[PATCH] D155610: [Clang][Sema] Fix display of characters on static assertion failure

[Tom Honermann via Phabricator via cfe-commits]

tahonermann added inline comments.


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Comment at: clang/test/SemaCXX/static-assert-cxx26.cpp:304
+static_assert('\u{9}' == (char)1, ""); // expected-error {{failed}} \
+                                       // expected-note {{evaluates to ''\t' (0x09, 9) == '<U+0001>' (0x01, 1)'}}
+static_assert((char8_t)-128 == (char8_t)-123, ""); // expected-error {{failed}} \
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cor3ntin wrote:
> tahonermann wrote:
> > Is the expected note up to date? I don't see code that would generate the `<U+0001>` output. Am I just missing it? Since U+0001 is a valid, though non-printable, character, I would expect more `'\u0001'`.
> See elsewhere in the discussion. this formating is pre existing and managed at the DiagnosticEngine level (pushEscapedString). the reason it's not `\u0001` is 1/ to avoid  reusing c++ syntactic elements for something that comes from diagnostics and is not represented as an escaped sequence in source 2/ `\u00011` is unreadable, and `\U000000001` is also not helpful :)
> 
Thanks for the explanation. I'm not sure that I agree with the rationale for (1) though. We're already putting the value in single quotes and representing some values with escapes in many of these cases when the value isn't produced by an escape sequence (or even a character/string literal); why exclude `\uXXXX`? I agree with the rationale for (2); we could use `'\u{1}'` in that case.


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  https://reviews.llvm.org/D155610/new/

https://reviews.llvm.org/D155610