clang-format improperly formats some string operators

[llvmbot]

Bugzilla Link	44542
Version	unspecified
OS	Linux
Reporter	LLVM Bugzilla Contributor
CC	@mydeveloperday

Extended Description

this line

log_error(log_, "from" << "asdf");

(we have some code written which makes it perfectly legal if not nicely looking c++)

is formatted into this

log_error(log_, "from"
<< "asdf");

None of the options that look even remotely relevant have any effect. It's specific to 2 strings, if you replace a string with some other type it doesn't break the line. Tested on versions from 6 till 9.

[llvmbot]

Tested on 10, same

[mydeveloperday]

This is caused by the following in "mustBreakBefore()" which to be honest I think looks wrong. I don't understand why we MUST break between 2 string literals.

(I've seen this bug reported before)

if (Right.is(tok::lessless) && Right.Next &&
Right.Previous->is(tok::string_literal) &&
Right.Next->is(tok::string_literal))
return true;

#38220

[mydeveloperday]

*** Bug #38220 has been marked as a duplicate of this bug. ***

[mydeveloperday]

we are discussing here https://reviews.llvm.org/D80950