librustc: Update the serializer to work properly with INHTWAMA, removing mutable fields in the process

src/libsyntax/codemap.rs

@@ -125,17 +125,34 @@ impl cmp::Eq for span {
     fn ne(&self, other: &span) -> bool { !(*self).eq(other) }
 }
 
+#[cfg(stage0)]
 impl<S:Encoder> Encodable<S> for span {
     /* Note #1972 -- spans are encoded but not decoded */
     fn encode(&self, _s: &S) { _s.emit_nil() }
 }
 
+#[cfg(not(stage0))]
+impl<S:Encoder> Encodable<S> for span {
+    /* Note #1972 -- spans are encoded but not decoded */
+    fn encode(&self, s: &mut S) {
+        s.emit_nil()
+    }
+}
+
+#[cfg(stage0)]
 impl<D:Decoder> Decodable<D> for span {
     fn decode(_d: &D) -> span {
         dummy_sp()
     }
 }
 
+#[cfg(not(stage0))]
+impl<D:Decoder> Decodable<D> for span {
+    fn decode(_d: &mut D) -> span {
+        dummy_sp()
+    }
+}
+
 pub fn spanned<T>(lo: BytePos, hi: BytePos, t: T) -> spanned<T> {
     respan(mk_sp(lo, hi), t)
 }