use if_chain::if_chain;
use matches::matches;
use rustc::hir;
-use rustc::hir::def::{DefKind, Res};
use rustc::hir::intravisit::{self, Visitor};
use rustc::lint::{in_external_macro, LateContext, LateLintPass, Lint, LintArray, LintContext, LintPass};
use rustc::ty::{self, Predicate, Ty};
use rustc::{declare_lint_pass, declare_tool_lint};
use rustc_errors::Applicability;
use syntax::ast;
-use syntax::source_map::{BytePos, Span};
+use syntax::source_map::Span;
use syntax::symbol::LocalInternedString;
-use crate::utils::paths;
use crate::utils::sugg;
use crate::utils::usage::mutated_variables;
use crate::utils::{
get_arg_name, get_parent_expr, get_trait_def_id, has_iter_method, implements_trait, in_macro, is_copy,
- is_ctor_function, 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, match_var, method_calls, method_chain_args, remove_blocks, return_ty,
- same_tys, single_segment_path, snippet, snippet_with_applicability, snippet_with_macro_callsite, span_lint,
- span_lint_and_sugg, span_lint_and_then, span_note_and_lint, walk_ptrs_ty, walk_ptrs_ty_depth, SpanlessEq,
+ is_ctor_function, is_expn_of, iter_input_pats, last_path_segment, match_def_path, match_qpath, match_trait_method,
+ match_type, match_var, method_calls, method_chain_args, remove_blocks, return_ty, same_tys, single_segment_path,
+ snippet, snippet_with_applicability, snippet_with_macro_callsite, span_lint, span_lint_and_sugg,
+ span_lint_and_then, span_note_and_lint, walk_ptrs_ty, walk_ptrs_ty_depth, SpanlessEq,
};
+use crate::utils::{paths, span_help_and_lint};
declare_clippy_lint! {
/// **What it does:** Checks for `.unwrap()` calls on `Option`s.
/// **Known problems:** None.
///
/// **Example:**
+ ///
+ /// Using unwrap on an `Option`:
+ ///
+ /// ```rust
+ /// let opt = Some(1);
+ /// opt.unwrap();
+ /// ```
+ ///
+ /// Better:
+ ///
/// ```rust
- /// x.unwrap()
+ /// let opt = Some(1);
+ /// opt.expect("more helpful message");
/// ```
pub OPTION_UNWRAP_USED,
restriction,
/// **Known problems:** None.
///
/// **Example:**
+ /// Using unwrap on an `Option`:
+ ///
/// ```rust
- /// x.unwrap()
+ /// let res: Result<usize, ()> = Ok(1);
+ /// res.unwrap();
+ /// ```
+ ///
+ /// Better:
+ ///
+ /// ```rust
+ /// let res: Result<usize, ()> = Ok(1);
+ /// res.expect("more helpful message");
/// ```
pub RESULT_UNWRAP_USED,
restriction,
///
/// **Example:**
/// ```rust
- /// impl X {
- /// pub fn as_str(self) -> &str {
- /// ..
+ /// # struct X;
+ /// impl<'a> X {
+ /// pub fn as_str(self) -> &'a str {
+ /// "foo"
/// }
/// }
/// ```
///
/// **Example:**
/// ```rust
- /// x.map(|a| a + 1).unwrap_or(0)
+ /// # let x = Some(1);
+ /// x.map(|a| a + 1).unwrap_or(0);
/// ```
pub OPTION_MAP_UNWRAP_OR,
pedantic,
///
/// **Example:**
/// ```rust
- /// x.map(|a| a + 1).unwrap_or_else(some_function)
+ /// # let x = Some(1);
+ /// # fn some_function() -> usize { 1 }
+ /// x.map(|a| a + 1).unwrap_or_else(some_function);
/// ```
pub OPTION_MAP_UNWRAP_OR_ELSE,
pedantic,
///
/// **Example:**
/// ```rust
- /// x.map(|a| a + 1).unwrap_or_else(some_function)
+ /// # let x: Result<usize, ()> = Ok(1);
+ /// # fn some_function(foo: ()) -> usize { 1 }
+ /// x.map(|a| a + 1).unwrap_or_else(some_function);
/// ```
pub RESULT_MAP_UNWRAP_OR_ELSE,
pedantic,
"using `Option.map_or(None, f)`, which is more succinctly expressed as `and_then(f)`"
}
+declare_clippy_lint! {
+ /// **What it does:** Checks for usage of `_.and_then(|x| Some(y))`.
+ ///
+ /// **Why is this bad?** Readability, this can be written more concisely as
+ /// `_.map(|x| y)`.
+ ///
+ /// **Known problems:** None
+ ///
+ /// **Example:**
+ ///
+ /// ```rust
+ /// let x = Some("foo");
+ /// let _ = x.and_then(|s| Some(s.len()));
+ /// ```
+ ///
+ /// The correct use would be:
+ ///
+ /// ```rust
+ /// let x = Some("foo");
+ /// let _ = x.map(|s| s.len());
+ /// ```
+ pub OPTION_AND_THEN_SOME,
+ complexity,
+ "using `Option.and_then(|x| Some(y))`, which is more succinctly expressed as `map(|x| y)`"
+}
+
declare_clippy_lint! {
/// **What it does:** Checks for usage of `_.filter(_).next()`.
