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Auto merge of #7095 - Y-Nak:match_single_binding, r=giraffate

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match_single_binding: Fix invalid suggestion when match scrutinee has side effects

fixes #7094

changelog: `match_single_binding`: Fix invalid suggestion when match scrutinee has side effects

---
`Expr::can_have_side_effects` is used to determine the scrutinee has side effects, while this method is a little bit conservative for our use case. But I'd like to use it to avoid reimplementation of the method and too much heuristics. If you think this is problematic, then I'll implement a custom visitor to address it.
This commit is contained in:
bors 2021-05-13 13:55:47 +00:00
commit 1fd9975249
7 changed files with 100 additions and 35 deletions
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37
clippy_lints/src/matches.rs
View file

@ -1478,15 +1478,34 @@ fn check_match_single_binding<'a>(cx: &LateContext<'a>, ex: &Expr<'a>, arms: &[A
);
},
PatKind::Wild => {
span_lint_and_sugg(
cx,
MATCH_SINGLE_BINDING,
expr.span,
"this match could be replaced by its body itself",
"consider using the match body instead",
snippet_body,
Applicability::MachineApplicable,
);
if ex.can_have_side_effects() {
let indent = " ".repeat(indent_of(cx, expr.span).unwrap_or(0));
let sugg = format!(
"{};\n{}{}",
snippet_with_applicability(cx, ex.span, "..", &mut applicability),
indent,
snippet_body
);
span_lint_and_sugg(
cx,
MATCH_SINGLE_BINDING,
expr.span,
"this match could be replaced by its scrutinee and body",
"consider using the scrutinee and body instead",
sugg,
applicability,
)
} else {
span_lint_and_sugg(
cx,
MATCH_SINGLE_BINDING,
expr.span,
"this match could be replaced by its body itself",
"consider using the match body instead",
snippet_body,
Applicability::MachineApplicable,
);
}
},
_ => (),
}