Let expressions on RHS shouldn't be terminating scopes
Fixes#100276.
Before this PR, we were unconditionally marking the RHS of short-circuiting binary expressions as a terminating scope.
In the case of a let chain where the `let` expression was on the RHS, this meant that temporaries within the `let` expr would only live until the end of the expression. Since this only affected the RHS, this led to surprising behavior ([example](https://play.rust-lang.org/?version=nightly&mode=debug&edition=2021&gist=d1b0a5d1f01882f9c89c2194a75eb19f)).
After this PR, we only mark the RHS as a terminating scope if it is not a `let` expression.
Standardize "use parentheses to call" suggestions between typeck and trait selection
1. Suggest calling constructors, since they're basically `FnDef`s but they have a different def kind and hir representation, so we were leaving them out.
2. Standardize the call suggestions between trait fulfillment errors and type mismatch. In the type mismatch suggestion, we suggest `/* Ty */` as the placeholder for an arg, and not the parameter's name, which is less helpful.
3. Use `predicate_must_hold_modulo_regions` instead of matching on `EvaluationResult` -- this might cause some suggestions to be filtered out, but we really shouldn't be suggesting a call if it "may" hold, only when it "must" hold.
4. Borrow some logic from `extract_callable_info` to generalize this suggestion to fn pointers, type parameters, and opaque types.
Fixes#102852
Handle core dumps output in QEMU user mode
In addition to the whole-system emulation/virtualization, QEMU also supports user-mode emulation, where the emulation happens as a normal process inside the parent system. This allows running most tests by simply spawning remote-test-server inside user-mode emulation.
Unfortunately, QEMU always writes its own message in addition to the system one when a core dump happens, which breaks a few tests which match on the exact output of the system.
This PR changes those tests to strip the (possible) QEMU output before checking if the output is expected.
Make diagnostic for unsatisfied `Termination` bounds more precise
Don't blindly emit a diagnostic claiming that “*`main` has an invalid return type*” if we encounter a type that should but doesn't implement `std::process::Termination` and isn't actually the return type of the program entry `main`.
Fixes#103052.
``@rustbot`` label A-diagnostics T-compiler T-libs
r? diagnostics
In addition to the whole-system emulation/virtualization, QEMU also
supports user-mode emulation, where the emulation happens as a normal
process inside the parent system. This allows running most tests by
simply spawning remote-test-server inside user-mode emulation.
Unfortunately, QEMU always writes its own message in addition to the
system one when a core dump happens, which breaks a few tests which
match on the exact output of the system.
This PR changes those tests to strip the (possible) QEMU output before
checking if the output is expected.
PR #98758 introduced code to avoid redundant assertions in derived code
like this:
```
let _: ::core::clone::AssertParamIsClone<u32>;
let _: ::core::clone::AssertParamIsClone<u32>;
```
But the predicate `is_simple_path` introduced as part of this failed to
account for generic arguments. Therefore the deriving code erroneously
considers types like `Option<bool>` and `Option<f32>` to be the same.
This commit fixes `is_simple_path`.
Fixes#103157.
Do not register placeholder `RegionOutlives` obligations when `considering_regions` is false
**NOTE:** I'm kinda just putting this up for discussion. I'm not certain this is correct...?
This was introduced in [`608625d`](608625dae9 (diff-6e54b18681342ec725d75591dbf384ad08cd73df29db00485fe51b4e90f76ff7R361)).
Interestingly, we only check `data.has_placeholders()` for `RegionOutlives`, and not for `TypeOutlives`... why? For the record, that different treatment between `RegionOutlives` and `TypeOutlives` is why the fix "The compiling succeeds when all `'a : 'b` are replaced with `&'a () : 'b`" in #100689 _"works"_, but it seems like an implementation detail considering this.
Also, why do we care about placeholder regions being registered if `considering_regions` is false? It doesn't seem to affect any UI tests, for example.
r? `@lcnr`
Fixes#102899Fixes#100689
Rollup of 5 pull requests
Successful merges:
- #103087 (Documentation BTreeMap::append's behavior for already existing keys)
- #103089 (Mark derived StructuralEq as automatically derived.)
- #103102 (Clarify the possible return values of `len_utf16`)
- #103109 (PhantomData: inline a macro that is used only once)
- #103120 (rustdoc: Do not expect `doc(primitive)` modules to always exist)
Failed merges:
r? `@ghost`
`@rustbot` modify labels: rollup
Fix subst issues with return-position `impl Trait` in trait
1. Fix an issue where we were rebase impl substs onto trait method substs, instead of trait substs
2. Fix an issue where early-bound regions aren't being mapped correctly for RPITIT hidden types
Fixes#102301Fixes#102310Fixes#102334Fixes#102918
Fix missing explanation of where the borrowed reference is used when the same borrow occurs multiple times due to loop iterations
Fix#99824.
