Auto merge of #77039 - ecstatic-morse:rollup-qv3jj4a, r=ecstatic-morse

Rollup of 13 pull requests

Successful merges:

 - #72734 (Reduce duplicate in liballoc reserve error handling)
 - #76131 (Don't use `zip` to compare iterators during pretty-print hack)
 - #76150 (Don't recommend ManuallyDrop to customize drop order)
 - #76275 (Implementation of Write for some immutable ref structs)
 - #76489 (Add explanation for E0756)
 - #76581 (do not ICE on bound variables, return `TooGeneric` instead)
 - #76655 (Make some methods of `Pin` unstable const)
 - #76783 (Only get ImplKind::Impl once)
 - #76807 (Use const-checking to forbid use of unstable features in const-stable functions)
 - #76888 (use if let instead of single match arm expressions)
 - #76914 (extend `Ty` and `TyCtxt` lints to self types)
 - #77022 (Reduce boilerplate for BytePos and CharPos)
 - #77032 (lint missing docs for extern items)

Failed merges:

r? `@ghost`

2 files changed, 8 insertions, 14 deletions

diff --git a/compiler/rustc_parse/src/lexer/tokentrees.rs b/compiler/rustc_parse/src/lexer/tokentrees.rs
index 0f364bffb13..6233549dc85 100644
--- a/compiler/rustc_parse/src/lexer/tokentrees.rs
+++ b/compiler/rustc_parse/src/lexer/tokentrees.rs
@@ -149,12 +149,9 @@ impl<'a> TokenTreesReader<'a> {
                             }
                         }
 
-                        match (open_brace, delim) {
-                            //only add braces
-                            (DelimToken::Brace, DelimToken::Brace) => {
-                                self.matching_block_spans.push((open_brace_span, close_brace_span));
-                            }
-                            _ => {}
+                        //only add braces
+                        if let (DelimToken::Brace, DelimToken::Brace) = (open_brace, delim) {
+                            self.matching_block_spans.push((open_brace_span, close_brace_span));
                         }
 
                         if self.open_braces.is_empty() {
diff --git a/compiler/rustc_parse/src/lib.rs b/compiler/rustc_parse/src/lib.rs
index 72a34b86ae2..21bbdc9ba8d 100644
--- a/compiler/rustc_parse/src/lib.rs
+++ b/compiler/rustc_parse/src/lib.rs
@@ -3,6 +3,7 @@
 #![feature(bool_to_option)]
 #![feature(crate_visibility_modifier)]
 #![feature(bindings_after_at)]
+#![feature(iter_order_by)]
 #![feature(or_patterns)]
 
 use rustc_ast as ast;
@@ -459,14 +460,10 @@ pub fn tokenstream_probably_equal_for_proc_macro(
 
     // Break tokens after we expand any nonterminals, so that we break tokens
     // that are produced as a result of nonterminal expansion.
-    let mut t1 = first.trees().filter(semantic_tree).flat_map(expand_nt).flat_map(break_tokens);
-    let mut t2 = other.trees().filter(semantic_tree).flat_map(expand_nt).flat_map(break_tokens);
-    for (t1, t2) in t1.by_ref().zip(t2.by_ref()) {
-        if !tokentree_probably_equal_for_proc_macro(&t1, &t2, sess) {
-            return false;
-        }
-    }
-    t1.next().is_none() && t2.next().is_none()
+    let t1 = first.trees().filter(semantic_tree).flat_map(expand_nt).flat_map(break_tokens);
+    let t2 = other.trees().filter(semantic_tree).flat_map(expand_nt).flat_map(break_tokens);
+
+    t1.eq_by(t2, |t1, t2| tokentree_probably_equal_for_proc_macro(&t1, &t2, sess))
 }
 
 // See comments in `Nonterminal::to_tokenstream` for why we care about