syntax: obsolete the `for Sized?` syntax

2 files changed, 12 insertions, 2 deletions

diff --git a/src/libsyntax/parse/obsolete.rs b/src/libsyntax/parse/obsolete.rs
index e1e456f880e..d63f432589d 100644
--- a/src/libsyntax/parse/obsolete.rs
+++ b/src/libsyntax/parse/obsolete.rs
@@ -24,6 +24,7 @@ use ptr::P;
 /// The specific types of unsupported syntax
 #[derive(Copy, PartialEq, Eq, Hash)]
 pub enum ObsoleteSyntax {
+    ObsoleteForSized,
     ObsoleteOwnedType,
     ObsoleteOwnedExpr,
     ObsoleteOwnedPattern,
@@ -55,6 +56,11 @@ impl<'a> ParserObsoleteMethods for parser::Parser<'a> {
     /// Reports an obsolete syntax non-fatal error.
     fn obsolete(&mut self, sp: Span, kind: ObsoleteSyntax) {
         let (kind_str, desc) = match kind {
+            ObsoleteForSized => (
+                "for Sized?",
+                "no longer required, traits apply to sized and unsized types by default, use \
+                `: Sized` to opt-out of unsized types",
+            ),
             ObsoleteProcType => (
                 "the `proc` type",
                 "use unboxed closures instead",
diff --git a/src/libsyntax/parse/parser.rs b/src/libsyntax/parse/parser.rs
index cc67079e538..aedfaac59c5 100644
--- a/src/libsyntax/parse/parser.rs
+++ b/src/libsyntax/parse/parser.rs
@@ -5003,6 +5003,7 @@ impl<'a> Parser<'a> {
         // re-jigged shortly in any case, so leaving the hacky version for now.
         if self.eat_keyword(keywords::For) {
             let span = self.span;
+
             let mut ate_question = false;
             if self.eat(&token::Question) {
                 ate_question = true;
@@ -5020,8 +5021,11 @@ impl<'a> Parser<'a> {
                     "expected `?Sized` after `for` in trait item");
                 return None;
             }
-            let tref = Parser::trait_ref_from_ident(ident, span);
-            Some(tref)
+            let _tref = Parser::trait_ref_from_ident(ident, span);
+
+            self.obsolete(span, ObsoleteForSized);
+
+            None
         } else {
             None
         }