Changing ?Sized related trait bounds is not detected

[weiznich]

Steps to reproduce the bug with the above code

git clone https://github.com/diesel-rs/diesel
cd diesel/diesel
cargo semver-checks --baseline-rev v2.0.4 --only-explicit-features --features postgres --features sqlite --features mysql --features extras --features with-deprecated --manifest-path .

Actual Behaviour

No breaking change is reported:

     Cloning v2.0.4
     Parsing diesel v2.1.1 (current)
     Parsing diesel v2.0.4 (baseline)
    Checking diesel v2.0.4 -> v2.1.1 (minor change)
   Completed [   0.150s] 39 checks; 39 passed, 6 unnecessary

Expected Behaviour

Cargo semver-checks should report a major breaking change. A trait function added a ?Sized bound to it's where clause.

Documentation:

• 2.1.1
• 2.0.4

Relevant function signature:
2.0.4:

    fn push_bound_value<T, U>(
        &mut self,
        bind: &'a U,
        metadata_lookup: &mut DB::MetadataLookup,
    ) -> QueryResult<()>
    where
        DB: Backend + HasSqlType<T>,
        U: ToSql<T, DB> + 'a;

2.1.1:

    fn push_bound_value<T, U>(
        &mut self,
        bind: &'a U,
        metadata_lookup: &mut DB::MetadataLookup,
    ) -> QueryResult<()>
    where
        DB: Backend + HasSqlType<T>,
        U: ToSql<T, DB> + ?Sized + 'a;

Note the added ?Sized bound in the newer version. From caller side this is a non-breaking change as it only extends the set of allowed values. For existing implementations outside of diesel of the given trait this is a breaking change as it requires updating the function signature. It also might break an implementation that assumes that U is Sized.

Generated System Information

Software version

cargo-semver-checks 0.22.1

Operating system

Linux 6.4.7-200.fc38.x86_64

Command-line

/home/weiznich/.cargo/bin/cargo-semver-checks semver-checks --bugreport 

cargo version

> cargo -V 
cargo 1.68.0 (115f34552 2023-02-26)

Compile time information

• Profile: release
• Target triple: x86_64-unknown-linux-gnu
• Family: unix
• OS: linux
• Architecture: x86_64
• Pointer width: 64
• Endian: little
• CPU features: fxsr,sse,sse2
• Host: x86_64-unknown-linux-gnu

Build Configuration

No response

Additional Context

No response

[obi1kenobi]

Thanks, this is awesome! Especially appreciate the details on how this might be breaking and for whom, which will be super helpful writing the diagnostic message this should show.