refactor: use path to get ident name

Author: Young-Flash

compiler/rustc_resolve/src/late/diagnostics.rs

@@ -1966,11 +1966,11 @@ impl<'a: 'ast, 'ast, 'tcx> LateResolutionVisitor<'a, '_, 'ast, 'tcx> {
     fn let_binding_suggestion(&mut self, err: &mut Diagnostic, ident_span: Span) -> bool {
         if let Some(Expr { kind: ExprKind::Assign(lhs, ..), .. }) =
             self.diagnostic_metadata.in_assignment
-            && let ast::ExprKind::Path(None, _) = lhs.kind
+            && let ast::ExprKind::Path(None, ref path) = lhs.kind
         {
             if !ident_span.from_expansion() {
-                let (span, text) = match self.r.tcx.sess.source_map().span_to_snippet(ident_span) {
-                    Ok(ref name) if let Some(name) = name.strip_prefix("let") => {
+                let (span, text) = match path.segments.first().map(|it| it.ident.as_str()) {
+                    Some(name) if let Some(name) = name.strip_prefix("let") => {
                         // a special case for #117894
                         let name = name.strip_prefix("_").unwrap_or(name);
                         (ident_span, format!("let {name}"))