use rustc::hir;
use rustc::lint::*;
use rustc::ty::{self, Ty};
use rustc::hir::def::Def;
use std::borrow::Cow;
use std::fmt;
use std::iter;
use syntax::ast;
use syntax::codemap::{Span, BytePos};
use crate::utils::{get_arg_name, get_trait_def_id, implements_trait, in_external_macro, in_macro, is_copy, is_expn_of, is_self,
is_self_ty, iter_input_pats, last_path_segment, match_def_path, match_path, match_qpath, match_trait_method,
match_type, method_chain_args, match_var, return_ty, remove_blocks, same_tys, single_segment_path, snippet,
span_lint, span_lint_and_sugg, span_lint_and_then, span_note_and_lint, walk_ptrs_ty, walk_ptrs_ty_depth};
use crate::utils::paths;
use crate::utils::sugg;
use crate::consts::{constant, Constant};
#[derive(Clone)]
pub struct Pass;
declare_clippy_lint! {
pub OPTION_UNWRAP_USED,
restriction,
"using `Option.unwrap()`, which should at least get a better message using `expect()`"
}
declare_clippy_lint! {
pub RESULT_UNWRAP_USED,
restriction,
"using `Result.unwrap()`, which might be better handled"
}
declare_clippy_lint! {
pub SHOULD_IMPLEMENT_TRAIT,
style,
"defining a method that should be implementing a std trait"
}
declare_clippy_lint! {
pub WRONG_SELF_CONVENTION,
style,
"defining a method named with an established prefix (like \"into_\") that takes \
`self` with the wrong convention"
}
declare_clippy_lint! {
pub WRONG_PUB_SELF_CONVENTION,
restriction,
"defining a public method named with an established prefix (like \"into_\") that takes \
`self` with the wrong convention"
}
declare_clippy_lint! {
pub OK_EXPECT,
style,
"using `ok().expect()`, which gives worse error messages than \
calling `expect` directly on the Result"
}
declare_clippy_lint! {
pub OPTION_MAP_UNWRAP_OR,
pedantic,
"using `Option.map(f).unwrap_or(a)`, which is more succinctly expressed as \
`map_or(a, f)`"
}
declare_clippy_lint! {
pub OPTION_MAP_UNWRAP_OR_ELSE,
pedantic,
"using `Option.map(f).unwrap_or_else(g)`, which is more succinctly expressed as \
`map_or_else(g, f)`"
}
declare_clippy_lint! {
pub RESULT_MAP_UNWRAP_OR_ELSE,
pedantic,
"using `Result.map(f).unwrap_or_else(g)`, which is more succinctly expressed as \
`.ok().map_or_else(g, f)`"
}
declare_clippy_lint! {
pub OPTION_MAP_OR_NONE,
style,
"using `Option.map_or(None, f)`, which is more succinctly expressed as \
`and_then(f)`"
}
declare_clippy_lint! {
pub FILTER_NEXT,
complexity,
"using `filter(p).next()`, which is more succinctly expressed as `.find(p)`"
}
declare_clippy_lint! {
pub FILTER_MAP,
pedantic,
"using combinations of `filter`, `map`, `filter_map` and `flat_map` which can \
usually be written as a single method call"
}
declare_clippy_lint! {
pub SEARCH_IS_SOME,
complexity,
"using an iterator search followed by `is_some()`, which is more succinctly \
expressed as a call to `any()`"
}
declare_clippy_lint! {
pub CHARS_NEXT_CMP,
complexity,
"using `.chars().next()` to check if a string starts with a char"
}
declare_clippy_lint! {
pub OR_FUN_CALL,
perf,
"using any `*or` method with a function call, which suggests `*or_else`"
}
declare_clippy_lint! {
pub EXPECT_FUN_CALL,
perf,
"using any `expect` method with a function call"
}
declare_clippy_lint! {
pub CLONE_ON_COPY,
complexity,
"using `clone` on a `Copy` type"
}
declare_clippy_lint! {
pub CLONE_ON_REF_PTR,
restriction,
"using 'clone' on a ref-counted pointer"
}
declare_clippy_lint! {
pub CLONE_DOUBLE_REF,
correctness,
"using `clone` on `&&T`"
}
declare_clippy_lint! {
pub NEW_RET_NO_SELF,
style,
"not returning `Self` in a `new` method"
}
declare_clippy_lint! {
pub SINGLE_CHAR_PATTERN,
perf,
"using a single-character str where a char could be used, e.g. \
`_.split(\"x\")`"
}
declare_clippy_lint! {
pub TEMPORARY_CSTRING_AS_PTR,
correctness,
"getting the inner pointer of a temporary `CString`"
}
declare_clippy_lint! {
pub ITER_NTH,
perf,
"using `.iter().nth()` on a standard library type with O(1) element access"
}
declare_clippy_lint! {
pub ITER_SKIP_NEXT,
style,
"using `.skip(x).next()` on an iterator"
}
declare_clippy_lint! {
pub GET_UNWRAP,
style,
"using `.get().unwrap()` or `.get_mut().unwrap()` when using `[]` would work instead"
}
declare_clippy_lint! {
pub STRING_EXTEND_CHARS,
style,
"using `x.extend(s.chars())` where s is a `&str` or `String`"
}
declare_clippy_lint! {
pub ITER_CLONED_COLLECT,
style,
"using `.cloned().collect()` on slice to create a `Vec`"
}
declare_clippy_lint! {
pub CHARS_LAST_CMP,
style,
"using `.chars().last()` or `.chars().next_back()` to check if a string ends with a char"
}
declare_clippy_lint! {
pub USELESS_ASREF,
complexity,
"using `as_ref` where the types before and after the call are the same"
}
declare_clippy_lint! {
pub UNNECESSARY_FOLD,
style,
"using `fold` when a more succinct alternative exists"
}
impl LintPass for Pass {
fn get_lints(&self) -> LintArray {
lint_array!(
OPTION_UNWRAP_USED,
RESULT_UNWRAP_USED,
SHOULD_IMPLEMENT_TRAIT,
WRONG_SELF_CONVENTION,
WRONG_PUB_SELF_CONVENTION,
OK_EXPECT,
OPTION_MAP_UNWRAP_OR,
OPTION_MAP_UNWRAP_OR_ELSE,
RESULT_MAP_UNWRAP_OR_ELSE,
OPTION_MAP_OR_NONE,
OR_FUN_CALL,
EXPECT_FUN_CALL,
CHARS_NEXT_CMP,
CHARS_LAST_CMP,
CLONE_ON_COPY,
CLONE_ON_REF_PTR,
CLONE_DOUBLE_REF,
NEW_RET_NO_SELF,
SINGLE_CHAR_PATTERN,
SEARCH_IS_SOME,
TEMPORARY_CSTRING_AS_PTR,
FILTER_NEXT,
FILTER_MAP,
ITER_NTH,
ITER_SKIP_NEXT,
GET_UNWRAP,
STRING_EXTEND_CHARS,
ITER_CLONED_COLLECT,
USELESS_ASREF,
UNNECESSARY_FOLD
)
}
}
impl<'a, 'tcx> LateLintPass<'a, 'tcx> for Pass {
#[allow(cyclomatic_complexity)]
fn check_expr(&mut self, cx: &LateContext<'a, 'tcx>, expr: &'tcx hir::Expr) {
if in_macro(expr.span) {
