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::{path_def_id, qpath_generic_tys};
   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     let app = Applicability::Unspecified;
  13     if cx.tcx.is_diagnostic_item(sym::Rc, def_id) {
  14         if let Some(alternate) = match_buffer_type(cx, qpath) {
  15             span_lint_and_sugg(
  16                 cx,
  17                 RC_BUFFER,
  18                 hir_ty.span,
  19                 "usage of `Rc<T>` when T is a buffer type",
  20                 "try",
  21                 format!("Rc<{alternate}>"),
  22                 app,
  23             );
  24         } else {
  25             let Some(ty) = qpath_generic_tys(qpath).next() else { return false };
  26             let Some(id) = path_def_id(cx, ty) else { return false };
  27             if !cx.tcx.is_diagnostic_item(sym::Vec, id) {
  28                 return false;
  29             }
  30             let TyKind::Path(qpath) = &ty.kind else { return false };
  31             let inner_span = match qpath_generic_tys(qpath).next() {
  32                 Some(ty) => ty.span,
  33                 None => return false,
  34             };
  35             let mut applicability = app;
  36             span_lint_and_sugg(
  37                 cx,
  38                 RC_BUFFER,
  39                 hir_ty.span,
  40                 "usage of `Rc<T>` when T is a buffer type",
  41                 "try",
  42                 format!(
  43                     "Rc<[{}]>",
  44                     snippet_with_applicability(cx, inner_span, "..", &mut applicability)
  45                 ),
  46                 app,
  47             );
  48             return true;
  49         }
  50     } else if cx.tcx.is_diagnostic_item(sym::Arc, def_id) {
  51         if let Some(alternate) = match_buffer_type(cx, qpath) {
  52             span_lint_and_sugg(
  53                 cx,
  54                 RC_BUFFER,
  55                 hir_ty.span,
  56                 "usage of `Arc<T>` when T is a buffer type",
  57                 "try",
  58                 format!("Arc<{alternate}>"),
  59                 app,
  60             );
  61         } else if let Some(ty) = qpath_generic_tys(qpath).next() {
  62             let Some(id) = path_def_id(cx, ty) else { return false };
  63             if !cx.tcx.is_diagnostic_item(sym::Vec, id) {
  64                 return false;
  65             }
  66             let TyKind::Path(qpath) = &ty.kind else { return false };
  67             let inner_span = match qpath_generic_tys(qpath).next() {
  68                 Some(ty) => ty.span,
  69                 None => return false,
  70             };
  71             let mut applicability = app;
  72             span_lint_and_sugg(
  73                 cx,
  74                 RC_BUFFER,
  75                 hir_ty.span,
  76                 "usage of `Arc<T>` when T is a buffer type",
  77                 "try",
  78                 format!(
  79                     "Arc<[{}]>",
  80                     snippet_with_applicability(cx, inner_span, "..", &mut applicability)
  81                 ),
  82                 app,
  83             );
  84             return true;
  85         }
  86     }
  87
  88     false
  89 }
  90
  91 fn match_buffer_type(cx: &LateContext<'_>, qpath: &QPath<'_>) -> Option<&'static str> {
  92     let ty = qpath_generic_tys(qpath).next()?;
  93     let id = path_def_id(cx, ty)?;
  94     let path = match cx.tcx.get_diagnostic_name(id)? {
  95         sym::String => "str",
  96         sym::OsString => "std::ffi::OsStr",
  97         sym::PathBuf => "std::path::Path",
  98         _ => return None,
  99     };
 100     Some(path)
 101 }