///
///
/// **Example:**
/// ```rust
- /// iter.filter(|x| x == 0).next()
+ /// # let vec = vec![1];
+ /// vec.iter().filter(|x| **x == 0).next();
/// ```
pub FILTER_NEXT,
complexity,
///
/// **Example:**
/// ```rust
- /// iter.map(|x| x.iter()).flatten()
+ /// let vec = vec![vec![1]];
+ /// vec.iter().map(|x| x.iter()).flatten();
/// ```
pub MAP_FLATTEN,
pedantic,
///
/// **Example:**
/// ```rust
- /// iter.filter(|x| x == 0).map(|x| x * 2)
+ /// let vec = vec![1];
+ /// vec.iter().filter(|x| **x == 0).map(|x| *x * 2);
/// ```
pub FILTER_MAP,
pedantic,
"using combination of `filter_map` and `next` which can usually be written as a single method call"
}
+declare_clippy_lint! {
+ /// **What it does:** Checks for usage of `flat_map(|x| x)`.
+ ///
+ /// **Why is this bad?** Readability, this can be written more concisely by using `flatten`.
+ ///
+ /// **Known problems:** None
+ ///
+ /// **Example:**
+ /// ```rust
+ /// # let iter = vec![vec![0]].into_iter();
+ /// iter.flat_map(|x| x);
+ /// ```
+ /// Can be written as
+ /// ```rust
+ /// # let iter = vec![vec![0]].into_iter();
+ /// iter.flatten();
+ /// ```
+ pub FLAT_MAP_IDENTITY,
+ complexity,
+ "call to `flat_map` where `flatten` is sufficient"
+}
+
declare_clippy_lint! {
/// **What it does:** Checks for usage of `_.find(_).map(_)`.
///
///
/// **Example:**
/// ```rust
- /// (0..3).find(|x| x == 2).map(|x| x * 2);
+ /// (0..3).find(|x| *x == 2).map(|x| x * 2);
/// ```
/// Can be written as
/// ```rust
///
/// **Example:**
/// ```rust
- /// iter.find(|x| x == 0).is_some()
+ /// # let vec = vec![1];
+ /// vec.iter().find(|x| **x == 0).is_some();
/// ```
pub SEARCH_IS_SOME,
complexity,
///
/// **Example:**
/// ```rust
- /// name.chars().next() == Some('_')
+ /// let name = "foo";
+ /// name.chars().next() == Some('_');
/// ```
pub CHARS_NEXT_CMP,
complexity,
///
/// **Example:**
/// ```rust
- /// foo.unwrap_or(String::new())
+ /// # let foo = Some(String::new());
+ /// foo.unwrap_or(String::new());
/// ```
/// this can instead be written:
/// ```rust
- /// foo.unwrap_or_else(String::new)
+ /// # let foo = Some(String::new());
+ /// foo.unwrap_or_else(String::new);
/// ```
/// or
/// ```rust
- /// foo.unwrap_or_default()
+ /// # let foo = Some(String::new());
+ /// foo.unwrap_or_default();
/// ```
pub OR_FUN_CALL,
perf,
///
/// **Example:**
/// ```rust
- /// foo.expect(&format!("Err {}: {}", err_code, err_msg))
+ /// # let foo = Some(String::new());
+ /// # let err_code = "418";
+ /// # let err_msg = "I'm a teapot";
+ /// foo.expect(&format!("Err {}: {}", err_code, err_msg));
/// ```
/// or
/// ```rust
- /// foo.expect(format!("Err {}: {}", err_code, err_msg).as_str())
+ /// # let foo = Some(String::new());
+ /// # let err_code = "418";
+ /// # let err_msg = "I'm a teapot";
+ /// foo.expect(format!("Err {}: {}", err_code, err_msg).as_str());
/// ```
/// this can instead be written:
/// ```rust
- /// foo.unwrap_or_else(|_| panic!("Err {}: {}", err_code, err_msg))
+ /// # let foo = Some(String::new());
+ /// # let err_code = "418";
+ /// # let err_msg = "I'm a teapot";
+ /// foo.unwrap_or_else(|| panic!("Err {}: {}", err_code, err_msg));
/// ```
pub EXPECT_FUN_CALL,
perf,
///
/// **Example:**
/// ```rust
- /// 42u64.clone()
+ /// 42u64.clone();
/// ```
pub CLONE_ON_COPY,
complexity,
///
/// **Example:**
/// ```rust
- /// x.clone()
+ /// # use std::rc::Rc;
+ /// let x = Rc::new(1);
+ /// x.clone();
/// ```
pub CLONE_ON_REF_PTR,
restriction,
///
/// **Example:**
/// ```rust
+ /// # fn do_stuff(x: &[i32]) {}
/// let x: &[i32] = &[1, 2, 3, 4, 5];
/// do_stuff(x.as_ref());
/// ```
/// The correct use would be:
/// ```rust
+ /// # fn do_stuff(x: &[i32]) {}
/// let x: &[i32] = &[1, 2, 3, 4, 5];
/// do_stuff(x);
/// ```
"using `.into_iter()` on a reference"
}
+declare_clippy_lint! {
+ /// **What it does:** Checks for calls to `map` followed by a `count`.
+ ///
+ /// **Why is this bad?** It looks suspicious. Maybe `map` was confused with `filter`.
+ /// If the `map` call is intentional, this should be rewritten.
