From 44440e5c18a1dbcc9685866ffffe00c508929079 Mon Sep 17 00:00:00 2001 From: Sean McArthur Date: Sat, 20 Dec 2014 00:09:35 -0800 Subject: core: split into fmt::Show and fmt::String fmt::Show is for debugging, and can and should be implemented for all public types. This trait is used with `{:?}` syntax. There still exists #[derive(Show)]. fmt::String is for types that faithfully be represented as a String. Because of this, there is no way to derive fmt::String, all implementations must be purposeful. It is used by the default format syntax, `{}`. This will break most instances of `{}`, since that now requires the type to impl fmt::String. In most cases, replacing `{}` with `{:?}` is the correct fix. Types that were being printed specifically for users should receive a fmt::String implementation to fix this. Part of #20013 [breaking-change] --- src/libstd/rand/reader.rs | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) (limited to 'src/libstd/rand/reader.rs') diff --git a/src/libstd/rand/reader.rs b/src/libstd/rand/reader.rs index 48d7f2e7854..177b7380831 100644 --- a/src/libstd/rand/reader.rs +++ b/src/libstd/rand/reader.rs @@ -67,7 +67,7 @@ impl Rng for ReaderRng { if v.len() == 0 { return } match self.reader.read_at_least(v.len(), v) { Ok(_) => {} - Err(e) => panic!("ReaderRng.fill_bytes error: {}", e) + Err(e) => panic!("ReaderRng.fill_bytes error: {:?}", e) } } } -- cgit 1.4.1-3-g733a5