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Auto merge of #9421 - xphoniex:fix-#9420, r=giraffate

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Suggest `unwrap_or_default` when closure returns `"".to_string`

Closes https://github.com/rust-lang/rust-clippy/issues/9420

changelog: [`unwrap_or_else_default`]: suggest `unwrap_or_default()` instead of `unwrap_or_else` with a closure that returns an empty `to_string`.
This commit is contained in:
bors 2022-09-06 23:44:38 +00:00
commit 7babd1b099
4 changed files with 35 additions and 3 deletions
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24
clippy_lints/src/methods/unwrap_or_else_default.rs
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@ -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
}