return;
}
match expr.node {
hir::ExprMethodCall(ref method_call, ref method_span, ref args) => {
if let Some(arglists) = method_chain_args(expr, &["get", "unwrap"]) {
lint_get_unwrap(cx, expr, arglists[0], false);
} else if let Some(arglists) = method_chain_args(expr, &["get_mut", "unwrap"]) {
lint_get_unwrap(cx, expr, arglists[0], true);
} else if let Some(arglists) = method_chain_args(expr, &["unwrap"]) {
lint_unwrap(cx, expr, arglists[0]);
} else if let Some(arglists) = method_chain_args(expr, &["ok", "expect"]) {
lint_ok_expect(cx, expr, arglists[0]);
} else if let Some(arglists) = method_chain_args(expr, &["map", "unwrap_or"]) {
lint_map_unwrap_or(cx, expr, arglists[0], arglists[1]);
} else if let Some(arglists) = method_chain_args(expr, &["map", "unwrap_or_else"]) {
lint_map_unwrap_or_else(cx, expr, arglists[0], arglists[1]);
} else if let Some(arglists) = method_chain_args(expr, &["map_or"]) {
lint_map_or_none(cx, expr, arglists[0]);
} else if let Some(arglists) = method_chain_args(expr, &["filter", "next"]) {
lint_filter_next(cx, expr, arglists[0]);
} else if let Some(arglists) = method_chain_args(expr, &["filter", "map"]) {
lint_filter_map(cx, expr, arglists[0], arglists[1]);
} else if let Some(arglists) = method_chain_args(expr, &["filter_map", "map"]) {
lint_filter_map_map(cx, expr, arglists[0], arglists[1]);
} else if let Some(arglists) = method_chain_args(expr, &["filter", "flat_map"]) {
lint_filter_flat_map(cx, expr, arglists[0], arglists[1]);
} else if let Some(arglists) = method_chain_args(expr, &["filter_map", "flat_map"]) {
lint_filter_map_flat_map(cx, expr, arglists[0], arglists[1]);
} else if let Some(arglists) = method_chain_args(expr, &["find", "is_some"]) {
lint_search_is_some(cx, expr, "find", arglists[0], arglists[1]);
} else if let Some(arglists) = method_chain_args(expr, &["position", "is_some"]) {
lint_search_is_some(cx, expr, "position", arglists[0], arglists[1]);
} else if let Some(arglists) = method_chain_args(expr, &["rposition", "is_some"]) {
lint_search_is_some(cx, expr, "rposition", arglists[0], arglists[1]);
} else if let Some(arglists) = method_chain_args(expr, &["extend"]) {
lint_extend(cx, expr, arglists[0]);
} else if let Some(arglists) = method_chain_args(expr, &["unwrap", "as_ptr"]) {
lint_cstring_as_ptr(cx, expr, &arglists[0][0], &arglists[1][0]);
} else if let Some(arglists) = method_chain_args(expr, &["iter", "nth"]) {
lint_iter_nth(cx, expr, arglists[0], false);
} else if let Some(arglists) = method_chain_args(expr, &["iter_mut", "nth"]) {
lint_iter_nth(cx, expr, arglists[0], true);
} else if method_chain_args(expr, &["skip", "next"]).is_some() {
lint_iter_skip_next(cx, expr);
} else if let Some(arglists) = method_chain_args(expr, &["cloned", "collect"]) {
lint_iter_cloned_collect(cx, expr, arglists[0]);
} else if let Some(arglists) = method_chain_args(expr, &["as_ref"]) {
lint_asref(cx, expr, "as_ref", arglists[0]);
} else if let Some(arglists) = method_chain_args(expr, &["as_mut"]) {
lint_asref(cx, expr, "as_mut", arglists[0]);
} else if let Some(arglists) = method_chain_args(expr, &["fold"]) {
lint_unnecessary_fold(cx, expr, arglists[0]);
}
lint_or_fun_call(cx, expr, *method_span, &method_call.name.as_str(), args);
lint_expect_fun_call(cx, expr, *method_span, &method_call.name.as_str(), args);
let self_ty = cx.tables.expr_ty_adjusted(&args[0]);
if args.len() == 1 && method_call.name == "clone" {
lint_clone_on_copy(cx, expr, &args[0], self_ty);
lint_clone_on_ref_ptr(cx, expr, &args[0]);
}
match self_ty.sty {
ty::TyRef(_, ty, _) if ty.sty == ty::TyStr => for &(method, pos) in &PATTERN_METHODS {
if method_call.name == method && args.len() > pos {
lint_single_char_pattern(cx, expr, &args[pos]);
}
},
_ => (),
}
},
hir::ExprBinary(op, ref lhs, ref rhs) if op.node == hir::BiEq || op.node == hir::BiNe => {
let mut info = BinaryExprInfo {
expr,
chain: lhs,
other: rhs,
eq: op.node == hir::BiEq,
};
lint_binary_expr_with_method_call(cx, &mut info);
},
_ => (),
}
}
fn check_impl_item(&mut self, cx: &LateContext<'a, 'tcx>, implitem: &'tcx hir::ImplItem) {
if in_external_macro(cx, implitem.span) {
return;
}
let name = implitem.name;
let parent = cx.tcx.hir.get_parent(implitem.id);
let item = cx.tcx.hir.expect_item(parent);
if_chain! {
if let hir::ImplItemKind::Method(ref sig, id) = implitem.node;
if let Some(first_arg_ty) = sig.decl.inputs.get(0);
if let Some(first_arg) = iter_input_pats(&sig.decl, cx.tcx.hir.body(id)).next();
if let hir::ItemImpl(_, _, _, _, None, ref self_ty, _) = item.node;
then {
if cx.access_levels.is_exported(implitem.id) {
for &(method_name, n_args, self_kind, out_type, trait_name) in &TRAIT_METHODS {
if name == method_name &&
sig.decl.inputs.len() == n_args &&
out_type.matches(&sig.decl.output) &&
self_kind.matches(first_arg_ty, first_arg, self_ty, false, &implitem.generics) {
span_lint(cx, SHOULD_IMPLEMENT_TRAIT, implitem.span, &format!(
"defining a method called `{}` on this type; consider implementing \
the `{}` trait or choosing a less ambiguous name", name, trait_name));
}
}
}
let def_id = cx.tcx.hir.local_def_id(item.id);
let ty = cx.tcx.type_of(def_id);
let is_copy = is_copy(cx, ty);
for &(ref conv, self_kinds) in &CONVENTIONS {
if_chain! {
if conv.check(&name.as_str());
if !self_kinds
.iter()
.any(|k| k.matches(first_arg_ty, first_arg, self_ty, is_copy, &implitem.generics));
then {
let lint = if item.vis == hir::Visibility::Public {
WRONG_PUB_SELF_CONVENTION
} else {
WRONG_SELF_CONVENTION
};
span_lint(cx,
lint,
first_arg.pat.span,
