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Auto merge of #6294 - giraffate:fix_suggestion_to_add_space_in_manual_async, r=Manishearth

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Fix suggestion to add unneeded space in `manual_async`

Fix a same case as https://github.com/rust-lang/rust-clippy/pull/6247

changelog: Fix suggestion to add unneeded space in `manual_async`
This commit is contained in:
bors 2020-11-06 18:10:43 +00:00
commit 2ea08e1c53
6 changed files with 140 additions and 32 deletions
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6
clippy_lints/src/manual_async_fn.rs
View File

@ -1,5 +1,5 @@
use crate::utils::paths::FUTURE_FROM_GENERATOR;
use crate::utils::{match_function_call, snippet_block, snippet_opt, span_lint_and_then};
use crate::utils::{match_function_call, position_before_rarrow, snippet_block, snippet_opt, span_lint_and_then};
use if_chain::if_chain;
use rustc_errors::Applicability;
use rustc_hir::intravisit::FnKind;
@ -69,7 +69,7 @@ fn check_fn(
|diag| {
if_chain! {
if let Some(header_snip) = snippet_opt(cx, header_span);
if let Some(ret_pos) = header_snip.rfind("->");
if let Some(ret_pos) = position_before_rarrow(header_snip.clone());
if let Some((ret_sugg, ret_snip)) = suggested_ret(cx, output);
then {
let help = format!("make the function `async` and {}", ret_sugg);
@ -194,7 +194,7 @@ fn suggested_ret(cx: &LateContext<'_>, output: &Ty<'_>) -> Option<(&'static str,
},
_ => {
let sugg = "return the output of the future directly";
snippet_opt(cx, output.span).map(|snip| (sugg, format!("-> {}", snip)))
snippet_opt(cx, output.span).map(|snip| (sugg, format!(" -> {}", snip)))
},
}
}

29
clippy_lints/src/unused_unit.rs
View File

@ -7,7 +7,7 @@
use rustc_span::source_map::Span;
use rustc_span::BytePos;
use crate::utils::span_lint_and_sugg;
use crate::utils::{position_before_rarrow, span_lint_and_sugg};
declare_clippy_lint! {
/// **What it does:** Checks for unit (`()`) expressions that can be removed.
@ -120,26 +120,13 @@ fn is_unit_expr(expr: &ast::Expr) -> bool {
fn lint_unneeded_unit_return(cx: &EarlyContext<'_>, ty: &ast::Ty, span: Span) {
let (ret_span, appl) = if let Ok(fn_source) = cx.sess().source_map().span_to_snippet(span.with_hi(ty.span.hi())) {
fn_source
.rfind("->")
.map_or((ty.span, Applicability::MaybeIncorrect), |rpos| {
let mut rpos = rpos;
let chars: Vec<char> = fn_source.chars().collect();
while rpos > 1 {
if let Some(c) = chars.get(rpos - 1) {
if c.is_whitespace() {
rpos -= 1;
continue;
}
}
break;
}
(
#[allow(clippy::cast_possible_truncation)]
ty.span.with_lo(BytePos(span.lo().0 + rpos as u32)),
Applicability::MachineApplicable,
)
})
position_before_rarrow(fn_source).map_or((ty.span, Applicability::MaybeIncorrect), |rpos| {
(
#[allow(clippy::cast_possible_truncation)]
ty.span.with_lo(BytePos(span.lo().0 + rpos as u32)),
Applicability::MachineApplicable,
)
})
} else {
(ty.span, Applicability::MaybeIncorrect)
};

29
clippy_lints/src/utils/mod.rs
View File

@ -659,6 +659,35 @@ pub fn indent_of<T: LintContext>(cx: &T, span: Span) -> Option<usize> {
snippet_opt(cx, line_span(cx, span)).and_then(|snip| snip.find(|c: char| !c.is_whitespace()))
}
/// Returns the positon just before rarrow
///
/// ```rust,ignore
/// fn into(self) -> () {}
/// ^
/// // in case of unformatted code
/// fn into2(self)-> () {}
/// ^
/// fn into3(self) -> () {}
/// ^
/// ```
#[allow(clippy::needless_pass_by_value)]
pub fn position_before_rarrow(s: String) -> Option<usize> {
s.rfind("->").map(|rpos| {
let mut rpos = rpos;
let chars: Vec<char> = s.chars().collect();
while rpos > 1 {
if let Some(c) = chars.get(rpos - 1) {
if c.is_whitespace() {
rpos -= 1;
continue;
}
}
break;
}
rpos
})
}
/// Extends the span to the beginning of the spans line, incl. whitespaces.
///
/// ```rust,ignore

14
tests/ui/manual_async_fn.fixed
View File

@ -7,7 +7,19 @@ use std::future::Future;
async fn fut() -> i32 { 42 }
async fn empty_fut() {}
#[rustfmt::skip]
async fn fut2() -> i32 { 42 }
#[rustfmt::skip]
async fn fut3() -> i32 { 42 }
async fn empty_fut() {}
#[rustfmt::skip]
async fn empty_fut2() {}
#[rustfmt::skip]
async fn empty_fut3() {}
async fn core_fut() -> i32 { 42 }

