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more idiomatic code

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This commit is contained in:
Daniele D'Orazio 2019-06-21 14:46:34 +02:00
parent e1a78ae528
commit 66dbc02b05
2 changed files with 53 additions and 43 deletions
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78
clippy_lints/src/returns.rs
View file

@ -86,7 +86,7 @@ declare_clippy_lint! {
#[derive(PartialEq, Eq, Copy, Clone)]
enum RetReplacement {
Empty,
Unit
Unit,
}
declare_lint_pass!(Return => [NEEDLESS_RETURN, LET_AND_RETURN, UNUSED_UNIT]);
@ -105,13 +105,24 @@ impl Return {
}
// Check a the final expression in a block if it's a return.
fn check_final_expr(&mut self, cx: &EarlyContext<'_>, expr: &ast::Expr, span: Option<Span>, replacement: RetReplacement) {
fn check_final_expr(
&mut self,
cx: &EarlyContext<'_>,
expr: &ast::Expr,
span: Option<Span>,
replacement: RetReplacement,
) {
match expr.node {
// simple return is always "bad"
ast::ExprKind::Ret(ref inner) => {
// allow `#[cfg(a)] return a; #[cfg(b)] return b;`
if !expr.attrs.iter().any(attr_is_cfg) {
self.emit_return_lint(cx, span.expect("`else return` is not possible"), inner.as_ref().map(|i| i.span), replacement);
self.emit_return_lint(
cx,
span.expect("`else return` is not possible"),
inner.as_ref().map(|i| i.span),
replacement,
);
}
},
// a whole block? check it!
@ -135,7 +146,13 @@ impl Return {
}
}
fn emit_return_lint(&mut self, cx: &EarlyContext<'_>, ret_span: Span, inner_span: Option<Span>, replacement: RetReplacement) {
fn emit_return_lint(
&mut self,
cx: &EarlyContext<'_>,
ret_span: Span,
inner_span: Option<Span>,
replacement: RetReplacement,
) {
match inner_span {
Some(inner_span) => {
if in_external_macro(cx.sess(), inner_span) || in_macro_or_desugar(inner_span) {
@ -144,39 +161,32 @@ impl Return {
span_lint_and_then(cx, NEEDLESS_RETURN, ret_span, "unneeded return statement", |db| {
if let Some(snippet) = snippet_opt(cx, inner_span) {
db.span_suggestion(
ret_span,
"remove `return` as shown",
snippet,
Applicability::MachineApplicable,
);
db.span_suggestion(ret_span, "remove `return`", snippet, Applicability::MachineApplicable);
}
})
},
None => {
match replacement {
RetReplacement::Empty => {
span_lint_and_then(cx, NEEDLESS_RETURN, ret_span, "unneeded return statement", |db| {
db.span_suggestion(
ret_span,
"remove `return`",
String::new(),
Applicability::MachineApplicable,
);
});
}
RetReplacement::Unit => {
span_lint_and_then(cx, NEEDLESS_RETURN, ret_span, "unneeded return statement", |db| {
db.span_suggestion(
ret_span,
"replace `return` with the unit type `()`",
"()".to_string(),
Applicability::MachineApplicable,
);
});
}
}
}
None => match replacement {
RetReplacement::Empty => {
span_lint_and_then(cx, NEEDLESS_RETURN, ret_span, "unneeded return statement", |db| {
db.span_suggestion(
ret_span,
"remove `return`",
String::new(),
Applicability::MachineApplicable,
);
});
},
RetReplacement::Unit => {
span_lint_and_then(cx, NEEDLESS_RETURN, ret_span, "unneeded return statement", |db| {
db.span_suggestion(
ret_span,
"replace `return` with the unit type",
"()".to_string(),
Applicability::MachineApplicable,
);
});
},
},
}
}

18
tests/ui/needless_return.stderr
View file

@ -2,7 +2,7 @@ error: unneeded return statement
--> $DIR/needless_return.rs:14:5
|
LL | return true;
| ^^^^^^^^^^^^ help: remove `return` as shown: `true`
| ^^^^^^^^^^^^ help: remove `return`: `true`
|
= note: `-D clippy::needless-return` implied by `-D warnings`
@ -10,43 +10,43 @@ error: unneeded return statement
--> $DIR/needless_return.rs:18:5
|
LL | return true;
| ^^^^^^^^^^^^ help: remove `return` as shown: `true`
| ^^^^^^^^^^^^ help: remove `return`: `true`
error: unneeded return statement
--> $DIR/needless_return.rs:23:9
|
LL | return true;
| ^^^^^^^^^^^^ help: remove `return` as shown: `true`
| ^^^^^^^^^^^^ help: remove `return`: `true`
error: unneeded return statement
--> $DIR/needless_return.rs:25:9
|
LL | return false;
| ^^^^^^^^^^^^^ help: remove `return` as shown: `false`
| ^^^^^^^^^^^^^ help: remove `return`: `false`
error: unneeded return statement
--> $DIR/needless_return.rs:31:17
|
LL | true => return false,
| ^^^^^^^^^^^^ help: remove `return` as shown: `false`
| ^^^^^^^^^^^^ help: remove `return`: `false`
error: unneeded return statement
--> $DIR/needless_return.rs:33:13
|
LL | return true;
| ^^^^^^^^^^^^ help: remove `return` as shown: `true`
| ^^^^^^^^^^^^ help: remove `return`: `true`
error: unneeded return statement
--> $DIR/needless_return.rs:40:9
|
LL | return true;
| ^^^^^^^^^^^^ help: remove `return` as shown: `true`
| ^^^^^^^^^^^^ help: remove `return`: `true`
error: unneeded return statement
--> $DIR/needless_return.rs:42:16
|
LL | let _ = || return true;
| ^^^^^^^^^^^ help: remove `return` as shown: `true`
| ^^^^^^^^^^^ help: remove `return`: `true`
error: unneeded return statement
--> $DIR/needless_return.rs:50:5
@ -70,7 +70,7 @@ error: unneeded return statement
--> $DIR/needless_return.rs:64:14
|
LL | _ => return,
| ^^^^^^ help: replace `return` with the unit type `()`: `()`
| ^^^^^^ help: replace `return` with the unit type: `()`
error: aborting due to 12 previous errors