remove code duplication

Author: matthri

clippy_lints/src/methods/get_first.rs

@@ -20,30 +20,23 @@ pub(super) fn check<'tcx>(
  if_chain! {
  if let Some(method_id) = cx.typeck_results().type_dependent_def_id(expr.hir_id);
  if let Some(impl_id) = cx.tcx.impl_of_method(method_id);
- if cx.tcx.type_of(impl_id).instantiate_identity().is_slice();
+ let identity = cx.tcx.type_of(impl_id).instantiate_identity();
  if let hir::ExprKind::Lit(Spanned { node: LitKind::Int(0, _), .. }) = arg.kind;
  then {
- let mut app = Applicability::MachineApplicable;
- let slice_name = snippet_with_applicability(cx, recv.span, "..", &mut app);
- span_lint_and_sugg(
- cx,
- GET_FIRST,
- expr.span,
- &format!("accessing first element with `{slice_name}.get(0)`"),
- "try",
- format!("{slice_name}.first()"),
- app,
- );
- }
- }
-
- if_chain! {
- if let Some(method_id) = cx.typeck_results().type_dependent_def_id(expr.hir_id);
- if let Some(impl_id) = cx.tcx.impl_of_method(method_id);
- if is_type_diagnostic_item(cx, cx.tcx.type_of(impl_id).instantiate_identity(), sym::VecDeque);
- if let hir::ExprKind::Lit(Spanned { node: LitKind::Int(0, _), .. }) = arg.kind;
- then {
- let mut app = Applicability::MachineApplicable;
+ if identity.is_slice() {
+ let mut app = Applicability::MachineApplicable;
+ let slice_name = snippet_with_applicability(cx, recv.span, "..", &mut app);
+ span_lint_and_sugg(
+ cx,
+ GET_FIRST,
+ expr.span,
+ &format!("accessing first element with `{slice_name}.get(0)`"),
+ "try",
+ format!("{slice_name}.first()"),
+ app,
+ );
+ } else if is_type_diagnostic_item(cx, identity, sym::VecDeque){
+ let mut app = Applicability::MachineApplicable;
  let slice_name = snippet_with_applicability(cx, recv.span, "..", &mut app);
  span_lint_and_sugg(
  cx,
@@ -54,6 +47,7 @@ pub(super) fn check<'tcx>(
  format!("{slice_name}.front()"),
  app,
  );
+ }
  }
  }
 }