diff --git a/src/librustc/session/config.rs b/src/librustc/session/config.rs
index 0134bcdf1757b..80bfbe4edda88 100644
--- a/src/librustc/session/config.rs
+++ b/src/librustc/session/config.rs
@@ -132,7 +132,6 @@ pub struct Options {
     pub prints: Vec<PrintRequest>,
     pub cg: CodegenOptions,
     pub color: ColorConfig,
-    pub show_span: Option<String>,
     pub externs: HashMap<String, Vec<String>>,
     pub crate_name: Option<String>,
     /// An optional name to use as the crate for std during std injection,
@@ -243,7 +242,6 @@ pub fn basic_options() -> Options {
         prints: Vec::new(),
         cg: basic_codegen_options(),
         color: ColorConfig::Auto,
-        show_span: None,
         externs: HashMap::new(),
         crate_name: None,
         alt_std_name: None,
@@ -634,6 +632,8 @@ options! {DebuggingOptions, DebuggingSetter, basic_debugging_options,
           "don't clear the resolution tables after analysis"),
     keep_ast: bool = (false, parse_bool,
           "keep the AST after lowering it to HIR"),
+    show_span: Option<String> = (None, parse_opt_string,
+          "show spans for compiler debugging (expr|pat|ty)"),
 }
 
 pub fn default_lib_output() -> CrateType {
@@ -882,7 +882,6 @@ pub fn rustc_optgroups() -> Vec<RustcOptGroup> {
                       `hir` (the HIR), `hir,identified`, or
                       `hir,typed` (HIR with types for each node).",
                      "TYPE"),
-        opt::opt_u("", "show-span", "Show spans for compiler debugging", "expr|pat|ty"),
     ]);
     opts
 }
@@ -1123,7 +1122,6 @@ pub fn build_session_options(matches: &getopts::Matches) -> Options {
         prints: prints,
         cg: cg,
         color: color,
-        show_span: None,
         externs: externs,
         crate_name: crate_name,
         alt_std_name: None,
diff --git a/src/librustc_driver/driver.rs b/src/librustc_driver/driver.rs
index d172bfb441358..840260da33086 100644
--- a/src/librustc_driver/driver.rs
+++ b/src/librustc_driver/driver.rs
@@ -428,7 +428,7 @@ pub fn phase_1_parse_input(sess: &Session, cfg: ast::CrateConfig, input: &Input)
         println!("Pre-expansion node count:  {}", count_nodes(&krate));
     }
 
-    if let Some(ref s) = sess.opts.show_span {
+    if let Some(ref s) = sess.opts.debugging_opts.show_span {
         syntax::show_span::run(sess.diagnostic(), s, &krate);
     }
 
diff --git a/src/librustc_driver/lib.rs b/src/librustc_driver/lib.rs
index 7b8970876f6e3..cdac3de3682e5 100644
--- a/src/librustc_driver/lib.rs
+++ b/src/librustc_driver/lib.rs
@@ -138,12 +138,9 @@ pub fn run_compiler<'a>(args: &[String], callbacks: &mut CompilerCalls<'a>) {
     };
 
     let cstore = Rc::new(CStore::new(token::get_ident_interner()));
-    let mut sess = build_session(sopts, input_file_path, descriptions,
+    let sess = build_session(sopts, input_file_path, descriptions,
                                  cstore.clone());
     rustc_lint::register_builtins(&mut sess.lint_store.borrow_mut(), Some(&sess));
-    if sess.unstable_options() {
-        sess.opts.show_span = matches.opt_str("show-span");
-    }
     let mut cfg = config::build_configuration(&sess);
     target_features::add_configuration(&mut cfg, &sess);
 
@@ -387,7 +384,7 @@ impl<'a> CompilerCalls<'a> for RustcDefaultCalls {
     fn build_controller(&mut self, sess: &Session) -> CompileController<'a> {
         let mut control = CompileController::basic();
 
-        if sess.opts.parse_only || sess.opts.show_span.is_some() ||
+        if sess.opts.parse_only || sess.opts.debugging_opts.show_span.is_some() ||
            sess.opts.debugging_opts.ast_json_noexpand {
             control.after_parse.stop = Compilation::Stop;
         }