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chore: multipart suggestions for let_unit_value lint (#13754)

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This should address #13099 for the let_unit test.

changelog: [let_unit]: Updated let_unit to use multipart_suggestions
where appropriate
This commit is contained in:
Alejandra González 2024-12-23 14:50:01 +00:00 • committed by GitHub
commit 988042e0b2
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GPG key ID: B5690EEEBB952194
4 changed files with 228 additions and 27 deletions
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35
clippy_lints/src/unit_types/let_unit_value.rs
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@ -1,6 +1,6 @@
use clippy_utils::diagnostics::span_lint_and_then;
use clippy_utils::source::snippet_with_context;
use clippy_utils::visitors::{for_each_local_assignment, for_each_value_source, is_local_used};
use clippy_utils::visitors::{for_each_local_assignment, for_each_value_source};
use core::ops::ControlFlow;
use rustc_errors::Applicability;
use rustc_hir::def::{DefKind, Res};
@ -71,25 +71,38 @@ pub(super) fn check<'tcx>(cx: &LateContext<'tcx>, local: &'tcx LetStmt<'_>) {
local.span,
"this let-binding has unit value",
|diag| {
let mut suggestions = Vec::new();
// Suggest omitting the `let` binding
if let Some(expr) = &local.init {
let mut app = Applicability::MachineApplicable;
let snip = snippet_with_context(cx, expr.span, local.span.ctxt(), "()", &mut app).0;
diag.span_suggestion(local.span, "omit the `let` binding", format!("{snip};"), app);
suggestions.push((local.span, format!("{snip};")));
}
if let PatKind::Binding(_, binding_hir_id, ident, ..) = local.pat.kind
// If this is a binding pattern, we need to add suggestions to remove any usages
// of the variable
if let PatKind::Binding(_, binding_hir_id, ..) = local.pat.kind
&& let Some(body_id) = cx.enclosing_body.as_ref()
&& let body = cx.tcx.hir().body(*body_id)
&& is_local_used(cx, body, binding_hir_id)
{
let identifier = ident.as_str();
let body = cx.tcx.hir().body(*body_id);
// Collect variable usages
let mut visitor = UnitVariableCollector::new(binding_hir_id);
walk_body(&mut visitor, body);
visitor.spans.into_iter().for_each(|span| {
let msg =
format!("variable `{identifier}` of type `()` can be replaced with explicit `()`");
diag.span_suggestion(span, msg, "()", Applicability::MachineApplicable);
});
// Add suggestions for replacing variable usages
suggestions.extend(visitor.spans.into_iter().map(|span| (span, "()".to_string())));
}
// Emit appropriate diagnostic based on whether there are usages of the let binding
if !suggestions.is_empty() {
let message = if suggestions.len() == 1 {
"omit the `let` binding"
} else {
"omit the `let` binding and replace variable usages with `()`"
};
diag.multipart_suggestion(message, suggestions, Applicability::MachineApplicable);
}
},
);