&format!("methods called `{}` usually take {}; consider choosing a less \
ambiguous name",
conv,
&self_kinds.iter()
.map(|k| k.description())
.collect::<Vec<_>>()
.join(" or ")));
}
}
}
let ret_ty = return_ty(cx, implitem.id);
if name == "new" &&
!ret_ty.walk().any(|t| same_tys(cx, t, ty)) {
span_lint(cx,
NEW_RET_NO_SELF,
implitem.span,
"methods called `new` usually return `Self`");
}
}
}
}
}
fn lint_or_fun_call(cx: &LateContext, expr: &hir::Expr, method_span: Span, name: &str, args: &[hir::Expr]) {
fn check_unwrap_or_default(
cx: &LateContext,
name: &str,
fun: &hir::Expr,
self_expr: &hir::Expr,
arg: &hir::Expr,
or_has_args: bool,
span: Span,
) -> bool {
if or_has_args {
return false;
}
if name == "unwrap_or" {
if let hir::ExprPath(ref qpath) = fun.node {
let path = &*last_path_segment(qpath).name.as_str();
if ["default", "new"].contains(&path) {
let arg_ty = cx.tables.expr_ty(arg);
let default_trait_id = if let Some(default_trait_id) = get_trait_def_id(cx, &paths::DEFAULT_TRAIT) {
default_trait_id
} else {
return false;
};
if implements_trait(cx, arg_ty, default_trait_id, &[]) {
span_lint_and_sugg(
cx,
OR_FUN_CALL,
span,
&format!("use of `{}` followed by a call to `{}`", name, path),
"try this",
format!("{}.unwrap_or_default()", snippet(cx, self_expr.span, "_")),
);
return true;
}
}
}
}
false
}
#[allow(too_many_arguments)]
fn check_general_case(
cx: &LateContext,
name: &str,
method_span: Span,
fun_span: Span,
self_expr: &hir::Expr,
arg: &hir::Expr,
or_has_args: bool,
span: Span,
) {
let know_types: &[(&[_], _, &[_], _)] = &[
(&paths::BTREEMAP_ENTRY, false, &["or_insert"], "with"),
(&paths::HASHMAP_ENTRY, false, &["or_insert"], "with"),
(&paths::OPTION, false, &["map_or", "ok_or", "or", "unwrap_or"], "else"),
(&paths::RESULT, true, &["or", "unwrap_or"], "else"),
];
if know_types.iter().all(|k| !k.2.contains(&name)) {
return;
}
let owner_def = cx.tcx.hir.get_parent_did(arg.id);
let promotable = cx.tcx.rvalue_promotable_map(owner_def).contains(&arg.hir_id.local_id);
if promotable {
return;
}
let self_ty = cx.tables.expr_ty(self_expr);
let (fn_has_arguments, poss, suffix) = if let Some(&(_, fn_has_arguments, poss, suffix)) =
know_types.iter().find(|&&i| match_type(cx, self_ty, i.0))
{
(fn_has_arguments, poss, suffix)
} else {
return;
};
if !poss.contains(&name) {
return;
}
let sugg: Cow<_> = match (fn_has_arguments, !or_has_args) {
(true, _) => format!("|_| {}", snippet(cx, arg.span, "..")).into(),
(false, false) => format!("|| {}", snippet(cx, arg.span, "..")).into(),
(false, true) => snippet(cx, fun_span, ".."),
};
let span_replace_word = method_span.with_hi(span.hi());
span_lint_and_sugg(
cx,
OR_FUN_CALL,
span_replace_word,
&format!("use of `{}` followed by a function call", name),
"try this",
format!("{}_{}({})", name, suffix, sugg),
);
}
if args.len() == 2 {
match args[1].node {
hir::ExprCall(ref fun, ref or_args) => {
let or_has_args = !or_args.is_empty();
if !check_unwrap_or_default(cx, name, fun, &args[0], &args[1], or_has_args, expr.span) {
check_general_case(cx, name, method_span, fun.span, &args[0], &args[1], or_has_args, expr.span);
}
},
hir::ExprMethodCall(_, span, ref or_args) => {
check_general_case(cx, name, method_span, span, &args[0], &args[1], !or_args.is_empty(), expr.span)
},
_ => {},
}
}
}
fn lint_expect_fun_call(cx: &LateContext, expr: &hir::Expr, method_span: Span, name: &str, args: &[hir::Expr]) {
fn extract_format_args(arg: &hir::Expr) -> Option<&hir::HirVec<hir::Expr>> {
if let hir::ExprAddrOf(_, ref addr_of) = arg.node {
if let hir::ExprCall(ref inner_fun, ref inner_args) = addr_of.node {
if is_expn_of(inner_fun.span, "format").is_some() && inner_args.len() == 1 {
if let hir::ExprCall(_, ref format_args) = inner_args[0].node {
return Some(format_args);
}
}
}
}
None
}
fn generate_format_arg_snippet(cx: &LateContext, a: &hir::Expr) -> String {
if let hir::ExprAddrOf(_, ref format_arg) = a.node {
if let hir::ExprMatch(ref format_arg_expr, _, _) = format_arg.node {
if let hir::ExprTup(ref format_arg_expr_tup) = format_arg_expr.node {
return snippet(cx, format_arg_expr_tup[0].span, "..").into_owned();
}
}
};
snippet(cx, a.span, "..").into_owned()
}
fn check_general_case(
cx: &LateContext,
name: &str,
method_span: Span,
self_expr: &hir::Expr,
arg: &hir::Expr,
span: Span,
) {
if name != "expect" {
return;
}
let self_type = cx.tables.expr_ty(self_expr);
let known_types = &[&paths::OPTION, &paths::RESULT];
if known_types.iter().all(|&k| !match_type(cx, self_type, k)) {
return;
}
let owner_def = cx.tcx.hir.get_parent_did(arg.id);
let promotable = cx.tcx.rvalue_promotable_map(owner_def).contains(&arg.hir_id.local_id);
if promotable {
return;
}
let closure = if match_type(cx, self_type, &paths::OPTION) { "||" } else { "|_|" };
let span_replace_word = method_span.with_hi(span.hi());
if let Some(format_args) = extract_format_args(arg) {
let args_len = format_args.len();
let args: Vec<String> = format_args
.into_iter()
.take(args_len - 1)
.map(|a| generate_format_arg_snippet(cx, a))
.collect();
let sugg = args.join(", ");
span_lint_and_sugg(
cx,
EXPECT_FUN_CALL,
span_replace_word,
&format!("use of `{}` followed by a function call", name),
"try this",
format!("unwrap_or_else({} panic!({}))", closure, sugg),
);
return;
}
let sugg: Cow<_> = snippet(cx, arg.span, "..");
span_lint_and_sugg(
cx,
EXPECT_FUN_CALL,
span_replace_word,
&format!("use of `{}` followed by a function call", name),
"try this",
format!("unwrap_or_else({} panic!({}))", closure, sugg),
);
}
if args.len() == 2 {
match args[1].node {
hir::ExprLit(_) => {},
