Rollup merge of #128762 - fmease:use-more-slice-pats, r=compiler-errors

Use more slice patterns inside the compiler

Nothing super noteworthy. Just replacing the common 'fragile' pattern of "length check followed by indexing or unwrap" with slice patterns for legibility and 'robustness'.

r? ghost

1 files changed, 3 insertions, 3 deletions

diff --git a/compiler/rustc_parse/src/parser/expr.rs b/compiler/rustc_parse/src/parser/expr.rs
index ccf8dcdf0b6..cf5d65708ab 100644
--- a/compiler/rustc_parse/src/parser/expr.rs
+++ b/compiler/rustc_parse/src/parser/expr.rs
@@ -694,12 +694,12 @@ impl<'a> Parser<'a> {
                         // `foo: `
                         ExprKind::Path(None, ast::Path { segments, .. }),
                         token::Ident(kw::For | kw::Loop | kw::While, IdentIsRaw::No),
-                    ) if segments.len() == 1 => {
+                    ) if let [segment] = segments.as_slice() => {
                         let snapshot = self.create_snapshot_for_diagnostic();
                         let label = Label {
                             ident: Ident::from_str_and_span(
-                                &format!("'{}", segments[0].ident),
-                                segments[0].ident.span,
+                                &format!("'{}", segment.ident),
+                                segment.ident.span,
                             ),
                         };
                         match self.parse_expr_labeled(label, false) {