diff --git a/src/librustc/driver/driver.rs b/src/librustc/driver/driver.rs
index b579a9b9c64c1..5aa22f7e6d561 100644
--- a/src/librustc/driver/driver.rs
+++ b/src/librustc/driver/driver.rs
@@ -210,7 +210,6 @@ pub fn phase_2_configure_and_expand(sess: &Session,
-> (ast::Crate, syntax::ast_map::Map) {
let time_passes = sess.time_passes();
- sess.building_library.set(session::building_library(&sess.opts, &krate));
*sess.crate_types.borrow_mut() = session::collect_crate_types(sess, krate.attrs.as_slice());
time(time_passes, "gated feature checking", (), |_|
@@ -1046,7 +1045,6 @@ pub fn build_session_(sopts: session::Options,
entry_type: Cell::new(None),
macro_registrar_fn: Cell::new(None),
default_sysroot: default_sysroot,
- building_library: Cell::new(false),
local_crate_source_file: local_crate_source_file,
working_dir: os::getcwd(),
lints: RefCell::new(NodeMap::new()),
diff --git a/src/librustc/driver/session.rs b/src/librustc/driver/session.rs
index 950e6bd8ee833..58ccfeab73d18 100644
--- a/src/librustc/driver/session.rs
+++ b/src/librustc/driver/session.rs
@@ -25,7 +25,6 @@ use syntax::codemap::Span;
use syntax::diagnostic;
use syntax::parse::ParseSess;
use syntax::{abi, ast, codemap};
-use syntax;
use std::cell::{Cell, RefCell};
use collections::HashSet;
@@ -185,7 +184,6 @@ pub struct Session {
pub entry_type: Cell