Make ptr_arg lint warn by default

README.md

@@ -48,7 +48,7 @@ name
 [nonsensical_open_options](https://github.com/Manishearth/rust-clippy/wiki#nonsensical_open_options)   | warn    | nonsensical combination of options for opening a file
 [option_unwrap_used](https://github.com/Manishearth/rust-clippy/wiki#option_unwrap_used)               | allow   | using `Option.unwrap()`, which should at least get a better message using `expect()`
 [precedence](https://github.com/Manishearth/rust-clippy/wiki#precedence)                               | warn    | catches operations where precedence may be unclear. See the wiki for a list of cases caught
-[ptr_arg](https://github.com/Manishearth/rust-clippy/wiki#ptr_arg)                                     | allow   | fn arguments of the type `&Vec<...>` or `&String`, suggesting to use `&[...]` or `&str` instead, respectively
+[ptr_arg](https://github.com/Manishearth/rust-clippy/wiki#ptr_arg)                                     | warn    | fn arguments of the type `&Vec<...>` or `&String`, suggesting to use `&[...]` or `&str` instead, respectively
 [range_step_by_zero](https://github.com/Manishearth/rust-clippy/wiki#range_step_by_zero)               | warn    | using Range::step_by(0), which produces an infinite iterator
 [redundant_closure](https://github.com/Manishearth/rust-clippy/wiki#redundant_closure)                 | warn    | using redundant closures, i.e. `|a| foo(a)` (which can be written as just `foo`)
 [redundant_pattern](https://github.com/Manishearth/rust-clippy/wiki#redundant_pattern)                 | warn    | using `name @ _` in a pattern

src/lib.rs

@@ -101,7 +101,6 @@ pub fn plugin_registrar(reg: &mut Registry) {
         methods::WRONG_PUB_SELF_CONVENTION,
         mut_mut::MUT_MUT,
         mutex_atomic::MUTEX_INTEGER,
-        ptr_arg::PTR_ARG,
         shadow::SHADOW_REUSE,
         shadow::SHADOW_SAME,
         shadow::SHADOW_UNRELATED,
@@ -153,6 +152,7 @@ pub fn plugin_registrar(reg: &mut Registry) {
         needless_bool::NEEDLESS_BOOL,
         open_options::NONSENSICAL_OPEN_OPTIONS,
         precedence::PRECEDENCE,
+        ptr_arg::PTR_ARG,
         ranges::RANGE_STEP_BY_ZERO,
         returns::LET_AND_RETURN,
         returns::NEEDLESS_RETURN,

src/ptr_arg.rs

@@ -1,6 +1,6 @@
 //! Checks for usage of &Vec[_] and &String
 //!
-//! This lint is **allow** by default
+//! This lint is **warn** by default
 
 use rustc::lint::*;
 use rustc_front::hir::*;
@@ -11,7 +11,7 @@ use utils::{STRING_PATH, VEC_PATH};
 
 declare_lint! {
     pub PTR_ARG,
-    Allow,
+    Warn,
     "fn arguments of the type `&Vec<...>` or `&String`, suggesting to use `&[...]` or `&str` \
      instead, respectively"
 }