:: is allowed to start an expression. Close #762.

src/comp/syntax/parse/token.rs

@@ -201,6 +201,7 @@ pred can_begin_expr(t: token) -> bool {
       NOT. { true }
       BINOP(MINUS.) { true }
       BINOP(STAR.) { true }
+      MOD_SEP. { true }
       _ { false }
     }
 }

src/test/run-pass/expr-scope.rs

@@ -0,0 +1,5 @@
+// Regression test for issue #762
+// xfail-stage0
+
+fn f() { }
+fn main() { ret ::f(); }