_ => check_general_case(cx, name, method_span, &args[0], &args[1], expr.span),
}
}
}
fn lint_clone_on_copy(cx: &LateContext, expr: &hir::Expr, arg: &hir::Expr, arg_ty: Ty) {
let ty = cx.tables.expr_ty(expr);
if let ty::TyRef(_, inner, _) = arg_ty.sty {
if let ty::TyRef(_, innermost, _) = inner.sty {
span_lint_and_then(
cx,
CLONE_DOUBLE_REF,
expr.span,
"using `clone` on a double-reference; \
this will copy the reference instead of cloning the inner type",
|db| if let Some(snip) = sugg::Sugg::hir_opt(cx, arg) {
let mut ty = innermost;
let mut n = 0;
while let ty::TyRef(_, inner, _) = ty.sty {
ty = inner;
n += 1;
}
let refs: String = iter::repeat('&').take(n + 1).collect();
let derefs: String = iter::repeat('*').take(n).collect();
let explicit = format!("{}{}::clone({})", refs, ty, snip);
db.span_suggestion(expr.span, "try dereferencing it", format!("{}({}{}).clone()", refs, derefs, snip.deref()));
db.span_suggestion(expr.span, "or try being explicit about what type to clone", explicit);
},
);
return; }
}
if is_copy(cx, ty) {
let snip;
if let Some(snippet) = sugg::Sugg::hir_opt(cx, arg) {
if let ty::TyRef(..) = cx.tables.expr_ty(arg).sty {
let parent = cx.tcx.hir.get_parent_node(expr.id);
match cx.tcx.hir.get(parent) {
hir::map::NodeExpr(parent) => match parent.node {
hir::ExprAddrOf(..) |
hir::ExprMethodCall(..) => return,
_ => {},
}
hir::map::NodeStmt(stmt) => {
if let hir::StmtDecl(ref decl, _) = stmt.node {
if let hir::DeclLocal(ref loc) = decl.node {
if let hir::PatKind::Ref(..) = loc.pat.node {
return;
}
}
}
},
_ => {},
}
snip = Some(("try dereferencing it", format!("{}", snippet.deref())));
} else {
snip = Some(("try removing the `clone` call", format!("{}", snippet)));
}
} else {
snip = None;
}
span_lint_and_then(cx, CLONE_ON_COPY, expr.span, "using `clone` on a `Copy` type", |db| {
if let Some((text, snip)) = snip {
db.span_suggestion(expr.span, text, snip);
}
});
}
}
fn lint_clone_on_ref_ptr(cx: &LateContext, expr: &hir::Expr, arg: &hir::Expr) {
let obj_ty = walk_ptrs_ty(cx.tables.expr_ty(arg));
if let ty::TyAdt(_, subst) = obj_ty.sty {
let caller_type = if match_type(cx, obj_ty, &paths::RC) {
"Rc"
} else if match_type(cx, obj_ty, &paths::ARC) {
"Arc"
} else if match_type(cx, obj_ty, &paths::WEAK_RC) || match_type(cx, obj_ty, &paths::WEAK_ARC) {
"Weak"
} else {
return;
};
span_lint_and_sugg(
cx,
CLONE_ON_REF_PTR,
expr.span,
"using '.clone()' on a ref-counted pointer",
"try this",
format!("{}::<{}>::clone(&{})", caller_type, subst.type_at(0), snippet(cx, arg.span, "_")),
);
}
}
fn lint_string_extend(cx: &LateContext, expr: &hir::Expr, args: &[hir::Expr]) {
let arg = &args[1];
if let Some(arglists) = method_chain_args(arg, &["chars"]) {
let target = &arglists[0][0];
let self_ty = walk_ptrs_ty(cx.tables.expr_ty(target));
let ref_str = if self_ty.sty == ty::TyStr {
""
} else if match_type(cx, self_ty, &paths::STRING) {
"&"
} else {
return;
};
span_lint_and_sugg(
cx,
STRING_EXTEND_CHARS,
expr.span,
"calling `.extend(_.chars())`",
"try this",
format!(
"{}.push_str({}{})",
snippet(cx, args[0].span, "_"),
ref_str,
snippet(cx, target.span, "_")
),
);
}
}
fn lint_extend(cx: &LateContext, expr: &hir::Expr, args: &[hir::Expr]) {
let obj_ty = walk_ptrs_ty(cx.tables.expr_ty(&args[0]));
if match_type(cx, obj_ty, &paths::STRING) {
lint_string_extend(cx, expr, args);
}
}
fn lint_cstring_as_ptr(cx: &LateContext, expr: &hir::Expr, new: &hir::Expr, unwrap: &hir::Expr) {
if_chain! {
if let hir::ExprCall(ref fun, ref args) = new.node;
if args.len() == 1;
if let hir::ExprPath(ref path) = fun.node;
if let Def::Method(did) = cx.tables.qpath_def(path, fun.hir_id);
if match_def_path(cx.tcx, did, &paths::CSTRING_NEW);
then {
span_lint_and_then(
cx,
TEMPORARY_CSTRING_AS_PTR,
expr.span,
"you are getting the inner pointer of a temporary `CString`",
|db| {
db.note("that pointer will be invalid outside this expression");
db.span_help(unwrap.span, "assign the `CString` to a variable to extend its lifetime");
});
}
}
}
fn lint_iter_cloned_collect(cx: &LateContext, expr: &hir::Expr, iter_args: &[hir::Expr]) {
if match_type(cx, cx.tables.expr_ty(expr), &paths::VEC)
&& derefs_to_slice(cx, &iter_args[0], cx.tables.expr_ty(&iter_args[0])).is_some()
{
span_lint(
cx,
ITER_CLONED_COLLECT,
expr.span,
"called `cloned().collect()` on a slice to create a `Vec`. Calling `to_vec()` is both faster and \
more readable",
);
}
}
fn lint_unnecessary_fold(cx: &LateContext, expr: &hir::Expr, fold_args: &[hir::Expr]) {
if !match_trait_method(cx, expr, &paths::ITERATOR) {
return;
}
assert!(fold_args.len() == 3,
"Expected fold_args to have three entries - the receiver, the initial value and the closure");
fn check_fold_with_op(
cx: &LateContext,
fold_args: &[hir::Expr],
op: hir::BinOp_,
replacement_method_name: &str,
replacement_has_args: bool) {
if_chain! {
if let hir::ExprClosure(_, _, body_id, _, _) = fold_args[2].node;
let closure_body = cx.tcx.hir.body(body_id);
let closure_expr = remove_blocks(&closure_body.value);
if let hir::ExprBinary(ref bin_op, ref left_expr, ref right_expr) = closure_expr.node;
if bin_op.node == op;
if let Some(first_arg_ident) = get_arg_name(&closure_body.arguments[0].pat);
if let Some(second_arg_ident) = get_arg_name(&closure_body.arguments[1].pat);
if match_var(&*left_expr, first_arg_ident);
if replacement_has_args || match_var(&*right_expr, second_arg_ident);
then {
let next_point = cx.sess().codemap().next_point(fold_args[0].span);
let fold_span = next_point.with_hi(fold_args[2].span.hi() + BytePos(1));
let sugg = if replacement_has_args {
format!(
".{replacement}(|{s}| {r})",
