use if_chain::if_chain;
use rustc_errors::Applicability;
use rustc_hir::{
- BinOpKind, BodyId, Expr, ExprKind, FnDecl, FnRetTy, GenericArg, HirId, ImplItem, ImplItemKind, Item, ItemKind,
- Lifetime, MutTy, Mutability, Node, PathSegment, QPath, TraitFn, TraitItem, TraitItemKind, Ty, TyKind,
+ BinOpKind, BodyId, Expr, ExprKind, FnDecl, FnRetTy, GenericArg, HirId, Impl, ImplItem, ImplItemKind, Item,
+ ItemKind, Lifetime, MutTy, Mutability, Node, PathSegment, QPath, TraitFn, TraitItem, TraitItemKind, Ty, TyKind,
};
use rustc_lint::{LateContext, LateLintPass};
use rustc_middle::ty;
use rustc_session::{declare_lint_pass, declare_tool_lint};
use rustc_span::source_map::Span;
-use rustc_span::MultiSpan;
+use rustc_span::{sym, MultiSpan};
use std::borrow::Cow;
declare_clippy_lint! {
/// argument may also fail to compile if you change the argument. Applying
/// this lint on them will fix the problem, but they may be in other crates.
///
+ /// One notable example of a function that may cause issues, and which cannot
+ /// easily be changed due to being in the standard library is `Vec::contains`.
+ /// when called on a `Vec<Vec<T>>`. If a `&Vec` is passed to that method then
+ /// it will compile, but if a `&[T]` is passed then it will not compile.
+ ///
+ /// ```ignore
+ /// fn cannot_take_a_slice(v: &Vec<u8>) -> bool {
+ /// let vec_of_vecs: Vec<Vec<u8>> = some_other_fn();
+ ///
+ /// vec_of_vecs.contains(v)
+ /// }
+ /// ```
+ ///
/// Also there may be `fn(&Vec)`-typed references pointing to your function.
/// If you have them, you will get a compiler error after applying this lint's
/// suggestions. You then have the choice to undo your changes or change the
/// type of the reference.
///
/// Note that if the function is part of your public interface, there may be
- /// other crates referencing it you may not be aware. Carefully deprecate the
- /// function before applying the lint suggestions in this case.
+ /// other crates referencing it, of which you may not be aware. Carefully
+ /// deprecate the function before applying the lint suggestions in this case.
///
/// **Example:**
/// ```ignore
if let ImplItemKind::Fn(ref sig, body_id) = item.kind {
let parent_item = cx.tcx.hir().get_parent_item(item.hir_id);
if let Some(Node::Item(it)) = cx.tcx.hir().find(parent_item) {
- if let ItemKind::Impl { of_trait: Some(_), .. } = it.kind {
+ if let ItemKind::Impl(Impl { of_trait: Some(_), .. }) = it.kind {
return; // ignore trait impls
}
}
}
}
- if let ty::Ref(_, ty, Mutability::Not) = ty.kind {
- if is_type_diagnostic_item(cx, ty, sym!(vec_type)) {
- let mut ty_snippet = None;
- if_chain! {
- if let TyKind::Path(QPath::Resolved(_, ref path)) = walk_ptrs_hir_ty(arg).kind;
- if let Some(&PathSegment{args: Some(ref parameters), ..}) = path.segments.last();
- then {
- let types: Vec<_> = parameters.args.iter().filter_map(|arg| match arg {
- GenericArg::Type(ty) => Some(ty),
- _ => None,
- }).collect();
- if types.len() == 1 {
- ty_snippet = snippet_opt(cx, types[0].span);
- }
- }
- };
+ if let ty::Ref(_, ty, Mutability::Not) = ty.kind() {
+ if is_type_diagnostic_item(cx, ty, sym::vec_type) {
if let Some(spans) = get_spans(cx, opt_body_id, idx, &[("clone", ".to_owned()")]) {
span_lint_and_then(
cx,
"writing `&Vec<_>` instead of `&[_]` involves one more reference and cannot be used \
with non-Vec-based slices.",
|diag| {
- if let Some(ref snippet) = ty_snippet {
+ if let Some(ref snippet) = get_only_generic_arg_snippet(cx, arg) {
diag.span_suggestion(
arg.span,
"change this to",
},
);
}
- } else if is_type_diagnostic_item(cx, ty, sym!(string_type)) {
+ } else if is_type_diagnostic_item(cx, ty, sym::string_type) {
if let Some(spans) = get_spans(cx, opt_body_id, idx, &[("clone", ".to_string()"), ("as_str", "")]) {
span_lint_and_then(
cx,
},
);
}
+ } else if match_type(cx, ty, &paths::PATH_BUF) {
+ if let Some(spans) = get_spans(cx, opt_body_id, idx, &[("clone", ".to_path_buf()"), ("as_path", "")]) {
+ span_lint_and_then(
+ cx,
+ PTR_ARG,
+ arg.span,
+ "writing `&PathBuf` instead of `&Path` involves a new object where a slice will do.",
+ |diag| {
+ diag.span_suggestion(
+ arg.span,
+ "change this to",
+ "&Path".into(),
+ Applicability::Unspecified,
+ );
+ for (clonespan, suggestion) in spans {
+ diag.span_suggestion_short(
+ clonespan,
+ &snippet_opt(cx, clonespan).map_or("change the call to".into(), |x| {
+ Cow::Owned(format!("change `{}` to", x))
+ }),
+ suggestion.into(),
+ Applicability::Unspecified,
+ );
+ }
+ },
+ );
+ }
} else if match_type(cx, ty, &paths::COW) {
if_chain! {
if let TyKind::Rptr(_, MutTy { ref ty, ..} ) = arg.kind;
- if let TyKind::Path(ref path) = ty.kind;
- if let QPath::Resolved(None, ref pp) = *path;
+ if let TyKind::Path(QPath::Resolved(None, ref pp)) = ty.kind;
if let [ref bx] = *pp.segments;
if let Some(ref params) = bx.args;
if !params.parenthesized;
}
}
+fn get_only_generic_arg_snippet(cx: &LateContext<'_>, arg: &Ty<'_>) -> Option<String> {
+ if_chain! {
+ if let TyKind::Path(QPath::Resolved(_, ref path)) = walk_ptrs_hir_ty(arg).kind;
+ if let Some(&PathSegment{args: Some(ref parameters), ..}) = path.segments.last();
+ let types: Vec<_> = parameters.args.iter().filter_map(|arg| match arg {
+ GenericArg::Type(ty) => Some(ty),
+ _ => None,
+ }).collect();
+ if types.len() == 1;
+ then {
+ snippet_opt(cx, types[0].span)
+ } else {
+ None
+ }
+ }
+}
+
fn get_rptr_lm<'tcx>(ty: &'tcx Ty<'tcx>) -> Option<(&'tcx Lifetime, Mutability, Span)> {
if let TyKind::Rptr(ref lt, ref m) = ty.kind {
Some((lt, m.mutbl, ty.span))
projects / rust.git / blobdiff