Problem of the issue:
If a borrow occurs in a loop, the borrowed reference could be invalidated at the same place at next iteration of the loop. When this happens, the point where the borrow occurs is the same as the intervening point that might invalidate the reference in the loop. This causes a problem for the current code finding the point where the resulting reference is used, so that the explanation of the cause will be missing. As the second point of "explain all errors in terms of three points" (see [leveraging intuition framing errors in terms of points"](https://rust-lang.github.io/rfcs/2094-nll.html#leveraging-intuition-framing-errors-in-terms-of-points), this explanation is very helpful for user to understand the error.
In the current implementation, the searching region for finding the location where the borrowed reference is used is limited to between the place where the borrow occurs and the place where the reference is invalidated. If those two places happen to be the same, which indicates that the borrow and invalidation occur at the same place in a loop, the search will fail.
One solution to the problem is when these two places are the same, find the terminator of the loop, and then use the location of the loop terminator instead of the location of the borrow for the region to find the place where the borrowed reference is used.
Rollup of 6 pull requests
Successful merges:
- #102773 (Use semaphores for thread parking on Apple platforms)
- #102884 (resolve: Some cleanup, asserts and tests for lifetime ribs)
- #102954 (Add missing checks for `doc(cfg_hide(...))`)
- #102998 (Drop temporaries created in a condition, even if it's a let chain)
- #103003 (Fix `suggest_floating_point_literal` ICE)
- #103041 (Update cargo)
Failed merges:
r? `@ghost`
`@rustbot` modify labels: rollup
Drop temporaries created in a condition, even if it's a let chain
Fixes#100513.
During the lowering from AST to HIR we wrap expressions acting as conditions in a `DropTemps` expression so that any temporaries created in the condition are dropped after the condition is executed. Effectively this means we transform
```rust
if Some(1).is_some() { .. }
```
into (roughly)
```rust
if { let _t = Some(1).is_some(); _t } { .. }
```
so that if we create any temporaries, they're lifted into the new scope surrounding the condition, so for example something along the lines of
```rust
if { let temp = Some(1); let _t = temp.is_some(); _t }.
```
Before this PR, if the condition contained any let expressions we would not introduce that new scope, instead leaving the condition alone. This meant that in a let-chain like
```rust
if get_drop("first").is_some() && let None = get_drop("last") {
println!("second");
} else { .. }
```
the temporary created for `get_drop("first")` would be lifted into the _surrounding block_, which caused it to be dropped after the execution of the entire `if` expression.
After this PR, we wrap everything but the `let` expression in terminating scopes. The upside to this solution is that it's minimally invasive, but the downside is that in the worst case, an expression with `let` exprs interspersed like
```rust
if get_drop("first").is_some()
&& let Some(_a) = get_drop("fifth")
&& get_drop("second").is_some()
&& let Some(_b) = get_drop("fourth") { .. }
```
gets _multiple_ new scopes, roughly
```rust
if { let _t = get_drop("first").is_some(); _t }
&& let Some(_a) = get_drop("fifth")
&& { let _t = get_drop("second").is_some(); _t }
&& let Some(_b) = get_drop("fourth") { .. }
```
so instead of all of the temporaries being dropped at the end of the entire condition, they will be dropped right after they're evaluated (before the subsequent `let` expr). So while I'd say the drop behavior around let-chains is _less_ surprising after this PR, it still might not exactly match what people might expect.
For tests, I've just extended the drop order tests added in #100526. I'm not sure if that's the best way to go about it, though, so suggestions are welcome.
Make `dyn*` casts into a coercion, allow `dyn*` upcasting
I know that `dyn*` is likely not going to be a feature exposed to surface Rust, but this makes it slightly more ergonomic to write tests for these types anyways. ... and this was just fun to implement anyways.
1. Make `dyn*` into a coercion instead of a cast
2. Enable `dyn*` upcasting since we basically get it for free
3. Simplify some of the cast checking code since we're using the coercion path now
r? `@eholk` but feel free to reassign
cc `@nikomatsakis` and `@tmandry` who might care about making `dyn*` casts into a coercion
Correctly handle path stability for 'use tree' items
PR #95956 started checking the stability of path segments.
However, this was not applied to 'use tree' items
(e.g. 'use some::path::{ItemOne, ItemTwo}') due to the way
that we desugar these items in HIR lowering.
This PR modifies 'use tree' lowering to preserve resolution
information, which is needed by stability checking.
sync thread_local key conditions exactly with what the macro uses
This makes the `cfg` in `mod.rs` syntactically the same as those in `local.rs`.
I don't think this should actually change anything, but seems better to be consistent?
I looked into this due to https://github.com/rust-lang/rust/issues/102549, but this PR would make it *less* likely that `__OsLocalKeyInner` is going to get provided, so this cannot help with that issue.
r? `@thomcc`
Suppress irrefutable let patterns lint for prefixes in match guards
In match guards, irrefutable prefixes might use the bindings created by the match pattern. Ideally, we check for this, but we can do the next best thing and just not lint for irrefutable prefixes in match guards.
Fixes#98361
More dupe word typos
I only picked those changes (from the regex search) that I am pretty certain doesn't change meaning and is just a typo fix. Do correct me if any fix is undesirable and I can revert those. Thanks.