replacement = replacement_method_name,
s = second_arg_ident,
r = snippet(cx, right_expr.span, "EXPR"),
)
} else {
format!(
".{replacement}()",
replacement = replacement_method_name,
)
};
span_lint_and_sugg(
cx,
UNNECESSARY_FOLD,
fold_span,
"this `.fold` can be written more succinctly using another method",
"try",
sugg,
);
}
}
}
match fold_args[1].node {
hir::ExprLit(ref lit) => {
match lit.node {
ast::LitKind::Bool(false) => check_fold_with_op(
cx, fold_args, hir::BinOp_::BiOr, "any", true
),
ast::LitKind::Bool(true) => check_fold_with_op(
cx, fold_args, hir::BinOp_::BiAnd, "all", true
),
ast::LitKind::Int(0, _) => check_fold_with_op(
cx, fold_args, hir::BinOp_::BiAdd, "sum", false
),
ast::LitKind::Int(1, _) => check_fold_with_op(
cx, fold_args, hir::BinOp_::BiMul, "product", false
),
_ => return
}
}
_ => return
};
}
fn lint_iter_nth(cx: &LateContext, expr: &hir::Expr, iter_args: &[hir::Expr], is_mut: bool) {
let mut_str = if is_mut { "_mut" } else { "" };
let caller_type = if derefs_to_slice(cx, &iter_args[0], cx.tables.expr_ty(&iter_args[0])).is_some() {
"slice"
} else if match_type(cx, cx.tables.expr_ty(&iter_args[0]), &paths::VEC) {
"Vec"
} else if match_type(cx, cx.tables.expr_ty(&iter_args[0]), &paths::VEC_DEQUE) {
"VecDeque"
} else {
return; };
span_lint(
cx,
ITER_NTH,
expr.span,
&format!(
"called `.iter{0}().nth()` on a {1}. Calling `.get{0}()` is both faster and more readable",
mut_str,
caller_type
),
);
}
fn lint_get_unwrap(cx: &LateContext, expr: &hir::Expr, get_args: &[hir::Expr], is_mut: bool) {
let expr_ty = cx.tables.expr_ty(&get_args[0]);
let caller_type = if derefs_to_slice(cx, &get_args[0], expr_ty).is_some() {
"slice"
} else if match_type(cx, expr_ty, &paths::VEC) {
"Vec"
} else if match_type(cx, expr_ty, &paths::VEC_DEQUE) {
"VecDeque"
} else if !is_mut && match_type(cx, expr_ty, &paths::HASHMAP) {
"HashMap"
} else if !is_mut && match_type(cx, expr_ty, &paths::BTREEMAP) {
"BTreeMap"
} else {
return; };
let mut_str = if is_mut { "_mut" } else { "" };
let borrow_str = if is_mut { "&mut " } else { "&" };
span_lint_and_sugg(
cx,
GET_UNWRAP,
expr.span,
&format!(
"called `.get{0}().unwrap()` on a {1}. Using `[]` is more clear and more concise",
mut_str,
caller_type
),
"try this",
format!(
"{}{}[{}]",
borrow_str,
snippet(cx, get_args[0].span, "_"),
snippet(cx, get_args[1].span, "_")
),
);
}
fn lint_iter_skip_next(cx: &LateContext, expr: &hir::Expr) {
if match_trait_method(cx, expr, &paths::ITERATOR) {
span_lint(
cx,
ITER_SKIP_NEXT,
expr.span,
"called `skip(x).next()` on an iterator. This is more succinctly expressed by calling `nth(x)`",
);
}
}
fn derefs_to_slice(cx: &LateContext, expr: &hir::Expr, ty: Ty) -> Option<sugg::Sugg<'static>> {
fn may_slice(cx: &LateContext, ty: Ty) -> bool {
match ty.sty {
ty::TySlice(_) => true,
ty::TyAdt(def, _) if def.is_box() => may_slice(cx, ty.boxed_ty()),
ty::TyAdt(..) => match_type(cx, ty, &paths::VEC),
ty::TyArray(_, size) => size.assert_usize(cx.tcx).expect("array length") < 32,
ty::TyRef(_, inner, _) => may_slice(cx, inner),
_ => false,
}
}
if let hir::ExprMethodCall(ref path, _, ref args) = expr.node {
if path.name == "iter" && may_slice(cx, cx.tables.expr_ty(&args[0])) {
sugg::Sugg::hir_opt(cx, &args[0]).map(|sugg| sugg.addr())
} else {
None
}
} else {
match ty.sty {
ty::TySlice(_) => sugg::Sugg::hir_opt(cx, expr),
ty::TyAdt(def, _) if def.is_box() && may_slice(cx, ty.boxed_ty()) => sugg::Sugg::hir_opt(cx, expr),
ty::TyRef(_, inner, _) => if may_slice(cx, inner) {
sugg::Sugg::hir_opt(cx, expr)
} else {
None
},
_ => None,
}
}
}
fn lint_unwrap(cx: &LateContext, expr: &hir::Expr, unwrap_args: &[hir::Expr]) {
let obj_ty = walk_ptrs_ty(cx.tables.expr_ty(&unwrap_args[0]));
let mess = if match_type(cx, obj_ty, &paths::OPTION) {
Some((OPTION_UNWRAP_USED, "an Option", "None"))
} else if match_type(cx, obj_ty, &paths::RESULT) {
Some((RESULT_UNWRAP_USED, "a Result", "Err"))
} else {
None
};
if let Some((lint, kind, none_value)) = mess {
span_lint(
cx,
lint,
expr.span,
&format!(
"used unwrap() on {} value. If you don't want to handle the {} case gracefully, consider \
using expect() to provide a better panic \
message",
kind,
none_value
),
);
}
}
fn lint_ok_expect(cx: &LateContext, expr: &hir::Expr, ok_args: &[hir::Expr]) {
if match_type(cx, cx.tables.expr_ty(&ok_args[0]), &paths::RESULT) {
let result_type = cx.tables.expr_ty(&ok_args[0]);
if let Some(error_type) = get_error_type(cx, result_type) {
if has_debug_impl(error_type, cx) {
span_lint(
cx,
OK_EXPECT,
expr.span,
"called `ok().expect()` on a Result value. You can call `expect` directly on the `Result`",
);
}
}
}
}
fn lint_map_unwrap_or(cx: &LateContext, expr: &hir::Expr, map_args: &[hir::Expr], unwrap_args: &[hir::Expr]) {
if match_type(cx, cx.tables.expr_ty(&map_args[0]), &paths::OPTION) {
let map_snippet = snippet(cx, map_args[1].span, "..");
let unwrap_snippet = snippet(cx, unwrap_args[1].span, "..");
let arg = if unwrap_snippet == "None" {
"None"
} else {
"a"
};
let suggest = if unwrap_snippet == "None" {
"and_then(f)"
} else {
"map_or(a, f)"
};
let msg = &format!(
"called `map(f).unwrap_or({})` on an Option value. \
This can be done more directly by calling `{}` instead",
arg,
suggest
);
let multiline = map_snippet.lines().count() > 1 || unwrap_snippet.lines().count() > 1;
let same_span = map_args[1].span.ctxt() == unwrap_args[1].span.ctxt();
if same_span && !multiline {
let suggest = if unwrap_snippet == "None" {
format!("and_then({})", map_snippet)
} else {
format!("map_or({}, {})", unwrap_snippet, map_snippet)
};
let note = format!(