+ ///
+ /// **Known problems:** None
+ ///
+ /// **Example:**
+ ///
+ /// ```rust
+ /// let _ = (0..3).map(|x| x + 2).count();
+ /// ```
+ pub SUSPICIOUS_MAP,
+ complexity,
+ "suspicious usage of map"
+}
+
declare_lint_pass!(Methods => [
OPTION_UNWRAP_USED,
RESULT_UNWRAP_USED,
OPTION_MAP_UNWRAP_OR_ELSE,
RESULT_MAP_UNWRAP_OR_ELSE,
OPTION_MAP_OR_NONE,
+ OPTION_AND_THEN_SOME,
OR_FUN_CALL,
EXPECT_FUN_CALL,
CHARS_NEXT_CMP,
FILTER_NEXT,
FILTER_MAP,
FILTER_MAP_NEXT,
+ FLAT_MAP_IDENTITY,
FIND_MAP,
MAP_FLATTEN,
ITER_NTH,
UNNECESSARY_FILTER_MAP,
INTO_ITER_ON_ARRAY,
INTO_ITER_ON_REF,
+ SUSPICIOUS_MAP,
]);
impl<'a, 'tcx> LateLintPass<'a, 'tcx> for Methods {
["unwrap_or", "map"] => option_map_unwrap_or::lint(cx, expr, arg_lists[1], arg_lists[0]),
["unwrap_or_else", "map"] => lint_map_unwrap_or_else(cx, expr, arg_lists[1], arg_lists[0]),
["map_or", ..] => lint_map_or_none(cx, expr, arg_lists[0]),
+ ["and_then", ..] => lint_option_and_then_some(cx, expr, arg_lists[0]),
["next", "filter"] => lint_filter_next(cx, expr, arg_lists[1]),
["map", "filter"] => lint_filter_map(cx, expr, arg_lists[1], arg_lists[0]),
["map", "filter_map"] => lint_filter_map_map(cx, expr, arg_lists[1], arg_lists[0]),
["map", "find"] => lint_find_map(cx, expr, arg_lists[1], arg_lists[0]),
["flat_map", "filter"] => lint_filter_flat_map(cx, expr, arg_lists[1], arg_lists[0]),
["flat_map", "filter_map"] => lint_filter_map_flat_map(cx, expr, arg_lists[1], arg_lists[0]),
+ ["flat_map", ..] => lint_flat_map_identity(cx, expr, arg_lists[0]),
["flatten", "map"] => lint_map_flatten(cx, expr, arg_lists[1]),
["is_some", "find"] => lint_search_is_some(cx, expr, "find", arg_lists[1], arg_lists[0]),
["is_some", "position"] => lint_search_is_some(cx, expr, "position", arg_lists[1], arg_lists[0]),
["is_some", "rposition"] => lint_search_is_some(cx, expr, "rposition", arg_lists[1], arg_lists[0]),
["extend", ..] => lint_extend(cx, expr, arg_lists[0]),
- ["as_ptr", "unwrap"] => lint_cstring_as_ptr(cx, expr, &arg_lists[1][0], &arg_lists[0][0]),
+ ["as_ptr", "unwrap"] | ["as_ptr", "expect"] => {
+ lint_cstring_as_ptr(cx, expr, &arg_lists[1][0], &arg_lists[0][0])
+ },
["nth", "iter"] => lint_iter_nth(cx, expr, arg_lists[1], false),
["nth", "iter_mut"] => lint_iter_nth(cx, expr, arg_lists[1], true),
["next", "skip"] => lint_iter_skip_next(cx, expr),
["as_mut"] => lint_asref(cx, expr, "as_mut", arg_lists[0]),
["fold", ..] => lint_unnecessary_fold(cx, expr, arg_lists[0]),
["filter_map", ..] => unnecessary_filter_map::lint(cx, expr, arg_lists[0]),
+ ["count", "map"] => lint_suspicious_map(cx, expr),
_ => {},
}
}
}
- fn check_impl_item(&mut self, cx: &LateContext<'a, 'tcx>, implitem: &'tcx hir::ImplItem) {
- if in_external_macro(cx.sess(), implitem.span) {
+ fn check_impl_item(&mut self, cx: &LateContext<'a, 'tcx>, impl_item: &'tcx hir::ImplItem) {
+ if in_external_macro(cx.sess(), impl_item.span) {
return;
}
- let name = implitem.ident.name.as_str();
- let parent = cx.tcx.hir().get_parent_item(implitem.hir_id);
+ let name = impl_item.ident.name.as_str();
+ let parent = cx.tcx.hir().get_parent_item(impl_item.hir_id);
let item = cx.tcx.hir().expect_item(parent);
let def_id = cx.tcx.hir().local_def_id(item.hir_id);
let ty = cx.tcx.type_of(def_id);
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 hir::ImplItemKind::Method(ref sig, id) = impl_item.node;
if let Some(first_arg) = iter_input_pats(&sig.decl, cx.tcx.hir().body(id)).next();
- if let hir::ItemKind::Impl(_, _, _, _, None, ref self_ty, _) = item.node;
+ if let hir::ItemKind::Impl(_, _, _, _, None, _, _) = item.node;
+
+ let method_def_id = cx.tcx.hir().local_def_id(impl_item.hir_id);
+ let method_sig = cx.tcx.fn_sig(method_def_id);
+ let method_sig = cx.tcx.erase_late_bound_regions(&method_sig);
+
+ let first_arg_ty = &method_sig.inputs().iter().next();
+
+ // check conventions w.r.t. conversion method names and predicates
+ if let Some(first_arg_ty) = first_arg_ty;
+
then {
- if cx.access_levels.is_exported(implitem.hir_id) {
+ if cx.access_levels.is_exported(impl_item.hir_id) {
// check missing trait implementations
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(cx, &sig.decl.output) &&
- self_kind.matches(cx, first_arg_ty, first_arg, self_ty, false, &implitem.generics) {
- span_lint(cx, SHOULD_IMPLEMENT_TRAIT, implitem.span, &format!(
+ self_kind.matches(cx, ty, first_arg_ty) {
+ span_lint(cx, SHOULD_IMPLEMENT_TRAIT, impl_item.span, &format!(
"defining a method called `{}` on this type; consider implementing \
the `{}` trait or choosing a less ambiguous name", name, trait_name));
}
}
}
- // check conventions w.r.t. conversion method names and predicates
- let is_copy = is_copy(cx, ty);
- for &(ref conv, self_kinds) in &CONVENTIONS {
- if conv.check(&name) {
- if !self_kinds
- .iter()
