Rollup merge of #72697 - ehuss:rm-rustc-ux-guidelines, r=nikomatsakis

Remove rustc-ux-guidelines

This is now in the rustc-dev-guide:
* https://github.com/rust-lang/rustc-dev-guide/pull/716
* https://github.com/rust-lang/rustc-dev-guide/pull/717

This is a public page, but it was not linked to anywhere, so I think it is safe to remove. Google searches don't show it being used anywhere.

1 files changed, 0 insertions, 90 deletions

diff --git a/src/doc/rustc-ux-guidelines.md b/src/doc/rustc-ux-guidelines.md
deleted file mode 100644
index b626923bcb5..00000000000
--- a/src/doc/rustc-ux-guidelines.md
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-% Rustc UX guidelines
-
-Don't forget the user. Whether human or another program, such as an IDE, a
-good user experience with the compiler goes a long way toward making developers'
-lives better. We do not want users to be baffled by compiler output or
-learn arcane patterns to compile their program.
-
-## Error, Warning, Help, Note Messages
-
-When the compiler detects a problem, it can emit one of the following: an error, a warning,
-a note, or a help message.
-
-An `error` is emitted when the compiler detects a problem that makes it unable
- to compile the program, either because the program is invalid or the
- programmer has decided to make a specific `warning` into an error.
-
-A `warning` is emitted when the compiler detects something odd about a
-program. For instance, dead code and unused `Result` values.
-
-A `help` message is emitted following an `error` or `warning` to give additional
-information to the user about how to solve their problem.
-
-A `note` is emitted to identify additional circumstances and parts of the code
-that caused the warning or error. For example, the borrow checker will note any
-previous conflicting borrows.
-
-* Write in plain simple English. If your message, when shown on a – possibly
-small – screen (which hasn't been cleaned for a while), cannot be understood
-by a normal programmer, who just came out of bed after a night partying, it's
-too complex.
-* `Errors` and `Warnings` should not suggest how to fix the problem. A `Help`
-message should be emitted instead.
-* `Error`, `Warning`, `Note`, and `Help` messages start with a lowercase
-letter and do not end with punctuation.
-* Error messages should be succinct. Users will see these error messages many
-times, and more verbose descriptions can be viewed with the `--explain` flag.
-That said, don't make it so terse that it's hard to understand.
-* The word "illegal" is illegal. Prefer "invalid" or a more specific word
-instead.
-* Errors should document the span of code where they occur – the `span_..`
-methods allow to easily do this. Also `note` other spans that have contributed
-to the error if the span isn't too large.
-* When emitting a message with span, try to reduce the span to the smallest
-amount possible that still signifies the issue
-* Try not to emit multiple error messages for the same error. This may require
-detecting duplicates.
-* When the compiler has too little information for a specific error message,
-lobby for annotations for library code that allow adding more. For example see
-`#[on_unimplemented]`. Use these annotations when available!
-* Keep in mind that Rust's learning curve is rather steep, and that the
-compiler messages are an important learning tool.
-
-## Error Explanations
-
-Error explanations are long form descriptions of error messages provided with
-the compiler. They are accessible via the `--explain` flag. Each explanation
-comes with an example of how to trigger it and advice on how to fix it.
-
-Please read [RFC 1567](https://github.com/rust-lang/rfcs/blob/master/text/1567-long-error-codes-explanation-normalization.md)
-for details on how to format and write long error codes.
-
-* All of them are accessible [online](http://doc.rust-lang.org/error-index.html),
-  which are auto-generated from rustc source code in different places:
-  [librustc](https://github.com/rust-lang/rust/blob/master/src/librustc/error_codes.rs),
-  [librustc_ast](https://github.com/rust-lang/rust/blob/master/src/librustc_ast/error_codes.rs),
-  [librustc_borrowck](https://github.com/rust-lang/rust/blob/master/src/librustc_borrowck/error_codes.rs),
-  [librustc_metadata](https://github.com/rust-lang/rust/blob/master/src/librustc_metadata/error_codes.rs),
-  [librustc_mir](https://github.com/rust-lang/rust/blob/master/src/librustc_mir/error_codes.rs),
-  [librustc_passes](https://github.com/rust-lang/rust/blob/master/src/librustc_passes/error_codes.rs),
-  [librustc_privacy](https://github.com/rust-lang/rust/blob/master/src/librustc_privacy/error_codes.rs),
-  [librustc_resolve](https://github.com/rust-lang/rust/blob/master/src/librustc_resolve/error_codes.rs),
-  [librustc_codegen_llvm](https://github.com/rust-lang/rust/blob/master/src/librustc_codegen_llvm/error_codes.rs),
-  [librustc_plugin_impl](https://github.com/rust-lang/rust/blob/master/src/librustc_plugin/error_codes.rs),
-  [librustc_typeck](https://github.com/rust-lang/rust/blob/master/src/librustc_typeck/error_codes.rs).
-* Explanations have full markdown support. Use it, especially to highlight
-code with backticks.
-* When talking about the compiler, call it `the compiler`, not `Rust` or
-`rustc`.
-
-## Compiler Flags
-
-* Flags should be orthogonal to each other. For example, if we'd have a
-json-emitting variant of multiple actions `foo` and `bar`, an additional
---json flag is better than adding `--foo-json` and `--bar-json`.
-* Always give options a long descriptive name, if only for more
-understandable compiler scripts.
-* The `--verbose` flag is for adding verbose information to `rustc` output
-when not compiling a program. For example, using it with the `--version` flag
-gives information about the hashes of the code.
-* Experimental flags and options must be guarded behind the `-Z unstable-options` flag.