lazy overflow checking

Author: ranjitjhala

library/core/Cargo.toml

@@ -47,8 +47,9 @@ check-cfg = [
 
 [package.metadata.flux]
 enabled = true
+check_overflow = "lazy"
 include = [ "src/ascii*.rs",
-            "src/pat.rs", 
+            "src/pat.rs",
             "src/bstr/*.rs",
             "src/hash/*.rs",
             "src/time.rs",

library/core/src/flux_info.rs

@@ -54,4 +54,4 @@
         fn fmt(self: &Self, f: &mut fmt::Formatter) -> fmt::Result;
     }
 }]
-const _: () = {};
+const _: () = ();