- .any(|k| k.matches(cx, first_arg_ty, first_arg, self_ty, is_copy, &implitem.generics)) {
- let lint = if item.vis.node.is_pub() {
- 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 ")));
- }
+ if let Some((ref conv, self_kinds)) = &CONVENTIONS
+ .iter()
+ .find(|(ref conv, _)| conv.check(&name))
+ {
+ if !self_kinds.iter().any(|k| k.matches(cx, ty, first_arg_ty)) {
+ let lint = if item.vis.node.is_pub() {
+ WRONG_PUB_SELF_CONVENTION
+ } else {
+ WRONG_SELF_CONVENTION
+ };
- // Only check the first convention to match (CONVENTIONS should be listed from most to least
- // specific)
- break;
+ 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 ")
+ ),
+ );
}
}
}
}
- if let hir::ImplItemKind::Method(_, _) = implitem.node {
- let ret_ty = return_ty(cx, implitem.hir_id);
+ if let hir::ImplItemKind::Method(_, _) = impl_item.node {
+ let ret_ty = return_ty(cx, impl_item.hir_id);
// walk the return type and check for Self (this does not check associated types)
- for inner_type in ret_ty.walk() {
- if same_tys(cx, ty, inner_type) {
- return;
- }
+ if ret_ty.walk().any(|inner_type| same_tys(cx, ty, inner_type)) {
+ return;
}
// if return type is impl trait, check the associated types
(Predicate::Projection(poly_projection_predicate), _) => {
let binder = poly_projection_predicate.ty();
let associated_type = binder.skip_binder();
- let associated_type_is_self_type = same_tys(cx, ty, associated_type);
- // if the associated type is self, early return and do not trigger lint
- if associated_type_is_self_type {
- return;
+ // walk the associated type and check for Self
+ for inner_type in associated_type.walk() {
+ if same_tys(cx, ty, inner_type) {
+ return;
+ }
}
},
(_, _) => {},
span_lint(
cx,
NEW_RET_NO_SELF,
- implitem.span,
+ impl_item.span,
"methods called `new` usually return `Self`",
);
}
or_has_args: bool,
span: Span,
) -> bool {
- if or_has_args {
- return false;
- }
-
- if name == "unwrap_or" {
- if let hir::ExprKind::Path(ref qpath) = fun.node {
- let path = &*last_path_segment(qpath).ident.as_str();
+ if_chain! {
+ if !or_has_args;
+ if name == "unwrap_or";
+ if let hir::ExprKind::Path(ref qpath) = fun.node;
+ let path = &*last_path_segment(qpath).ident.as_str();
+ if ["default", "new"].contains(&path);
+ let arg_ty = cx.tables.expr_ty(arg);
+ if let Some(default_trait_id) = get_trait_def_id(cx, &paths::DEFAULT_TRAIT);
+ if implements_trait(cx, arg_ty, default_trait_id, &[]);
- 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;
- };
+ then {
+ let mut applicability = Applicability::MachineApplicable;
+ 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_with_applicability(cx, self_expr.span, "_", &mut applicability)
+ ),
+ applicability,
+ );
- if implements_trait(cx, arg_ty, default_trait_id, &[]) {
- let mut applicability = Applicability::MachineApplicable;
- 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_with_applicability(cx, self_expr.span, "_", &mut applicability)
- ),
- applicability,
- );
- return true;
- }
- }
+ true
+ } else {
+ false
}
}
-
- false
}
/// Checks for `*or(foo())`.
(&paths::RESULT, true, &["or", "unwrap_or"], "else"),
];
- // early check if the name is one we care about
- if know_types.iter().all(|k| !k.2.contains(&name)) {
- return;
- }
+ if_chain! {
+ if know_types.iter().any(|k| k.2.contains(&name));
- let mut finder = FunCallFinder { cx: &cx, found: false };
- finder.visit_expr(&arg);
- if !finder.found {
- return;
- }
+ let mut finder = FunCallFinder { cx: &cx, found: false };
+ if { finder.visit_expr(&arg); finder.found };
- let self_ty = cx.tables.expr_ty(self_expr);
+ 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 let Some(&(_, fn_has_arguments, poss, suffix)) =
+ know_types.iter().find(|&&i| match_type(cx, self_ty, i.0));
- if !poss.contains(&name) {
- return;
- }
+ if poss.contains(&name);
- let sugg: Cow<'_, _> = match (fn_has_arguments, !or_has_args) {
- (true, _) => format!("|_| {}", snippet_with_macro_callsite(cx, arg.span, "..")).into(),
- (false, false) => format!("|| {}", snippet_with_macro_callsite(cx, arg.span, "..")).into(),
- (false, true) => snippet_with_macro_callsite(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),
- Applicability::HasPlaceholders,
- );
+ then {
+ let sugg: Cow<'_, _> = match (fn_has_arguments, !or_has_args) {
+ (true, _) => format!("|_| {}", snippet_with_macro_callsite(cx, arg.span, "..")).into(),
+ (false, false) => format!("|| {}", snippet_with_macro_callsite(cx, arg.span, "..")).into(),
+ (false, true) => snippet_with_macro_callsite(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),
+ Applicability::HasPlaceholders,
+ );
+ }
+ }
}
if args.len() == 2 {
a: &hir::Expr,
applicability: &mut Applicability,
) -> Vec<String> {
- if let hir::ExprKind::AddrOf(_, ref format_arg) = a.node {
