Auto merge of #70534 - Centril:rollup-t59tcx2, r=Centril

Rollup of 3 pull requests

Successful merges:

 - #70140 (Add Result<Result<T, E>, E>::flatten -> Result<T, E>)
 - #70526 (reduce `rustc_attr` usage in places)
 - #70527 (Update LLVM submodule)

Failed merges:

r? @ghost

Cargo.lock

@@ -4013,7 +4013,6 @@ dependencies = [
  "log",
  "rustc_ast",
  "rustc_ast_pretty",
- "rustc_attr",
  "rustc_data_structures",
  "rustc_errors",
  "rustc_feature",

src/libcore/result.rs

@@ -230,9 +230,9 @@
 
 #![stable(feature = "rust1", since = "1.0.0")]
 
-use crate::fmt;
 use crate::iter::{self, FromIterator, FusedIterator, TrustedLen};
 use crate::ops::{self, Deref, DerefMut};
+use crate::{convert, fmt};
 
 /// `Result` is a type that represents either success ([`Ok`]) or failure ([`Err`]).
 ///
@@ -1214,6 +1214,38 @@ impl<T, E> Result<Option<T>, E> {
     }
 }
 
+impl<T, E> Result<Result<T, E>, E> {
+    /// Converts from `Result<Result<T, E>, E>` to `Result<T, E>`
+    ///
+    /// # Examples
+    /// Basic usage:
+    /// ```
+    /// #![feature(result_flattening)]
+    /// let x: Result<Result<&'static str, u32>, u32> = Ok(Ok("hello"));
+    /// assert_eq!(Ok("hello"), x.flatten());
+    ///
+    /// let x: Result<Result<&'static str, u32>, u32> = Ok(Err(6));
+    /// assert_eq!(Err(6), x.flatten());
+    ///
+    /// let x: Result<Result<&'static str, u32>, u32> = Err(6);
+    /// assert_eq!(Err(6), x.flatten());
+    /// ```
+    ///
+    /// Flattening once only removes one level of nesting:
+    ///
+    /// ```
+    /// #![feature(result_flattening)]
+    /// let x: Result<Result<Result<&'static str, u32>, u32>, u32> = Ok(Ok(Ok("hello")));
+    /// assert_eq!(Ok(Ok("hello")), x.flatten());
+    /// assert_eq!(Ok("hello"), x.flatten().flatten());
+    /// ```
+    #[inline]
+    #[unstable(feature = "result_flattening", issue = "70142")]
+    pub fn flatten(self) -> Result<T, E> {
+        self.and_then(convert::identity)
+    }
+}
+
 // This is a separate function to reduce the code size of the methods
 #[inline(never)]
 #[cold]

src/librustc_codegen_llvm/attributes.rs

@@ -21,7 +21,7 @@ use crate::attributes;
 use crate::llvm::AttributePlace::Function;
 use crate::llvm::{self, Attribute};
 use crate::llvm_util;
-pub use rustc_attr::{self as attr, InlineAttr, OptimizeAttr};
+pub use rustc_attr::{InlineAttr, OptimizeAttr};
 
 use crate::context::CodegenCx;
 use crate::value::Value;

src/librustc_parse/Cargo.toml

@@ -13,7 +13,6 @@ doctest = false
 bitflags = "1.0"
 log = "0.4"
 rustc_ast_pretty = { path = "../librustc_ast_pretty" }
-rustc_attr = { path = "../librustc_attr" }
 rustc_data_structures = { path = "../librustc_data_structures" }
 rustc_feature = { path = "../librustc_feature" }
 rustc_lexer = { path = "../librustc_lexer" }