Auto merge of #31120 - alexcrichton:attribute-deny-warnings, r=brson

This commit removes the `-D warnings` flag being passed through the makefiles to
all crates to instead be a crate attribute. We want these attributes always
applied for all our standard builds, and this is more amenable to Cargo-based
builds as well.

Note that all `deny(warnings)` attributes are gated with a `cfg(stage0)`
attribute currently to match the same semantics we have today

Author: bors

mk/target.mk

@@ -17,14 +17,6 @@ export CFG_COMPILER_HOST_TRIPLE
 export CFG_DEFAULT_LINKER
 export CFG_DEFAULT_AR
 
-# The standard libraries should be held up to a higher standard than any old
-# code, make sure that these common warnings are denied by default. These can
-# be overridden during development temporarily. For stage0, we allow warnings
-# which may be bugs in stage0 (should be fixed in stage1+)
-RUST_LIB_FLAGS_ST0 += -W warnings
-RUST_LIB_FLAGS_ST1 += -D warnings
-RUST_LIB_FLAGS_ST2 += -D warnings
-
 # Macro that generates the full list of dependencies for a crate at a particular
 # stage/target/host tuple.
 #

src/liballoc/boxed_test.rs

@@ -15,7 +15,6 @@ use core::ops::Deref;
 use core::result::Result::{Ok, Err};
 use core::clone::Clone;
 
-use std::boxed;
 use std::boxed::Box;
 
 #[test]

src/liballoc/lib.rs

@@ -70,35 +70,33 @@
        test(no_crate_inject, attr(allow(unused_variables), deny(warnings))))]
 #![no_std]
 #![needs_allocator]
+#![cfg_attr(not(stage0), deny(warnings))]
 
 #![feature(allocator)]
 #![feature(box_syntax)]
 #![feature(coerce_unsized)]
+#![feature(const_fn)]
 #![feature(core_intrinsics)]
 #![feature(custom_attribute)]
+#![feature(drop_in_place)]
+#![feature(dropck_parametricity)]
 #![feature(fundamental)]
 #![feature(lang_items)]
+#![feature(needs_allocator)]
 #![feature(optin_builtin_traits)]
 #![feature(placement_in_syntax)]
-#![feature(placement_new_protocol)]
-#![feature(raw)]
 #![feature(shared)]
 #![feature(staged_api)]
 #![feature(unboxed_closures)]
 #![feature(unique)]
 #![feature(unsafe_no_drop_flag, filling_drop)]
-#![feature(dropck_parametricity)]
 #![feature(unsize)]
-#![feature(drop_in_place)]
-#![feature(fn_traits)]
-#![feature(const_fn)]
-
-#![feature(needs_allocator)]
 
 // Issue# 30592: Systematically use alloc_system during stage0 since jemalloc
 // might be unavailable or disabled
 #![cfg_attr(stage0, feature(alloc_system))]
 
+#![cfg_attr(not(test), feature(raw, fn_traits, placement_new_protocol))]
 #![cfg_attr(test, feature(test, rustc_private, box_heap))]
 
 #[cfg(stage0)]

src/liballoc_jemalloc/lib.rs

@@ -16,6 +16,7 @@
             reason = "this library is unlikely to be stabilized in its current \
                       form or name",
             issue = "27783")]
+#![cfg_attr(not(stage0), deny(warnings))]
 #![feature(allocator)]
 #![feature(libc)]
 #![feature(staged_api)]

src/liballoc_system/lib.rs

@@ -12,6 +12,7 @@
 #![crate_type = "rlib"]
 #![no_std]
 #![allocator]
+#![cfg_attr(not(stage0), deny(warnings))]
 #![unstable(feature = "alloc_system",
             reason = "this library is unlikely to be stabilized in its current \
                       form or name",

src/libarena/lib.rs

@@ -27,6 +27,7 @@
        html_favicon_url = "https://doc.rust-lang.org/favicon.ico",
        html_root_url = "https://doc.rust-lang.org/nightly/",
        test(no_crate_inject, attr(deny(warnings))))]
+#![cfg_attr(not(stage0), deny(warnings))]
 
 #![feature(alloc)]
 #![feature(core_intrinsics)]

src/libcollections/lib.rs

@@ -28,6 +28,7 @@
 
 #![allow(trivial_casts)]
 #![cfg_attr(test, allow(deprecated))] // rand
+#![cfg_attr(not(stage0), deny(warnings))]
 
 #![feature(alloc)]
 #![feature(box_patterns)]
@@ -55,7 +56,7 @@
 #![feature(unicode)]
 #![feature(unique)]
 #![feature(unsafe_no_drop_flag)]
-#![cfg_attr(test, feature(clone_from_slice, rand, test))]
+#![cfg_attr(test, feature(rand, test))]
 
 #![no_std]
 

src/libcollections/slice.rs

@@ -83,20 +83,14 @@
 
 // Many of the usings in this module are only used in the test configuration.
 // It's cleaner to just turn off the unused_imports warning than to fix them.
-#![allow(unused_imports)]
+#![cfg_attr(test, allow(unused_imports, dead_code))]
 
 use alloc::boxed::Box;
-use core::clone::Clone;
 use core::cmp::Ordering::{self, Greater, Less};
-use core::cmp::{self, Ord, PartialEq};
-use core::iter::Iterator;
-use core::marker::Sized;
+use core::cmp;
 use core::mem::size_of;
 use core::mem;
-use core::ops::FnMut;
-use core::option::Option::{self, Some, None};
 use core::ptr;
-use core::result::Result;
 use core::slice as core_slice;
 
 use borrow::{Borrow, BorrowMut, ToOwned};
@@ -136,12 +130,7 @@ pub use self::hack::to_vec;
 // `test_permutations` test
 mod hack {
     use alloc::boxed::Box;
-    use core::clone::Clone;
-    #[cfg(test)]
-    use core::iter::Iterator;
     use core::mem;
-    #[cfg(test)]
-    use core::option::Option::{Some, None};
 
     #[cfg(test)]
     use string::ToString;

src/libcollections/str.rs

@@ -19,10 +19,6 @@
 // It's cleaner to just turn off the unused_imports warning than to fix them.
 #![allow(unused_imports)]
 
-use core::clone::Clone;
-use core::iter::{Iterator, Extend};
-use core::option::Option::{self, Some, None};
-use core::result::Result;
 use core::str as core_str;
 use core::str::pattern::Pattern;
 use core::str::pattern::{Searcher, ReverseSearcher, DoubleEndedSearcher};

src/libcollectionstest/slice.rs

@@ -9,7 +9,6 @@
 // except according to those terms.
 
 use std::cmp::Ordering::{Equal, Greater, Less};
-use std::default::Default;
 use std::mem;
 use std::__rand::{Rng, thread_rng};
 use std::rc::Rc;