Function interpret_mir 

pub fn interpret_mir<'db>(
    db: &'db dyn HirDatabase,
    body: &'db MirBody<'db>,
    assert_placeholder_ty_is_unused: bool,
    trait_env: Option<ParamEnvAndCrate<'db>>,
) -> Result<(Result<Allocation<'db>, MirEvalError<'db>>, MirOutput), MirEvalError<'db>>