#![no_std]` if `std` is missing but not core
- On nightly, suggest using `cargo build -Z build-std` if `CARGO` is set
- Add a note that std may be unsupported if `std` is missing but not core
- Don't suggest `#![no_std]` when the load isn't injected by the
compiler
various const parameter defaults improvements
Actually resolve names in const parameter defaults, fixing `struct Foo<const N: usize = { usize::MAX }>`.
---
Split generic parameter ban rib for types and consts, allowing
```rust
#![feature(const_generics_defaults)]
struct Q;
struct Foo<T = Q, const Q: usize = 3>(T);
```
---
Remove the type/const ordering restriction if `const_generics_defaults` is active, even if `const_generics` is not. allowing us to stabilize and test const param defaults separately.
---
Check well formedness of const parameter defaults, eagerly emitting an error for `struct Foo<const N: usize = { 0 - 1 }>`
---
Do not forbid const parameters in param defaults, allowing `struct Foo<const N: usize, T = [u8; N]>(T)` and `struct Foo<const N: usize, const M: usize = N>`. Note that this should not change anything which is stabilized, as on stable, type parameters must be in front of const parameters, which means that type parameter defaults are only allowed if no const parameters exist.
We still forbid generic parameters inside of const param types.
r? `@varkor` `@petrochenkov`
move core::hint::black_box under its own feature gate
The `black_box` function had its own RFC and is tracked separately from the `test` feature at https://github.com/rust-lang/rust/issues/64102. Let's reflect this in the feature gate.
To avoid breaking all the benchmarks, libtest's `test::black_box` is a wrapping definition, not a reexport -- this means it is still under the `test` feature gate.