- if let hir::ExprKind::Match(ref format_arg_expr, _, _) = format_arg.node {
- if let hir::ExprKind::Tup(ref format_arg_expr_tup) = format_arg_expr.node {
- return format_arg_expr_tup
- .iter()
- .map(|a| snippet_with_applicability(cx, a.span, "..", applicability).into_owned())
- .collect();
- }
- }
- };
+ if_chain! {
+ if let hir::ExprKind::AddrOf(_, ref format_arg) = a.node;
+ if let hir::ExprKind::Match(ref format_arg_expr, _, _) = format_arg.node;
+ if let hir::ExprKind::Tup(ref format_arg_expr_tup) = format_arg_expr.node;
- unreachable!()
+ then {
+ format_arg_expr_tup
+ .iter()
+ .map(|a| snippet_with_applicability(cx, a.span, "..", applicability).into_owned())
+ .collect()
+ } else {
+ unreachable!()
+ }
+ }
}
fn is_call(node: &hir::ExprKind) -> bool {
if is_copy(cx, ty) {
let snip;
if let Some(snippet) = sugg::Sugg::hir_opt(cx, arg) {
+ let parent = cx.tcx.hir().get_parent_node(expr.hir_id);
+ match &cx.tcx.hir().get(parent) {
+ hir::Node::Expr(parent) => match parent.node {
+ // &*x is a nop, &x.clone() is not
+ hir::ExprKind::AddrOf(..) |
+ // (*x).func() is useless, x.clone().func() can work in case func borrows mutably
+ hir::ExprKind::MethodCall(..) => return,
+ _ => {},
+ },
+ hir::Node::Stmt(stmt) => {
+ if let hir::StmtKind::Local(ref loc) = stmt.node {
+ if let hir::PatKind::Ref(..) = loc.pat.node {
+ // let ref y = *x borrows x, let ref y = x.clone() does not
+ return;
+ }
+ }
+ },
+ _ => {},
+ }
+
// x.clone() might have dereferenced x, possibly through Deref impls
if cx.tables.expr_ty(arg) == ty {
snip = Some(("try removing the `clone` call", format!("{}", snippet)));
} else {
- let parent = cx.tcx.hir().get_parent_node(expr.hir_id);
- match cx.tcx.hir().get(parent) {
- hir::Node::Expr(parent) => match parent.node {
- // &*x is a nop, &x.clone() is not
- hir::ExprKind::AddrOf(..) |
- // (*x).func() is useless, x.clone().func() can work in case func borrows mutably
- hir::ExprKind::MethodCall(..) => return,
- _ => {},
- },
- hir::Node::Stmt(stmt) => {
- if let hir::StmtKind::Local(ref loc) = stmt.node {
- if let hir::PatKind::Ref(..) = loc.pat.node {
- // let ref y = *x borrows x, let ref y = x.clone() does not
- return;
- }
- }
- },
- _ => {},
- }
-
let deref_count = cx
.tables
.expr_adjustments(arg)
}
}
-fn lint_cstring_as_ptr(cx: &LateContext<'_, '_>, expr: &hir::Expr, new: &hir::Expr, unwrap: &hir::Expr) {
+fn lint_cstring_as_ptr(cx: &LateContext<'_, '_>, expr: &hir::Expr, source: &hir::Expr, unwrap: &hir::Expr) {
if_chain! {
- if let hir::ExprKind::Call(ref fun, ref args) = new.node;
- if args.len() == 1;
- if let hir::ExprKind::Path(ref path) = fun.node;
- if let Res::Def(DefKind::Method, did) = cx.tables.qpath_res(path, fun.hir_id);
- if match_def_path(cx, did, &paths::CSTRING_NEW);
+ let source_type = cx.tables.expr_ty(source);
+ if let ty::Adt(def, substs) = source_type.sty;
+ if match_def_path(cx, def.did, &paths::RESULT);
+ if match_type(cx, substs.type_at(0), &paths::CSTRING);
then {
span_lint_and_then(
cx,
}
fn lint_iter_cloned_collect<'a, 'tcx>(cx: &LateContext<'a, 'tcx>, expr: &hir::Expr, iter_args: &'tcx [hir::Expr]) {
- if match_type(cx, cx.tables.expr_ty(expr), &paths::VEC) {
- if let Some(slice) = derefs_to_slice(cx, &iter_args[0], cx.tables.expr_ty(&iter_args[0])) {
- if let Some(to_replace) = expr.span.trim_start(slice.span.source_callsite()) {
- span_lint_and_sugg(
- cx,
- ITER_CLONED_COLLECT,
- to_replace,
- "called `iter().cloned().collect()` on a slice to create a `Vec`. Calling `to_vec()` is both faster and \
- more readable",
- "try",
- ".to_vec()".to_string(),
- Applicability::MachineApplicable,
- );
- }
+ if_chain! {
+ if match_type(cx, cx.tables.expr_ty(expr), &paths::VEC);
+ if let Some(slice) = derefs_to_slice(cx, &iter_args[0], cx.tables.expr_ty(&iter_args[0]));
+ if let Some(to_replace) = expr.span.trim_start(slice.span.source_callsite());
+
+ then {
+ span_lint_and_sugg(
+ cx,
+ ITER_CLONED_COLLECT,
+ to_replace,
+ "called `iter().cloned().collect()` on a slice to create a `Vec`. Calling `to_vec()` is both faster and \
+ more readable",
+ "try",
+ ".to_vec()".to_string(),
+ Applicability::MachineApplicable,
+ );
}
}
}
fn lint_unnecessary_fold(cx: &LateContext<'_, '_>, expr: &hir::Expr, fold_args: &[hir::Expr]) {
fn check_fold_with_op(
cx: &LateContext<'_, '_>,
+ expr: &hir::Expr,
fold_args: &[hir::Expr],
op: hir::BinOpKind,
replacement_method_name: &str,
if match_var(&*left_expr, first_arg_ident);
if replacement_has_args || match_var(&*right_expr, second_arg_ident);
- then {
- // Span containing `.fold(...)`
- let next_point = cx.sess().source_map().next_point(fold_args[0].span);
- let fold_span = next_point.with_hi(fold_args[2].span.hi() + BytePos(1));
+ if let hir::ExprKind::MethodCall(_, span, _) = &expr.node;
+ then {
