137 lines
4.9 KiB
Rust
137 lines
4.9 KiB
Rust
use crate::utils::paths::{BEGIN_PANIC, BEGIN_PANIC_FMT, FROM_TRAIT, OPTION, RESULT};
|
|
use crate::utils::{is_expn_of, match_def_path, method_chain_args, opt_def_id, span_lint_and_then, walk_ptrs_ty};
|
|
use if_chain::if_chain;
|
|
use rustc::hir;
|
|
use rustc::lint::{LateContext, LateLintPass, LintArray, LintPass};
|
|
use rustc::ty;
|
|
use rustc::{declare_tool_lint, lint_array};
|
|
use syntax_pos::Span;
|
|
|
|
/// **What it does:** Checks for impls of `From<..>` that contain `panic!()` or `unwrap()`
|
|
///
|
|
/// **Why is this bad?** `TryFrom` should be used if there's a possibility of failure.
|
|
///
|
|
/// **Known problems:** None.
|
|
///
|
|
/// **Example:**
|
|
/// ```rust
|
|
/// struct Foo(i32);
|
|
/// impl From<String> for Foo {
|
|
/// fn from(s: String) -> Self {
|
|
/// Foo(s.parse().unwrap())
|
|
/// }
|
|
/// }
|
|
/// ```
|
|
declare_clippy_lint! {
|
|
pub FALLIBLE_IMPL_FROM,
|
|
nursery,
|
|
"Warn on impls of `From<..>` that contain `panic!()` or `unwrap()`"
|
|
}
|
|
|
|
pub struct FallibleImplFrom;
|
|
|
|
impl LintPass for FallibleImplFrom {
|
|
fn get_lints(&self) -> LintArray {
|
|
lint_array!(FALLIBLE_IMPL_FROM)
|
|
}
|
|
}
|
|
|
|
impl<'a, 'tcx> LateLintPass<'a, 'tcx> for FallibleImplFrom {
|
|
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_chain! {
|
|
if let hir::ItemKind::Impl(.., 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);
|
|
}
|
|
}
|
|
}
|
|
}
|
|
|
|
fn lint_impl_body<'a, 'tcx>(cx: &LateContext<'a, 'tcx>, impl_span: Span, impl_items: &hir::HirVec<hir::ImplItemRef>) {
|
|
use rustc::hir::intravisit::{self, NestedVisitorMap, Visitor};
|
|
use rustc::hir::*;
|
|
|
|
struct FindPanicUnwrap<'a, 'tcx: 'a> {
|
|
tcx: ty::TyCtxt<'a, 'tcx, 'tcx>,
|
|
tables: &'tcx ty::TypeckTables<'tcx>,
|
|
result: Vec<Span>,
|
|
}
|
|
|
|
impl<'a, 'tcx: 'a> Visitor<'tcx> for FindPanicUnwrap<'a, 'tcx> {
|
|
fn visit_expr(&mut self, expr: &'tcx Expr) {
|
|
// check for `begin_panic`
|
|
if_chain! {
|
|
if let ExprKind::Call(ref func_expr, _) = expr.node;
|
|
if let ExprKind::Path(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) {
|
|
self.result.push(expr.span);
|
|
}
|
|
}
|
|
|
|
// and check sub-expressions
|
|
intravisit::walk_expr(self, expr);
|
|
}
|
|
|
|
fn nested_visit_map<'this>(&'this mut self) -> NestedVisitorMap<'this, 'tcx> {
|
|
NestedVisitorMap::None
|
|
}
|
|
}
|
|
|
|
for impl_item in impl_items {
|
|
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)");
|
|
});
|
|
}
|
|
}
|
|
}
|
|
}
|
|
}
|
|
|
|
fn match_type(tcx: ty::TyCtxt<'_, '_, '_>, ty: ty::Ty<'_>, path: &[&str]) -> bool {
|
|
match ty.sty {
|
|
ty::Adt(adt, _) => match_def_path(tcx, adt.did, path),
|
|
_ => false,
|
|
}
|
|
}
|