Remove error about obsolete dereferencing of newtype structs.

A built-in feature enabling the dereferencing of newtype structs was removed
in PR #11188, and this error (E0068) was added at the same time to warn of
its removal. It seems to make sense to remove the error now, given that
the obsolete feature it is warning about was removed nearly a year and a
half ago.

diff --git a/src/librustc_typeck/check/mod.rs b/src/librustc_typeck/check/mod.rs
index f13305bba343eab0ef7aea151675a13b4fa5b88f..db39d3c05ed4b3ff7ee9a7d2ba1aa2a46ce3e817 100644 (file)
--- a/src/librustc_typeck/check/mod.rs
+++ b/src/librustc_typeck/check/mod.rs
@@ -3153,26 +3153,10 @@ fn check_struct_fields_on_error<'a,'tcx>(fcx: &FnCtxt<'a,'tcx>,
                                                            Some(&**oprnd), oprnd_t, lvalue_pref) {
                             Some(mt) => mt.ty,
                             None => {
-                                let is_newtype = match oprnd_t.sty {
-                                    ty::ty_struct(did, substs) => {
-                                        let fields = ty::struct_fields(fcx.tcx(), did, substs);
-                                        fields.len() == 1
-                                        && fields[0].name ==
-                                        token::special_idents::unnamed_field.name
-                                    }
-                                    _ => false
-                                };
-                                if is_newtype {
-                                    // This is an obsolete struct deref
-                                    span_err!(tcx.sess, expr.span, E0068,
-                                        "single-field tuple-structs can \
-                                         no longer be dereferenced");
-                                } else {
-                                    fcx.type_error_message(expr.span, |actual| {
-                                        format!("type `{}` cannot be \
-                                                dereferenced", actual)
-                                    }, oprnd_t, None);
-                                }
+                                fcx.type_error_message(expr.span, |actual| {
+                                    format!("type `{}` cannot be \
+                                            dereferenced", actual)
+                                }, oprnd_t, None);
                                 tcx.types.err
                             }
                         }