Auto merge of #39060 - jseyfried:improve_unused, r=nrc

Improve unused `extern crate` and unused `#[macro_use]` warnings

This PR
 - adds `unused_imports` warnings for unused `#[macro_use] extern crate` macro imports,
 - improves `unused_extern_crates` warnings (avoids false negatives), and
 - removes unused `#[macro_use]` imports and unused `extern crate`s.

r? @nrc

Author: bors

src/Cargo.lock

@@ -11,5 +11,4 @@ crate-type = ["dylib"]
 log = { path = "../liblog" }
 rustc_plugin = { path = "../librustc_plugin" }
 syntax = { path = "../libsyntax" }
-syntax_pos = { path = "../libsyntax_pos" }
 proc_macro_tokens = { path = "../libproc_macro_tokens" }

src/libproc_macro_plugin/Cargo.toml

@@ -88,7 +88,6 @@
 
 extern crate rustc_plugin;
 extern crate syntax;
-extern crate syntax_pos;
 extern crate proc_macro_tokens;
 #[macro_use] extern crate log;
 

src/libproc_macro_plugin/lib.rs

@@ -10,5 +10,3 @@ crate-type = ["dylib"]
 
 [dependencies]
 syntax = { path = "../libsyntax" }
-syntax_pos = { path = "../libsyntax_pos" }
-log = { path = "../liblog" }

src/libproc_macro_tokens/Cargo.toml

@@ -8,9 +8,6 @@
 // option. This file may not be copied, modified, or distributed
 // except according to those terms.
 
-extern crate syntax;
-extern crate syntax_pos;
-
 use syntax::ast::Ident;
 use syntax::codemap::DUMMY_SP;
 use syntax::parse::token::{self, Token};

src/libproc_macro_tokens/build.rs

@@ -58,8 +58,6 @@
 #![feature(rustc_private)]
 
 extern crate syntax;
-extern crate syntax_pos;
-#[macro_use] extern crate log;
 
 pub mod build;
 pub mod parse;

src/libproc_macro_tokens/lib.rs

@@ -10,8 +10,6 @@
 
 //! Parsing utilities for writing procedural macros.
 
-extern crate syntax;
-
 use syntax::parse::{ParseSess, filemap_to_tts};
 use syntax::tokenstream::TokenStream;
 

src/libproc_macro_tokens/parse.rs

@@ -10,7 +10,6 @@ crate-type = ["dylib"]
 
 [dependencies]
 arena = { path = "../libarena" }
-flate = { path = "../libflate" }
 fmt_macros = { path = "../libfmt_macros" }
 graphviz = { path = "../libgraphviz" }
 log = { path = "../liblog" }

src/librustc/Cargo.toml

@@ -26,7 +26,6 @@
 #![feature(associated_consts)]
 #![feature(box_patterns)]
 #![feature(box_syntax)]
-#![feature(collections)]
 #![feature(conservative_impl_trait)]
 #![feature(const_fn)]
 #![feature(core_intrinsics)]
@@ -39,11 +38,9 @@
 #![feature(slice_patterns)]
 #![feature(staged_api)]
 #![feature(unboxed_closures)]
-#![cfg_attr(test, feature(test))]
 
 extern crate arena;
 extern crate core;
-extern crate flate;
 extern crate fmt_macros;
 extern crate getopts;
 extern crate graphviz;
@@ -52,22 +49,18 @@ extern crate rustc_llvm as llvm;
 extern crate rustc_back;
 extern crate rustc_data_structures;
 extern crate serialize;
-extern crate collections;
 extern crate rustc_const_math;
 extern crate rustc_errors as errors;
 #[macro_use] extern crate log;
 #[macro_use] extern crate syntax;
-#[macro_use] extern crate syntax_pos;
+extern crate syntax_pos;
 #[macro_use] #[no_link] extern crate rustc_bitflags;
 
 extern crate serialize as rustc_serialize; // used by deriving
 
 // SNAP:
 extern crate rustc_i128;
 
-#[cfg(test)]
-extern crate test;
-
 #[macro_use]
 mod macros;
 

src/librustc/lib.rs

@@ -11,7 +11,6 @@ crate-type = ["dylib"]
 [dependencies]
 arena = { path = "../libarena" }
 log = { path = "../liblog" }
-serialize = { path = "../libserialize" }
 rustc = { path = "../librustc" }
 rustc_back = { path = "../librustc_back" }
 rustc_const_math = { path = "../librustc_const_math" }

src/librustc_const_eval/Cargo.toml

@@ -40,7 +40,6 @@ extern crate rustc_data_structures;
 extern crate rustc_errors;
 extern crate graphviz;
 extern crate syntax_pos;
-extern crate serialize as rustc_serialize; // used by deriving
 
 extern crate rustc_i128;
 

src/librustc_const_eval/lib.rs

@@ -9,7 +9,6 @@ path = "lib.rs"
 crate-type = ["dylib"]
 
 [dependencies]
-log = { path = "../liblog" }
 serialize = { path = "../libserialize" }
 syntax = { path = "../libsyntax" }
 rustc_i128 = { path = "../librustc_i128" }

src/librustc_const_math/Cargo.toml

@@ -28,8 +28,7 @@
 #![feature(const_fn)]
 #![cfg_attr(not(stage0), feature(i128))]
 
