auto merge of #5179 : alexcrichton/rust/default-warn-unused-import, r=graydon

I've found that unused imports can often start cluttering a project after a long time, and it's very useful to keep them under control. I don't like how Go forces a compiler error by default and it can't be changed, but I certainly want to know about them so I think that a warn is a good default.

Now that the `unused_imports` lint option is a bit smarter, I think it's possible to change the default level to warn. This commit also removes all unused imports throughout the compiler and libraries (500+).

The only odd things that I ran into were that some `use` statements had to have `#[cfg(notest)]` or `#[cfg(test)]` based on where they were. The ones with `notest` were mostly in core for modules like `cmp` whereas `cfg(test)` was for tests that weren't part of a normal `mod test` module. 

3 files changed, 0 insertions, 11 deletions

diff --git a/src/libcore/task/local_data.rs b/src/libcore/task/local_data.rs
index 185d8caae01..d9fdd51fdce 100644
--- a/src/libcore/task/local_data.rs
+++ b/src/libcore/task/local_data.rs
@@ -29,7 +29,6 @@ magic.
 use prelude::*;
 use task::local_data_priv::{local_get, local_pop, local_modify, local_set};
 use task::rt;
-use task;
 
 /**
  * Indexes a task-local data slot. The function's code pointer is used for
diff --git a/src/libcore/task/mod.rs b/src/libcore/task/mod.rs
index 0835d4400ed..ff3c8386f0b 100644
--- a/src/libcore/task/mod.rs
+++ b/src/libcore/task/mod.rs
@@ -33,22 +33,14 @@
  * ~~~
  */
 
-use cast;
 use cell::Cell;
-use cmp;
 use cmp::Eq;
-use iter;
-use libc;
 use option;
 use result::Result;
 use comm::{stream, Chan, GenericChan, GenericPort, Port, SharedChan};
-use pipes;
 use prelude::*;
-use ptr;
 use result;
-use task::local_data_priv::{local_get, local_set};
 use task::rt::{task_id, sched_id, rust_task};
-use task;
 use util;
 use util::replace;
 
diff --git a/src/libcore/task/spawn.rs b/src/libcore/task/spawn.rs
index 152e602eeee..74384ee3d93 100644
--- a/src/libcore/task/spawn.rs
+++ b/src/libcore/task/spawn.rs
@@ -77,14 +77,12 @@ use cell::Cell;
 use container::Map;
 use option;
 use comm::{Chan, GenericChan, GenericPort, Port, stream};
-use pipes;
 use prelude::*;
 use unstable;
 use ptr;
 use hashmap::linear::LinearSet;
 use task::local_data_priv::{local_get, local_set};
 use task::rt::rust_task;
-use task::rt::rust_closure;
 use task::rt;
 use task::{Failure, ManualThreads, PlatformThread, SchedOpts, SingleThreaded};
 use task::{Success, TaskOpts, TaskResult, ThreadPerCore, ThreadPerTask};