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Fix manual_map: don't lint when partially moved values are used.

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Fix `manual_map`: don't lint when `return`, `break`, and `continue` are used.
This commit is contained in:
Jason Newcomb 2021-02-26 11:50:12 -05:00
parent 6343446b89
commit ef87e58993
No known key found for this signature in database
GPG Key ID: DA59E8643A37ED06
5 changed files with 168 additions and 22 deletions
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54
clippy_lints/src/manual_map.rs
View File

@ -2,13 +2,17 @@
map_unit_fn::OPTION_MAP_UNIT_FN,
matches::MATCH_AS_REF,
utils::{
is_allowed, is_type_diagnostic_item, match_def_path, match_var, paths, peel_hir_expr_refs,
peel_mid_ty_refs_is_mutable, snippet_with_applicability, span_lint_and_sugg,
can_partially_move_ty, is_allowed, is_type_diagnostic_item, match_def_path, match_var, paths,
peel_hir_expr_refs, peel_mid_ty_refs_is_mutable, snippet_with_applicability, span_lint_and_sugg,
},
};
use rustc_ast::util::parser::PREC_POSTFIX;
use rustc_errors::Applicability;
use rustc_hir::{Arm, BindingAnnotation, Block, Expr, ExprKind, Mutability, Pat, PatKind, QPath};
use rustc_hir::{
def::Res,
intravisit::{walk_expr, ErasedMap, NestedVisitorMap, Visitor},
Arm, BindingAnnotation, Block, Expr, ExprKind, Mutability, Pat, PatKind, Path, QPath,
};
use rustc_lint::{LateContext, LateLintPass, LintContext};
use rustc_middle::lint::in_external_macro;
use rustc_session::{declare_lint_pass, declare_tool_lint};
@ -99,6 +103,10 @@ fn check_expr(&mut self, cx: &LateContext<'tcx>, expr: &'tcx Expr<'_>) {
return;
}
if !can_move_expr_to_closure(cx, some_expr) {
return;
}
// Determine which binding mode to use.
let explicit_ref = some_pat.contains_explicit_ref_binding();
let binding_ref = explicit_ref.or_else(|| (ty_ref_count != pat_ref_count).then(|| ty_mutability));
@ -171,6 +179,46 @@ fn check_expr(&mut self, cx: &LateContext<'tcx>, expr: &'tcx Expr<'_>) {
}
}
// Checks if the expression can be moved into a closure as is.
fn can_move_expr_to_closure(cx: &LateContext<'tcx>, expr: &'tcx Expr<'_>) -> bool {
struct V<'cx, 'tcx> {
cx: &'cx LateContext<'tcx>,
make_closure: bool,
}
impl Visitor<'tcx> for V<'_, 'tcx> {
type Map = ErasedMap<'tcx>;
fn nested_visit_map(&mut self) -> NestedVisitorMap<Self::Map> {
NestedVisitorMap::None
}
fn visit_expr(&mut self, e: &'tcx Expr<'_>) {
match e.kind {
ExprKind::Break(..) | ExprKind::Continue(_) | ExprKind::Ret(_) => {
self.make_closure = false;
},
// Accessing a field of a local value can only be done if the type isn't
// partially moved.
ExprKind::Field(base_expr, _)
if matches!(
base_expr.kind,
ExprKind::Path(QPath::Resolved(_, Path { res: Res::Local(_), .. }))
) && can_partially_move_ty(self.cx, self.cx.typeck_results().expr_ty(base_expr)) =>
{
// TODO: check if the local has been partially moved. Assume it has for now.
self.make_closure = false;
return;
}
_ => (),
};
walk_expr(self, e);
}
}
let mut v = V { cx, make_closure: true };
v.visit_expr(expr);
v.make_closure
}
// Checks whether the expression could be passed as a function, or whether a closure is needed.
// Returns the function to be passed to `map` if it exists.
fn can_pass_as_func(cx: &LateContext<'tcx>, binding: Ident, expr: &'tcx Expr<'_>) -> Option<&'tcx Expr<'tcx>> {

12
clippy_utils/src/lib.rs
View File

@ -456,6 +456,18 @@ pub fn has_drop<'tcx>(cx: &LateContext<'tcx>, ty: Ty<'tcx>) -> bool {
}
}
/// Checks whether a type can be partially moved.
pub fn can_partially_move_ty(cx: &LateContext<'tcx>, ty: Ty<'tcx>) -> bool {
if has_drop(cx, ty) || is_copy(cx, ty) {
return false;
}
match ty.kind() {
ty::Param(_) => false,
ty::Adt(def, subs) => def.all_fields().any(|f| !is_copy(cx, f.ty(cx.tcx, subs))),
_ => true,
}
}
/// Returns the method names and argument list of nested method call expressions that make up
/// `expr`. method/span lists are sorted with the most recent call first.
pub fn method_calls<'tcx>(

