Rollup merge of #66498 - bjorn3:less_feature_flags, r=Dylan-DPC

Remove unused feature gates

I think many of the remaining unstable things can be easily be replaced with stable things. I have kept the `#![feature(nll)]` even though it is only necessary in `libstd`, to make regressions of it harder.

2 files changed, 13 insertions, 18 deletions

diff --git a/src/librustc_codegen_llvm/lib.rs b/src/librustc_codegen_llvm/lib.rs
index 8091a748540..98a3e695fa0 100644
--- a/src/librustc_codegen_llvm/lib.rs
+++ b/src/librustc_codegen_llvm/lib.rs
@@ -6,18 +6,11 @@
 
 #![doc(html_root_url = "https://doc.rust-lang.org/nightly/")]
 #![feature(bool_to_option)]
-#![feature(box_patterns)]
-#![feature(box_syntax)]
 #![feature(const_cstr_unchecked)]
 #![feature(crate_visibility_modifier)]
 #![feature(extern_types)]
 #![feature(in_band_lifetimes)]
-#![feature(libc)]
 #![feature(nll)]
-#![feature(optin_builtin_traits)]
-#![feature(concat_idents)]
-#![feature(link_args)]
-#![feature(static_nobundle)]
 #![feature(trusted_len)]
 #![recursion_limit = "256"]
 
@@ -196,7 +189,7 @@ unsafe impl Sync for LlvmCodegenBackend {}
 
 impl LlvmCodegenBackend {
     pub fn new() -> Box<dyn CodegenBackend> {
-        box LlvmCodegenBackend(())
+        Box::new(LlvmCodegenBackend(()))
     }
 }
 
@@ -245,7 +238,7 @@ impl CodegenBackend for LlvmCodegenBackend {
     }
 
     fn metadata_loader(&self) -> Box<MetadataLoaderDyn> {
-        box metadata::LlvmMetadataLoader
+        Box::new(metadata::LlvmMetadataLoader)
     }
 
     fn provide(&self, providers: &mut ty::query::Providers<'_>) {
@@ -262,12 +255,12 @@ impl CodegenBackend for LlvmCodegenBackend {
         metadata: EncodedMetadata,
         need_metadata_module: bool,
     ) -> Box<dyn Any> {
-        box rustc_codegen_ssa::base::codegen_crate(
+        Box::new(rustc_codegen_ssa::base::codegen_crate(
             LlvmCodegenBackend(()),
             tcx,
             metadata,
             need_metadata_module,
-        )
+        ))
     }
 
     fn join_codegen(
diff --git a/src/librustc_codegen_llvm/metadata.rs b/src/librustc_codegen_llvm/metadata.rs
index abe34bb148c..0f30c2c020d 100644
--- a/src/librustc_codegen_llvm/metadata.rs
+++ b/src/librustc_codegen_llvm/metadata.rs
@@ -22,10 +22,11 @@ impl MetadataLoader for LlvmMetadataLoader {
         // Use ArchiveRO for speed here, it's backed by LLVM and uses mmap
         // internally to read the file. We also avoid even using a memcpy by
         // just keeping the archive along while the metadata is in use.
-        let archive = ArchiveRO::open(filename).map(|ar| OwningRef::new(box ar)).map_err(|e| {
-            debug!("llvm didn't like `{}`: {}", filename.display(), e);
-            format!("failed to read rlib metadata in '{}': {}", filename.display(), e)
-        })?;
+        let archive =
+            ArchiveRO::open(filename).map(|ar| OwningRef::new(Box::new(ar))).map_err(|e| {
+                debug!("llvm didn't like `{}`: {}", filename.display(), e);
+                format!("failed to read rlib metadata in '{}': {}", filename.display(), e)
+            })?;
         let buf: OwningRef<_, [u8]> = archive.try_map(|ar| {
             ar.iter()
                 .filter_map(|s| s.ok())
@@ -44,9 +45,10 @@ impl MetadataLoader for LlvmMetadataLoader {
             let buf = path_to_c_string(filename);
             let mb = llvm::LLVMRustCreateMemoryBufferWithContentsOfFile(buf.as_ptr())
                 .ok_or_else(|| format!("error reading library: '{}'", filename.display()))?;
-            let of = ObjectFile::new(mb).map(|of| OwningRef::new(box of)).ok_or_else(|| {
-                format!("provided path not an object file: '{}'", filename.display())
-            })?;
+            let of =
+                ObjectFile::new(mb).map(|of| OwningRef::new(Box::new(of))).ok_or_else(|| {
+                    format!("provided path not an object file: '{}'", filename.display())
+                })?;
             let buf = of.try_map(|of| search_meta_section(of, target, filename))?;
             Ok(rustc_erase_owner!(buf))
         }