[clang-tools-extra] [clang-tidy] Add a new check 'performance-string-view-conversions' (PR #174288)

[Zinovy Nis via cfe-commits]

irishrover wrote:

Supported cases for

 -  `foo_sv(42, std::string("foo").append("bar"), 3.14);`
 -  `foo_sv(42, std::string(sv).substr(0, 5), 3.14);`
 -  `foo_sv(42, std::string(sv).c_str(), 3.14);`


https://github.com/llvm/llvm-project/pull/174288