"replace `map({}).unwrap_or({})` with `{}`",
map_snippet,
unwrap_snippet,
suggest
);
span_note_and_lint(cx, OPTION_MAP_UNWRAP_OR, expr.span, msg, expr.span, ¬e);
} else if same_span && multiline {
span_lint(cx, OPTION_MAP_UNWRAP_OR, expr.span, msg);
};
}
}
fn lint_map_unwrap_or_else<'a, 'tcx>(
cx: &LateContext<'a, 'tcx>,
expr: &'tcx hir::Expr,
map_args: &'tcx [hir::Expr],
unwrap_args: &'tcx [hir::Expr],
) {
let is_option = match_type(cx, cx.tables.expr_ty(&map_args[0]), &paths::OPTION);
let is_result = match_type(cx, cx.tables.expr_ty(&map_args[0]), &paths::RESULT);
if is_option || is_result {
let msg = if is_option {
"called `map(f).unwrap_or_else(g)` on an Option value. This can be done more directly by calling \
`map_or_else(g, f)` instead"
} else {
"called `map(f).unwrap_or_else(g)` on a Result value. This can be done more directly by calling \
`ok().map_or_else(g, f)` instead"
};
let map_snippet = snippet(cx, map_args[1].span, "..");
let unwrap_snippet = snippet(cx, unwrap_args[1].span, "..");
let multiline = map_snippet.lines().count() > 1 || unwrap_snippet.lines().count() > 1;
let same_span = map_args[1].span.ctxt() == unwrap_args[1].span.ctxt();
if same_span && !multiline {
span_note_and_lint(
cx,
if is_option {
OPTION_MAP_UNWRAP_OR_ELSE
} else {
RESULT_MAP_UNWRAP_OR_ELSE
},
expr.span,
msg,
expr.span,
&format!(
"replace `map({0}).unwrap_or_else({1})` with `{2}map_or_else({1}, {0})`",
map_snippet,
unwrap_snippet,
if is_result { "ok()." } else { "" }
),
);
} else if same_span && multiline {
span_lint(
cx,
if is_option {
OPTION_MAP_UNWRAP_OR_ELSE
} else {
RESULT_MAP_UNWRAP_OR_ELSE
},
expr.span,
msg,
);
};
}
}
fn lint_map_or_none<'a, 'tcx>(cx: &LateContext<'a, 'tcx>, expr: &'tcx hir::Expr, map_or_args: &'tcx [hir::Expr]) {
if match_type(cx, cx.tables.expr_ty(&map_or_args[0]), &paths::OPTION) {
let map_or_arg_is_none = if let hir::Expr_::ExprPath(ref qpath) = map_or_args[1].node {
match_qpath(qpath, &paths::OPTION_NONE)
} else {
false
};
if map_or_arg_is_none {
let msg = "called `map_or(None, f)` on an Option value. This can be done more directly by calling \
`and_then(f)` instead";
let map_or_self_snippet = snippet(cx, map_or_args[0].span, "..");
let map_or_func_snippet = snippet(cx, map_or_args[2].span, "..");
let hint = format!("{0}.and_then({1})", map_or_self_snippet, map_or_func_snippet);
span_lint_and_then(cx, OPTION_MAP_OR_NONE, expr.span, msg, |db| {
db.span_suggestion(expr.span, "try using and_then instead", hint);
});
}
}
}
fn lint_filter_next<'a, 'tcx>(cx: &LateContext<'a, 'tcx>, expr: &'tcx hir::Expr, filter_args: &'tcx [hir::Expr]) {
if match_trait_method(cx, expr, &paths::ITERATOR) {
let msg = "called `filter(p).next()` on an `Iterator`. This is more succinctly expressed by calling \
`.find(p)` instead.";
let filter_snippet = snippet(cx, filter_args[1].span, "..");
if filter_snippet.lines().count() <= 1 {
span_note_and_lint(
cx,
FILTER_NEXT,
expr.span,
msg,
expr.span,
&format!("replace `filter({0}).next()` with `find({0})`", filter_snippet),
);
} else {
span_lint(cx, FILTER_NEXT, expr.span, msg);
}
}
}
fn lint_filter_map<'a, 'tcx>(
cx: &LateContext<'a, 'tcx>,
expr: &'tcx hir::Expr,
_filter_args: &'tcx [hir::Expr],
_map_args: &'tcx [hir::Expr],
) {
if match_trait_method(cx, expr, &paths::ITERATOR) {
let msg = "called `filter(p).map(q)` on an `Iterator`. \
This is more succinctly expressed by calling `.filter_map(..)` instead.";
span_lint(cx, FILTER_MAP, expr.span, msg);
}
}
fn lint_filter_map_map<'a, 'tcx>(
cx: &LateContext<'a, 'tcx>,
expr: &'tcx hir::Expr,
_filter_args: &'tcx [hir::Expr],
_map_args: &'tcx [hir::Expr],
) {
if match_trait_method(cx, expr, &paths::ITERATOR) {
let msg = "called `filter_map(p).map(q)` on an `Iterator`. \
This is more succinctly expressed by only calling `.filter_map(..)` instead.";
span_lint(cx, FILTER_MAP, expr.span, msg);
}
}
fn lint_filter_flat_map<'a, 'tcx>(
cx: &LateContext<'a, 'tcx>,
expr: &'tcx hir::Expr,
_filter_args: &'tcx [hir::Expr],
_map_args: &'tcx [hir::Expr],
) {
if match_trait_method(cx, expr, &paths::ITERATOR) {
let msg = "called `filter(p).flat_map(q)` on an `Iterator`. \
This is more succinctly expressed by calling `.flat_map(..)` \
and filtering by returning an empty Iterator.";
span_lint(cx, FILTER_MAP, expr.span, msg);
}
}
fn lint_filter_map_flat_map<'a, 'tcx>(
cx: &LateContext<'a, 'tcx>,
expr: &'tcx hir::Expr,
_filter_args: &'tcx [hir::Expr],
_map_args: &'tcx [hir::Expr],
) {
if match_trait_method(cx, expr, &paths::ITERATOR) {
let msg = "called `filter_map(p).flat_map(q)` on an `Iterator`. \
This is more succinctly expressed by calling `.flat_map(..)` \
and filtering by returning an empty Iterator.";
span_lint(cx, FILTER_MAP, expr.span, msg);
}
}
fn lint_search_is_some<'a, 'tcx>(
cx: &LateContext<'a, 'tcx>,
expr: &'tcx hir::Expr,
search_method: &str,
search_args: &'tcx [hir::Expr],
is_some_args: &'tcx [hir::Expr],
) {
if match_trait_method(cx, &is_some_args[0], &paths::ITERATOR) {
let msg = format!(
"called `is_some()` after searching an `Iterator` with {}. This is more succinctly \
expressed by calling `any()`.",
search_method
);
let search_snippet = snippet(cx, search_args[1].span, "..");
if search_snippet.lines().count() <= 1 {
span_note_and_lint(
cx,
SEARCH_IS_SOME,
expr.span,
&msg,
expr.span,
&format!("replace `{0}({1}).is_some()` with `any({1})`", search_method, search_snippet),
);
} else {
span_lint(cx, SEARCH_IS_SOME, expr.span, &msg);
}
}
}
#[derive(Copy, Clone)]
struct BinaryExprInfo<'a> {
expr: &'a hir::Expr,
chain: &'a hir::Expr,
other: &'a hir::Expr,
eq: bool,
