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Suggest unwrap_or_default when closure returns "".to_string

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Signed-off-by: xphoniex <xphoniex@users.noreply.github.com>
This commit is contained in:
xphoniex 2022-09-06 04:38:29 +00:00
parent 99ab5fe53a
commit b21d9d307b
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GPG key ID: 1B07CD425A75CACB
4 changed files with 35 additions and 3 deletions
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24
clippy_lints/src/methods/unwrap_or_else_default.rs
View file

@ -5,10 +5,11 @@ use clippy_utils::{
diagnostics::span_lint_and_sugg, is_default_equivalent_call, source::snippet_with_applicability,
ty::is_type_diagnostic_item,
};
use rustc_ast::ast::LitKind;
use rustc_errors::Applicability;
use rustc_hir as hir;
use rustc_lint::LateContext;
use rustc_span::sym;
use rustc_span::{sym, symbol};
pub(super) fn check<'tcx>(
cx: &LateContext<'tcx>,
@ -25,7 +26,7 @@ pub(super) fn check<'tcx>(
if_chain! {
if is_option || is_result;
if is_default_equivalent_call(cx, u_arg);
if closure_body_returns_empty_to_string(cx, u_arg) || is_default_equivalent_call(cx, u_arg);
then {
let mut applicability = Applicability::MachineApplicable;
@ -44,3 +45,22 @@ pub(super) fn check<'tcx>(
}
}
}
fn closure_body_returns_empty_to_string(cx: &LateContext<'_>, e: &hir::Expr<'_>) -> bool {
if let hir::ExprKind::Closure(&hir::Closure { body, .. }) = e.kind {
let body = cx.tcx.hir().body(body);
if body.params.is_empty()
&& let hir::Expr{ kind, .. } = &body.value
&& let hir::ExprKind::MethodCall(hir::PathSegment {ident, ..}, [self_arg], _) = kind
&& ident == &symbol::Ident::from_str("to_string")
&& let hir::Expr{ kind, .. } = self_arg
&& let hir::ExprKind::Lit(lit) = kind
&& let LitKind::Str(symbol::kw::Empty, _) = lit.node
{
return true;
}
}
false
}

3
tests/ui/unwrap_or_else_default.fixed
View file

@ -69,6 +69,9 @@ fn unwrap_or_else_default() {
let with_default_type: Option<Vec<u64>> = None;
with_default_type.unwrap_or_default();
let empty_string = None::<String>;
empty_string.unwrap_or_default();
}
fn main() {}

3
tests/ui/unwrap_or_else_default.rs
View file

@ -69,6 +69,9 @@ fn unwrap_or_else_default() {
let with_default_type: Option<Vec<u64>> = None;
with_default_type.unwrap_or_else(Vec::new);
let empty_string = None::<String>;
empty_string.unwrap_or_else(|| "".to_string());
}
fn main() {}

8
tests/ui/unwrap_or_else_default.stderr
View file

@ -30,5 +30,11 @@ error: use of `.unwrap_or_else(..)` to construct default value
LL | with_default_type.unwrap_or_else(Vec::new);
| ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: try: `with_default_type.unwrap_or_default()`
error: aborting due to 5 previous errors
error: use of `.unwrap_or_else(..)` to construct default value
--> $DIR/unwrap_or_else_default.rs:74:5
|
LL | empty_string.unwrap_or_else(|| "".to_string());
| ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: try: `empty_string.unwrap_or_default()`
error: aborting due to 6 previous errors