clang-tidy modernize-use-std-format breaks enums when used with '%x', and fails replacements when signed stdint types are used.

[DaveBrantonCTCT]

These examples illustrate the two problems

int8_t int_8_value;
printf("%d", int_8_value) ;

Will fail to replace correctly. The int8_t will cause this error message, and the replacement will be skipped.

Unknown corresponding signed type for non-BuiltinType 'int8_t'

SomeEnum enum_value;
printf("%x %d", enum_value) ;

This example will proceed with the replacement, but will fail to add the necessary cast to the enum's underlying type, and so the format string will break your build.

[llvmbot]

@llvm/issue-subscribers-clang-tidy

Author: None (DaveBrantonCTCT)

These examples illustrate the two problems

int8_t int_8_value;
printf("%d", int_8_value) ;

Will fail to replace correctly. The int8_t will cause this error message, and the replacement will be skipped.

Unknown corresponding signed type for non-BuiltinType 'int8_t'

SomeEnum enum_value;
printf("%x %d", enum_value) ;

This example will proceed with the replacement, but will fail to add the necessary cast to the enum's underlying type, and so the format string will break your build.

[DaveBrantonCTCT]

Correction: The second example should be

SomeEnum enum_value;
printf("%x", enum_value) ;

This will be replaced with

SomeEnum enum_value;
fmt::print("{:x}", enum_value) ;

Instead of

SomeEnum enum_value;
fmt::print("{:x}", static_cast<int>(enum_value)) ;

[chrchr-github]

So far I can only reproduce the second (enum) example:
https://godbolt.org/z/q6rnMrs1f