}
fn lint_binary_expr_with_method_call<'a, 'tcx: 'a>(cx: &LateContext<'a, 'tcx>, info: &mut BinaryExprInfo) {
macro_rules! lint_with_both_lhs_and_rhs {
($func:ident, $cx:expr, $info:ident) => {
if !$func($cx, $info) {
::std::mem::swap(&mut $info.chain, &mut $info.other);
if $func($cx, $info) {
return;
}
}
}
}
lint_with_both_lhs_and_rhs!(lint_chars_next_cmp, cx, info);
lint_with_both_lhs_and_rhs!(lint_chars_last_cmp, cx, info);
lint_with_both_lhs_and_rhs!(lint_chars_next_cmp_with_unwrap, cx, info);
lint_with_both_lhs_and_rhs!(lint_chars_last_cmp_with_unwrap, cx, info);
}
fn lint_chars_cmp<'a, 'tcx>(
cx: &LateContext<'a, 'tcx>,
info: &BinaryExprInfo,
chain_methods: &[&str],
lint: &'static Lint,
suggest: &str,
) -> bool {
if_chain! {
if let Some(args) = method_chain_args(info.chain, chain_methods);
if let hir::ExprCall(ref fun, ref arg_char) = info.other.node;
if arg_char.len() == 1;
if let hir::ExprPath(ref qpath) = fun.node;
if let Some(segment) = single_segment_path(qpath);
if segment.name == "Some";
then {
let self_ty = walk_ptrs_ty(cx.tables.expr_ty_adjusted(&args[0][0]));
if self_ty.sty != ty::TyStr {
return false;
}
span_lint_and_sugg(cx,
lint,
info.expr.span,
&format!("you should use the `{}` method", suggest),
"like this",
format!("{}{}.{}({})",
if info.eq { "" } else { "!" },
snippet(cx, args[0][0].span, "_"),
suggest,
snippet(cx, arg_char[0].span, "_")));
return true;
}
}
false
}
fn lint_chars_next_cmp<'a, 'tcx>(cx: &LateContext<'a, 'tcx>, info: &BinaryExprInfo) -> bool {
lint_chars_cmp(cx, info, &["chars", "next"], CHARS_NEXT_CMP, "starts_with")
}
fn lint_chars_last_cmp<'a, 'tcx>(cx: &LateContext<'a, 'tcx>, info: &BinaryExprInfo) -> bool {
if lint_chars_cmp(cx, info, &["chars", "last"], CHARS_NEXT_CMP, "ends_with") {
true
} else {
lint_chars_cmp(cx, info, &["chars", "next_back"], CHARS_NEXT_CMP, "ends_with")
}
}
fn lint_chars_cmp_with_unwrap<'a, 'tcx>(
cx: &LateContext<'a, 'tcx>,
info: &BinaryExprInfo,
chain_methods: &[&str],
lint: &'static Lint,
suggest: &str,
) -> bool {
if_chain! {
if let Some(args) = method_chain_args(info.chain, chain_methods);
if let hir::ExprLit(ref lit) = info.other.node;
if let ast::LitKind::Char(c) = lit.node;
then {
span_lint_and_sugg(
cx,
lint,
info.expr.span,
&format!("you should use the `{}` method", suggest),
"like this",
format!("{}{}.{}('{}')",
if info.eq { "" } else { "!" },
snippet(cx, args[0][0].span, "_"),
suggest,
c)
);
return true;
}
}
false
}
fn lint_chars_next_cmp_with_unwrap<'a, 'tcx>(cx: &LateContext<'a, 'tcx>, info: &BinaryExprInfo) -> bool {
lint_chars_cmp_with_unwrap(cx, info, &["chars", "next", "unwrap"], CHARS_NEXT_CMP, "starts_with")
}
fn lint_chars_last_cmp_with_unwrap<'a, 'tcx>(cx: &LateContext<'a, 'tcx>, info: &BinaryExprInfo) -> bool {
if lint_chars_cmp_with_unwrap(cx, info, &["chars", "last", "unwrap"], CHARS_LAST_CMP, "ends_with") {
true
} else {
lint_chars_cmp_with_unwrap(cx, info, &["chars", "next_back", "unwrap"], CHARS_LAST_CMP, "ends_with")
}
}
fn lint_single_char_pattern<'a, 'tcx>(cx: &LateContext<'a, 'tcx>, expr: &'tcx hir::Expr, arg: &'tcx hir::Expr) {
if let Some((Constant::Str(r), _)) = constant(cx, cx.tables, arg) {
if r.len() == 1 {
let c = r.chars().next().unwrap();
let snip = snippet(cx, expr.span, "..");
let hint = snip.replace(
&format!("\"{}\"", c.escape_default()),
&format!("'{}'", c.escape_default()));
span_lint_and_then(
cx,
SINGLE_CHAR_PATTERN,
arg.span,
"single-character string constant used as pattern",
|db| {
db.span_suggestion(expr.span, "try using a char instead", hint);
},
);
}
}
}
fn lint_asref(cx: &LateContext, expr: &hir::Expr, call_name: &str, as_ref_args: &[hir::Expr]) {
if match_trait_method(cx, expr, &paths::ASREF_TRAIT) || match_trait_method(cx, expr, &paths::ASMUT_TRAIT) {
let recvr = &as_ref_args[0];
let rcv_ty = cx.tables.expr_ty(recvr);
let res_ty = cx.tables.expr_ty(expr);
let (base_res_ty, res_depth) = walk_ptrs_ty_depth(res_ty);
let (base_rcv_ty, rcv_depth) = walk_ptrs_ty_depth(rcv_ty);
if base_rcv_ty == base_res_ty && rcv_depth >= res_depth {
span_lint_and_sugg(
cx,
USELESS_ASREF,
expr.span,
&format!("this call to `{}` does nothing", call_name),
"try this",
snippet(cx, recvr.span, "_").into_owned(),
);
}
}
}
fn get_error_type<'a>(cx: &LateContext, ty: Ty<'a>) -> Option<Ty<'a>> {
if let ty::TyAdt(_, substs) = ty.sty {
if match_type(cx, ty, &paths::RESULT) {
substs.types().nth(1)
} else {
None
}
} else {
None
}
}
fn has_debug_impl<'a, 'b>(ty: Ty<'a>, cx: &LateContext<'b, 'a>) -> bool {
match cx.tcx.lang_items().debug_trait() {
Some(debug) => implements_trait(cx, ty, debug, &[]),
None => false,
}
}
enum Convention {
Eq(&'static str),
StartsWith(&'static str),
}
#[cfg_attr(rustfmt, rustfmt_skip)]
const CONVENTIONS: [(Convention, &[SelfKind]); 6] = [
(Convention::Eq("new"), &[SelfKind::No]),
(Convention::StartsWith("as_"), &[SelfKind::Ref, SelfKind::RefMut]),
(Convention::StartsWith("from_"), &[SelfKind::No]),
(Convention::StartsWith("into_"), &[SelfKind::Value]),
(Convention::StartsWith("is_"), &[SelfKind::Ref, SelfKind::No]),
(Convention::StartsWith("to_"), &[SelfKind::Ref]),
];
#[cfg_attr(rustfmt, rustfmt_skip)]
const TRAIT_METHODS: [(&str, usize, SelfKind, OutType, &str); 30] = [
("add", 2, SelfKind::Value, OutType::Any, "std::ops::Add"),
("as_mut", 1, SelfKind::RefMut, OutType::Ref, "std::convert::AsMut"),
("as_ref", 1, SelfKind::Ref, OutType::Ref, "std::convert::AsRef"),
("bitand", 2, SelfKind::Value, OutType::Any, "std::ops::BitAnd"),
("bitor", 2, SelfKind::Value, OutType::Any, "std::ops::BitOr"),
