mathieu/os-rust
1
0
Fork 0
Code Issues Pull requests Projects Releases Packages Wiki Activity Actions

Don't use zip to compare iterators during pretty-print hack

Browse source 
If the right-hand iterator has exactly one more element than the
left-hand iterator, then both iterators will be fully consumed, but
the extra element will never be compared.
This commit is contained in:
Aaron Hill 2020-08-30 18:08:16 -04:00
parent 4eff9b0b29
commit f5d71a9b3c
No known key found for this signature in database
GPG key ID: B4087E510E98B164
1 changed files with 5 additions and 8 deletions
Show stats Download patch file Download diff file Expand all files Collapse all files

13
compiler/rustc_parse/src/lib.rs
View file

@ -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