src/tools/clippy/clippy_lints/src/types/rc_buffer.rs

   1 use clippy_utils::diagnostics::span_lint_and_sugg;
   2 use clippy_utils::source::snippet_with_applicability;
   3 use clippy_utils::{get_qpath_generic_tys, is_ty_param_diagnostic_item};
   4 use rustc_errors::Applicability;
   5 use rustc_hir::{self as hir, def_id::DefId, QPath, TyKind};
   6 use rustc_lint::LateContext;
   7 use rustc_span::symbol::sym;
   8
   9 use super::RC_BUFFER;
  10
  11 pub(super) fn check(cx: &LateContext<'_>, hir_ty: &hir::Ty<'_>, qpath: &QPath<'_>, def_id: DefId) -> bool {
  12     if cx.tcx.is_diagnostic_item(sym::Rc, def_id) {
  13         if let Some(alternate) = match_buffer_type(cx, qpath) {
  14             span_lint_and_sugg(
  15                 cx,
  16                 RC_BUFFER,
  17                 hir_ty.span,
  18                 "usage of `Rc<T>` when T is a buffer type",
  19                 "try",
  20                 format!("Rc<{}>", alternate),
  21                 Applicability::MachineApplicable,
  22             );
  23         } else if let Some(ty) = is_ty_param_diagnostic_item(cx, qpath, sym::vec_type) {
  24             let qpath = match &ty.kind {
  25                 TyKind::Path(qpath) => qpath,
  26                 _ => return false,
  27             };
  28             let inner_span = match get_qpath_generic_tys(qpath).next() {
  29                 Some(ty) => ty.span,
  30                 None => return false,
  31             };
  32             let mut applicability = Applicability::MachineApplicable;
  33             span_lint_and_sugg(
  34                 cx,
  35                 RC_BUFFER,
  36                 hir_ty.span,
  37                 "usage of `Rc<T>` when T is a buffer type",
  38                 "try",
  39                 format!(
  40                     "Rc<[{}]>",
  41                     snippet_with_applicability(cx, inner_span, "..", &mut applicability)
  42                 ),
  43                 Applicability::MachineApplicable,
  44             );
  45             return true;
  46         }
  47     } else if cx.tcx.is_diagnostic_item(sym::Arc, def_id) {
  48         if let Some(alternate) = match_buffer_type(cx, qpath) {
  49             span_lint_and_sugg(
  50                 cx,
  51                 RC_BUFFER,
  52                 hir_ty.span,
  53                 "usage of `Arc<T>` when T is a buffer type",
  54                 "try",
  55                 format!("Arc<{}>", alternate),
  56                 Applicability::MachineApplicable,
  57             );
  58         } else if let Some(ty) = is_ty_param_diagnostic_item(cx, qpath, sym::vec_type) {
  59             let qpath = match &ty.kind {
  60                 TyKind::Path(qpath) => qpath,
  61                 _ => return false,
  62             };
  63             let inner_span = match get_qpath_generic_tys(qpath).next() {
  64                 Some(ty) => ty.span,
  65                 None => return false,
  66             };
  67             let mut applicability = Applicability::MachineApplicable;
  68             span_lint_and_sugg(
  69                 cx,
  70                 RC_BUFFER,
  71                 hir_ty.span,
  72                 "usage of `Arc<T>` when T is a buffer type",
  73                 "try",
  74                 format!(
  75                     "Arc<[{}]>",
  76                     snippet_with_applicability(cx, inner_span, "..", &mut applicability)
  77                 ),
  78                 Applicability::MachineApplicable,
  79             );
  80             return true;
  81         }
  82     }
  83
  84     false
  85 }
  86
  87 fn match_buffer_type(cx: &LateContext<'_>, qpath: &QPath<'_>) -> Option<&'static str> {
  88     if is_ty_param_diagnostic_item(cx, qpath, sym::string_type).is_some() {
  89         Some("str")
  90     } else if is_ty_param_diagnostic_item(cx, qpath, sym::OsString).is_some() {
  91         Some("std::ffi::OsStr")
  92     } else if is_ty_param_diagnostic_item(cx, qpath, sym::PathBuf).is_some() {
  93         Some("std::path::Path")
  94     } else {
  95         None
  96     }
  97 }