("bitxor", 2, SelfKind::Value, OutType::Any, "std::ops::BitXor"),
("borrow", 1, SelfKind::Ref, OutType::Ref, "std::borrow::Borrow"),
("borrow_mut", 1, SelfKind::RefMut, OutType::Ref, "std::borrow::BorrowMut"),
("clone", 1, SelfKind::Ref, OutType::Any, "std::clone::Clone"),
("cmp", 2, SelfKind::Ref, OutType::Any, "std::cmp::Ord"),
("default", 0, SelfKind::No, OutType::Any, "std::default::Default"),
("deref", 1, SelfKind::Ref, OutType::Ref, "std::ops::Deref"),
("deref_mut", 1, SelfKind::RefMut, OutType::Ref, "std::ops::DerefMut"),
("div", 2, SelfKind::Value, OutType::Any, "std::ops::Div"),
("drop", 1, SelfKind::RefMut, OutType::Unit, "std::ops::Drop"),
("eq", 2, SelfKind::Ref, OutType::Bool, "std::cmp::PartialEq"),
("from_iter", 1, SelfKind::No, OutType::Any, "std::iter::FromIterator"),
("from_str", 1, SelfKind::No, OutType::Any, "std::str::FromStr"),
("hash", 2, SelfKind::Ref, OutType::Unit, "std::hash::Hash"),
("index", 2, SelfKind::Ref, OutType::Ref, "std::ops::Index"),
("index_mut", 2, SelfKind::RefMut, OutType::Ref, "std::ops::IndexMut"),
("into_iter", 1, SelfKind::Value, OutType::Any, "std::iter::IntoIterator"),
("mul", 2, SelfKind::Value, OutType::Any, "std::ops::Mul"),
("neg", 1, SelfKind::Value, OutType::Any, "std::ops::Neg"),
("next", 1, SelfKind::RefMut, OutType::Any, "std::iter::Iterator"),
("not", 1, SelfKind::Value, OutType::Any, "std::ops::Not"),
("rem", 2, SelfKind::Value, OutType::Any, "std::ops::Rem"),
("shl", 2, SelfKind::Value, OutType::Any, "std::ops::Shl"),
("shr", 2, SelfKind::Value, OutType::Any, "std::ops::Shr"),
("sub", 2, SelfKind::Value, OutType::Any, "std::ops::Sub"),
];
#[cfg_attr(rustfmt, rustfmt_skip)]
const PATTERN_METHODS: [(&str, usize); 17] = [
("contains", 1),
("starts_with", 1),
("ends_with", 1),
("find", 1),
("rfind", 1),
("split", 1),
("rsplit", 1),
("split_terminator", 1),
("rsplit_terminator", 1),
("splitn", 2),
("rsplitn", 2),
("matches", 1),
("rmatches", 1),
("match_indices", 1),
("rmatch_indices", 1),
("trim_left_matches", 1),
("trim_right_matches", 1),
];
#[derive(Clone, Copy, PartialEq, Debug)]
enum SelfKind {
Value,
Ref,
RefMut,
No,
}
impl SelfKind {
fn matches(
self,
ty: &hir::Ty,
arg: &hir::Arg,
self_ty: &hir::Ty,
allow_value_for_ref: bool,
generics: &hir::Generics,
) -> bool {
let is_actually_self = |ty| is_self_ty(ty) || ty == self_ty;
if is_self(arg) {
match self {
SelfKind::Value => is_actually_self(ty),
SelfKind::Ref | SelfKind::RefMut => {
if allow_value_for_ref && is_actually_self(ty) {
return true;
}
match ty.node {
hir::TyRptr(_, ref mt_ty) => {
let mutability_match = if self == SelfKind::Ref {
mt_ty.mutbl == hir::MutImmutable
} else {
mt_ty.mutbl == hir::MutMutable
};
is_actually_self(&mt_ty.ty) && mutability_match
},
_ => false,
}
},
_ => false,
}
} else {
match self {
SelfKind::Value => false,
SelfKind::Ref => is_as_ref_or_mut_trait(ty, self_ty, generics, &paths::ASREF_TRAIT),
SelfKind::RefMut => is_as_ref_or_mut_trait(ty, self_ty, generics, &paths::ASMUT_TRAIT),
SelfKind::No => true,
}
}
}
fn description(self) -> &'static str {
match self {
SelfKind::Value => "self by value",
SelfKind::Ref => "self by reference",
SelfKind::RefMut => "self by mutable reference",
SelfKind::No => "no self",
}
}
}
fn is_as_ref_or_mut_trait(ty: &hir::Ty, self_ty: &hir::Ty, generics: &hir::Generics, name: &[&str]) -> bool {
single_segment_ty(ty).map_or(false, |seg| {
generics.params.iter().any(|param| match param.kind {
hir::GenericParamKind::Type { .. } => {
param.name.name() == seg.name && param.bounds.iter().any(|bound| {
if let hir::GenericBound::Trait(ref ptr, ..) = *bound {
let path = &ptr.trait_ref.path;
match_path(path, name) && path.segments.last().map_or(false, |s| {
if let Some(ref params) = s.args {
if params.parenthesized {
false
} else {
let types: Vec<_> = params.args.iter().filter_map(|arg| match arg {
hir::GenericArg::Type(ty) => Some(ty),
_ => None,
}).collect();
types.len() == 1
&& (is_self_ty(&types[0]) || is_ty(&*types[0], self_ty))
}
} else {
false
}
})
} else {
false
}
})
},
_ => false,
})
})
}
fn is_ty(ty: &hir::Ty, self_ty: &hir::Ty) -> bool {
match (&ty.node, &self_ty.node) {
(
&hir::TyPath(hir::QPath::Resolved(_, ref ty_path)),
&hir::TyPath(hir::QPath::Resolved(_, ref self_ty_path)),
) => ty_path
.segments
.iter()
.map(|seg| seg.name)
.eq(self_ty_path.segments.iter().map(|seg| seg.name)),
_ => false,
}
}
fn single_segment_ty(ty: &hir::Ty) -> Option<&hir::PathSegment> {
if let hir::TyPath(ref path) = ty.node {
single_segment_path(path)
} else {
None
}
}
impl Convention {
fn check(&self, other: &str) -> bool {
match *self {
Convention::Eq(this) => this == other,
Convention::StartsWith(this) => other.starts_with(this) && this != other,
}
}
}
impl fmt::Display for Convention {
fn fmt(&self, f: &mut fmt::Formatter) -> Result<(), fmt::Error> {
match *self {
Convention::Eq(this) => this.fmt(f),
Convention::StartsWith(this) => this.fmt(f).and_then(|_| '*'.fmt(f)),
}
}
}
#[derive(Clone, Copy)]
enum OutType {
Unit,
Bool,
Any,
Ref,
}
impl OutType {
fn matches(self, ty: &hir::FunctionRetTy) -> bool {
match (self, ty) {
(OutType::Unit, &hir::DefaultReturn(_)) => true,
(OutType::Unit, &hir::Return(ref ty)) if ty.node == hir::TyTup(vec![].into()) => true,
(OutType::Bool, &hir::Return(ref ty)) if is_bool(ty) => true,
(OutType::Any, &hir::Return(ref ty)) if ty.node != hir::TyTup(vec![].into()) => true,
(OutType::Ref, &hir::Return(ref ty)) => matches!(ty.node, hir::TyRptr(_, _)),
_ => false,
}
}
}
fn is_bool(ty: &hir::Ty) -> bool {
if let hir::TyPath(ref p) = ty.node {
match_qpath(p, &["bool"])
} else {
false
}
}