20
tests/ui/manual_async_fn.rs
View File

@ -9,10 +9,30 @@ fn fut() -> impl Future<Output = i32> {
async { 42 }
}
#[rustfmt::skip]
fn fut2() ->impl Future<Output = i32> {
async { 42 }
}
#[rustfmt::skip]
fn fut3()-> impl Future<Output = i32> {
async { 42 }
}
fn empty_fut() -> impl Future<Output = ()> {
async {}
}
#[rustfmt::skip]
fn empty_fut2() ->impl Future<Output = ()> {
async {}
}
#[rustfmt::skip]
fn empty_fut3()-> impl Future<Output = ()> {
async {}
}
fn core_fut() -> impl core::future::Future<Output = i32> {
async move { 42 }
}

74
tests/ui/manual_async_fn.stderr
View File

@ -15,14 +15,44 @@ LL | fn fut() -> impl Future<Output = i32> { 42 }
| ^^^^^^
error: this function can be simplified using the `async fn` syntax
--> $DIR/manual_async_fn.rs:12:1
--> $DIR/manual_async_fn.rs:13:1
|
LL | fn fut2() ->impl Future<Output = i32> {
| ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
|
help: make the function `async` and return the output of the future directly
|
LL | async fn fut2() -> i32 {
| ^^^^^^^^^^^^^^^^^^^^^^
help: move the body of the async block to the enclosing function
|
LL | fn fut2() ->impl Future<Output = i32> { 42 }
| ^^^^^^
error: this function can be simplified using the `async fn` syntax
--> $DIR/manual_async_fn.rs:18:1
|
LL | fn fut3()-> impl Future<Output = i32> {
| ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
|
help: make the function `async` and return the output of the future directly
|
LL | async fn fut3() -> i32 {
| ^^^^^^^^^^^^^^^^^^^^^^
help: move the body of the async block to the enclosing function
|
LL | fn fut3()-> impl Future<Output = i32> { 42 }
| ^^^^^^
error: this function can be simplified using the `async fn` syntax
--> $DIR/manual_async_fn.rs:22:1
|
LL | fn empty_fut() -> impl Future<Output = ()> {
| ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
|
help: make the function `async` and remove the return type
|
LL | async fn empty_fut() {
LL | async fn empty_fut() {
| ^^^^^^^^^^^^^^^^^^^^
help: move the body of the async block to the enclosing function
|
@ -30,7 +60,37 @@ LL | fn empty_fut() -> impl Future<Output = ()> {}
| ^^
error: this function can be simplified using the `async fn` syntax
--> $DIR/manual_async_fn.rs:16:1
--> $DIR/manual_async_fn.rs:27:1
|
LL | fn empty_fut2() ->impl Future<Output = ()> {
| ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
|
help: make the function `async` and remove the return type
|
LL | async fn empty_fut2() {
| ^^^^^^^^^^^^^^^^^^^^^
help: move the body of the async block to the enclosing function
|
LL | fn empty_fut2() ->impl Future<Output = ()> {}
| ^^
error: this function can be simplified using the `async fn` syntax
--> $DIR/manual_async_fn.rs:32:1
|
LL | fn empty_fut3()-> impl Future<Output = ()> {
| ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
|
help: make the function `async` and remove the return type
|
LL | async fn empty_fut3() {
| ^^^^^^^^^^^^^^^^^^^^^
help: move the body of the async block to the enclosing function
|
LL | fn empty_fut3()-> impl Future<Output = ()> {}
| ^^
error: this function can be simplified using the `async fn` syntax
--> $DIR/manual_async_fn.rs:36:1
|
LL | fn core_fut() -> impl core::future::Future<Output = i32> {
| ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
@ -45,7 +105,7 @@ LL | fn core_fut() -> impl core::future::Future<Output = i32> { 42 }
| ^^^^^^
error: this function can be simplified using the `async fn` syntax
--> $DIR/manual_async_fn.rs:38:5
--> $DIR/manual_async_fn.rs:58:5
|
LL | fn inh_fut() -> impl Future<Output = i32> {
| ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
@ -65,7 +125,7 @@ LL | let c = 21;
...
error: this function can be simplified using the `async fn` syntax
--> $DIR/manual_async_fn.rs:73:1
--> $DIR/manual_async_fn.rs:93:1
|
LL | fn elided(_: &i32) -> impl Future<Output = i32> + '_ {
| ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
@ -80,7 +140,7 @@ LL | fn elided(_: &i32) -> impl Future<Output = i32> + '_ { 42 }
| ^^^^^^
error: this function can be simplified using the `async fn` syntax
--> $DIR/manual_async_fn.rs:82:1
--> $DIR/manual_async_fn.rs:102:1
|
LL | fn explicit<'a, 'b>(_: &'a i32, _: &'b i32) -> impl Future<Output = i32> + 'a + 'b {
| ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
@ -94,5 +154,5 @@ help: move the body of the async block to the enclosing function
LL | fn explicit<'a, 'b>(_: &'a i32, _: &'b i32) -> impl Future<Output = i32> + 'a + 'b { 42 }
| ^^^^^^
error: aborting due to 6 previous errors
error: aborting due to 10 previous errors