Propagate expected type more widely so that we can rewrite the

issue-14039 test in a more natural way. Previously the "type we will
cast to" was hidden unless it was an integer.

Author: nikomatsakis

src/librustc/middle/typeck/check/mod.rs

@@ -1382,13 +1382,7 @@ fn check_cast(fcx: &FnCtxt,
     let t_1 = fcx.to_ty(t);
     let t_1 = structurally_resolved_type(fcx, span, t_1);
 
-    if ty::type_is_scalar(t_1) {
-        // Supply the type as a hint so as to influence integer
-        // literals and other things that might care.
-        check_expr_with_expectation(fcx, e, ExpectCastableToType(t_1))
-    } else {
-        check_expr(fcx, e)
-    }
+    check_expr_with_expectation(fcx, e, ExpectCastableToType(t_1));
 
     let t_e = fcx.expr_ty(e);
 

src/test/run-pass/issue-14039.rs

@@ -13,10 +13,10 @@
 fn foo<'a>() {
     if true {
         // in this branch, the lifetime is bound
-        (box move|&mut: _: &mut ()| {}) as Box<FnMut(&mut ())>
+        (box move|_| {}) as Box<FnMut(&mut ())>
     } else {
         // in this branch, the lifetime is free
-        (box move|&mut: _: &mut ()| {}) as Box<FnMut(&'a mut ())>
+        (box move|_| {}) as Box<FnMut(&'a mut ())>
     };
 }