Why clang-tidy readability-isolate-declaration not fixing code?

Question

I tried to use readability-isolate-declaration check in clang-tidy, but nothing fixed. Example of code from test.cpp file:

void f() {
    int a = 0, b = 1, c = 2;
}

What I've done:

clang-tidy -checks='readability-isolate-declaration' -fix test.cpp

Output:

Error while trying to load a compilation database:
Could not auto-detect compilation database for file "test.cpp"
No compilation database found in /home/anzipex/Downloads/clang-test or any parent directory
fixed-compilation-database: Error while opening fixed database: No such file or directory
json-compilation-database: Error while opening JSON database: No such file or directory
Running without flags.

Answer 1

There are several problems here:

1. readability-isolate-declaration check didn't exist in clang-tidy 6. Upgrade to a more recent version
2. If you don't have a compilation database, you can use --(double dash) to specify compilation options. Even if you specify none, this will tell clang-tidy to compile the file. See the documentation.
3. You didn't tell clang-tidy to exclude other checks besides the one you want

This is what the command should look like:

clang-tidy -checks='-*,readability-isolate-declaration' test.cpp -fix --

Output:

void f() {
    int a = 0;
    int b = 1;
    int c = 2;
}