3 files changed, 5 insertions, 4 deletions
diff --git a/src/libsyntax/ext/base.rs b/src/libsyntax/ext/base.rs
index 35449bde0b2..b679456b353 100644
--- a/src/libsyntax/ext/base.rs
+++ b/src/libsyntax/ext/base.rs
@@ -264,7 +264,7 @@ macro_rules! make_MacEager {
                     box MacEager {
                         $fld: Some(v),
                         ..Default::default()
-                    } as Box<MacResult>
+                    }
                 }
             )*
         }
@@ -330,7 +330,7 @@ impl DummyResult {
     /// Use this as a return value after hitting any errors and
     /// calling `span_err`.
     pub fn any(sp: Span) -> Box<MacResult+'static> {
-        box DummyResult { expr_only: false, span: sp } as Box<MacResult+'static>
+        box DummyResult { expr_only: false, span: sp }
     }
 
     /// Create a default MacResult that can only be an expression.
@@ -339,7 +339,7 @@ impl DummyResult {
     /// if an error is encountered internally, the user will receive
     /// an error that they also used it in the wrong place.
     pub fn expr(sp: Span) -> Box<MacResult+'static> {
-        box DummyResult { expr_only: true, span: sp } as Box<MacResult+'static>
+        box DummyResult { expr_only: true, span: sp }
     }
 
     /// A plain dummy expression.
diff --git a/src/libsyntax/ext/quote.rs b/src/libsyntax/ext/quote.rs
index c11ffe66e6c..a25a6451918 100644
--- a/src/libsyntax/ext/quote.rs
+++ b/src/libsyntax/ext/quote.rs
@@ -262,6 +262,7 @@ pub mod rt {
         (unsigned, $t:ty, $tag:expr) => (
             impl ToSource for $t {
                 fn to_source(&self) -> String {
+                    #![allow(trivial_numeric_casts)]
                     let lit = ast::LitInt(*self as u64, ast::UnsignedIntLit($tag));
                     pprust::lit_to_string(&dummy_spanned(lit))
                 }
diff --git a/src/libsyntax/ext/tt/macro_rules.rs b/src/libsyntax/ext/tt/macro_rules.rs
index 5940b791843..1e53db60301 100644
--- a/src/libsyntax/ext/tt/macro_rules.rs
+++ b/src/libsyntax/ext/tt/macro_rules.rs
@@ -169,7 +169,7 @@ fn generic_extension<'cx>(cx: &'cx ExtCtxt,
                 // Weird, but useful for X-macros.
                 return box ParserAnyMacro {
                     parser: RefCell::new(p),
-                } as Box<MacResult+'cx>
+                }
               }
               Failure(sp, ref msg) => if sp.lo >= best_fail_spot.lo {
                 best_fail_spot = sp;