Upvar(HirId, Symbol),
}
+struct CollectLitsVisitor<'tcx> {
+ lit_exprs: Vec<&'tcx hir::Expr<'tcx>>,
+}
+
+impl<'tcx> Visitor<'tcx> for CollectLitsVisitor<'tcx> {
+ fn visit_expr(&mut self, expr: &'tcx Expr<'tcx>) {
+ if let hir::ExprKind::Lit(_) = expr.kind {
+ self.lit_exprs.push(expr);
+ }
+ intravisit::walk_expr(self, expr);
+ }
+}
+
struct IrMaps<'tcx> {
tcx: TyCtxt<'tcx>,
live_node_map: HirIdMap<LiveNode>,
impl<'a, 'tcx> Visitor<'tcx> for Liveness<'a, 'tcx> {
fn visit_local(&mut self, local: &'tcx hir::Local<'tcx>) {
- self.check_unused_vars_in_pat(&local.pat, None, |spans, hir_id, ln, var| {
+ self.check_unused_vars_in_pat(&local.pat, None, None, |spans, hir_id, ln, var| {
if local.init.is_some() {
self.warn_about_dead_assign(spans, hir_id, ln, var);
}
}
fn visit_arm(&mut self, arm: &'tcx hir::Arm<'tcx>) {
- self.check_unused_vars_in_pat(&arm.pat, None, |_, _, _, _| {});
+ self.check_unused_vars_in_pat(&arm.pat, None, None, |_, _, _, _| {});
intravisit::walk_arm(self, arm);
}
}
}
hir::ExprKind::Let(let_expr) => {
- this.check_unused_vars_in_pat(let_expr.pat, None, |_, _, _, _| {});
+ this.check_unused_vars_in_pat(let_expr.pat, None, None, |_, _, _, _| {});
}
// no correctness conditions related to liveness
fn warn_about_unused_args(&self, body: &hir::Body<'_>, entry_ln: LiveNode) {
for p in body.params {
- self.check_unused_vars_in_pat(&p.pat, Some(entry_ln), |spans, hir_id, ln, var| {
- if !self.live_on_entry(ln, var) {
- self.report_unused_assign(hir_id, spans, var, |name| {
- format!("value passed to `{}` is never read", name)
- });
- }
- });
+ self.check_unused_vars_in_pat(
+ &p.pat,
+ Some(entry_ln),
+ Some(body),
+ |spans, hir_id, ln, var| {
+ if !self.live_on_entry(ln, var) {
+ self.report_unused_assign(hir_id, spans, var, |name| {
+ format!("value passed to `{}` is never read", name)
+ });
+ }
+ },
+ );
}
}
&self,
pat: &hir::Pat<'_>,
entry_ln: Option<LiveNode>,
+ opt_body: Option<&hir::Body<'_>>,
on_used_on_entry: impl Fn(Vec<Span>, HirId, LiveNode, Variable),
) {
// In an or-pattern, only consider the variable; any later patterns must have the same
hir_ids_and_spans.into_iter().map(|(_, _, ident_span)| ident_span).collect();
on_used_on_entry(spans, id, ln, var);
} else {
- self.report_unused(hir_ids_and_spans, ln, var, can_remove);
+ self.report_unused(hir_ids_and_spans, ln, var, can_remove, pat, opt_body);
}
}
}
ln: LiveNode,
var: Variable,
can_remove: bool,
+ pat: &hir::Pat<'_>,
+ opt_body: Option<&hir::Body<'_>>,
) {
let first_hir_id = hir_ids_and_spans[0].0;
.collect::<Vec<_>>(),
|lint| {
let mut err = lint.build(&format!("unused variable: `{}`", name));
+ if self.has_added_lit_match_name_span(&name, opt_body, &mut err) {
+ err.span_label(pat.span, "unused variable");
+ }
err.multipart_suggestion(
"if this is intentional, prefix it with an underscore",
non_shorthands,
}
}
+ fn has_added_lit_match_name_span(
+ &self,
+ name: &str,
+ opt_body: Option<&hir::Body<'_>>,
+ err: &mut rustc_errors::DiagnosticBuilder<'_, ()>,
+ ) -> bool {
+ let mut has_litstring = false;
+ let Some(opt_body) = opt_body else {return false;};
+ let mut visitor = CollectLitsVisitor { lit_exprs: vec![] };
+ intravisit::walk_body(&mut visitor, opt_body);
+ for lit_expr in visitor.lit_exprs {
+ let hir::ExprKind::Lit(litx) = &lit_expr.kind else { continue };
+ let rustc_ast::LitKind::Str(syb, _) = litx.node else{ continue; };
+ let name_str: &str = syb.as_str();
+ let mut name_pa = String::from("{");
+ name_pa.push_str(&name);
+ name_pa.push('}');
+ if name_str.contains(&name_pa) {
+ err.span_label(
+ lit_expr.span,
+ "you might have meant to use string interpolation in this string literal",
+ );
+ err.multipart_suggestion(
+ "string interpolation only works in `format!` invocations",
+ vec![
+ (lit_expr.span.shrink_to_lo(), "format!(".to_string()),
+ (lit_expr.span.shrink_to_hi(), ")".to_string()),
+ ],
+ Applicability::MachineApplicable,
+ );
+ has_litstring = true;
+ }
+ }
+ has_litstring
+ }
+
fn warn_about_dead_assign(&self, spans: Vec<Span>, hir_id: HirId, ln: LiveNode, var: Variable) {
if !self.live_on_exit(ln, var) {
self.report_unused_assign(hir_id, spans, var, |name| {