45
tests/ui/manual_map_option.fixed
View File

@ -1,7 +1,13 @@
// run-rustfix
#![warn(clippy::manual_map)]
#![allow(clippy::no_effect, clippy::map_identity, clippy::unit_arg, clippy::match_ref_pats)]
#![allow(
clippy::no_effect,
clippy::map_identity,
clippy::unit_arg,
clippy::match_ref_pats,
dead_code
)]
fn main() {
Some(0).map(|_| 2);
@ -67,4 +73,41 @@ fn main() {
Some(Some((x, 1))) => Some(x),
_ => None,
};
// #6795
fn f1() -> Result<(), ()> {
let _ = match Some(Ok(())) {
Some(x) => Some(x?),
None => None,
};
Ok(())
}
for &x in Some(Some(true)).iter() {
let _ = match x {
Some(x) => Some(if x { continue } else { x }),
None => None,
};
}
// #6797
let x1 = (Some(String::new()), 0);
let x2 = x1.0;
match x2 {
Some(x) => Some((x, x1.1)),
None => None,
};
struct S1 {
x: Option<String>,
y: u32,
}
impl S1 {
fn f(self) -> Option<(String, u32)> {
match self.x {
Some(x) => Some((x, self.y)),
None => None,
}
}
}
}

45
tests/ui/manual_map_option.rs
View File

@ -1,7 +1,13 @@
// run-rustfix
#![warn(clippy::manual_map)]
#![allow(clippy::no_effect, clippy::map_identity, clippy::unit_arg, clippy::match_ref_pats)]
#![allow(
clippy::no_effect,
clippy::map_identity,
clippy::unit_arg,
clippy::match_ref_pats,
dead_code
)]
fn main() {
match Some(0) {
@ -119,4 +125,41 @@ fn main() {
Some(Some((x, 1))) => Some(x),
_ => None,
};
// #6795
fn f1() -> Result<(), ()> {
let _ = match Some(Ok(())) {
Some(x) => Some(x?),
None => None,
};
Ok(())
}
for &x in Some(Some(true)).iter() {
let _ = match x {
Some(x) => Some(if x { continue } else { x }),
None => None,
};
}
// #6797
let x1 = (Some(String::new()), 0);
let x2 = x1.0;
match x2 {
Some(x) => Some((x, x1.1)),
None => None,
};
struct S1 {
x: Option<String>,
y: u32,
}
impl S1 {
fn f(self) -> Option<(String, u32)> {
match self.x {
Some(x) => Some((x, self.y)),
None => None,
}
}
}
}

