use clippy_utils::diagnostics::span_lint_and_sugg;
-use clippy_utils::paths;
-use clippy_utils::source::snippet_with_macro_callsite;
-use clippy_utils::ty::{is_type_diagnostic_item, is_type_ref_to_diagnostic_item};
+use clippy_utils::source::snippet_with_context;
+use clippy_utils::ty::is_type_diagnostic_item;
+use clippy_utils::visitors::is_expr_unsafe;
+use clippy_utils::{get_parent_node, match_libc_symbol};
use if_chain::if_chain;
use rustc_errors::Applicability;
-use rustc_hir as hir;
+use rustc_hir::{Block, BlockCheckMode, Expr, ExprKind, Node, UnsafeSource};
use rustc_lint::{LateContext, LateLintPass};
use rustc_session::{declare_lint_pass, declare_tool_lint};
-use rustc_span::symbol::{sym, Symbol};
+use rustc_span::symbol::sym;
declare_clippy_lint! {
/// ### What it does
declare_lint_pass!(StrlenOnCStrings => [STRLEN_ON_C_STRINGS]);
-impl LateLintPass<'tcx> for StrlenOnCStrings {
- fn check_expr(&mut self, cx: &LateContext<'tcx>, expr: &'tcx hir::Expr<'_>) {
- if expr.span.from_expansion() {
- return;
- }
-
+impl<'tcx> LateLintPass<'tcx> for StrlenOnCStrings {
+ fn check_expr(&mut self, cx: &LateContext<'tcx>, expr: &'tcx Expr<'_>) {
if_chain! {
- if let hir::ExprKind::Call(func, [recv]) = expr.kind;
- if let hir::ExprKind::Path(hir::QPath::Resolved(_, path)) = func.kind;
-
- if (&paths::LIBC_STRLEN).iter().map(|x| Symbol::intern(x)).eq(
- path.segments.iter().map(|seg| seg.ident.name));
- if let hir::ExprKind::MethodCall(path, _, args, _) = recv.kind;
- if args.len() == 1;
- if !args.iter().any(|e| e.span.from_expansion());
+ if !expr.span.from_expansion();
+ if let ExprKind::Call(func, [recv]) = expr.kind;
+ if let ExprKind::Path(path) = &func.kind;
+ if let Some(did) = cx.qpath_res(path, func.hir_id).opt_def_id();
+ if match_libc_symbol(cx, did, "strlen");
+ if let ExprKind::MethodCall(path, [self_arg], _) = recv.kind;
+ if !recv.span.from_expansion();
if path.ident.name == sym::as_ptr;
then {
- let cstring = &args[0];
- let ty = cx.typeck_results().expr_ty(cstring);
- let val_name = snippet_with_macro_callsite(cx, cstring.span, "..");
- let sugg = if is_type_diagnostic_item(cx, ty, sym::cstring_type){
- format!("{}.as_bytes().len()", val_name)
- } else if is_type_ref_to_diagnostic_item(cx, ty, sym::CStr){
- format!("{}.to_bytes().len()", val_name)
+ let ctxt = expr.span.ctxt();
+ let span = match get_parent_node(cx.tcx, expr.hir_id) {
+ Some(Node::Block(&Block {
+ rules: BlockCheckMode::UnsafeBlock(UnsafeSource::UserProvided), span, ..
+ }))
+ if span.ctxt() == ctxt && !is_expr_unsafe(cx, self_arg) => {
+ span
+ }
+ _ => expr.span,
+ };
+
+ let ty = cx.typeck_results().expr_ty(self_arg).peel_refs();
+ let mut app = Applicability::MachineApplicable;
+ let val_name = snippet_with_context(cx, self_arg.span, ctxt, "..", &mut app).0;
+ let method_name = if is_type_diagnostic_item(cx, ty, sym::cstring_type) {
+ "as_bytes"
+ } else if is_type_diagnostic_item(cx, ty, sym::CStr) {
+ "to_bytes"
} else {
return;
};
span_lint_and_sugg(
cx,
STRLEN_ON_C_STRINGS,
- expr.span,
+ span,
"using `libc::strlen` on a `CString` or `CStr` value",
- "try this (you might also need to get rid of `unsafe` block in some cases):",
- sugg,
- Applicability::Unspecified // Sometimes unnecessary `unsafe` block
+ "try this",
+ format!("{}.{}().len()", val_name, method_name),
+ app,
);
}
}