Rollup merge of #76131 - Aaron1011:fix/pretty-print-zip, r=lcnr

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

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.

Split out from https://github.com/rust-lang/rust/pull/76130
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ecstatic-morse 2020-09-21 20:40:39 -07:00 committed by GitHub
commit dc42aa8cd4
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@ -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