Revert "Disable clippy until Manishearth/rust-clippy#1174 is fixed"

This reverts commit 2bc1d62e50b799e06b51742a8490b546395e04ec.

serde/Cargo.toml

@@ -18,7 +18,7 @@ std = []
 unstable = []
 alloc = ["unstable"]
 collections = ["alloc"]
-unstable-testing = ["unstable", "std"]
+unstable-testing = ["clippy", "unstable", "std"]
 
 [dependencies]
 clippy = { version = "^0.*", optional = true }

serde_codegen/Cargo.toml

@@ -14,7 +14,7 @@ include = ["Cargo.toml", "build.rs", "src/**/*.rs", "src/lib.rs.in"]
 [features]
 default = ["with-syntex"]
 unstable = ["quasi_macros"]
-unstable-testing = []
+unstable-testing = ["clippy"]
 with-syntex = [
     "quasi/with-syntex",
     "quasi_codegen",

serde_codegen_internals/Cargo.toml

@@ -12,7 +12,7 @@ include = ["Cargo.toml", "src/**/*.rs"]
 
 [features]
 default = ["with-syntex"]
-unstable-testing = []
+unstable-testing = ["clippy"]
 with-syntex = ["syntex_syntax", "syntex_errors"]
 
 [dependencies]

serde_macros/Cargo.toml

@@ -17,6 +17,7 @@ plugin = true
 
 [features]
 unstable-testing = [
+    "clippy",
     "skeptic",
     "serde_json",
     "serde/unstable-testing",

serde_macros/tests/run-pass/identity-op.rs

@@ -1,5 +1,5 @@
 #![feature(custom_derive, plugin)]
-#![plugin(serde_macros)]
+#![plugin(serde_macros, clippy)]
 
 #![deny(identity_op)]
 

testing/Cargo.toml

@@ -12,7 +12,7 @@ keywords = ["serialization"]
 build = "build.rs"
 
 [features]
-unstable-testing = ["serde/unstable-testing", "serde_codegen/unstable-testing"]
+unstable-testing = ["clippy", "serde/unstable-testing", "serde_codegen/unstable-testing"]
 
 [build-dependencies]
 serde_codegen = { path = "../serde_codegen", features = ["with-syntex"] }