34
tests/ui/manual_map_option.stderr
View File

@ -1,5 +1,5 @@
error: manual implementation of `Option::map`
--> $DIR/manual_map_option.rs:7:5
--> $DIR/manual_map_option.rs:13:5
|
LL | / match Some(0) {
LL | | Some(_) => Some(2),
@ -10,7 +10,7 @@ LL | | };
= note: `-D clippy::manual-map` implied by `-D warnings`
error: manual implementation of `Option::map`
--> $DIR/manual_map_option.rs:12:5
--> $DIR/manual_map_option.rs:18:5
|
LL | / match Some(0) {
LL | | Some(x) => Some(x + 1),
@ -19,7 +19,7 @@ LL | | };
| |_____^ help: try this: `Some(0).map(|x| x + 1)`
error: manual implementation of `Option::map`
--> $DIR/manual_map_option.rs:17:5
--> $DIR/manual_map_option.rs:23:5
|
LL | / match Some("") {
LL | | Some(x) => Some(x.is_empty()),
@ -28,7 +28,7 @@ LL | | };
| |_____^ help: try this: `Some("").map(|x| x.is_empty())`
error: manual implementation of `Option::map`
--> $DIR/manual_map_option.rs:22:5
--> $DIR/manual_map_option.rs:28:5
|
LL | / if let Some(x) = Some(0) {
LL | | Some(!x)
@ -38,7 +38,7 @@ LL | | };
| |_____^ help: try this: `Some(0).map(|x| !x)`
error: manual implementation of `Option::map`
--> $DIR/manual_map_option.rs:29:5
--> $DIR/manual_map_option.rs:35:5
|
LL | / match Some(0) {
LL | | Some(x) => { Some(std::convert::identity(x)) }
@ -47,7 +47,7 @@ LL | | };
| |_____^ help: try this: `Some(0).map(std::convert::identity)`
error: manual implementation of `Option::map`
--> $DIR/manual_map_option.rs:34:5
--> $DIR/manual_map_option.rs:40:5
|
LL | / match Some(&String::new()) {
LL | | Some(x) => Some(str::len(x)),
@ -56,7 +56,7 @@ LL | | };
| |_____^ help: try this: `Some(&String::new()).map(|x| str::len(x))`
error: manual implementation of `Option::map`
--> $DIR/manual_map_option.rs:44:5
--> $DIR/manual_map_option.rs:50:5
|
LL | / match &Some([0, 1]) {
LL | | Some(x) => Some(x[0]),
@ -65,7 +65,7 @@ LL | | };
| |_____^ help: try this: `Some([0, 1]).as_ref().map(|x| x[0])`
error: manual implementation of `Option::map`
--> $DIR/manual_map_option.rs:49:5
--> $DIR/manual_map_option.rs:55:5
|
LL | / match &Some(0) {
LL | | &Some(x) => Some(x * 2),
@ -74,7 +74,7 @@ LL | | };
| |_____^ help: try this: `Some(0).map(|x| x * 2)`
error: manual implementation of `Option::map`
--> $DIR/manual_map_option.rs:54:5
--> $DIR/manual_map_option.rs:60:5
|
LL | / match Some(String::new()) {
LL | | Some(ref x) => Some(x.is_empty()),
@ -83,7 +83,7 @@ LL | | };
| |_____^ help: try this: `Some(String::new()).as_ref().map(|x| x.is_empty())`
error: manual implementation of `Option::map`
--> $DIR/manual_map_option.rs:59:5
--> $DIR/manual_map_option.rs:65:5
|
LL | / match &&Some(String::new()) {
LL | | Some(x) => Some(x.len()),
@ -92,7 +92,7 @@ LL | | };
| |_____^ help: try this: `Some(String::new()).as_ref().map(|x| x.len())`
error: manual implementation of `Option::map`
--> $DIR/manual_map_option.rs:64:5
--> $DIR/manual_map_option.rs:70:5
|
LL | / match &&Some(0) {
LL | | &&Some(x) => Some(x + x),
@ -101,7 +101,7 @@ LL | | };
| |_____^ help: try this: `Some(0).map(|x| x + x)`
error: manual implementation of `Option::map`
--> $DIR/manual_map_option.rs:77:9
--> $DIR/manual_map_option.rs:83:9
|
LL | / match &mut Some(String::new()) {
LL | | Some(x) => Some(x.push_str("")),
@ -110,7 +110,7 @@ LL | | };
| |_________^ help: try this: `Some(String::new()).as_mut().map(|x| x.push_str(""))`
error: manual implementation of `Option::map`
--> $DIR/manual_map_option.rs:83:5
--> $DIR/manual_map_option.rs:89:5
|
LL | / match &mut Some(String::new()) {
LL | | Some(ref x) => Some(x.len()),
@ -119,7 +119,7 @@ LL | | };
| |_____^ help: try this: `Some(String::new()).as_ref().map(|x| x.len())`
error: manual implementation of `Option::map`
--> $DIR/manual_map_option.rs:88:5
--> $DIR/manual_map_option.rs:94:5
|
LL | / match &mut &Some(String::new()) {
LL | | Some(x) => Some(x.is_empty()),
@ -128,7 +128,7 @@ LL | | };
| |_____^ help: try this: `Some(String::new()).as_ref().map(|x| x.is_empty())`
error: manual implementation of `Option::map`
--> $DIR/manual_map_option.rs:93:5
--> $DIR/manual_map_option.rs:99:5
|
LL | / match Some((0, 1, 2)) {
LL | | Some((x, y, z)) => Some(x + y + z),
@ -137,7 +137,7 @@ LL | | };
| |_____^ help: try this: `Some((0, 1, 2)).map(|(x, y, z)| x + y + z)`
error: manual implementation of `Option::map`
--> $DIR/manual_map_option.rs:98:5
--> $DIR/manual_map_option.rs:104:5
|
LL | / match Some([1, 2, 3]) {
LL | | Some([first, ..]) => Some(first),
@ -146,7 +146,7 @@ LL | | };
| |_____^ help: try this: `Some([1, 2, 3]).map(|[first, ..]| first)`
error: manual implementation of `Option::map`
--> $DIR/manual_map_option.rs:103:5
--> $DIR/manual_map_option.rs:109:5
|
LL | / match &Some((String::new(), "test")) {
LL | | Some((x, y)) => Some((y, x)),