message: Make lifetime explicit
diff: @@ -30,11 +30,11 @@ impl<'arena, 'env> Context<'arena, 'env> {
  }
  }
  - fn elim_context(&self) -> semantics::ElimContext<'arena, '_> {
  + fn elim_context(&self) -> semantics::ElimContext<'arena, 'env> {
  semantics::ElimContext::new(self.flexible_exprs)
  }
  - fn conversion_context(&self) -> semantics::ConversionContext<'arena, '_> {
  + fn conversion_context(&self) -> semantics::ConversionContext<'arena, 'env> {
  semantics::ConversionContext::new(EnvLen::new(), self.flexible_exprs)
  }
  