Function interpret_mir 

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