let mut applicability = Applicability::MachineApplicable;
let sugg = if replacement_has_args {
format!(
- ".{replacement}(|{s}| {r})",
+ "{replacement}(|{s}| {r})",
replacement = replacement_method_name,
s = second_arg_ident,
r = snippet_with_applicability(cx, right_expr.span, "EXPR", &mut applicability),
)
} else {
format!(
- ".{replacement}()",
+ "{replacement}()",
replacement = replacement_method_name,
)
};
span_lint_and_sugg(
cx,
UNNECESSARY_FOLD,
- fold_span,
+ span.with_hi(expr.span.hi()),
// TODO #2371 don't suggest e.g., .any(|x| f(x)) if we can suggest .any(f)
"this `.fold` can be written more succinctly using another method",
"try",
// Check if the first argument to .fold is a suitable literal
if let hir::ExprKind::Lit(ref lit) = fold_args[1].node {
match lit.node {
- ast::LitKind::Bool(false) => check_fold_with_op(cx, fold_args, hir::BinOpKind::Or, "any", true),
- ast::LitKind::Bool(true) => check_fold_with_op(cx, fold_args, hir::BinOpKind::And, "all", true),
- ast::LitKind::Int(0, _) => check_fold_with_op(cx, fold_args, hir::BinOpKind::Add, "sum", false),
- ast::LitKind::Int(1, _) => check_fold_with_op(cx, fold_args, hir::BinOpKind::Mul, "product", false),
+ ast::LitKind::Bool(false) => check_fold_with_op(cx, expr, fold_args, hir::BinOpKind::Or, "any", true),
+ ast::LitKind::Bool(true) => check_fold_with_op(cx, expr, fold_args, hir::BinOpKind::And, "all", true),
+ ast::LitKind::Int(0, _) => check_fold_with_op(cx, expr, fold_args, hir::BinOpKind::Add, "sum", false),
+ ast::LitKind::Int(1, _) => check_fold_with_op(cx, expr, fold_args, hir::BinOpKind::Mul, "product", false),
_ => (),
}
}
ty::Slice(_) => true,
ty::Adt(def, _) if def.is_box() => may_slice(cx, ty.boxed_ty()),
ty::Adt(..) => match_type(cx, ty, &paths::VEC),
- ty::Array(_, size) => size.assert_usize(cx.tcx).expect("array length") < 32,
+ ty::Array(_, size) => size.eval_usize(cx.tcx, cx.param_env) < 32,
ty::Ref(_, inner, _) => may_slice(cx, inner),
_ => false,
}
/// lint use of `ok().expect()` for `Result`s
fn lint_ok_expect(cx: &LateContext<'_, '_>, expr: &hir::Expr, ok_args: &[hir::Expr]) {
- // lint if the caller of `ok()` is a `Result`
- if match_type(cx, cx.tables.expr_ty(&ok_args[0]), &paths::RESULT) {
+ if_chain! {
+ // lint if the caller of `ok()` is a `Result`
+ 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`",
- );
- }
+ if let Some(error_type) = get_error_type(cx, result_type);
+ if has_debug_impl(error_type, cx);
+
+ then {
+ span_lint(
+ cx,
+ OK_EXPECT,
+ expr.span,
+ "called `ok().expect()` on a Result value. You can call `expect` directly on the `Result`",
+ );
}
}
}
}
}
+/// Lint use of `_.and_then(|x| Some(y))` for `Option`s
+fn lint_option_and_then_some(cx: &LateContext<'_, '_>, expr: &hir::Expr, args: &[hir::Expr]) {
+ const LINT_MSG: &str = "using `Option.and_then(|x| Some(y))`, which is more succinctly expressed as `map(|x| y)`";
+ const NO_OP_MSG: &str = "using `Option.and_then(Some)`, which is a no-op";
+
+ // Searches an return expressions in `y` in `_.and_then(|x| Some(y))`, which we don't lint
+ struct RetCallFinder {
+ found: bool,
+ }
+
+ impl<'tcx> intravisit::Visitor<'tcx> for RetCallFinder {
+ fn visit_expr(&mut self, expr: &'tcx hir::Expr) {
+ if self.found {
+ return;
+ }
+ if let hir::ExprKind::Ret(..) = &expr.node {
+ self.found = true;
+ } else {
+ intravisit::walk_expr(self, expr);
+ }
+ }
+
+ fn nested_visit_map<'this>(&'this mut self) -> intravisit::NestedVisitorMap<'this, 'tcx> {
+ intravisit::NestedVisitorMap::None
+ }
+ }
+
+ let ty = cx.tables.expr_ty(&args[0]);
+ if !match_type(cx, ty, &paths::OPTION) {
+ return;
+ }
+
+ match args[1].node {
+ hir::ExprKind::Closure(_, _, body_id, closure_args_span, _) => {
+ let closure_body = cx.tcx.hir().body(body_id);
+ let closure_expr = remove_blocks(&closure_body.value);
+ if_chain! {
+ if let hir::ExprKind::Call(ref some_expr, ref some_args) = closure_expr.node;
+ if let hir::ExprKind::Path(ref qpath) = some_expr.node;
+ if match_qpath(qpath, &paths::OPTION_SOME);
+ if some_args.len() == 1;
+ then {
+ let inner_expr = &some_args[0];
+
+ let mut finder = RetCallFinder { found: false };
+ finder.visit_expr(inner_expr);
+ if finder.found {
+ return;
+ }
+
+ let some_inner_snip = if inner_expr.span.from_expansion() {
+ snippet_with_macro_callsite(cx, inner_expr.span, "_")
+ } else {
+ snippet(cx, inner_expr.span, "_")
+ };
+
+ let closure_args_snip = snippet(cx, closure_args_span, "..");
+ let option_snip = snippet(cx, args[0].span, "..");
+ let note = format!("{}.map({} {})", option_snip, closure_args_snip, some_inner_snip);
+ span_lint_and_sugg(
+ cx,
+ OPTION_AND_THEN_SOME,
+ expr.span,
+ LINT_MSG,
+ "try this",
+ note,
+ Applicability::MachineApplicable,
+ );
+ }
+ }
+ },
+ // `_.and_then(Some)` case, which is no-op.
