Fix some issues around rustc_public

compiler/rustc_public/src/compiler_interface.rs

@@ -835,6 +835,8 @@ impl<'tcx> CompilerInterface<'tcx> {
 // A thread local variable that stores a pointer to [`CompilerInterface`].
 scoped_tls::scoped_thread_local!(static TLV: Cell<*const ()>);
 
+// remove this cfg when we have a stable driver.
+#[cfg(feature = "rustc_internal")]
 pub(crate) fn run<'tcx, F, T>(interface: &CompilerInterface<'tcx>, f: F) -> Result<T, Error>
 where
     F: FnOnce() -> T,

compiler/rustc_public/src/unstable/mod.rs

@@ -22,6 +22,7 @@ mod internal_cx;
 ///
 /// This trait is only for [`RustcInternal`]. Any other other access to rustc's internals
 /// should go through [`rustc_public_bridge::context::CompilerCtxt`].
+#[cfg_attr(not(feature = "rustc_internal"), allow(unreachable_pub))]
 pub trait InternalCx<'tcx>: Copy + Clone {
     fn tcx(self) -> TyCtxt<'tcx>;
 
@@ -59,6 +60,7 @@ pub trait InternalCx<'tcx>: Copy + Clone {
 /// between internal MIR and rustc_public's IR constructs.
 /// However, they should be used seldom and they have no influence in this crate semver.
 #[doc(hidden)]
+#[cfg_attr(not(feature = "rustc_internal"), allow(unreachable_pub))]
 pub trait Stable<'tcx>: PointeeSized {
     /// The stable representation of the type implementing Stable.
     type T;
@@ -78,6 +80,7 @@ pub trait Stable<'tcx>: PointeeSized {
 /// between internal MIR and rustc_public's IR constructs.
 /// They should be used seldom as they have no stability guarantees.
 #[doc(hidden)]
+#[cfg_attr(not(feature = "rustc_internal"), allow(unreachable_pub))]
 pub trait RustcInternal {
     type T<'tcx>;
     fn internal<'tcx>(