use rustc::hir;
use rustc::ty;
use syntax_pos::Span;
-use utils::{method_chain_args, match_def_path, span_lint_and_then, walk_ptrs_ty};
-use utils::paths::{BEGIN_PANIC, BEGIN_PANIC_FMT, FROM_TRAIT, OPTION, RESULT};
+use crate::utils::{match_def_path, method_chain_args, span_lint_and_then, walk_ptrs_ty, is_expn_of, opt_def_id};
+use crate::utils::paths::{BEGIN_PANIC, BEGIN_PANIC_FMT, FROM_TRAIT, OPTION, RESULT};
/// **What it does:** Checks for impls of `From<..>` that contain `panic!()` or `unwrap()`
///
/// }
/// }
/// ```
-declare_lint! {
- pub FALLIBLE_IMPL_FROM, Allow,
+declare_clippy_lint! {
+ pub FALLIBLE_IMPL_FROM,
+ nursery,
"Warn on impls of `From<..>` that contain `panic!()` or `unwrap()`"
}
fn check_item(&mut self, cx: &LateContext<'a, 'tcx>, item: &'tcx hir::Item) {
// check for `impl From<???> for ..`
let impl_def_id = cx.tcx.hir.local_def_id(item.id);
- if_let_chain!{[
- let hir::ItemImpl(.., ref impl_items) = item.node,
- let Some(impl_trait_ref) = cx.tcx.impl_trait_ref(impl_def_id),
- match_def_path(cx.tcx, impl_trait_ref.def_id, &FROM_TRAIT),
- ], {
- lint_impl_body(cx, item.span, impl_items);
- }}
+ if_chain! {
+ if let hir::ItemImpl(.., ref impl_items) = item.node;
+ if let Some(impl_trait_ref) = cx.tcx.impl_trait_ref(impl_def_id);
+ if match_def_path(cx.tcx, impl_trait_ref.def_id, &FROM_TRAIT);
+ then {
+ lint_impl_body(cx, item.span, impl_items);
+ }
+ }
}
}
impl<'a, 'tcx: 'a> Visitor<'tcx> for FindPanicUnwrap<'a, 'tcx> {
fn visit_expr(&mut self, expr: &'tcx Expr) {
// check for `begin_panic`
- if_let_chain!{[
- let ExprCall(ref func_expr, _) = expr.node,
- let ExprPath(QPath::Resolved(_, ref path)) = func_expr.node,
- match_def_path(self.tcx, path.def.def_id(), &BEGIN_PANIC) ||
- match_def_path(self.tcx, path.def.def_id(), &BEGIN_PANIC_FMT),
- ], {
- self.result.push(expr.span);
- }}
+ if_chain! {
+ if let ExprCall(ref func_expr, _) = expr.node;
+ if let ExprPath(QPath::Resolved(_, ref path)) = func_expr.node;
+ if let Some(path_def_id) = opt_def_id(path.def);
+ if match_def_path(self.tcx, path_def_id, &BEGIN_PANIC) ||
+ match_def_path(self.tcx, path_def_id, &BEGIN_PANIC_FMT);
+ if is_expn_of(expr.span, "unreachable").is_none();
+ then {
+ self.result.push(expr.span);
+ }
+ }
// check for `unwrap`
if let Some(arglists) = method_chain_args(expr, &["unwrap"]) {
let reciever_ty = walk_ptrs_ty(self.tables.expr_ty(&arglists[0][0]));
- if match_type(self.tcx, reciever_ty, &OPTION) ||
- match_type(self.tcx, reciever_ty, &RESULT)
- {
+ if match_type(self.tcx, reciever_ty, &OPTION) || match_type(self.tcx, reciever_ty, &RESULT) {
self.result.push(expr.span);
}
}
}
for impl_item in impl_items {
- if_let_chain!{[
- impl_item.name == "from",
- let ImplItemKind::Method(_, body_id) =
- cx.tcx.hir.impl_item(impl_item.id).node,
- ], {
- // check the body for `begin_panic` or `unwrap`
- let body = cx.tcx.hir.body(body_id);
- let impl_item_def_id = cx.tcx.hir.local_def_id(impl_item.id.node_id);
- let mut fpu = FindPanicUnwrap {
- tcx: cx.tcx,
- tables: cx.tcx.typeck_tables_of(impl_item_def_id),
- result: Vec::new(),
- };
- fpu.visit_expr(&body.value);
+ if_chain! {
+ if impl_item.ident.name == "from";
+ if let ImplItemKind::Method(_, body_id) =
+ cx.tcx.hir.impl_item(impl_item.id).node;
+ then {
+ // check the body for `begin_panic` or `unwrap`
+ let body = cx.tcx.hir.body(body_id);
+ let impl_item_def_id = cx.tcx.hir.local_def_id(impl_item.id.node_id);
+ let mut fpu = FindPanicUnwrap {
+ tcx: cx.tcx,
+ tables: cx.tcx.typeck_tables_of(impl_item_def_id),
+ result: Vec::new(),
+ };
+ fpu.visit_expr(&body.value);
- // if we've found one, lint
- if !fpu.result.is_empty() {
- span_lint_and_then(
- cx,
- FALLIBLE_IMPL_FROM,
- impl_span,
- "consider implementing `TryFrom` instead",
- move |db| {
- db.help(
- "`From` is intended for infallible conversions only. \
- Use `TryFrom` if there's a possibility for the conversion to fail.");
- db.span_note(fpu.result, "potential failure(s)");
- });
+ // if we've found one, lint
+ if !fpu.result.is_empty() {
+ span_lint_and_then(
+ cx,
+ FALLIBLE_IMPL_FROM,
+ impl_span,
+ "consider implementing `TryFrom` instead",
+ move |db| {
+ db.help(
+ "`From` is intended for infallible conversions only. \
+ Use `TryFrom` if there's a possibility for the conversion to fail.");
+ db.span_note(fpu.result, "potential failure(s)");
+ });
+ }
}
- }}
+ }
}
}