+ hir::ExprKind::Path(ref qpath) => {
+ if match_qpath(qpath, &paths::OPTION_SOME) {
+ let option_snip = snippet(cx, args[0].span, "..");
+ let note = format!("{}", option_snip);
+ span_lint_and_sugg(
+ cx,
+ OPTION_AND_THEN_SOME,
+ expr.span,
+ NO_OP_MSG,
+ "use the expression directly",
+ note,
+ Applicability::MachineApplicable,
+ );
+ }
+ },
+ _ => {},
+ }
+}
+
/// lint use of `filter().next()` for `Iterators`
fn lint_filter_next<'a, 'tcx>(cx: &LateContext<'a, 'tcx>, expr: &'tcx hir::Expr, filter_args: &'tcx [hir::Expr]) {
// lint if caller of `.filter().next()` is an Iterator
}
}
+/// lint use of `flat_map` for `Iterators` where `flatten` would be sufficient
+fn lint_flat_map_identity<'a, 'tcx>(
+ cx: &LateContext<'a, 'tcx>,
+ expr: &'tcx hir::Expr,
+ flat_map_args: &'tcx [hir::Expr],
+) {
+ if match_trait_method(cx, expr, &paths::ITERATOR) {
+ let arg_node = &flat_map_args[1].node;
+
+ let apply_lint = |message: &str| {
+ if let hir::ExprKind::MethodCall(_, span, _) = &expr.node {
+ span_lint_and_sugg(
+ cx,
+ FLAT_MAP_IDENTITY,
+ span.with_hi(expr.span.hi()),
+ message,
+ "try",
+ "flatten()".to_string(),
+ Applicability::MachineApplicable,
+ );
+ }
+ };
+
+ if_chain! {
+ if let hir::ExprKind::Closure(_, _, body_id, _, _) = arg_node;
+ let body = cx.tcx.hir().body(*body_id);
+
+ if let hir::PatKind::Binding(_, _, binding_ident, _) = body.arguments[0].pat.node;
+ if let hir::ExprKind::Path(hir::QPath::Resolved(_, ref path)) = body.value.node;
+
+ if path.segments.len() == 1;
+ if path.segments[0].ident.as_str() == binding_ident.as_str();
+
+ then {
+ apply_lint("called `flat_map(|x| x)` on an `Iterator`");
+ }
+ }
+
+ if_chain! {
+ if let hir::ExprKind::Path(ref qpath) = arg_node;
+
+ if match_qpath(qpath, &paths::STD_CONVERT_IDENTITY);
+
+ then {
+ apply_lint("called `flat_map(std::convert::identity)` on an `Iterator`");
+ }
+ }
+ }
+}
+
/// lint searching an Iterator followed by `is_some()`
fn lint_search_is_some<'a, 'tcx>(
cx: &LateContext<'a, 'tcx>,
applicability,
);
- return true;
+ true
+ } else {
+ false
}
}
-
- false
}
/// Checks for the `CHARS_NEXT_CMP` lint with `unwrap()`.
fn lint_single_char_pattern<'a, 'tcx>(cx: &LateContext<'a, 'tcx>, _expr: &'tcx hir::Expr, arg: &'tcx hir::Expr) {
if_chain! {
if let hir::ExprKind::Lit(lit) = &arg.node;
- if let ast::LitKind::Str(r, _) = lit.node;
+ if let ast::LitKind::Str(r, style) = lit.node;
if r.as_str().len() == 1;
then {
let mut applicability = Applicability::MachineApplicable;
let snip = snippet_with_applicability(cx, arg.span, "..", &mut applicability);
- let c = &snip[1..snip.len() - 1];
- let hint = format!("'{}'", if c == "'" { "\\'" } else { c });
+ let ch = if let ast::StrStyle::Raw(nhash) = style {
+ let nhash = nhash as usize;
+ // for raw string: r##"a"##
+ &snip[(nhash + 2)..(snip.len() - 1 - nhash)]
+ } else {
+ // for regular string: "a"
+ &snip[1..(snip.len() - 1)]
+ };
+ let hint = format!("'{}'", if ch == "'" { "\\'" } else { ch });
span_lint_and_sugg(
cx,
SINGLE_CHAR_PATTERN,
cx: &LateContext<'_, '_>,
self_ref_ty: Ty<'_>,
) -> Option<(&'static Lint, &'static str, &'static str)> {
- if let Some(ty_name) = has_iter_method(cx, self_ref_ty) {
+ has_iter_method(cx, self_ref_ty).map(|ty_name| {
let lint = if ty_name == "array" || ty_name == "PathBuf" {
INTO_ITER_ON_ARRAY
} else {
hir::MutImmutable => "iter",
hir::MutMutable => "iter_mut",
};
- Some((lint, ty_name, method_name))
- } else {
- None
- }
+ (lint, ty_name, method_name)
+ })
}
fn lint_into_iter(cx: &LateContext<'_, '_>, expr: &hir::Expr, self_ref_ty: Ty<'_>, method_span: Span) {
}
}
+fn lint_suspicious_map(cx: &LateContext<'_, '_>, expr: &hir::Expr) {
+ span_help_and_lint(
+ cx,
+ SUSPICIOUS_MAP,
+ expr.span,
+ "this call to `map()` won't have an effect on the call to `count()`",
+ "make sure you did not confuse `map` with `filter`",
+ );
+}
+
/// Given a `Result<T, E>` type, return its error type (`E`).
