Overhaul borrowck error messages and compiler error formatting generally
This is a major overhaul of how the compiler reports errors. The primary goal is to be able to give many spans within the same overall context, such as this:
```
./borrow-errors.rs:73:17: 73:20: error: cannot borrow `*vec` as immutable because previous closure requires unique access [E0501]
70 let append = |e| {
~~~ closure construction occurs here
71 vec.push(e)
~~~ previous borrow occurs due to use of `vec` in closure
72 };
73 let data = &vec[3];
~~~ borrow occurs here
74 }
~ borrow from closure ends here
```
However, in the process we made a number of other changes:
- Removed the repetitive filenames from snippets and just give the line number.
- Color the line numbers blue so they "fade away"
- Remove the file name and line number from the error code suggestions since they don't seem to fit anymore. (This should probably happen in more places, like existing notes.)
- Newlines in between errors to help group them better.
This PR is not quite ready to land, but we thought it made sense to stop here and get some feedback from people at large. It'd be great if people can check out the branch and play with it. We'd be especially interested in hearing about cases that don't look good with the new formatting (I suspect they exist).
Here is a checklist of some pending work items for this PR. Some of them may be best left for follow-up PRs:
- [x] Accommodate multiple files in a `MultiSpan` (this should be easy)
- In this case, we want to print filenames though.
- [x] Remove duplicate E0500 code.
- [x] Make the header message bold, rather than current hack that makes all errors/warnings bold
- [x] Update warning text color (yellow is hard to read w/ a white background)
Moved numerous follow-ups to: https://github.com/rust-lang/rust/issues/33240
Joint work with @jonathandturner.
Fixes https://github.com/rust-lang/rust/issues/3533
Add CodeGen options to optimize for size.
Add CodeGen options to annotate functions with the attributes OptimizeSize and/or MinSize used by LLVM to reduce .text size.
Closes#32296
The compiler created a directory as part of `-Z incremental` but that may be
hierarchically used concurrently so we need to protect ourselves against that.
Fix alloc_jemalloc on windows gnu targets
jemalloc prefixes the symbols by default on Windows so we need to account
for that to avoid link errors such as: `undefined reference to 'mallocx'`
when using alloc_jemalloc.
There is now a CoreEmitter that everything desugars to, but without
losing any information. Also remove RenderSpan::FileLine. This lets the
rustc_driver tests build.
The extra filename and line was mainly there to keep the indentation
relative to the main snippet; now that this doesn't include
filename/line-number as a prefix, it is distracted.
This API pulls the "expected type foo, found type bar" out after the
main snippet. There are some other places where it makes sense, but this
is a start.
Major changes:
- Remove old snippet rendering code and use the new stuff.
- Introduce `span_label` method to add a label
- Remove EndSpan mode and replace with a fn to get the last
character of a span.
- Stop using `Option<MultiSpan>` and just use an empty `MultiSpan`
- and probably a bunch of other stuff :)
