[clang][Diagnostics] Make 'note' color CYAN

[tbaederr]

Just using BLACK makes it invisible in terminals with a dark background.

See this screenshot:

With current clang, the "note:" part of the note is almost invisible, because we select BLACK as its color.

Use CYAN instead, which is also what gcc does.

[llvmbot]

@llvm/pr-subscribers-clang

Changes

Just using BLACK makes it invisible in terminals with a dark background.

See this screenshot:

With current clang, the "note:" part of the note is almost invisible, because we select BLACK as its color.

Use CYAN instead, which is also what gcc does.

---

Full diff: https://github.com/llvm/llvm-project/pull/66997.diff

1 Files Affected:

• (modified) clang/lib/Frontend/TextDiagnostic.cpp (+1-1)

diff --git a/clang/lib/Frontend/TextDiagnostic.cpp b/clang/lib/Frontend/TextDiagnostic.cpp
index eaa6e8d29a1dece..89c7ef505159e13 100644
--- a/clang/lib/Frontend/TextDiagnostic.cpp
+++ b/clang/lib/Frontend/TextDiagnostic.cpp
@@ -25,7 +25,7 @@
 using namespace clang;
 
 static const enum raw_ostream::Colors noteColor =
-  raw_ostream::BLACK;
+  raw_ostream::CYAN;
 static const enum raw_ostream::Colors remarkColor =
   raw_ostream::BLUE;
 static const enum raw_ostream::Colors fixitColor =

[cjdb]

This doesn't really fix the problem, it just shuffles it around. I expect people with blue(ish) terminals will experience the same issue after this is applied, so we ought to try and detect what colours to print out, and then have compatible themes.

[tbaederr]

I know, this only fixes the problem in the vast majority of cases. I don't know of any tool implementing dynamic background color checking so it can adjust the foreground color though.

This is a one-liner that fixes the problem on terminals with a dark background and the solution also works on light backgrounds. So, basically all of them.

[cjdb]

This is a one-liner that fixes the problem on terminals with a dark background and the solution also works on light backgrounds. So, basically all of them.

Before approving this change, I want confirmation that it doesn't adversely impact popular themes. The Tomorrow Night Blue theme that's in my Visual Studio Code client (not my theme, but one of the defaults, I think) does need to change the hue of its blue text.

If we can't detect the background, then I think it's extra important that we test this on as many themes as possible, and with colourblind filters as well.

[cor3ntin]

This doesn't really fix the problem, it just shuffles it around. I expect people with blue(ish) terminals will experience the same issue after this is applied, so we ought to try and detect what colours to print out, and then have compatible themes.

Not really, CYAN is only cyan if that's what your terminal decides to render the color 6 as, you can configure it to be orange if you want.

[cor3ntin]

A shed by any other color would store bikes as well.

[cjdb]

Not really, CYAN is only cyan if that's what your terminal decides to render the color 6 as, you can configure it to be orange if you want.

Oh, interesting. In that case, I see no problems.

[tbaederr]

I keep forgetting to add release notes and @AaronBallman hasn't reminded me in a while - is this worth a release note?

[cor3ntin]

I keep forgetting to add release notes and @AaronBallman hasn't reminded me in a while - is this worth a release note?

Yes!