-#[macro_use] extern crate log;
-#[macro_use] extern crate syntax;
+extern crate syntax;
 
 // SNAP: remove use of this crate
 extern crate rustc_i128;

src/librustc_const_math/lib.rs

@@ -10,7 +10,6 @@ crate-type = ["dylib"]
 
 [dependencies]
 arena = { path = "../libarena" }
-flate = { path = "../libflate" }
 graphviz = { path = "../libgraphviz" }
 log = { path = "../liblog" }
 proc_macro_plugin = { path = "../libproc_macro_plugin" }

src/librustc_driver/Cargo.toml

@@ -32,7 +32,6 @@
 #![feature(staged_api)]
 
 extern crate arena;
-extern crate flate;
 extern crate getopts;
 extern crate graphviz;
 extern crate libc;
@@ -57,7 +56,6 @@ extern crate serialize;
 extern crate rustc_llvm as llvm;
 #[macro_use]
 extern crate log;
-#[macro_use]
 extern crate syntax;
 extern crate syntax_ext;
 extern crate syntax_pos;

src/librustc_driver/lib.rs

@@ -9,6 +9,4 @@ path = "lib.rs"
 crate-type = ["dylib"]
 
 [dependencies]
-log = { path = "../liblog" }
-serialize = { path = "../libserialize" }
 syntax_pos = { path = "../libsyntax_pos" }

src/librustc_errors/Cargo.toml

@@ -23,16 +23,9 @@
 #![feature(staged_api)]
 #![feature(range_contains)]
 #![feature(libc)]
-#![feature(unicode)]
 
-extern crate serialize;
 extern crate term;
-#[macro_use]
-extern crate log;
-#[macro_use]
 extern crate libc;
-extern crate std_unicode;
-extern crate serialize as rustc_serialize; // used by deriving
 extern crate syntax_pos;
 
 pub use emitter::ColorConfig;

src/librustc_errors/lib.rs

@@ -16,4 +16,3 @@ serialize = { path = "../libserialize" }
 log = { path = "../liblog" }
 syntax = { path = "../libsyntax" }
 syntax_pos = { path = "../libsyntax_pos" }
-rustc_i128 = { path = "../librustc_i128" }

src/librustc_incremental/Cargo.toml

@@ -30,11 +30,9 @@ extern crate rustc_data_structures;
 extern crate serialize as rustc_serialize;
 
 #[macro_use] extern crate log;
-#[macro_use] extern crate syntax;
+extern crate syntax;
 extern crate syntax_pos;
 
-extern crate rustc_i128;
-
 const ATTR_DIRTY: &'static str = "rustc_dirty";
 const ATTR_CLEAN: &'static str = "rustc_clean";
 const ATTR_DIRTY_METADATA: &'static str = "rustc_metadata_dirty";

src/librustc_incremental/lib.rs

@@ -37,7 +37,6 @@
 #![feature(slice_patterns)]
 #![feature(staged_api)]
 
-#[macro_use]
 extern crate syntax;
 #[macro_use]
 extern crate rustc;

src/librustc_lint/lib.rs

@@ -12,7 +12,6 @@ crate-type = ["dylib"]
 graphviz = { path = "../libgraphviz" }
 log = { path = "../liblog" }
 rustc = { path = "../librustc" }
-rustc_back = { path = "../librustc_back" }
 rustc_const_eval = { path = "../librustc_const_eval" }
 rustc_const_math = { path = "../librustc_const_math" }
 rustc_data_structures = { path = "../librustc_data_structures" }

src/librustc_mir/Cargo.toml

@@ -31,7 +31,6 @@ extern crate graphviz as dot;
 #[macro_use]
 extern crate rustc;
 extern crate rustc_data_structures;
-extern crate rustc_back;
 #[macro_use]
 #[no_link]
 extern crate rustc_bitflags;

src/librustc_mir/lib.rs

@@ -27,7 +27,6 @@
 #![feature(staged_api)]
 #![feature(rustc_private)]
 
-extern crate core;
 #[macro_use]
 extern crate rustc;
 extern crate rustc_const_eval;

src/librustc_passes/lib.rs

@@ -10,10 +10,8 @@ path = "lib.rs"
 crate-type = ["dylib"]
 
 [dependencies]
-log = { path = "../liblog" }
 rustc = { path = "../librustc" }
 rustc_back = { path = "../librustc_back" }
-rustc_bitflags = { path = "../librustc_bitflags" }
 rustc_metadata = { path = "../librustc_metadata" }
 syntax = { path = "../libsyntax" }
 syntax_pos = { path = "../libsyntax_pos" }

src/librustc_plugin/Cargo.toml

@@ -63,9 +63,7 @@
 #![feature(rustc_diagnostic_macros)]
 #![feature(rustc_private)]
 
-#[macro_use] extern crate log;
 #[macro_use] extern crate syntax;
-#[macro_use] #[no_link] extern crate rustc_bitflags;
 
 extern crate rustc;
 extern crate rustc_back;