src/tools/clippy/clippy_lints/src/methods/iter_cloned_collect.rs

   1 use crate::methods::derefs_to_slice;
   2 use crate::utils::{is_type_diagnostic_item, span_lint_and_sugg};
   3 use if_chain::if_chain;
   4 use rustc_errors::Applicability;
   5 use rustc_hir as hir;
   6 use rustc_lint::LateContext;
   7 use rustc_span::sym;
   8
   9 use super::ITER_CLONED_COLLECT;
  10
  11 pub(super) fn check<'tcx>(cx: &LateContext<'tcx>, expr: &hir::Expr<'_>, iter_args: &'tcx [hir::Expr<'_>]) {
  12     if_chain! {
  13         if is_type_diagnostic_item(cx, cx.typeck_results().expr_ty(expr), sym::vec_type);
  14         if let Some(slice) = derefs_to_slice(cx, &iter_args[0], cx.typeck_results().expr_ty(&iter_args[0]));
  15         if let Some(to_replace) = expr.span.trim_start(slice.span.source_callsite());
  16
  17         then {
  18             span_lint_and_sugg(
  19                 cx,
  20                 ITER_CLONED_COLLECT,
  21                 to_replace,
  22                 "called `iter().cloned().collect()` on a slice to create a `Vec`. Calling `to_vec()` is both faster and \
  23                 more readable",
  24                 "try",
  25                 ".to_vec()".to_string(),
  26                 Applicability::MachineApplicable,
  27             );
  28         }
  29     }
  30 }