fn get_error_type<'a>(cx: &LateContext<'_, '_>, ty: Ty<'a>) -> Option<Ty<'a>> {
- if let ty::Adt(_, substs) = ty.sty {
- if match_type(cx, ty, &paths::RESULT) {
- substs.types().nth(1)
- } else {
- None
- }
- } else {
- None
+ match ty.sty {
+ ty::Adt(_, substs) if match_type(cx, ty, &paths::RESULT) => substs.types().nth(1),
+ _ => None,
}
}
}
impl SelfKind {
- fn matches(
- self,
- cx: &LateContext<'_, '_>,
- ty: &hir::Ty,
- arg: &hir::Arg,
- self_ty: &hir::Ty,
- allow_value_for_ref: bool,
- generics: &hir::Generics,
- ) -> bool {
- // Self types in the HIR are desugared to explicit self types. So it will
- // always be `self:
- // SomeType`,
- // where SomeType can be `Self` or an explicit impl self type (e.g., `Foo` if
- // the impl is on `Foo`)
- // Thus, we only need to test equality against the impl self type or if it is
- // an explicit
- // `Self`. Furthermore, the only possible types for `self: ` are `&Self`,
- // `Self`, `&mut Self`,
- // and `Box<Self>`, including the equivalent types with `Foo`.
-
- let is_actually_self = |ty| is_self_ty(ty) || SpanlessEq::new(cx).eq_ty(ty, self_ty);
- if is_self(arg) {
- match self {
- Self::Value => is_actually_self(ty),
- Self::Ref | Self::RefMut => {
- if allow_value_for_ref && is_actually_self(ty) {
- return true;
- }
- match ty.node {
- hir::TyKind::Rptr(_, ref mt_ty) => {
- let mutability_match = if self == Self::Ref {
- mt_ty.mutbl == hir::MutImmutable
- } else {
- mt_ty.mutbl == hir::MutMutable
- };
- is_actually_self(&mt_ty.ty) && mutability_match
- },
- _ => false,
- }
- },
- _ => false,
+ fn matches<'a>(self, cx: &LateContext<'_, 'a>, parent_ty: Ty<'a>, ty: Ty<'a>) -> bool {
+ fn matches_value(parent_ty: Ty<'_>, ty: Ty<'_>) -> bool {
+ if ty == parent_ty {
+ true
+ } else if ty.is_box() {
+ ty.boxed_ty() == parent_ty
+ } else if ty.is_rc() || ty.is_arc() {
+ if let ty::Adt(_, substs) = ty.sty {
+ substs.types().next().map_or(false, |t| t == parent_ty)
+ } else {
+ false
+ }
+ } else {
+ false
}
- } else {
- match self {
- Self::Value => false,
- Self::Ref => is_as_ref_or_mut_trait(ty, self_ty, generics, &paths::ASREF_TRAIT),
- Self::RefMut => is_as_ref_or_mut_trait(ty, self_ty, generics, &paths::ASMUT_TRAIT),
- Self::No => true,
+ }
+
+ fn matches_ref<'a>(
+ cx: &LateContext<'_, 'a>,
+ mutability: hir::Mutability,
+ parent_ty: Ty<'a>,
+ ty: Ty<'a>,
+ ) -> bool {
+ if let ty::Ref(_, t, m) = ty.sty {
+ return m == mutability && t == parent_ty;
}
+
+ let trait_path = match mutability {
+ hir::Mutability::MutImmutable => &paths::ASREF_TRAIT,
+ hir::Mutability::MutMutable => &paths::ASMUT_TRAIT,
+ };
+
+ let trait_def_id = match get_trait_def_id(cx, trait_path) {
+ Some(did) => did,
+ None => return false,
+ };
+ implements_trait(cx, ty, trait_def_id, &[parent_ty.into()])
+ }
+
+ match self {
+ Self::Value => matches_value(parent_ty, ty),
+ Self::Ref => {
+ matches_ref(cx, hir::Mutability::MutImmutable, parent_ty, ty) || ty == parent_ty && is_copy(cx, ty)
+ },
+ Self::RefMut => matches_ref(cx, hir::Mutability::MutMutable, parent_ty, ty),
+ Self::No => ty != parent_ty,
}
}
}
}
-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.ident().name == seg.ident.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 {
- // FIXME(flip1995): messy, improve if there is a better option
- // in the compiler
- 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::TyKind::Path(hir::QPath::Resolved(_, ref ty_path)),
- &hir::TyKind::Path(hir::QPath::Resolved(_, ref self_ty_path)),
- ) => ty_path
- .segments
- .iter()
- .map(|seg| seg.ident.name)
- .eq(self_ty_path.segments.iter().map(|seg| seg.ident.name)),
- _ => false,
- }
-}
-
-fn single_segment_ty(ty: &hir::Ty) -> Option<&hir::PathSegment> {
- if let hir::TyKind::Path(ref path) = ty.node {
- single_segment_path(path)
- } else {
- None
- }
-}
-
impl Convention {
fn check(&self, other: &str) -> bool {
match *self {
projects / rust.git / blobdiff