This is based on the feedback from estebank:
"""
I believe that test can be removed outright. It'd be impossible for a
new change to go through that breaks this kind of output without it
being picked up by multiple other `stderr` tests. This is an artifact
of the transition period to the "new" output style.
"""
see: https://github.com/rust-lang/rust/issues/52663#issuecomment-422155551
Give a special message when the later use is from a call. Use the span
of the callee instead of the whole expression. For conflicting borrow
messages say that the later use is of the first borrow.
* Arguably this change is sometimes injecting noise into the output
(namely in the cases where the suggested rewrite is inline with the
suggestion and we end up highlighting the original source code).
I would not be opposed to something more aggressive/dynamic, like
revising the suggestion code to automatically print the original
source when necessary (e.g. when the error does not have a span
that includes the span of the suggestion).
* Also, as another note on this change: The doc comment for `Diagnostic::span_suggestion`
says:
/// The message
///
/// * should not end in any punctuation (a `:` is added automatically)
/// * should not be a question
/// * should not contain any parts like "the following", "as shown"
but the `:` is *not* added when the emitted line appears
out-of-line relative to the suggestion. I find that to be an
unfortunate UI experience.
----
As a drive-by fix, also changed code to combine multiple suggestions
for a pattern into a single multipart suggestion (which vastly
improves user experience IMO).
----
Includes the updates to expected NLL diagnostics.
Technically, there are requirements imposed by the LLVM
`AMDGPUTargetMachine` on functions with this ABI (eg, the return type
must be void), but I'm unsure exactly where this should be enforced.
Various changes to existing diagnostics
* [Add code to `invalid ABI` error, add span label, move list to help to make message shorter](https://github.com/rust-lang/rust/pull/51463/commits/23ae5af274defa9ff884f593e44a2bbcaf814a02):
```
error[E0697]: invalid ABI: found `路濫狼á́́`
--> $DIR/unicode.rs:11:8
|
LL | extern "路濫狼á́́" fn foo() {} //~ ERROR invalid ABI
| ^^^^^^^^^ invalid ABI
|
= help: valid ABIs: cdecl, stdcall, fastcall, vectorcall, thiscall, aapcs, win64, sysv64, ptx-kernel, msp430-interrupt, x86-interrupt, Rust, C, system, rust-intrinsic, rust-call, platform-intrinsic, unadjusted
```
* [Add code to incorrect `pub` restriction error](https://github.com/rust-lang/rust/pull/51463/commits/e96fdea8a38f39f99f8b9a4000a689187a457e08)
* [Add message to `rustc_on_unimplemented` attributes in core to have them set a custom message _and_ label](https://github.com/rust-lang/rust/pull/51463/commits/2cc7e5ed307aee936c20479cfdc7409d6b52a464):
```
error[E0277]: `W` does not have a constant size known at compile-time
--> $DIR/unsized-enum2.rs:33:8
|
LL | VA(W),
| ^ `W` does not have a constant size known at compile-time
|
= help: the trait `std::marker::Sized` is not implemented for `W`
= help: consider adding a `where W: std::marker::Sized` bound
= note: no field of an enum variant may have a dynamically sized type
```
```
error[E0277]: `Foo` cannot be sent between threads safely
--> $DIR/E0277-2.rs:26:5
|
LL | is_send::<Foo>();
| ^^^^^^^^^^^^^^ `Foo` cannot be sent between threads safely
|
= help: the trait `std::marker::Send` is not implemented for `Foo`
```
```
error[E0277]: can't compare `{integer}` with `std::string::String`
--> $DIR/binops.rs:16:7
|
LL | 5 < String::new();
| ^ no implementation for `{integer} < std::string::String` and `{integer} > std::string::String`
|
= help: the trait `std::cmp::PartialOrd<std::string::String>` is not implemented for `{integer}`
```
```
error[E0277]: can't compare `{integer}` with `std::result::Result<{integer}, _>`
--> $DIR/binops.rs:17:7
|
LL | 6 == Ok(1);
| ^^ no implementation for `{integer} == std::result::Result<{integer}, _>`
|
= help: the trait `std::cmp::PartialEq<std::result::Result<{integer}, _>>` is not implemented for `{integer}`
```
```
error[E0277]: a collection of type `i32` cannot be built from an iterator over elements of type `i32`
--> $DIR/type-check-defaults.rs:16:19
|
LL | struct WellFormed<Z = Foo<i32, i32>>(Z);
| ^ a collection of type `i32` cannot be built from `std::iter::Iterator<Item=i32>`
|
= help: the trait `std::iter::FromIterator<i32>` is not implemented for `i32`
note: required by `Foo`
--> $DIR/type-check-defaults.rs:15:1
|
LL | struct Foo<T, U: FromIterator<T>>(T, U);
| ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
```
* [Add link to book for `Sized` errors](https://github.com/rust-lang/rust/pull/51463/commits/1244dc7c283323aea1a3457a4458d590a3e160c8):
```
error[E0277]: `std::fmt::Debug + std::marker::Sync + 'static` does not have a constant size known at compile-time
--> $DIR/const-unsized.rs:13:29
|
LL | const CONST_0: Debug+Sync = *(&0 as &(Debug+Sync));
| ^^^^^^^^^^^^^^^^^^^^^^ `std::fmt::Debug + std::marker::Sync + 'static` does not have a constant size known at compile-time
|
= help: the trait `std::marker::Sized` is not implemented for `std::fmt::Debug + std::marker::Sync + 'static`
= note: to learn more, visit <https://doc.rust-lang.org/book/second-edition/ch19-04-advanced-types.html#dynamically-sized-types--sized>
= note: constant expressions must have a statically known size
```
* [Point to previous line for single expected token not found](https://github.com/rust-lang/rust/pull/51463/commits/48165168fb0f059d8536cd4a2276b609d4a7f721) (if the current token is in a different line)
NOTE: I was careful to make each change in a manner that preserves the
existing diagnostic output (usually by ensuring that no lines were
added or removed). This means that the resulting source files are not
as nice to read as they were at the start. But we will have to review
these cases by hand anyway as follow-up work, so cleanup could
reasonably happen then (or not at all).
Make `assert` a built-in procedural macro
Makes `assert` macro a built-in one without touching its functionality. This is a prerequisite for RFC 2011 (#44838).
Display `\t` in diagnostics code as four spaces
Follow up to #44386 using the unicode variable width machinery from #45711 to replace tabs in the source code when displaying a diagnostic error with four spaces (instead of only one), while properly accounting for this when calculating underlines.
Partly addresses #44618.
Fixes#38384
Most of the Rust community uses 4 spaces for indentation,
but there are also tab users of Rust (including myself!).
This patch fixes a bug in error printing which mispositions
error indicators when near code with tabs.
The code attempted to fix the issue by replacing spaces
with tabs, but it sadly wasn't enough, as sometimes
you may not print spaces but _ or ^ instead.
This patch employs the reverse strategy: it replaces each
tab with a space, so that the number of _ and ^ and spaces
in error indicators below the code snippet line up
perfectly.
In a study [1] preceeding this patch, we could see that
this strategy is also chosen by gcc version 6.3.0.
Its not perfect, as the output is not beautiful, but its
the easiest to implement. If anyone wants to improve on
this, be my guest! This patch is meant as improvement of
the status quo, not as perfect end status. It fixes the
actual issue of mispositioning error indicators.
[1]: https://github.com/rust-lang/rust/issues/38384#issuecomment-326813710
